LinuxTV Patchwork [v2,3/5] media: sunxi: Add A10 CSI driver

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Submitter Maxime Ripard
Date Jan. 28, 2019, 2:52 p.m.
Message ID <c1a7d46f8504decb58ff224b0b5f2f0733282cc6.1548687041.git-series.maxime.ripard@bootlin.com>
Download mbox | patch
Permalink /patch/54190/
State New
Headers show

Comments

Maxime Ripard - Jan. 28, 2019, 2:52 p.m.
The older CSI drivers have camera capture interface different from the one
in the newer ones.

This IP is pretty simple. Some variants (one controller out of two
instances on some SoCs) have an ISP embedded, but there's no code that make
use of it, so we ignored that part for now.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
---
 MAINTAINERS                                         |   8 +-
 drivers/media/platform/sunxi/Kconfig                |   1 +-
 drivers/media/platform/sunxi/Makefile               |   1 +-
 drivers/media/platform/sunxi/sun4i-csi/Kconfig      |  12 +-
 drivers/media/platform/sunxi/sun4i-csi/Makefile     |   5 +-
 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c  | 261 ++++++++-
 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h  | 142 ++++-
 drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c  | 435 +++++++++++++-
 drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c | 305 +++++++++-
 9 files changed, 1170 insertions(+)
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Kconfig
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Makefile
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
 create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
Sakari Ailus - Jan. 29, 2019, 12:39 p.m.
Hi Maxime,

Thanks for the update.

On Mon, Jan 28, 2019 at 03:52:34PM +0100, Maxime Ripard wrote:
> The older CSI drivers have camera capture interface different from the one
> in the newer ones.
> 
> This IP is pretty simple. Some variants (one controller out of two
> instances on some SoCs) have an ISP embedded, but there's no code that make
> use of it, so we ignored that part for now.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  MAINTAINERS                                         |   8 +-
>  drivers/media/platform/sunxi/Kconfig                |   1 +-
>  drivers/media/platform/sunxi/Makefile               |   1 +-
>  drivers/media/platform/sunxi/sun4i-csi/Kconfig      |  12 +-
>  drivers/media/platform/sunxi/sun4i-csi/Makefile     |   5 +-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c  | 261 ++++++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h  | 142 ++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c  | 435 +++++++++++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c | 305 +++++++++-
>  9 files changed, 1170 insertions(+)
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Kconfig
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Makefile
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 32d444476a90..5f703ed9adb1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1295,6 +1295,14 @@ F:	drivers/pinctrl/sunxi/
>  F:	drivers/soc/sunxi/
>  T:	git git://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git
>  
> +Allwinner A10 CSI driver
> +M:	Maxime Ripard <maxime.ripard@bootlin.com>
> +L:	linux-media@vger.kernel.org
> +T:	git git://linuxtv.org/media_tree.git
> +S:	Maintained
> +F:	drivers/media/platform/sunxi/sun4i-csi/
> +F:	Documentation/devicetree/bindings/media/sun4i-csi.txt

I guess this would need to be updated for YAML bindings.

> +
>  ARM/Amlogic Meson SoC CLOCK FRAMEWORK
>  M:	Neil Armstrong <narmstrong@baylibre.com>
>  M:	Jerome Brunet <jbrunet@baylibre.com>
> diff --git a/drivers/media/platform/sunxi/Kconfig b/drivers/media/platform/sunxi/Kconfig
> index 1b6e89cb78b2..71808e93ac2e 100644
> --- a/drivers/media/platform/sunxi/Kconfig
> +++ b/drivers/media/platform/sunxi/Kconfig
> @@ -1 +1,2 @@
> +source "drivers/media/platform/sunxi/sun4i-csi/Kconfig"
>  source "drivers/media/platform/sunxi/sun6i-csi/Kconfig"
> diff --git a/drivers/media/platform/sunxi/Makefile b/drivers/media/platform/sunxi/Makefile
> index 8d06f98500ee..a05127529006 100644
> --- a/drivers/media/platform/sunxi/Makefile
> +++ b/drivers/media/platform/sunxi/Makefile
> @@ -1 +1,2 @@
> +obj-y		+= sun4i-csi/
>  obj-y		+= sun6i-csi/
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/Kconfig b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
> new file mode 100644
> index 000000000000..841a6f4d9c99
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
> @@ -0,0 +1,12 @@
> +config VIDEO_SUN4I_CSI
> +	tristate "Allwinner A10 CMOS Sensor Interface Support"
> +	depends on VIDEO_DEV && VIDEO_V4L2 && HAS_DMA
> +	depends on ARCH_SUNXI || COMPILE_TEST
> +	select VIDEOBUF2_DMA_CONTIG
> +	select V4L2_FWNODE
> +	select V4L2_MEM2MEM_DEV

Is the mem2mem framework needed for something? Or did you mean 

> +	help
> +	  This is a V4L2 driver for the Allwinner A10 CSI
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called sun4i_csi.
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/Makefile b/drivers/media/platform/sunxi/sun4i-csi/Makefile
> new file mode 100644
> index 000000000000..7c790a57f5ee
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/Makefile
> @@ -0,0 +1,5 @@
> +sun4i-csi-y += sun4i_csi.o
> +sun4i-csi-y += sun4i_dma.o
> +sun4i-csi-y += sun4i_v4l2.o
> +
> +obj-$(CONFIG_VIDEO_SUN4I_CSI)	+= sun4i-csi.o
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> new file mode 100644
> index 000000000000..9b58b42c0043
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> @@ -0,0 +1,261 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2016 NextThing Co
> + * Copyright (C) 2016-2018 Bootlin
> + *
> + * Author: Maxime Ripard <maxime.ripard@bootlin.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <linux/videodev2.h>
> +
> +#include <media/v4l2-dev.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mediabus.h>
> +
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include "sun4i_csi.h"
> +
> +static int csi_notify_bound(struct v4l2_async_notifier *notifier,
> +			    struct v4l2_subdev *subdev,
> +			    struct v4l2_async_subdev *asd)
> +{
> +	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> +					     notifier);
> +
> +	csi->src_subdev = subdev;
> +	csi->src_pad = media_entity_get_fwnode_pad(&subdev->entity,
> +						   subdev->fwnode,
> +						   MEDIA_PAD_FL_SOURCE);
> +	if (csi->src_pad < 0) {

The type of the src_pad field is unsigned int.

> +		dev_err(csi->dev, "Couldn't find output pad for subdev %s\n",
> +			subdev->name);
> +		return csi->src_pad;
> +	}
> +
> +	dev_dbg(csi->dev, "Bound %s pad: %d\n", subdev->name, csi->src_pad);
> +	return 0;
> +}
> +
> +static int csi_notify_complete(struct v4l2_async_notifier *notifier)
> +{
> +	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> +					     notifier);
> +	int ret;
> +
> +	ret = v4l2_device_register_subdev_nodes(&csi->v4l);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = sun4i_csi_v4l2_register(csi);
> +	if (ret < 0)
> +		return ret;
> +
> +	return media_create_pad_link(&csi->src_subdev->entity, csi->src_pad,
> +				     &csi->vdev.entity, 0,
> +				     MEDIA_LNK_FL_ENABLED |
> +				     MEDIA_LNK_FL_IMMUTABLE);

This appears to create a link directly from the sensor entity to the video
device entity. Is that intentional? I'd expect to see a CSI-2 receiver
sub-device as well, which I don't see being created by the driver.

This is indeed a novel proposal. I have some concerns though.

The user doesn't have access to the configured media bus format (reflecting
the format on the CSI-2 bus on receiver's side). It's thus difficult to
figure out whether the V4L2 pixel format configured on the video node
matches what the sensor outputs. Admittedly, we don't have a perfect
solution to that whenever the DMA hardware supports multiple V4L2 pixel
formats on a single media bus format. We might need to have a different
solution for this one, should it be without that receiver sub-device.

Could you add the CSI-2 receiver sub-device, please?

> +}
> +
> +static const struct v4l2_async_notifier_operations csi_notify_ops = {
> +	.bound		= csi_notify_bound,
> +	.complete	= csi_notify_complete,
> +};
> +
> +static int sun4i_csi_async_parse(struct device *dev,
> +				 struct v4l2_fwnode_endpoint *vep,
> +				 struct v4l2_async_subdev *asd)
> +{
> +	struct sun4i_csi *csi = dev_get_drvdata(dev);
> +
> +	if (vep->base.port || vep->base.id)
> +		return -EINVAL;
> +
> +	if (vep->bus_type != V4L2_MBUS_PARALLEL)
> +		return -EINVAL;
> +
> +	csi->bus = vep->bus.parallel;
> +
> +	return 0;
> +}
> +
> +static int csi_probe(struct platform_device *pdev)
> +{
> +	struct sun4i_csi *csi;
> +	struct resource *res;
> +	int ret;
> +	int irq;
> +
> +	csi = devm_kzalloc(&pdev->dev, sizeof(*csi), GFP_KERNEL);
> +	if (!csi)
> +		return -ENOMEM;
> +	platform_set_drvdata(pdev, csi);
> +	csi->dev = &pdev->dev;
> +
> +	csi->mdev.dev = csi->dev;
> +	strscpy(csi->mdev.model, "Allwinner Video Capture Device",
> +		sizeof(csi->mdev.model));
> +	csi->mdev.hw_revision = 0;
> +	media_device_init(&csi->mdev);
> +	v4l2_async_notifier_init(&csi->notifier);
> +
> +	csi->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;

Could you make it IMMUTABLE and ENABLED? If there is no need to disable it,
that is.

> +	ret = media_entity_pads_init(&csi->vdev.entity, 1, &csi->pad);
> +	if (ret < 0)

media_device_cleanup(&csi->mdev) is needed to clean up the media device
here. A new label? I'd actually move it down until you've acquired the
clocks etc. below.

> +		return 0;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	csi->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(csi->regs))
> +		return PTR_ERR(csi->regs);
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	csi->bus_clk = devm_clk_get(&pdev->dev, "bus");
> +	if (IS_ERR(csi->bus_clk)) {
> +		dev_err(&pdev->dev, "Couldn't get our bus clock\n");
> +		return PTR_ERR(csi->bus_clk);
> +	}
> +
> +	csi->isp_clk = devm_clk_get(&pdev->dev, "isp");
> +	if (IS_ERR(csi->isp_clk)) {
> +		dev_err(&pdev->dev, "Couldn't get our ISP clock\n");
> +		return PTR_ERR(csi->isp_clk);
> +	}
> +
> +	csi->mod_clk = devm_clk_get(&pdev->dev, "mod");
> +	if (IS_ERR(csi->mod_clk)) {
> +		dev_err(&pdev->dev, "Couldn't get our mod clock\n");
> +		return PTR_ERR(csi->mod_clk);
> +	}
> +
> +	csi->ram_clk = devm_clk_get(&pdev->dev, "ram");
> +	if (IS_ERR(csi->ram_clk)) {
> +		dev_err(&pdev->dev, "Couldn't get our ram clock\n");
> +		return PTR_ERR(csi->ram_clk);
> +	}
> +
> +	csi->rst = devm_reset_control_get(&pdev->dev, NULL);
> +	if (IS_ERR(csi->rst)) {
> +		dev_err(&pdev->dev, "Couldn't get our reset line\n");
> +		return PTR_ERR(csi->rst);
> +	}
> +
> +	ret = sun4i_csi_dma_register(csi, irq);
> +	if (ret)
> +		return ret;
> +
> +	csi->v4l.mdev = &csi->mdev;
> +
> +	ret = media_device_register(&csi->mdev);

Could you put the media_device_register() in the async complete handler?
That way the device registration is all done when the media device becomes
accessible to the user space.

> +	if (ret)
> +		goto err_unregister_dma;
> +
> +	ret = v4l2_async_notifier_parse_fwnode_endpoints(csi->dev,
> +							 &csi->notifier,
> +							 sizeof(struct v4l2_async_subdev),
> +							 sun4i_csi_async_parse);
> +	if (ret)
> +		goto err_unregister_media;
> +	csi->notifier.ops = &csi_notify_ops;
> +
> +	ret = v4l2_async_notifier_register(&csi->v4l, &csi->notifier);
> +	if (ret) {
> +		dev_err(csi->dev,
> +			"Couldn't register our v4l2-async notifier\n");
> +		goto err_free_notifier;
> +	}
> +
> +	pm_runtime_enable(&pdev->dev);
> +
> +	return 0;
> +
> +err_free_notifier:
> +	v4l2_async_notifier_cleanup(&csi->notifier);
> +
> +err_unregister_media:
> +	media_device_unregister(&csi->mdev);
> +
> +err_unregister_dma:
> +	sun4i_csi_dma_unregister(csi);
> +	return ret;
> +}
> +
> +static int csi_remove(struct platform_device *pdev)
> +{
> +	struct sun4i_csi *csi = platform_get_drvdata(pdev);
> +
> +	v4l2_async_notifier_unregister(&csi->notifier);
> +	v4l2_async_notifier_cleanup(&csi->notifier);
> +	media_device_unregister(&csi->mdev);
> +	sun4i_csi_dma_unregister(csi);

media_device_cleanup(&csi->mdev);

> +
> +	return 0;
> +}
> +
> +static const struct of_device_id csi_of_match[] = {
> +	{ .compatible = "allwinner,sun4i-a10-csi0" },
> +	{ /* Sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, csi_of_match);
> +
> +static int csi_runtime_resume(struct device *dev)
> +{
> +	struct sun4i_csi *csi = dev_get_drvdata(dev);
> +
> +	reset_control_deassert(csi->rst);
> +	clk_prepare_enable(csi->bus_clk);
> +	clk_prepare_enable(csi->ram_clk);
> +	clk_set_rate(csi->isp_clk, 80000000);
> +	clk_prepare_enable(csi->isp_clk);
> +	clk_set_rate(csi->mod_clk, 24000000);
> +	clk_prepare_enable(csi->mod_clk);
> +
> +	writel(1, csi->regs + CSI_EN_REG);
> +
> +	return 0;
> +}
> +
> +static int csi_runtime_suspend(struct device *dev)

__maybe_unused; same for csi_runtime_resume above.

> +{
> +	struct sun4i_csi *csi = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(csi->mod_clk);
> +	clk_disable_unprepare(csi->isp_clk);
> +	clk_disable_unprepare(csi->ram_clk);
> +	clk_disable_unprepare(csi->bus_clk);
> +
> +	reset_control_assert(csi->rst);
> +
> +	return 0;
> +}
> +
> +static const struct dev_pm_ops csi_pm_ops = {
> +	.runtime_resume		= csi_runtime_resume,
> +	.runtime_suspend	= csi_runtime_suspend,
> +};

SET_RUNTIME_PM_OPS instead?

> +
> +static struct platform_driver csi_driver = {
> +	.probe	= csi_probe,
> +	.remove	= csi_remove,
> +	.driver	= {
> +		.name		= "sun4i-csi",
> +		.of_match_table	= csi_of_match,
> +		.pm		= &csi_pm_ops,
> +	},
> +};
> +module_platform_driver(csi_driver);
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
> new file mode 100644
> index 000000000000..563368c64567
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
> @@ -0,0 +1,142 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * Copyright (C) 2016 NextThing Co
> + * Copyright (C) 2016-2018 Bootlin
> + *
> + * Author: Maxime Ripard <maxime.ripard@bootlin.com>
> + */
> +
> +#ifndef _SUN4I_CSI_H_
> +#define _SUN4I_CSI_H_
> +
> +#include <media/media-device.h>
> +#include <media/v4l2-async.h>
> +#include <media/v4l2-dev.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/videobuf2-core.h>
> +
> +#define CSI_EN_REG			0x00
> +
> +#define CSI_CFG_REG			0x04
> +#define CSI_CFG_INPUT_FMT(fmt)			((fmt) << 20)
> +#define CSI_CFG_OUTPUT_FMT(fmt)			((fmt) << 16)
> +#define CSI_CFG_YUV_DATA_SEQ(seq)		((seq) << 8)
> +#define CSI_CFG_VSYNC_POL(pol)			((pol) << 2)
> +#define CSI_CFG_HSYNC_POL(pol)			((pol) << 1)
> +#define CSI_CFG_PCLK_POL(pol)			((pol) << 0)
> +
> +#define CSI_CPT_CTRL_REG		0x08
> +#define CSI_CPT_CTRL_VIDEO_START		BIT(1)
> +#define CSI_CPT_CTRL_IMAGE_START		BIT(0)
> +
> +#define CSI_BUF_ADDR_REG(fifo, buf)	(0x10 + (0x8 * (fifo)) + (0x4 * (buf)))
> +
> +#define CSI_BUF_CTRL_REG		0x28
> +#define CSI_BUF_CTRL_DBN			BIT(2)
> +#define CSI_BUF_CTRL_DBS			BIT(1)
> +#define CSI_BUF_CTRL_DBE			BIT(0)
> +
> +#define CSI_INT_EN_REG			0x30
> +#define CSI_INT_FRM_DONE			BIT(1)
> +#define CSI_INT_CPT_DONE			BIT(0)
> +
> +#define CSI_INT_STA_REG			0x34
> +
> +#define CSI_WIN_CTRL_W_REG		0x40
> +#define CSI_WIN_CTRL_W_ACTIVE(w)		((w) << 16)
> +
> +#define CSI_WIN_CTRL_H_REG		0x44
> +#define CSI_WIN_CTRL_H_ACTIVE(h)		((h) << 16)
> +
> +#define CSI_BUF_LEN_REG			0x48
> +
> +#define CSI_MAX_BUFFER	2
> +
> +enum csi_input {
> +	CSI_INPUT_RAW	= 0,
> +	CSI_INPUT_BT656	= 2,
> +	CSI_INPUT_YUV	= 3,
> +};
> +
> +enum csi_output_raw {
> +	CSI_OUTPUT_RAW_PASSTHROUGH = 0,
> +};
> +
> +enum csi_output_yuv {
> +	CSI_OUTPUT_YUV_422_PLANAR	= 0,
> +	CSI_OUTPUT_YUV_420_PLANAR	= 1,
> +	CSI_OUTPUT_YUV_422_UV		= 4,
> +	CSI_OUTPUT_YUV_420_UV		= 5,
> +	CSI_OUTPUT_YUV_422_MACRO	= 8,
> +	CSI_OUTPUT_YUV_420_MACRO	= 9,
> +};
> +
> +enum csi_yuv_data_seq {
> +	CSI_YUV_DATA_SEQ_YUYV	= 0,
> +	CSI_YUV_DATA_SEQ_YVYU	= 1,
> +	CSI_YUV_DATA_SEQ_UYVY	= 2,
> +	CSI_YUV_DATA_SEQ_VYUY	= 3,
> +};
> +
> +struct sun4i_csi_format {
> +	u32			mbus;
> +	u32			fourcc;
> +	enum csi_input		input;
> +	u32			output;
> +	unsigned int		num_planes;
> +	u8			bpp[3];
> +	unsigned int		hsub;
> +	unsigned int		vsub;
> +};
> +
> +struct sun4i_csi {
> +	/* Device resources */
> +	struct device			*dev;
> +
> +	void __iomem			*regs;
> +	struct clk			*bus_clk;
> +	struct clk			*isp_clk;
> +	struct clk			*mod_clk;
> +	struct clk			*ram_clk;
> +	struct reset_control		*rst;
> +
> +	const struct sun4i_csi_format	*p_fmt;
> +	struct v4l2_pix_format_mplane	v_fmt;
> +
> +	struct vb2_v4l2_buffer		*current_buf[CSI_MAX_BUFFER];
> +
> +	struct {
> +		size_t			size;
> +		void			*vaddr;
> +		dma_addr_t		paddr;
> +	} scratch;
> +
> +	struct media_device		mdev;
> +	struct media_pad		pad;
> +
> +	struct v4l2_fwnode_bus_parallel	bus;
> +
> +	/* V4L2 Async variables */
> +	struct v4l2_async_notifier	notifier;
> +	struct v4l2_subdev		*src_subdev;
> +	unsigned int			src_pad;
> +
> +	/* V4L2 variables */
> +	struct mutex			lock;
> +	struct v4l2_device		v4l;
> +	struct video_device		vdev;
> +
> +	/* Videobuf2 */
> +	struct vb2_queue		queue;
> +	struct list_head		buf_list;
> +	spinlock_t			qlock;
> +	unsigned int			sequence;
> +};
> +
> +int sun4i_csi_dma_register(struct sun4i_csi *csi, int irq);
> +void sun4i_csi_dma_unregister(struct sun4i_csi *csi);
> +
> +int sun4i_csi_v4l2_register(struct sun4i_csi *csi);
> +
> +#endif /* _SUN4I_CSI_H_ */
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
> new file mode 100644
> index 000000000000..f238709ff50a
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
> @@ -0,0 +1,435 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2016 NextThing Co
> + * Copyright (C) 2016-2019 Bootlin
> + *
> + * Author: Maxime Ripard <maxime.ripard@bootlin.com>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/list.h>
> +#include <linux/mutex.h>
> +#include <linux/spinlock.h>
> +#include <media/videobuf2-dma-contig.h>
> +#include <media/videobuf2-v4l2.h>
> +
> +#include "sun4i_csi.h"
> +
> +struct csi_buffer {
> +	struct vb2_v4l2_buffer	vb;
> +	struct list_head	list;
> +};
> +
> +static inline struct csi_buffer *vb2_v4l2_to_csi_buffer(const struct vb2_v4l2_buffer *p)
> +{
> +	return container_of(p, struct csi_buffer, vb);
> +}
> +
> +static inline struct csi_buffer *vb2_to_csi_buffer(const struct vb2_buffer *p)
> +{
> +	return vb2_v4l2_to_csi_buffer(to_vb2_v4l2_buffer(p));
> +}
> +
> +static void csi_capture_start(struct sun4i_csi *csi)
> +{
> +	writel(CSI_CPT_CTRL_VIDEO_START, csi->regs + CSI_CPT_CTRL_REG);
> +}
> +
> +static void csi_capture_stop(struct sun4i_csi *csi)
> +{
> +	writel(0, csi->regs + CSI_CPT_CTRL_REG);
> +}
> +
> +static int csi_queue_setup(struct vb2_queue *vq,
> +			   unsigned int *nbuffers,
> +			   unsigned int *nplanes,
> +			   unsigned int sizes[],
> +			   struct device *alloc_devs[])
> +
> +{
> +	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
> +	unsigned int num_planes = csi->p_fmt->num_planes;
> +	unsigned int i;
> +
> +	if (*nplanes) {
> +                if (*nplanes != num_planes)
> +                        return -EINVAL;
> +
> +                for (i = 0; i < num_planes; i++)
> +                        if (sizes[i] < csi->v_fmt.plane_fmt[i].sizeimage)
> +                                return -EINVAL;
> +                return 0;
> +        }
> +
> +	*nplanes = num_planes;
> +	for (i = 0; i < num_planes; i++)
> +		sizes[i] = csi->v_fmt.plane_fmt[i].sizeimage;
> +
> +	return 0;
> +};
> +
> +static int csi_buffer_prepare(struct vb2_buffer *vb)
> +{
> +	struct sun4i_csi *csi = vb2_get_drv_priv(vb->vb2_queue);
> +	unsigned int i;
> +
> +	for (i = 0; i < csi->p_fmt->num_planes; i++) {
> +		unsigned long size = csi->v_fmt.plane_fmt[i].sizeimage;
> +
> +		if (vb2_plane_size(vb, i) < size) {
> +			dev_err(csi->dev, "buffer too small (%lu < %lu)\n",
> +				vb2_plane_size(vb, i), size);
> +			return -EINVAL;
> +		}
> +
> +		vb2_set_plane_payload(vb, i, size);
> +	}
> +
> +	return 0;
> +}
> +
> +static int csi_setup_scratch_buffer(struct sun4i_csi *csi, unsigned int slot)
> +{
> +	dma_addr_t addr = csi->scratch.paddr;
> +	unsigned int plane;
> +
> +	dev_dbg(csi->dev,
> +		"No more available buffer, using the scratch buffer\n");
> +
> +	for (plane = 0; plane < csi->p_fmt->num_planes; plane++) {
> +		writel(addr, csi->regs + CSI_BUF_ADDR_REG(plane, slot));
> +		addr += csi->v_fmt.plane_fmt[plane].sizeimage;
> +	}
> +
> +	csi->current_buf[slot] = NULL;
> +	return 0;
> +}
> +
> +static int csi_buffer_fill_slot(struct sun4i_csi *csi, unsigned int slot)
> +{
> +	struct csi_buffer *c_buf;
> +	struct vb2_v4l2_buffer *v_buf;
> +	unsigned int plane;
> +
> +	/*
> +	 * We should never end up in a situation where we overwrite an
> +	 * already filled slot.
> +	 */
> +	if (WARN_ON(csi->current_buf[slot]))
> +		return -EINVAL;
> +
> +	if (list_empty(&csi->buf_list))
> +		return csi_setup_scratch_buffer(csi, slot);
> +
> +	c_buf = list_first_entry(&csi->buf_list, struct csi_buffer, list);
> +	list_del_init(&c_buf->list);
> +
> +	v_buf = &c_buf->vb;
> +	csi->current_buf[slot] = v_buf;
> +
> +	for (plane = 0; plane < csi->p_fmt->num_planes; plane++) {
> +		dma_addr_t buf_addr;
> +
> +		buf_addr = vb2_dma_contig_plane_dma_addr(&v_buf->vb2_buf,
> +							 plane);
> +		writel(buf_addr, csi->regs + CSI_BUF_ADDR_REG(plane, slot));
> +	}
> +
> +	return 0;
> +}
> +
> +static int csi_buffer_fill_all(struct sun4i_csi *csi)
> +{
> +	unsigned int slot;
> +	int ret;
> +
> +	for (slot = 0; slot < CSI_MAX_BUFFER; slot++) {
> +		ret = csi_buffer_fill_slot(csi, slot);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void csi_buffer_mark_done(struct sun4i_csi *csi,
> +				 unsigned int slot,
> +				 unsigned int sequence)
> +{
> +	struct vb2_v4l2_buffer *v_buf;
> +
> +	if (!csi->current_buf[slot]) {
> +		dev_dbg(csi->dev, "Scratch buffer was used, ignoring..\n");
> +		return;
> +	}
> +
> +	v_buf = csi->current_buf[slot];
> +	v_buf->field = csi->v_fmt.field;
> +	v_buf->sequence = sequence;
> +	v_buf->vb2_buf.timestamp = ktime_get_ns();
> +	vb2_buffer_done(&v_buf->vb2_buf, VB2_BUF_STATE_DONE);
> +
> +	csi->current_buf[slot] = NULL;
> +}
> +
> +static int csi_buffer_flip(struct sun4i_csi *csi, unsigned int sequence)
> +{
> +	u32 reg = readl(csi->regs + CSI_BUF_CTRL_REG);
> +	unsigned int curr, next;
> +
> +	/* Our next buffer is not the current buffer */
> +	curr = !!(reg & CSI_BUF_CTRL_DBS);
> +	next = !curr;
> +
> +	/* Report the previous buffer as done */
> +	csi_buffer_mark_done(csi, next, sequence);
> +
> +	/* Put a new buffer in there */
> +	return csi_buffer_fill_slot(csi, next);
> +}
> +
> +static void csi_buffer_queue(struct vb2_buffer *vb)
> +{
> +	struct sun4i_csi *csi = vb2_get_drv_priv(vb->vb2_queue);
> +	struct csi_buffer *buf = vb2_to_csi_buffer(vb);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&csi->qlock, flags);
> +	list_add_tail(&buf->list, &csi->buf_list);
> +	spin_unlock_irqrestore(&csi->qlock, flags);
> +}
> +
> +static void return_all_buffers(struct sun4i_csi *csi,
> +			       enum vb2_buffer_state state)
> +{
> +	struct csi_buffer *buf, *node;
> +	unsigned int slot;
> +
> +	list_for_each_entry_safe(buf, node, &csi->buf_list, list) {
> +		vb2_buffer_done(&buf->vb.vb2_buf, state);
> +		list_del(&buf->list);
> +	}
> +
> +	for (slot = 0; slot < CSI_MAX_BUFFER; slot++) {
> +		struct vb2_v4l2_buffer *v_buf = csi->current_buf[slot];
> +
> +		if (!v_buf)
> +			continue;
> +
> +		vb2_buffer_done(&v_buf->vb2_buf, state);
> +		csi->current_buf[slot] = NULL;
> +	}
> +}
> +
> +static int csi_start_streaming(struct vb2_queue *vq, unsigned int count)
> +{
> +	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
> +	struct v4l2_fwnode_bus_parallel *bus = &csi->bus;
> +	unsigned long hsync_pol, pclk_pol, vsync_pol;
> +	unsigned long flags;
> +	unsigned int i;
> +	int ret;
> +
> +	dev_dbg(csi->dev, "Starting capture\n");
> +
> +	csi->sequence = 0;
> +
> +	/*
> +	 * We need a scratch buffer in case where we'll not have any
> +	 * more buffer queued so that we don't error out. One of those
> +	 * cases is when you end up at the last frame to capture, you
> +	 * don't havea any buffer queued any more, and yet it doesn't
> +	 * really matter since you'll never reach the next buffer.
> +	 *
> +	 * Since we support the multi-planar API, we need to have a
> +	 * buffer for each plane. Allocating a single one large enough
> +	 * to hold all the buffers is simpler, so let's go for that.
> +	 */
> +	csi->scratch.size = 0;
> +	for (i = 0; i < csi->p_fmt->num_planes; i++)
> +		csi->scratch.size += csi->v_fmt.plane_fmt[i].sizeimage;
> +
> +	csi->scratch.vaddr = dma_alloc_coherent(csi->dev,
> +						csi->scratch.size,
> +						&csi->scratch.paddr,
> +						GFP_KERNEL);
> +	if (!csi->scratch.vaddr) {
> +		dev_err(csi->dev, "Failed to allocate scratch buffer\n");
> +		ret = -ENOMEM;
> +		goto clear_dma_queue;
> +	}
> +
> +	ret = media_pipeline_start(&csi->vdev.entity, &csi->vdev.pipe);
> +	if (ret < 0)
> +		goto free_scratch_buffer;
> +
> +	spin_lock_irqsave(&csi->qlock, flags);
> +
> +	/* Setup timings */
> +	writel(CSI_WIN_CTRL_W_ACTIVE(csi->v_fmt.width * 2),
> +	       csi->regs + CSI_WIN_CTRL_W_REG);
> +	writel(CSI_WIN_CTRL_H_ACTIVE(csi->v_fmt.height),
> +	       csi->regs + CSI_WIN_CTRL_H_REG);
> +
> +	hsync_pol = !!(bus->flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH);
> +	pclk_pol = !!(bus->flags & V4L2_MBUS_DATA_ACTIVE_HIGH);
> +	vsync_pol = !!(bus->flags & V4L2_MBUS_VSYNC_ACTIVE_HIGH);
> +	writel(CSI_CFG_INPUT_FMT(csi->p_fmt->input) |
> +	       CSI_CFG_OUTPUT_FMT(csi->p_fmt->output) |
> +	       CSI_CFG_VSYNC_POL(vsync_pol) |
> +	       CSI_CFG_HSYNC_POL(hsync_pol) |
> +	       CSI_CFG_PCLK_POL(pclk_pol),
> +	       csi->regs + CSI_CFG_REG);
> +
> +	/* Setup buffer length */
> +	writel(csi->v_fmt.plane_fmt[0].bytesperline,
> +	       csi->regs + CSI_BUF_LEN_REG);
> +
> +	/* Prepare our buffers in hardware */
> +	ret = csi_buffer_fill_all(csi);
> +	if (ret) {
> +		spin_unlock_irqrestore(&csi->qlock, flags);
> +		goto disable_pipeline;
> +	}
> +
> +	/* Enable double buffering */
> +	writel(CSI_BUF_CTRL_DBE, csi->regs + CSI_BUF_CTRL_REG);
> +
> +	/* Clear the pending interrupts */
> +	writel(CSI_INT_FRM_DONE, csi->regs + 0x34);
> +
> +	/* Enable frame done interrupt */
> +	writel(CSI_INT_FRM_DONE, csi->regs + CSI_INT_EN_REG);
> +
> +	csi_capture_start(csi);
> +
> +	spin_unlock_irqrestore(&csi->qlock, flags);
> +
> +	ret = v4l2_subdev_call(csi->src_subdev, video, s_stream, 1);
> +	if (ret < 0 && ret != -ENOIOCTLCMD)
> +		goto disable_pipeline;
> +
> +	return 0;
> +
> +disable_pipeline:

Don't you need to stop the CSI-2 receiver here?

> +	media_pipeline_stop(&csi->vdev.entity);
> +
> +free_scratch_buffer:
> +	dma_free_coherent(csi->dev, csi->scratch.size, csi->scratch.vaddr,
> +			  csi->scratch.paddr);
> +
> +clear_dma_queue:
> +	spin_lock_irqsave(&csi->qlock, flags);
> +	return_all_buffers(csi, VB2_BUF_STATE_QUEUED);
> +	spin_unlock_irqrestore(&csi->qlock, flags);
> +
> +	return ret;
> +}
> +
> +static void csi_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
> +	unsigned long flags;
> +
> +	dev_dbg(csi->dev, "Stopping capture\n");
> +
> +	v4l2_subdev_call(csi->src_subdev, video, s_stream, 0);
> +	csi_capture_stop(csi);
> +
> +	/* Release all active buffers */
> +	spin_lock_irqsave(&csi->qlock, flags);
> +	return_all_buffers(csi, VB2_BUF_STATE_ERROR);
> +	spin_unlock_irqrestore(&csi->qlock, flags);
> +
> +	media_pipeline_stop(&csi->vdev.entity);
> +
> +	dma_free_coherent(csi->dev, csi->scratch.size, csi->scratch.vaddr,
> +			  csi->scratch.paddr);
> +}
> +
> +static struct vb2_ops csi_qops = {
> +	.queue_setup		= csi_queue_setup,
> +	.buf_prepare		= csi_buffer_prepare,
> +	.buf_queue		= csi_buffer_queue,
> +	.start_streaming	= csi_start_streaming,
> +	.stop_streaming		= csi_stop_streaming,
> +	.wait_prepare		= vb2_ops_wait_prepare,
> +	.wait_finish		= vb2_ops_wait_finish,
> +};
> +
> +static irqreturn_t csi_irq(int irq, void *data)
> +{
> +	struct sun4i_csi *csi = data;
> +	u32 reg;
> +
> +	reg = readl(csi->regs + CSI_INT_STA_REG);
> +
> +	/* Acknowledge the interrupts */
> +	writel(reg, csi->regs + CSI_INT_STA_REG);
> +
> +	if (!(reg & CSI_INT_FRM_DONE))
> +		goto out;
> +
> +	spin_lock(&csi->qlock);
> +	if (csi_buffer_flip(csi, csi->sequence++)) {
> +		dev_warn(csi->dev, "%s: Flip failed\n", __func__);
> +		csi_capture_stop(csi);
> +	}
> +	spin_unlock(&csi->qlock);
> +
> +out:
> +	return IRQ_HANDLED;
> +}
> +
> +int sun4i_csi_dma_register(struct sun4i_csi *csi, int irq)
> +{
> +	struct vb2_queue *q = &csi->queue;
> +	int ret;
> +	int i;
> +
> +	ret = v4l2_device_register(csi->dev, &csi->v4l);
> +	if (ret) {
> +		dev_err(csi->dev, "Couldn't register the v4l2 device\n");
> +		return ret;
> +	}
> +
> +	spin_lock_init(&csi->qlock);
> +	mutex_init(&csi->lock);
> +
> +	INIT_LIST_HEAD(&csi->buf_list);
> +	for (i = 0; i < CSI_MAX_BUFFER; i++)
> +		csi->current_buf[i] = NULL;
> +
> +	q->min_buffers_needed = 3;
> +	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
> +	q->io_modes = VB2_MMAP;
> +	q->lock = &csi->lock;
> +	q->drv_priv = csi;
> +	q->buf_struct_size = sizeof(struct csi_buffer);
> +	q->ops = &csi_qops;
> +	q->mem_ops = &vb2_dma_contig_memops;
> +	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->dev = csi->dev;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret < 0) {
> +		dev_err(csi->dev, "failed to initialize VB2 queue\n");
> +		return ret;
> +	}
> +
> +	ret = devm_request_irq(csi->dev, irq, csi_irq, 0,
> +			       dev_name(csi->dev), csi);
> +	if (ret) {
> +		dev_err(csi->dev, "Couldn't register our interrupt\n");
> +		vb2_queue_release(q);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +void sun4i_csi_dma_unregister(struct sun4i_csi *csi)
> +{
> +	v4l2_device_unregister(&csi->v4l);
> +}
> +
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
> new file mode 100644
> index 000000000000..1be91f4d498e
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
> @@ -0,0 +1,305 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2016 NextThing Co
> + * Copyright (C) 2016-2019 Bootlin
> + *
> + * Author: Maxime Ripard <maxime.ripard@bootlin.com>
> + */
> +
> +#include <linux/device.h>
> +#include <linux/pm_runtime.h>
> +
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mc.h>
> +#include <media/videobuf2-v4l2.h>
> +
> +#include "sun4i_csi.h"
> +
> +#define CSI_DEFAULT_FORMAT	V4L2_PIX_FMT_YUV420M
> +#define CSI_DEFAULT_WIDTH	640
> +#define CSI_DEFAULT_HEIGHT	480
> +
> +#define CSI_MAX_HEIGHT		8192U
> +#define CSI_MAX_WIDTH		8192U
> +
> +static const struct sun4i_csi_format csi_formats[] = {
> +	/* YUV422 inputs */
> +	{
> +		.mbus		= MEDIA_BUS_FMT_YUYV8_2X8,
> +		.fourcc		= V4L2_PIX_FMT_YUV420M,
> +		.input		= CSI_INPUT_YUV,
> +		.output		= CSI_OUTPUT_YUV_420_PLANAR,
> +		.num_planes	= 3,
> +		.bpp		= { 8, 8, 8 },
> +		.hsub		= 2,
> +		.vsub		= 2,
> +	},
> +};
> +
> +static const struct sun4i_csi_format *
> +csi_get_format_by_fourcc(struct sun4i_csi *csi, u32 fourcc)
> +{
> +	unsigned int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(csi_formats); i++)
> +		if (csi_formats[i].fourcc == fourcc)
> +			return &csi_formats[i];
> +
> +	return NULL;
> +}
> +
> +static int csi_querycap(struct file *file, void *priv,
> +			struct v4l2_capability *cap)
> +{
> +	struct sun4i_csi *csi = video_drvdata(file);
> +
> +	strscpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
> +	strscpy(cap->card, "sun4i-csi", sizeof(cap->card));
> +	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
> +		 dev_name(csi->dev));
> +
> +	return 0;
> +}
> +
> +static int csi_enum_input(struct file *file, void *priv,
> +			  struct v4l2_input *inp)
> +{
> +	if (inp->index != 0)
> +		return -EINVAL;
> +
> +	inp->type = V4L2_INPUT_TYPE_CAMERA;
> +	strscpy(inp->name, "Camera", sizeof(inp->name));
> +
> +	return 0;
> +}
> +
> +static int csi_g_input(struct file *file, void *fh,
> +		       unsigned int *i)
> +{
> +	*i = 0;
> +
> +	return 0;
> +}
> +
> +static int csi_s_input(struct file *file, void *fh,
> +		       unsigned int i)
> +{
> +	if (i != 0)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int _csi_try_fmt(struct sun4i_csi *csi,
> +			struct v4l2_pix_format_mplane *pix,
> +			const struct sun4i_csi_format **fmt)
> +{
> +	const struct sun4i_csi_format *_fmt;
> +	unsigned int width = pix->width;
> +	unsigned int height = pix->height;
> +	unsigned int i;
> +
> +	_fmt = csi_get_format_by_fourcc(csi, pix->pixelformat);
> +	if (!_fmt)
> +		_fmt = csi_get_format_by_fourcc(csi, csi_formats[0].fourcc);
> +
> +	pix->field = V4L2_FIELD_NONE;
> +	pix->colorspace = V4L2_COLORSPACE_SRGB;
> +	pix->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(pix->colorspace);
> +	pix->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(pix->colorspace);
> +	pix->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true, pix->colorspace,
> +							  pix->ycbcr_enc);
> +
> +	pix->num_planes = _fmt->num_planes;
> +	pix->pixelformat = _fmt->fourcc;
> +
> +	memset(pix->reserved, 0, sizeof(pix->reserved));
> +
> +	/* Align the width and height on the subsampling */
> +	width = ALIGN(width, _fmt->hsub);
> +	height = ALIGN(height, _fmt->vsub);
> +
> +	/* Clamp the width and height to our capabilities */
> +	pix->width = clamp(width, _fmt->hsub, CSI_MAX_WIDTH);
> +	pix->height = clamp(height, _fmt->vsub, CSI_MAX_HEIGHT);
> +
> +	for (i = 0; i < _fmt->num_planes; i++) {
> +		unsigned int hsub = i > 0 ? _fmt->hsub : 1;
> +		unsigned int vsub = i > 0 ? _fmt->vsub : 1;
> +		unsigned int bpl;
> +
> +		bpl = pix->width / hsub * _fmt->bpp[i] / 8;
> +		pix->plane_fmt[i].bytesperline = bpl;
> +		pix->plane_fmt[i].sizeimage = bpl * pix->height / vsub;
> +		memset(pix->plane_fmt[i].reserved, 0,
> +		       sizeof(pix->plane_fmt[i].reserved));
> +	}
> +
> +	if (fmt)
> +		*fmt = _fmt;
> +
> +	return 0;
> +}
> +
> +static int csi_try_fmt_vid_cap(struct file *file, void *priv,
> +			       struct v4l2_format *f)
> +{
> +	struct sun4i_csi *csi = video_drvdata(file);
> +
> +	return _csi_try_fmt(csi, &f->fmt.pix_mp, NULL);
> +}
> +
> +static int csi_s_fmt_vid_cap(struct file *file, void *priv,
> +			     struct v4l2_format *f)
> +{
> +	const struct sun4i_csi_format *fmt;
> +	struct sun4i_csi *csi = video_drvdata(file);
> +	int ret;
> +
> +	ret = _csi_try_fmt(csi, &f->fmt.pix_mp, &fmt);
> +	if (ret)
> +		return ret;

_csi_try_fmt() always returns 0. You could change the return type to void.

> +
> +	csi->v_fmt = f->fmt.pix_mp;
> +	csi->p_fmt = fmt;
> +
> +	return 0;
> +}
> +
> +static int csi_g_fmt_vid_cap(struct file *file, void *priv,
> +			     struct v4l2_format *f)
> +{
> +	struct sun4i_csi *csi = video_drvdata(file);
> +
> +	f->fmt.pix_mp = csi->v_fmt;
> +
> +	return 0;
> +}
> +
> +static int csi_enum_fmt_vid_cap(struct file *file, void *priv,
> +				struct v4l2_fmtdesc *f)
> +{
> +	if (f->index >= ARRAY_SIZE(csi_formats))
> +		return -EINVAL;
> +
> +	f->pixelformat = csi_formats[f->index].fourcc;
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ioctl_ops csi_ioctl_ops = {
> +	.vidioc_querycap	= csi_querycap,
> +
> +	.vidioc_enum_fmt_vid_cap_mplane	= csi_enum_fmt_vid_cap,
> +	.vidioc_g_fmt_vid_cap_mplane	= csi_g_fmt_vid_cap,
> +	.vidioc_s_fmt_vid_cap_mplane	= csi_s_fmt_vid_cap,
> +	.vidioc_try_fmt_vid_cap_mplane	= csi_try_fmt_vid_cap,
> +
> +	.vidioc_enum_input	= csi_enum_input,
> +	.vidioc_g_input		= csi_g_input,
> +	.vidioc_s_input		= csi_s_input,
> +
> +	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
> +	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
> +	.vidioc_querybuf	= vb2_ioctl_querybuf,
> +	.vidioc_qbuf		= vb2_ioctl_qbuf,
> +	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
> +	.vidioc_expbuf		= vb2_ioctl_expbuf,
> +	.vidioc_prepare_buf	= vb2_ioctl_prepare_buf,
> +	.vidioc_streamon	= vb2_ioctl_streamon,
> +	.vidioc_streamoff	= vb2_ioctl_streamoff,
> +};
> +
> +static int csi_open(struct file *file)
> +{
> +	struct sun4i_csi *csi = video_drvdata(file);
> +	int ret;
> +
> +	ret = mutex_lock_interruptible(&csi->lock);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_get_sync(csi->dev);
> +	if (ret < 0)
> +		goto err_unlock;

If pm_runtime_get_sync() fails, it still increments the use count. So the
label is err_pm_put. And you can drop the err_unlock label.

> +
> +	ret = v4l2_pipeline_pm_use(&csi->vdev.entity, 1);
> +	if (ret)
> +		goto err_pm_put;
> +
> +	ret = v4l2_fh_open(file);
> +	if (ret)
> +		goto err_pipeline_pm_put;
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return 0;
> +
> +err_pipeline_pm_put:
> +	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
> +err_pm_put:
> +	pm_runtime_put(csi->dev);
> +err_unlock:
> +	mutex_unlock(&csi->lock);
> +	return ret;
> +}
> +
> +static int csi_release(struct file *file)
> +{
> +	struct sun4i_csi *csi = video_drvdata(file);
> +	int ret;
> +
> +	mutex_lock(&csi->lock);
> +
> +	ret = v4l2_fh_release(file);

v4l2_fh_release() always returns 0. I guess it could be changed to return
void. The reason it has int is that it could be used as the release
callback as such.

> +	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
> +	pm_runtime_put(csi->dev);
> +
> +	mutex_unlock(&csi->lock);
> +
> +	return ret;
> +}
> +
> +static const struct v4l2_file_operations csi_fops = {
> +	.owner		= THIS_MODULE,
> +	.open		= csi_open,
> +	.release	= csi_release,
> +	.unlocked_ioctl	= video_ioctl2,
> +	.read		= vb2_fop_read,
> +	.write		= vb2_fop_write,
> +	.poll		= vb2_fop_poll,
> +	.mmap		= vb2_fop_mmap,
> +};
> +
> +int sun4i_csi_v4l2_register(struct sun4i_csi *csi)
> +{
> +	struct video_device *vdev = &csi->vdev;
> +	int ret;
> +
> +	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE_MPLANE | V4L2_CAP_STREAMING;
> +	vdev->v4l2_dev = &csi->v4l;
> +	vdev->queue = &csi->queue;
> +	strscpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
> +	vdev->release = video_device_release_empty;
> +	vdev->lock = &csi->lock;
> +
> +	/* Set a default format */
> +	csi->v_fmt.pixelformat = CSI_DEFAULT_FORMAT;
> +	csi->v_fmt.width = CSI_DEFAULT_WIDTH;
> +	csi->v_fmt.height = CSI_DEFAULT_HEIGHT;
> +	_csi_try_fmt(csi, &csi->v_fmt, NULL);
> +
> +	vdev->fops = &csi_fops;
> +	vdev->ioctl_ops = &csi_ioctl_ops;
> +	video_set_drvdata(vdev, csi);
> +
> +	ret = video_register_device(&csi->vdev, VFL_TYPE_GRABBER, -1);
> +	if (ret)
> +		return ret;
> +
> +	dev_info(csi->dev, "Device registered as %s\n",
> +		 video_device_node_name(vdev));
> +
> +	return 0;
> +}
> +
Maxime Ripard - Feb. 6, 2019, 9:16 p.m.
Hi Sakari,

Thanks for your review, I have a few questions though, and the rest
will be addressed in the next version.

On Tue, Jan 29, 2019 at 02:39:49PM +0200, Sakari Ailus wrote:
> > +static int csi_notify_complete(struct v4l2_async_notifier *notifier)
> > +{
> > +	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> > +					     notifier);
> > +	int ret;
> > +
> > +	ret = v4l2_device_register_subdev_nodes(&csi->v4l);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	ret = sun4i_csi_v4l2_register(csi);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return media_create_pad_link(&csi->src_subdev->entity, csi->src_pad,
> > +				     &csi->vdev.entity, 0,
> > +				     MEDIA_LNK_FL_ENABLED |
> > +				     MEDIA_LNK_FL_IMMUTABLE);
> 
> This appears to create a link directly from the sensor entity to the video
> device entity. Is that intentional? I'd expect to see a CSI-2 receiver
> sub-device as well, which I don't see being created by the driver.
> 
> This is indeed a novel proposal. I have some concerns though.
> 
> The user doesn't have access to the configured media bus format (reflecting
> the format on the CSI-2 bus on receiver's side). It's thus difficult to
> figure out whether the V4L2 pixel format configured on the video node
> matches what the sensor outputs. Admittedly, we don't have a perfect
> solution to that whenever the DMA hardware supports multiple V4L2 pixel
> formats on a single media bus format. We might need to have a different
> solution for this one, should it be without that receiver sub-device.
> 
> Could you add the CSI-2 receiver sub-device, please?

Even though the name of the controller is *very* confusing, this isn't
a MIPI-CSI receiver, but a parallel one that supports RGB and BT656
buses.

> > +	csi->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
> 
> Could you make it IMMUTABLE and ENABLED? If there is no need to disable it,
> that is.

The link is already created with those flags, and as far as I know it
doesn't exist for the pads

> > +static int csi_release(struct file *file)
> > +{
> > +	struct sun4i_csi *csi = video_drvdata(file);
> > +	int ret;
> > +
> > +	mutex_lock(&csi->lock);
> > +
> > +	ret = v4l2_fh_release(file);
> 
> v4l2_fh_release() always returns 0. I guess it could be changed to return
> void. The reason it has int is that it could be used as the release
> callback as such.
> 
> > +	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
> > +	pm_runtime_put(csi->dev);
> > +
> > +	mutex_unlock(&csi->lock);
> > +
> > +	return ret;
> > +}

Do you want me to change the construct then?

Thanks!
Maxime
Ezequiel Garcia - Feb. 6, 2019, 10:59 p.m.
On Mon, 28 Jan 2019 at 11:53, Maxime Ripard <maxime.ripard@bootlin.com> wrote:
>
> The older CSI drivers have camera capture interface different from the one
> in the newer ones.
>
> This IP is pretty simple. Some variants (one controller out of two
> instances on some SoCs) have an ISP embedded, but there's no code that make
> use of it, so we ignored that part for now.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
> ---
>  MAINTAINERS                                         |   8 +-
>  drivers/media/platform/sunxi/Kconfig                |   1 +-
>  drivers/media/platform/sunxi/Makefile               |   1 +-
>  drivers/media/platform/sunxi/sun4i-csi/Kconfig      |  12 +-
>  drivers/media/platform/sunxi/sun4i-csi/Makefile     |   5 +-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c  | 261 ++++++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h  | 142 ++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c  | 435 +++++++++++++-
>  drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c | 305 +++++++++-
>  9 files changed, 1170 insertions(+)
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Kconfig
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/Makefile
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
>  create mode 100644 drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 32d444476a90..5f703ed9adb1 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1295,6 +1295,14 @@ F:       drivers/pinctrl/sunxi/
>  F:     drivers/soc/sunxi/
>  T:     git git://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git
>
> +Allwinner A10 CSI driver
> +M:     Maxime Ripard <maxime.ripard@bootlin.com>
> +L:     linux-media@vger.kernel.org
> +T:     git git://linuxtv.org/media_tree.git
> +S:     Maintained
> +F:     drivers/media/platform/sunxi/sun4i-csi/
> +F:     Documentation/devicetree/bindings/media/sun4i-csi.txt
> +
>  ARM/Amlogic Meson SoC CLOCK FRAMEWORK
>  M:     Neil Armstrong <narmstrong@baylibre.com>
>  M:     Jerome Brunet <jbrunet@baylibre.com>
> diff --git a/drivers/media/platform/sunxi/Kconfig b/drivers/media/platform/sunxi/Kconfig
> index 1b6e89cb78b2..71808e93ac2e 100644
> --- a/drivers/media/platform/sunxi/Kconfig
> +++ b/drivers/media/platform/sunxi/Kconfig
> @@ -1 +1,2 @@
> +source "drivers/media/platform/sunxi/sun4i-csi/Kconfig"
>  source "drivers/media/platform/sunxi/sun6i-csi/Kconfig"
> diff --git a/drivers/media/platform/sunxi/Makefile b/drivers/media/platform/sunxi/Makefile
> index 8d06f98500ee..a05127529006 100644
> --- a/drivers/media/platform/sunxi/Makefile
> +++ b/drivers/media/platform/sunxi/Makefile
> @@ -1 +1,2 @@
> +obj-y          += sun4i-csi/
>  obj-y          += sun6i-csi/
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/Kconfig b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
> new file mode 100644
> index 000000000000..841a6f4d9c99
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
> @@ -0,0 +1,12 @@
> +config VIDEO_SUN4I_CSI
> +       tristate "Allwinner A10 CMOS Sensor Interface Support"
> +       depends on VIDEO_DEV && VIDEO_V4L2 && HAS_DMA
> +       depends on ARCH_SUNXI || COMPILE_TEST
> +       select VIDEOBUF2_DMA_CONTIG
> +       select V4L2_FWNODE
> +       select V4L2_MEM2MEM_DEV
> +       help
> +         This is a V4L2 driver for the Allwinner A10 CSI
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called sun4i_csi.
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/Makefile b/drivers/media/platform/sunxi/sun4i-csi/Makefile
> new file mode 100644
> index 000000000000..7c790a57f5ee
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/Makefile
> @@ -0,0 +1,5 @@
> +sun4i-csi-y += sun4i_csi.o
> +sun4i-csi-y += sun4i_dma.o
> +sun4i-csi-y += sun4i_v4l2.o
> +
> +obj-$(CONFIG_VIDEO_SUN4I_CSI)  += sun4i-csi.o
> diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> new file mode 100644
> index 000000000000..9b58b42c0043
> --- /dev/null
> +++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
> @@ -0,0 +1,261 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright (C) 2016 NextThing Co
> + * Copyright (C) 2016-2018 Bootlin
> + *
> + * Author: Maxime Ripard <maxime.ripard@bootlin.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_graph.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <linux/videodev2.h>
> +
> +#include <media/v4l2-dev.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-fwnode.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/v4l2-mediabus.h>
> +
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include "sun4i_csi.h"
> +
> +static int csi_notify_bound(struct v4l2_async_notifier *notifier,
> +                           struct v4l2_subdev *subdev,
> +                           struct v4l2_async_subdev *asd)
> +{
> +       struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> +                                            notifier);
> +
> +       csi->src_subdev = subdev;
> +       csi->src_pad = media_entity_get_fwnode_pad(&subdev->entity,
> +                                                  subdev->fwnode,
> +                                                  MEDIA_PAD_FL_SOURCE);
> +       if (csi->src_pad < 0) {
> +               dev_err(csi->dev, "Couldn't find output pad for subdev %s\n",
> +                       subdev->name);
> +               return csi->src_pad;
> +       }
> +
> +       dev_dbg(csi->dev, "Bound %s pad: %d\n", subdev->name, csi->src_pad);
> +       return 0;
> +}
> +
> +static int csi_notify_complete(struct v4l2_async_notifier *notifier)
> +{
> +       struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> +                                            notifier);
> +       int ret;
> +
> +       ret = v4l2_device_register_subdev_nodes(&csi->v4l);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = sun4i_csi_v4l2_register(csi);
> +       if (ret < 0)
> +               return ret;
> +
> +       return media_create_pad_link(&csi->src_subdev->entity, csi->src_pad,
> +                                    &csi->vdev.entity, 0,
> +                                    MEDIA_LNK_FL_ENABLED |
> +                                    MEDIA_LNK_FL_IMMUTABLE);
> +}
> +
> +static const struct v4l2_async_notifier_operations csi_notify_ops = {
> +       .bound          = csi_notify_bound,
> +       .complete       = csi_notify_complete,
> +};
> +
> +static int sun4i_csi_async_parse(struct device *dev,
> +                                struct v4l2_fwnode_endpoint *vep,
> +                                struct v4l2_async_subdev *asd)
> +{
> +       struct sun4i_csi *csi = dev_get_drvdata(dev);
> +
> +       if (vep->base.port || vep->base.id)
> +               return -EINVAL;
> +
> +       if (vep->bus_type != V4L2_MBUS_PARALLEL)
> +               return -EINVAL;
> +
> +       csi->bus = vep->bus.parallel;
> +
> +       return 0;
> +}
> +
> +static int csi_probe(struct platform_device *pdev)
> +{
> +       struct sun4i_csi *csi;
> +       struct resource *res;
> +       int ret;
> +       int irq;
> +
> +       csi = devm_kzalloc(&pdev->dev, sizeof(*csi), GFP_KERNEL);
> +       if (!csi)
> +               return -ENOMEM;
> +       platform_set_drvdata(pdev, csi);
> +       csi->dev = &pdev->dev;
> +
> +       csi->mdev.dev = csi->dev;
> +       strscpy(csi->mdev.model, "Allwinner Video Capture Device",
> +               sizeof(csi->mdev.model));
> +       csi->mdev.hw_revision = 0;
> +       media_device_init(&csi->mdev);
> +       v4l2_async_notifier_init(&csi->notifier);
> +
> +       csi->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
> +       ret = media_entity_pads_init(&csi->vdev.entity, 1, &csi->pad);
> +       if (ret < 0)
> +               return 0;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       csi->regs = devm_ioremap_resource(&pdev->dev, res);
> +       if (IS_ERR(csi->regs))
> +               return PTR_ERR(csi->regs);
> +
> +       irq = platform_get_irq(pdev, 0);
> +       if (irq < 0)
> +               return irq;
> +
> +       csi->bus_clk = devm_clk_get(&pdev->dev, "bus");
> +       if (IS_ERR(csi->bus_clk)) {
> +               dev_err(&pdev->dev, "Couldn't get our bus clock\n");
> +               return PTR_ERR(csi->bus_clk);
> +       }
> +
> +       csi->isp_clk = devm_clk_get(&pdev->dev, "isp");
> +       if (IS_ERR(csi->isp_clk)) {
> +               dev_err(&pdev->dev, "Couldn't get our ISP clock\n");
> +               return PTR_ERR(csi->isp_clk);
> +       }
> +
> +       csi->mod_clk = devm_clk_get(&pdev->dev, "mod");
> +       if (IS_ERR(csi->mod_clk)) {
> +               dev_err(&pdev->dev, "Couldn't get our mod clock\n");
> +               return PTR_ERR(csi->mod_clk);
> +       }
> +
> +       csi->ram_clk = devm_clk_get(&pdev->dev, "ram");
> +       if (IS_ERR(csi->ram_clk)) {
> +               dev_err(&pdev->dev, "Couldn't get our ram clock\n");
> +               return PTR_ERR(csi->ram_clk);
> +       }
> +

Minor comment: perhaps you can take advantage
of the clock bulk API and simplify the clock management.

Regards,
Ezequiel
Maxime Ripard - Feb. 8, 2019, 8:19 p.m.
Hi Ezequiel,

On Wed, Feb 06, 2019 at 07:59:43PM -0300, Ezequiel Garcia wrote:
> > +       csi->isp_clk = devm_clk_get(&pdev->dev, "isp");
> > +       if (IS_ERR(csi->isp_clk)) {
> > +               dev_err(&pdev->dev, "Couldn't get our ISP clock\n");
> > +               return PTR_ERR(csi->isp_clk);
> > +       }
> > +
> > +       csi->mod_clk = devm_clk_get(&pdev->dev, "mod");
> > +       if (IS_ERR(csi->mod_clk)) {
> > +               dev_err(&pdev->dev, "Couldn't get our mod clock\n");
> > +               return PTR_ERR(csi->mod_clk);
> > +       }
> > +
> > +       csi->ram_clk = devm_clk_get(&pdev->dev, "ram");
> > +       if (IS_ERR(csi->ram_clk)) {
> > +               dev_err(&pdev->dev, "Couldn't get our ram clock\n");
> > +               return PTR_ERR(csi->ram_clk);
> > +       }
> > +
> 
> Minor comment: perhaps you can take advantage
> of the clock bulk API and simplify the clock management.

Our clocks have usually very different usages for each IP (the RAM
controls the DMA side of the IP, the mod one controls the "logic" part
of it, the bus one the register, etc.) so they needed to be handled
quite differently. I'd rather stick with the current API.

Thanks!
Maxime
Sakari Ailus - Feb. 8, 2019, 11:17 p.m.
Hi Maxime,

On Wed, Feb 06, 2019 at 10:16:05PM +0100, Maxime Ripard wrote:
> Hi Sakari,
> 
> Thanks for your review, I have a few questions though, and the rest
> will be addressed in the next version.
> 
> On Tue, Jan 29, 2019 at 02:39:49PM +0200, Sakari Ailus wrote:
> > > +static int csi_notify_complete(struct v4l2_async_notifier *notifier)
> > > +{
> > > +	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
> > > +					     notifier);
> > > +	int ret;
> > > +
> > > +	ret = v4l2_device_register_subdev_nodes(&csi->v4l);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	ret = sun4i_csi_v4l2_register(csi);
> > > +	if (ret < 0)
> > > +		return ret;
> > > +
> > > +	return media_create_pad_link(&csi->src_subdev->entity, csi->src_pad,
> > > +				     &csi->vdev.entity, 0,
> > > +				     MEDIA_LNK_FL_ENABLED |
> > > +				     MEDIA_LNK_FL_IMMUTABLE);
> > 
> > This appears to create a link directly from the sensor entity to the video
> > device entity. Is that intentional? I'd expect to see a CSI-2 receiver
> > sub-device as well, which I don't see being created by the driver.
> > 
> > This is indeed a novel proposal. I have some concerns though.
> > 
> > The user doesn't have access to the configured media bus format (reflecting
> > the format on the CSI-2 bus on receiver's side). It's thus difficult to
> > figure out whether the V4L2 pixel format configured on the video node
> > matches what the sensor outputs. Admittedly, we don't have a perfect
> > solution to that whenever the DMA hardware supports multiple V4L2 pixel
> > formats on a single media bus format. We might need to have a different
> > solution for this one, should it be without that receiver sub-device.
> > 
> > Could you add the CSI-2 receiver sub-device, please?
> 
> Even though the name of the controller is *very* confusing, this isn't
> a MIPI-CSI receiver, but a parallel one that supports RGB and BT656
> buses.

Right.

> 
> > > +	csi->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
> > 
> > Could you make it IMMUTABLE and ENABLED? If there is no need to disable it,
> > that is.
> 
> The link is already created with those flags, and as far as I know it
> doesn't exist for the pads

Oops. And it wasn't even late when I reviewed the patch. :-P Please ignore
the comment --- I agree on the pad flags and the link flags (some lines up)
appear fine, too.

> 
> > > +static int csi_release(struct file *file)
> > > +{
> > > +	struct sun4i_csi *csi = video_drvdata(file);
> > > +	int ret;
> > > +
> > > +	mutex_lock(&csi->lock);
> > > +
> > > +	ret = v4l2_fh_release(file);
> > 
> > v4l2_fh_release() always returns 0. I guess it could be changed to return
> > void. The reason it has int is that it could be used as the release
> > callback as such.
> > 
> > > +	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
> > > +	pm_runtime_put(csi->dev);
> > > +
> > > +	mutex_unlock(&csi->lock);
> > > +
> > > +	return ret;
> > > +}
> 
> Do you want me to change the construct then?

Please.

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 32d444476a90..5f703ed9adb1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1295,6 +1295,14 @@  F:	drivers/pinctrl/sunxi/
 F:	drivers/soc/sunxi/
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux.git
 
+Allwinner A10 CSI driver
+M:	Maxime Ripard <maxime.ripard@bootlin.com>
+L:	linux-media@vger.kernel.org
+T:	git git://linuxtv.org/media_tree.git
+S:	Maintained
+F:	drivers/media/platform/sunxi/sun4i-csi/
+F:	Documentation/devicetree/bindings/media/sun4i-csi.txt
+
 ARM/Amlogic Meson SoC CLOCK FRAMEWORK
 M:	Neil Armstrong <narmstrong@baylibre.com>
 M:	Jerome Brunet <jbrunet@baylibre.com>
diff --git a/drivers/media/platform/sunxi/Kconfig b/drivers/media/platform/sunxi/Kconfig
index 1b6e89cb78b2..71808e93ac2e 100644
--- a/drivers/media/platform/sunxi/Kconfig
+++ b/drivers/media/platform/sunxi/Kconfig
@@ -1 +1,2 @@ 
+source "drivers/media/platform/sunxi/sun4i-csi/Kconfig"
 source "drivers/media/platform/sunxi/sun6i-csi/Kconfig"
diff --git a/drivers/media/platform/sunxi/Makefile b/drivers/media/platform/sunxi/Makefile
index 8d06f98500ee..a05127529006 100644
--- a/drivers/media/platform/sunxi/Makefile
+++ b/drivers/media/platform/sunxi/Makefile
@@ -1 +1,2 @@ 
+obj-y		+= sun4i-csi/
 obj-y		+= sun6i-csi/
diff --git a/drivers/media/platform/sunxi/sun4i-csi/Kconfig b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
new file mode 100644
index 000000000000..841a6f4d9c99
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/Kconfig
@@ -0,0 +1,12 @@ 
+config VIDEO_SUN4I_CSI
+	tristate "Allwinner A10 CMOS Sensor Interface Support"
+	depends on VIDEO_DEV && VIDEO_V4L2 && HAS_DMA
+	depends on ARCH_SUNXI || COMPILE_TEST
+	select VIDEOBUF2_DMA_CONTIG
+	select V4L2_FWNODE
+	select V4L2_MEM2MEM_DEV
+	help
+	  This is a V4L2 driver for the Allwinner A10 CSI
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called sun4i_csi.
diff --git a/drivers/media/platform/sunxi/sun4i-csi/Makefile b/drivers/media/platform/sunxi/sun4i-csi/Makefile
new file mode 100644
index 000000000000..7c790a57f5ee
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/Makefile
@@ -0,0 +1,5 @@ 
+sun4i-csi-y += sun4i_csi.o
+sun4i-csi-y += sun4i_dma.o
+sun4i-csi-y += sun4i_v4l2.o
+
+obj-$(CONFIG_VIDEO_SUN4I_CSI)	+= sun4i-csi.o
diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
new file mode 100644
index 000000000000..9b58b42c0043
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c
@@ -0,0 +1,261 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 NextThing Co
+ * Copyright (C) 2016-2018 Bootlin
+ *
+ * Author: Maxime Ripard <maxime.ripard@bootlin.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/reset.h>
+#include <linux/videodev2.h>
+
+#include <media/v4l2-dev.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-mediabus.h>
+
+#include <media/videobuf2-core.h>
+#include <media/videobuf2-dma-contig.h>
+
+#include "sun4i_csi.h"
+
+static int csi_notify_bound(struct v4l2_async_notifier *notifier,
+			    struct v4l2_subdev *subdev,
+			    struct v4l2_async_subdev *asd)
+{
+	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
+					     notifier);
+
+	csi->src_subdev = subdev;
+	csi->src_pad = media_entity_get_fwnode_pad(&subdev->entity,
+						   subdev->fwnode,
+						   MEDIA_PAD_FL_SOURCE);
+	if (csi->src_pad < 0) {
+		dev_err(csi->dev, "Couldn't find output pad for subdev %s\n",
+			subdev->name);
+		return csi->src_pad;
+	}
+
+	dev_dbg(csi->dev, "Bound %s pad: %d\n", subdev->name, csi->src_pad);
+	return 0;
+}
+
+static int csi_notify_complete(struct v4l2_async_notifier *notifier)
+{
+	struct sun4i_csi *csi = container_of(notifier, struct sun4i_csi,
+					     notifier);
+	int ret;
+
+	ret = v4l2_device_register_subdev_nodes(&csi->v4l);
+	if (ret < 0)
+		return ret;
+
+	ret = sun4i_csi_v4l2_register(csi);
+	if (ret < 0)
+		return ret;
+
+	return media_create_pad_link(&csi->src_subdev->entity, csi->src_pad,
+				     &csi->vdev.entity, 0,
+				     MEDIA_LNK_FL_ENABLED |
+				     MEDIA_LNK_FL_IMMUTABLE);
+}
+
+static const struct v4l2_async_notifier_operations csi_notify_ops = {
+	.bound		= csi_notify_bound,
+	.complete	= csi_notify_complete,
+};
+
+static int sun4i_csi_async_parse(struct device *dev,
+				 struct v4l2_fwnode_endpoint *vep,
+				 struct v4l2_async_subdev *asd)
+{
+	struct sun4i_csi *csi = dev_get_drvdata(dev);
+
+	if (vep->base.port || vep->base.id)
+		return -EINVAL;
+
+	if (vep->bus_type != V4L2_MBUS_PARALLEL)
+		return -EINVAL;
+
+	csi->bus = vep->bus.parallel;
+
+	return 0;
+}
+
+static int csi_probe(struct platform_device *pdev)
+{
+	struct sun4i_csi *csi;
+	struct resource *res;
+	int ret;
+	int irq;
+
+	csi = devm_kzalloc(&pdev->dev, sizeof(*csi), GFP_KERNEL);
+	if (!csi)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, csi);
+	csi->dev = &pdev->dev;
+
+	csi->mdev.dev = csi->dev;
+	strscpy(csi->mdev.model, "Allwinner Video Capture Device",
+		sizeof(csi->mdev.model));
+	csi->mdev.hw_revision = 0;
+	media_device_init(&csi->mdev);
+	v4l2_async_notifier_init(&csi->notifier);
+
+	csi->pad.flags = MEDIA_PAD_FL_SINK | MEDIA_PAD_FL_MUST_CONNECT;
+	ret = media_entity_pads_init(&csi->vdev.entity, 1, &csi->pad);
+	if (ret < 0)
+		return 0;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	csi->regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(csi->regs))
+		return PTR_ERR(csi->regs);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	csi->bus_clk = devm_clk_get(&pdev->dev, "bus");
+	if (IS_ERR(csi->bus_clk)) {
+		dev_err(&pdev->dev, "Couldn't get our bus clock\n");
+		return PTR_ERR(csi->bus_clk);
+	}
+
+	csi->isp_clk = devm_clk_get(&pdev->dev, "isp");
+	if (IS_ERR(csi->isp_clk)) {
+		dev_err(&pdev->dev, "Couldn't get our ISP clock\n");
+		return PTR_ERR(csi->isp_clk);
+	}
+
+	csi->mod_clk = devm_clk_get(&pdev->dev, "mod");
+	if (IS_ERR(csi->mod_clk)) {
+		dev_err(&pdev->dev, "Couldn't get our mod clock\n");
+		return PTR_ERR(csi->mod_clk);
+	}
+
+	csi->ram_clk = devm_clk_get(&pdev->dev, "ram");
+	if (IS_ERR(csi->ram_clk)) {
+		dev_err(&pdev->dev, "Couldn't get our ram clock\n");
+		return PTR_ERR(csi->ram_clk);
+	}
+
+	csi->rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(csi->rst)) {
+		dev_err(&pdev->dev, "Couldn't get our reset line\n");
+		return PTR_ERR(csi->rst);
+	}
+
+	ret = sun4i_csi_dma_register(csi, irq);
+	if (ret)
+		return ret;
+
+	csi->v4l.mdev = &csi->mdev;
+
+	ret = media_device_register(&csi->mdev);
+	if (ret)
+		goto err_unregister_dma;
+
+	ret = v4l2_async_notifier_parse_fwnode_endpoints(csi->dev,
+							 &csi->notifier,
+							 sizeof(struct v4l2_async_subdev),
+							 sun4i_csi_async_parse);
+	if (ret)
+		goto err_unregister_media;
+	csi->notifier.ops = &csi_notify_ops;
+
+	ret = v4l2_async_notifier_register(&csi->v4l, &csi->notifier);
+	if (ret) {
+		dev_err(csi->dev,
+			"Couldn't register our v4l2-async notifier\n");
+		goto err_free_notifier;
+	}
+
+	pm_runtime_enable(&pdev->dev);
+
+	return 0;
+
+err_free_notifier:
+	v4l2_async_notifier_cleanup(&csi->notifier);
+
+err_unregister_media:
+	media_device_unregister(&csi->mdev);
+
+err_unregister_dma:
+	sun4i_csi_dma_unregister(csi);
+	return ret;
+}
+
+static int csi_remove(struct platform_device *pdev)
+{
+	struct sun4i_csi *csi = platform_get_drvdata(pdev);
+
+	v4l2_async_notifier_unregister(&csi->notifier);
+	v4l2_async_notifier_cleanup(&csi->notifier);
+	media_device_unregister(&csi->mdev);
+	sun4i_csi_dma_unregister(csi);
+
+	return 0;
+}
+
+static const struct of_device_id csi_of_match[] = {
+	{ .compatible = "allwinner,sun4i-a10-csi0" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, csi_of_match);
+
+static int csi_runtime_resume(struct device *dev)
+{
+	struct sun4i_csi *csi = dev_get_drvdata(dev);
+
+	reset_control_deassert(csi->rst);
+	clk_prepare_enable(csi->bus_clk);
+	clk_prepare_enable(csi->ram_clk);
+	clk_set_rate(csi->isp_clk, 80000000);
+	clk_prepare_enable(csi->isp_clk);
+	clk_set_rate(csi->mod_clk, 24000000);
+	clk_prepare_enable(csi->mod_clk);
+
+	writel(1, csi->regs + CSI_EN_REG);
+
+	return 0;
+}
+
+static int csi_runtime_suspend(struct device *dev)
+{
+	struct sun4i_csi *csi = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(csi->mod_clk);
+	clk_disable_unprepare(csi->isp_clk);
+	clk_disable_unprepare(csi->ram_clk);
+	clk_disable_unprepare(csi->bus_clk);
+
+	reset_control_assert(csi->rst);
+
+	return 0;
+}
+
+static const struct dev_pm_ops csi_pm_ops = {
+	.runtime_resume		= csi_runtime_resume,
+	.runtime_suspend	= csi_runtime_suspend,
+};
+
+static struct platform_driver csi_driver = {
+	.probe	= csi_probe,
+	.remove	= csi_remove,
+	.driver	= {
+		.name		= "sun4i-csi",
+		.of_match_table	= csi_of_match,
+		.pm		= &csi_pm_ops,
+	},
+};
+module_platform_driver(csi_driver);
diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
new file mode 100644
index 000000000000..563368c64567
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.h
@@ -0,0 +1,142 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2016 NextThing Co
+ * Copyright (C) 2016-2018 Bootlin
+ *
+ * Author: Maxime Ripard <maxime.ripard@bootlin.com>
+ */
+
+#ifndef _SUN4I_CSI_H_
+#define _SUN4I_CSI_H_
+
+#include <media/media-device.h>
+#include <media/v4l2-async.h>
+#include <media/v4l2-dev.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-fwnode.h>
+#include <media/videobuf2-core.h>
+
+#define CSI_EN_REG			0x00
+
+#define CSI_CFG_REG			0x04
+#define CSI_CFG_INPUT_FMT(fmt)			((fmt) << 20)
+#define CSI_CFG_OUTPUT_FMT(fmt)			((fmt) << 16)
+#define CSI_CFG_YUV_DATA_SEQ(seq)		((seq) << 8)
+#define CSI_CFG_VSYNC_POL(pol)			((pol) << 2)
+#define CSI_CFG_HSYNC_POL(pol)			((pol) << 1)
+#define CSI_CFG_PCLK_POL(pol)			((pol) << 0)
+
+#define CSI_CPT_CTRL_REG		0x08
+#define CSI_CPT_CTRL_VIDEO_START		BIT(1)
+#define CSI_CPT_CTRL_IMAGE_START		BIT(0)
+
+#define CSI_BUF_ADDR_REG(fifo, buf)	(0x10 + (0x8 * (fifo)) + (0x4 * (buf)))
+
+#define CSI_BUF_CTRL_REG		0x28
+#define CSI_BUF_CTRL_DBN			BIT(2)
+#define CSI_BUF_CTRL_DBS			BIT(1)
+#define CSI_BUF_CTRL_DBE			BIT(0)
+
+#define CSI_INT_EN_REG			0x30
+#define CSI_INT_FRM_DONE			BIT(1)
+#define CSI_INT_CPT_DONE			BIT(0)
+
+#define CSI_INT_STA_REG			0x34
+
+#define CSI_WIN_CTRL_W_REG		0x40
+#define CSI_WIN_CTRL_W_ACTIVE(w)		((w) << 16)
+
+#define CSI_WIN_CTRL_H_REG		0x44
+#define CSI_WIN_CTRL_H_ACTIVE(h)		((h) << 16)
+
+#define CSI_BUF_LEN_REG			0x48
+
+#define CSI_MAX_BUFFER	2
+
+enum csi_input {
+	CSI_INPUT_RAW	= 0,
+	CSI_INPUT_BT656	= 2,
+	CSI_INPUT_YUV	= 3,
+};
+
+enum csi_output_raw {
+	CSI_OUTPUT_RAW_PASSTHROUGH = 0,
+};
+
+enum csi_output_yuv {
+	CSI_OUTPUT_YUV_422_PLANAR	= 0,
+	CSI_OUTPUT_YUV_420_PLANAR	= 1,
+	CSI_OUTPUT_YUV_422_UV		= 4,
+	CSI_OUTPUT_YUV_420_UV		= 5,
+	CSI_OUTPUT_YUV_422_MACRO	= 8,
+	CSI_OUTPUT_YUV_420_MACRO	= 9,
+};
+
+enum csi_yuv_data_seq {
+	CSI_YUV_DATA_SEQ_YUYV	= 0,
+	CSI_YUV_DATA_SEQ_YVYU	= 1,
+	CSI_YUV_DATA_SEQ_UYVY	= 2,
+	CSI_YUV_DATA_SEQ_VYUY	= 3,
+};
+
+struct sun4i_csi_format {
+	u32			mbus;
+	u32			fourcc;
+	enum csi_input		input;
+	u32			output;
+	unsigned int		num_planes;
+	u8			bpp[3];
+	unsigned int		hsub;
+	unsigned int		vsub;
+};
+
+struct sun4i_csi {
+	/* Device resources */
+	struct device			*dev;
+
+	void __iomem			*regs;
+	struct clk			*bus_clk;
+	struct clk			*isp_clk;
+	struct clk			*mod_clk;
+	struct clk			*ram_clk;
+	struct reset_control		*rst;
+
+	const struct sun4i_csi_format	*p_fmt;
+	struct v4l2_pix_format_mplane	v_fmt;
+
+	struct vb2_v4l2_buffer		*current_buf[CSI_MAX_BUFFER];
+
+	struct {
+		size_t			size;
+		void			*vaddr;
+		dma_addr_t		paddr;
+	} scratch;
+
+	struct media_device		mdev;
+	struct media_pad		pad;
+
+	struct v4l2_fwnode_bus_parallel	bus;
+
+	/* V4L2 Async variables */
+	struct v4l2_async_notifier	notifier;
+	struct v4l2_subdev		*src_subdev;
+	unsigned int			src_pad;
+
+	/* V4L2 variables */
+	struct mutex			lock;
+	struct v4l2_device		v4l;
+	struct video_device		vdev;
+
+	/* Videobuf2 */
+	struct vb2_queue		queue;
+	struct list_head		buf_list;
+	spinlock_t			qlock;
+	unsigned int			sequence;
+};
+
+int sun4i_csi_dma_register(struct sun4i_csi *csi, int irq);
+void sun4i_csi_dma_unregister(struct sun4i_csi *csi);
+
+int sun4i_csi_v4l2_register(struct sun4i_csi *csi);
+
+#endif /* _SUN4I_CSI_H_ */
diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
new file mode 100644
index 000000000000..f238709ff50a
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_dma.c
@@ -0,0 +1,435 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 NextThing Co
+ * Copyright (C) 2016-2019 Bootlin
+ *
+ * Author: Maxime Ripard <maxime.ripard@bootlin.com>
+ */
+
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <media/videobuf2-dma-contig.h>
+#include <media/videobuf2-v4l2.h>
+
+#include "sun4i_csi.h"
+
+struct csi_buffer {
+	struct vb2_v4l2_buffer	vb;
+	struct list_head	list;
+};
+
+static inline struct csi_buffer *vb2_v4l2_to_csi_buffer(const struct vb2_v4l2_buffer *p)
+{
+	return container_of(p, struct csi_buffer, vb);
+}
+
+static inline struct csi_buffer *vb2_to_csi_buffer(const struct vb2_buffer *p)
+{
+	return vb2_v4l2_to_csi_buffer(to_vb2_v4l2_buffer(p));
+}
+
+static void csi_capture_start(struct sun4i_csi *csi)
+{
+	writel(CSI_CPT_CTRL_VIDEO_START, csi->regs + CSI_CPT_CTRL_REG);
+}
+
+static void csi_capture_stop(struct sun4i_csi *csi)
+{
+	writel(0, csi->regs + CSI_CPT_CTRL_REG);
+}
+
+static int csi_queue_setup(struct vb2_queue *vq,
+			   unsigned int *nbuffers,
+			   unsigned int *nplanes,
+			   unsigned int sizes[],
+			   struct device *alloc_devs[])
+
+{
+	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
+	unsigned int num_planes = csi->p_fmt->num_planes;
+	unsigned int i;
+
+	if (*nplanes) {
+                if (*nplanes != num_planes)
+                        return -EINVAL;
+
+                for (i = 0; i < num_planes; i++)
+                        if (sizes[i] < csi->v_fmt.plane_fmt[i].sizeimage)
+                                return -EINVAL;
+                return 0;
+        }
+
+	*nplanes = num_planes;
+	for (i = 0; i < num_planes; i++)
+		sizes[i] = csi->v_fmt.plane_fmt[i].sizeimage;
+
+	return 0;
+};
+
+static int csi_buffer_prepare(struct vb2_buffer *vb)
+{
+	struct sun4i_csi *csi = vb2_get_drv_priv(vb->vb2_queue);
+	unsigned int i;
+
+	for (i = 0; i < csi->p_fmt->num_planes; i++) {
+		unsigned long size = csi->v_fmt.plane_fmt[i].sizeimage;
+
+		if (vb2_plane_size(vb, i) < size) {
+			dev_err(csi->dev, "buffer too small (%lu < %lu)\n",
+				vb2_plane_size(vb, i), size);
+			return -EINVAL;
+		}
+
+		vb2_set_plane_payload(vb, i, size);
+	}
+
+	return 0;
+}
+
+static int csi_setup_scratch_buffer(struct sun4i_csi *csi, unsigned int slot)
+{
+	dma_addr_t addr = csi->scratch.paddr;
+	unsigned int plane;
+
+	dev_dbg(csi->dev,
+		"No more available buffer, using the scratch buffer\n");
+
+	for (plane = 0; plane < csi->p_fmt->num_planes; plane++) {
+		writel(addr, csi->regs + CSI_BUF_ADDR_REG(plane, slot));
+		addr += csi->v_fmt.plane_fmt[plane].sizeimage;
+	}
+
+	csi->current_buf[slot] = NULL;
+	return 0;
+}
+
+static int csi_buffer_fill_slot(struct sun4i_csi *csi, unsigned int slot)
+{
+	struct csi_buffer *c_buf;
+	struct vb2_v4l2_buffer *v_buf;
+	unsigned int plane;
+
+	/*
+	 * We should never end up in a situation where we overwrite an
+	 * already filled slot.
+	 */
+	if (WARN_ON(csi->current_buf[slot]))
+		return -EINVAL;
+
+	if (list_empty(&csi->buf_list))
+		return csi_setup_scratch_buffer(csi, slot);
+
+	c_buf = list_first_entry(&csi->buf_list, struct csi_buffer, list);
+	list_del_init(&c_buf->list);
+
+	v_buf = &c_buf->vb;
+	csi->current_buf[slot] = v_buf;
+
+	for (plane = 0; plane < csi->p_fmt->num_planes; plane++) {
+		dma_addr_t buf_addr;
+
+		buf_addr = vb2_dma_contig_plane_dma_addr(&v_buf->vb2_buf,
+							 plane);
+		writel(buf_addr, csi->regs + CSI_BUF_ADDR_REG(plane, slot));
+	}
+
+	return 0;
+}
+
+static int csi_buffer_fill_all(struct sun4i_csi *csi)
+{
+	unsigned int slot;
+	int ret;
+
+	for (slot = 0; slot < CSI_MAX_BUFFER; slot++) {
+		ret = csi_buffer_fill_slot(csi, slot);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static void csi_buffer_mark_done(struct sun4i_csi *csi,
+				 unsigned int slot,
+				 unsigned int sequence)
+{
+	struct vb2_v4l2_buffer *v_buf;
+
+	if (!csi->current_buf[slot]) {
+		dev_dbg(csi->dev, "Scratch buffer was used, ignoring..\n");
+		return;
+	}
+
+	v_buf = csi->current_buf[slot];
+	v_buf->field = csi->v_fmt.field;
+	v_buf->sequence = sequence;
+	v_buf->vb2_buf.timestamp = ktime_get_ns();
+	vb2_buffer_done(&v_buf->vb2_buf, VB2_BUF_STATE_DONE);
+
+	csi->current_buf[slot] = NULL;
+}
+
+static int csi_buffer_flip(struct sun4i_csi *csi, unsigned int sequence)
+{
+	u32 reg = readl(csi->regs + CSI_BUF_CTRL_REG);
+	unsigned int curr, next;
+
+	/* Our next buffer is not the current buffer */
+	curr = !!(reg & CSI_BUF_CTRL_DBS);
+	next = !curr;
+
+	/* Report the previous buffer as done */
+	csi_buffer_mark_done(csi, next, sequence);
+
+	/* Put a new buffer in there */
+	return csi_buffer_fill_slot(csi, next);
+}
+
+static void csi_buffer_queue(struct vb2_buffer *vb)
+{
+	struct sun4i_csi *csi = vb2_get_drv_priv(vb->vb2_queue);
+	struct csi_buffer *buf = vb2_to_csi_buffer(vb);
+	unsigned long flags;
+
+	spin_lock_irqsave(&csi->qlock, flags);
+	list_add_tail(&buf->list, &csi->buf_list);
+	spin_unlock_irqrestore(&csi->qlock, flags);
+}
+
+static void return_all_buffers(struct sun4i_csi *csi,
+			       enum vb2_buffer_state state)
+{
+	struct csi_buffer *buf, *node;
+	unsigned int slot;
+
+	list_for_each_entry_safe(buf, node, &csi->buf_list, list) {
+		vb2_buffer_done(&buf->vb.vb2_buf, state);
+		list_del(&buf->list);
+	}
+
+	for (slot = 0; slot < CSI_MAX_BUFFER; slot++) {
+		struct vb2_v4l2_buffer *v_buf = csi->current_buf[slot];
+
+		if (!v_buf)
+			continue;
+
+		vb2_buffer_done(&v_buf->vb2_buf, state);
+		csi->current_buf[slot] = NULL;
+	}
+}
+
+static int csi_start_streaming(struct vb2_queue *vq, unsigned int count)
+{
+	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
+	struct v4l2_fwnode_bus_parallel *bus = &csi->bus;
+	unsigned long hsync_pol, pclk_pol, vsync_pol;
+	unsigned long flags;
+	unsigned int i;
+	int ret;
+
+	dev_dbg(csi->dev, "Starting capture\n");
+
+	csi->sequence = 0;
+
+	/*
+	 * We need a scratch buffer in case where we'll not have any
+	 * more buffer queued so that we don't error out. One of those
+	 * cases is when you end up at the last frame to capture, you
+	 * don't havea any buffer queued any more, and yet it doesn't
+	 * really matter since you'll never reach the next buffer.
+	 *
+	 * Since we support the multi-planar API, we need to have a
+	 * buffer for each plane. Allocating a single one large enough
+	 * to hold all the buffers is simpler, so let's go for that.
+	 */
+	csi->scratch.size = 0;
+	for (i = 0; i < csi->p_fmt->num_planes; i++)
+		csi->scratch.size += csi->v_fmt.plane_fmt[i].sizeimage;
+
+	csi->scratch.vaddr = dma_alloc_coherent(csi->dev,
+						csi->scratch.size,
+						&csi->scratch.paddr,
+						GFP_KERNEL);
+	if (!csi->scratch.vaddr) {
+		dev_err(csi->dev, "Failed to allocate scratch buffer\n");
+		ret = -ENOMEM;
+		goto clear_dma_queue;
+	}
+
+	ret = media_pipeline_start(&csi->vdev.entity, &csi->vdev.pipe);
+	if (ret < 0)
+		goto free_scratch_buffer;
+
+	spin_lock_irqsave(&csi->qlock, flags);
+
+	/* Setup timings */
+	writel(CSI_WIN_CTRL_W_ACTIVE(csi->v_fmt.width * 2),
+	       csi->regs + CSI_WIN_CTRL_W_REG);
+	writel(CSI_WIN_CTRL_H_ACTIVE(csi->v_fmt.height),
+	       csi->regs + CSI_WIN_CTRL_H_REG);
+
+	hsync_pol = !!(bus->flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH);
+	pclk_pol = !!(bus->flags & V4L2_MBUS_DATA_ACTIVE_HIGH);
+	vsync_pol = !!(bus->flags & V4L2_MBUS_VSYNC_ACTIVE_HIGH);
+	writel(CSI_CFG_INPUT_FMT(csi->p_fmt->input) |
+	       CSI_CFG_OUTPUT_FMT(csi->p_fmt->output) |
+	       CSI_CFG_VSYNC_POL(vsync_pol) |
+	       CSI_CFG_HSYNC_POL(hsync_pol) |
+	       CSI_CFG_PCLK_POL(pclk_pol),
+	       csi->regs + CSI_CFG_REG);
+
+	/* Setup buffer length */
+	writel(csi->v_fmt.plane_fmt[0].bytesperline,
+	       csi->regs + CSI_BUF_LEN_REG);
+
+	/* Prepare our buffers in hardware */
+	ret = csi_buffer_fill_all(csi);
+	if (ret) {
+		spin_unlock_irqrestore(&csi->qlock, flags);
+		goto disable_pipeline;
+	}
+
+	/* Enable double buffering */
+	writel(CSI_BUF_CTRL_DBE, csi->regs + CSI_BUF_CTRL_REG);
+
+	/* Clear the pending interrupts */
+	writel(CSI_INT_FRM_DONE, csi->regs + 0x34);
+
+	/* Enable frame done interrupt */
+	writel(CSI_INT_FRM_DONE, csi->regs + CSI_INT_EN_REG);
+
+	csi_capture_start(csi);
+
+	spin_unlock_irqrestore(&csi->qlock, flags);
+
+	ret = v4l2_subdev_call(csi->src_subdev, video, s_stream, 1);
+	if (ret < 0 && ret != -ENOIOCTLCMD)
+		goto disable_pipeline;
+
+	return 0;
+
+disable_pipeline:
+	media_pipeline_stop(&csi->vdev.entity);
+
+free_scratch_buffer:
+	dma_free_coherent(csi->dev, csi->scratch.size, csi->scratch.vaddr,
+			  csi->scratch.paddr);
+
+clear_dma_queue:
+	spin_lock_irqsave(&csi->qlock, flags);
+	return_all_buffers(csi, VB2_BUF_STATE_QUEUED);
+	spin_unlock_irqrestore(&csi->qlock, flags);
+
+	return ret;
+}
+
+static void csi_stop_streaming(struct vb2_queue *vq)
+{
+	struct sun4i_csi *csi = vb2_get_drv_priv(vq);
+	unsigned long flags;
+
+	dev_dbg(csi->dev, "Stopping capture\n");
+
+	v4l2_subdev_call(csi->src_subdev, video, s_stream, 0);
+	csi_capture_stop(csi);
+
+	/* Release all active buffers */
+	spin_lock_irqsave(&csi->qlock, flags);
+	return_all_buffers(csi, VB2_BUF_STATE_ERROR);
+	spin_unlock_irqrestore(&csi->qlock, flags);
+
+	media_pipeline_stop(&csi->vdev.entity);
+
+	dma_free_coherent(csi->dev, csi->scratch.size, csi->scratch.vaddr,
+			  csi->scratch.paddr);
+}
+
+static struct vb2_ops csi_qops = {
+	.queue_setup		= csi_queue_setup,
+	.buf_prepare		= csi_buffer_prepare,
+	.buf_queue		= csi_buffer_queue,
+	.start_streaming	= csi_start_streaming,
+	.stop_streaming		= csi_stop_streaming,
+	.wait_prepare		= vb2_ops_wait_prepare,
+	.wait_finish		= vb2_ops_wait_finish,
+};
+
+static irqreturn_t csi_irq(int irq, void *data)
+{
+	struct sun4i_csi *csi = data;
+	u32 reg;
+
+	reg = readl(csi->regs + CSI_INT_STA_REG);
+
+	/* Acknowledge the interrupts */
+	writel(reg, csi->regs + CSI_INT_STA_REG);
+
+	if (!(reg & CSI_INT_FRM_DONE))
+		goto out;
+
+	spin_lock(&csi->qlock);
+	if (csi_buffer_flip(csi, csi->sequence++)) {
+		dev_warn(csi->dev, "%s: Flip failed\n", __func__);
+		csi_capture_stop(csi);
+	}
+	spin_unlock(&csi->qlock);
+
+out:
+	return IRQ_HANDLED;
+}
+
+int sun4i_csi_dma_register(struct sun4i_csi *csi, int irq)
+{
+	struct vb2_queue *q = &csi->queue;
+	int ret;
+	int i;
+
+	ret = v4l2_device_register(csi->dev, &csi->v4l);
+	if (ret) {
+		dev_err(csi->dev, "Couldn't register the v4l2 device\n");
+		return ret;
+	}
+
+	spin_lock_init(&csi->qlock);
+	mutex_init(&csi->lock);
+
+	INIT_LIST_HEAD(&csi->buf_list);
+	for (i = 0; i < CSI_MAX_BUFFER; i++)
+		csi->current_buf[i] = NULL;
+
+	q->min_buffers_needed = 3;
+	q->type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
+	q->io_modes = VB2_MMAP;
+	q->lock = &csi->lock;
+	q->drv_priv = csi;
+	q->buf_struct_size = sizeof(struct csi_buffer);
+	q->ops = &csi_qops;
+	q->mem_ops = &vb2_dma_contig_memops;
+	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	q->dev = csi->dev;
+
+	ret = vb2_queue_init(q);
+	if (ret < 0) {
+		dev_err(csi->dev, "failed to initialize VB2 queue\n");
+		return ret;
+	}
+
+	ret = devm_request_irq(csi->dev, irq, csi_irq, 0,
+			       dev_name(csi->dev), csi);
+	if (ret) {
+		dev_err(csi->dev, "Couldn't register our interrupt\n");
+		vb2_queue_release(q);
+		return ret;
+	}
+
+	return 0;
+}
+
+void sun4i_csi_dma_unregister(struct sun4i_csi *csi)
+{
+	v4l2_device_unregister(&csi->v4l);
+}
+
diff --git a/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c b/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
new file mode 100644
index 000000000000..1be91f4d498e
--- /dev/null
+++ b/drivers/media/platform/sunxi/sun4i-csi/sun4i_v4l2.c
@@ -0,0 +1,305 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2016 NextThing Co
+ * Copyright (C) 2016-2019 Bootlin
+ *
+ * Author: Maxime Ripard <maxime.ripard@bootlin.com>
+ */
+
+#include <linux/device.h>
+#include <linux/pm_runtime.h>
+
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-mc.h>
+#include <media/videobuf2-v4l2.h>
+
+#include "sun4i_csi.h"
+
+#define CSI_DEFAULT_FORMAT	V4L2_PIX_FMT_YUV420M
+#define CSI_DEFAULT_WIDTH	640
+#define CSI_DEFAULT_HEIGHT	480
+
+#define CSI_MAX_HEIGHT		8192U
+#define CSI_MAX_WIDTH		8192U
+
+static const struct sun4i_csi_format csi_formats[] = {
+	/* YUV422 inputs */
+	{
+		.mbus		= MEDIA_BUS_FMT_YUYV8_2X8,
+		.fourcc		= V4L2_PIX_FMT_YUV420M,
+		.input		= CSI_INPUT_YUV,
+		.output		= CSI_OUTPUT_YUV_420_PLANAR,
+		.num_planes	= 3,
+		.bpp		= { 8, 8, 8 },
+		.hsub		= 2,
+		.vsub		= 2,
+	},
+};
+
+static const struct sun4i_csi_format *
+csi_get_format_by_fourcc(struct sun4i_csi *csi, u32 fourcc)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(csi_formats); i++)
+		if (csi_formats[i].fourcc == fourcc)
+			return &csi_formats[i];
+
+	return NULL;
+}
+
+static int csi_querycap(struct file *file, void *priv,
+			struct v4l2_capability *cap)
+{
+	struct sun4i_csi *csi = video_drvdata(file);
+
+	strscpy(cap->driver, KBUILD_MODNAME, sizeof(cap->driver));
+	strscpy(cap->card, "sun4i-csi", sizeof(cap->card));
+	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
+		 dev_name(csi->dev));
+
+	return 0;
+}
+
+static int csi_enum_input(struct file *file, void *priv,
+			  struct v4l2_input *inp)
+{
+	if (inp->index != 0)
+		return -EINVAL;
+
+	inp->type = V4L2_INPUT_TYPE_CAMERA;
+	strscpy(inp->name, "Camera", sizeof(inp->name));
+
+	return 0;
+}
+
+static int csi_g_input(struct file *file, void *fh,
+		       unsigned int *i)
+{
+	*i = 0;
+
+	return 0;
+}
+
+static int csi_s_input(struct file *file, void *fh,
+		       unsigned int i)
+{
+	if (i != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int _csi_try_fmt(struct sun4i_csi *csi,
+			struct v4l2_pix_format_mplane *pix,
+			const struct sun4i_csi_format **fmt)
+{
+	const struct sun4i_csi_format *_fmt;
+	unsigned int width = pix->width;
+	unsigned int height = pix->height;
+	unsigned int i;
+
+	_fmt = csi_get_format_by_fourcc(csi, pix->pixelformat);
+	if (!_fmt)
+		_fmt = csi_get_format_by_fourcc(csi, csi_formats[0].fourcc);
+
+	pix->field = V4L2_FIELD_NONE;
+	pix->colorspace = V4L2_COLORSPACE_SRGB;
+	pix->xfer_func = V4L2_MAP_XFER_FUNC_DEFAULT(pix->colorspace);
+	pix->ycbcr_enc = V4L2_MAP_YCBCR_ENC_DEFAULT(pix->colorspace);
+	pix->quantization = V4L2_MAP_QUANTIZATION_DEFAULT(true, pix->colorspace,
+							  pix->ycbcr_enc);
+
+	pix->num_planes = _fmt->num_planes;
+	pix->pixelformat = _fmt->fourcc;
+
+	memset(pix->reserved, 0, sizeof(pix->reserved));
+
+	/* Align the width and height on the subsampling */
+	width = ALIGN(width, _fmt->hsub);
+	height = ALIGN(height, _fmt->vsub);
+
+	/* Clamp the width and height to our capabilities */
+	pix->width = clamp(width, _fmt->hsub, CSI_MAX_WIDTH);
+	pix->height = clamp(height, _fmt->vsub, CSI_MAX_HEIGHT);
+
+	for (i = 0; i < _fmt->num_planes; i++) {
+		unsigned int hsub = i > 0 ? _fmt->hsub : 1;
+		unsigned int vsub = i > 0 ? _fmt->vsub : 1;
+		unsigned int bpl;
+
+		bpl = pix->width / hsub * _fmt->bpp[i] / 8;
+		pix->plane_fmt[i].bytesperline = bpl;
+		pix->plane_fmt[i].sizeimage = bpl * pix->height / vsub;
+		memset(pix->plane_fmt[i].reserved, 0,
+		       sizeof(pix->plane_fmt[i].reserved));
+	}
+
+	if (fmt)
+		*fmt = _fmt;
+
+	return 0;
+}
+
+static int csi_try_fmt_vid_cap(struct file *file, void *priv,
+			       struct v4l2_format *f)
+{
+	struct sun4i_csi *csi = video_drvdata(file);
+
+	return _csi_try_fmt(csi, &f->fmt.pix_mp, NULL);
+}
+
+static int csi_s_fmt_vid_cap(struct file *file, void *priv,
+			     struct v4l2_format *f)
+{
+	const struct sun4i_csi_format *fmt;
+	struct sun4i_csi *csi = video_drvdata(file);
+	int ret;
+
+	ret = _csi_try_fmt(csi, &f->fmt.pix_mp, &fmt);
+	if (ret)
+		return ret;
+
+	csi->v_fmt = f->fmt.pix_mp;
+	csi->p_fmt = fmt;
+
+	return 0;
+}
+
+static int csi_g_fmt_vid_cap(struct file *file, void *priv,
+			     struct v4l2_format *f)
+{
+	struct sun4i_csi *csi = video_drvdata(file);
+
+	f->fmt.pix_mp = csi->v_fmt;
+
+	return 0;
+}
+
+static int csi_enum_fmt_vid_cap(struct file *file, void *priv,
+				struct v4l2_fmtdesc *f)
+{
+	if (f->index >= ARRAY_SIZE(csi_formats))
+		return -EINVAL;
+
+	f->pixelformat = csi_formats[f->index].fourcc;
+
+	return 0;
+}
+
+static const struct v4l2_ioctl_ops csi_ioctl_ops = {
+	.vidioc_querycap	= csi_querycap,
+
+	.vidioc_enum_fmt_vid_cap_mplane	= csi_enum_fmt_vid_cap,
+	.vidioc_g_fmt_vid_cap_mplane	= csi_g_fmt_vid_cap,
+	.vidioc_s_fmt_vid_cap_mplane	= csi_s_fmt_vid_cap,
+	.vidioc_try_fmt_vid_cap_mplane	= csi_try_fmt_vid_cap,
+
+	.vidioc_enum_input	= csi_enum_input,
+	.vidioc_g_input		= csi_g_input,
+	.vidioc_s_input		= csi_s_input,
+
+	.vidioc_reqbufs		= vb2_ioctl_reqbufs,
+	.vidioc_create_bufs	= vb2_ioctl_create_bufs,
+	.vidioc_querybuf	= vb2_ioctl_querybuf,
+	.vidioc_qbuf		= vb2_ioctl_qbuf,
+	.vidioc_dqbuf		= vb2_ioctl_dqbuf,
+	.vidioc_expbuf		= vb2_ioctl_expbuf,
+	.vidioc_prepare_buf	= vb2_ioctl_prepare_buf,
+	.vidioc_streamon	= vb2_ioctl_streamon,
+	.vidioc_streamoff	= vb2_ioctl_streamoff,
+};
+
+static int csi_open(struct file *file)
+{
+	struct sun4i_csi *csi = video_drvdata(file);
+	int ret;
+
+	ret = mutex_lock_interruptible(&csi->lock);
+	if (ret)
+		return ret;
+
+	ret = pm_runtime_get_sync(csi->dev);
+	if (ret < 0)
+		goto err_unlock;
+
+	ret = v4l2_pipeline_pm_use(&csi->vdev.entity, 1);
+	if (ret)
+		goto err_pm_put;
+
+	ret = v4l2_fh_open(file);
+	if (ret)
+		goto err_pipeline_pm_put;
+
+	mutex_unlock(&csi->lock);
+
+	return 0;
+
+err_pipeline_pm_put:
+	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
+err_pm_put:
+	pm_runtime_put(csi->dev);
+err_unlock:
+	mutex_unlock(&csi->lock);
+	return ret;
+}
+
+static int csi_release(struct file *file)
+{
+	struct sun4i_csi *csi = video_drvdata(file);
+	int ret;
+
+	mutex_lock(&csi->lock);
+
+	ret = v4l2_fh_release(file);
+	v4l2_pipeline_pm_use(&csi->vdev.entity, 0);
+	pm_runtime_put(csi->dev);
+
+	mutex_unlock(&csi->lock);
+
+	return ret;
+}
+
+static const struct v4l2_file_operations csi_fops = {
+	.owner		= THIS_MODULE,
+	.open		= csi_open,
+	.release	= csi_release,
+	.unlocked_ioctl	= video_ioctl2,
+	.read		= vb2_fop_read,
+	.write		= vb2_fop_write,
+	.poll		= vb2_fop_poll,
+	.mmap		= vb2_fop_mmap,
+};
+
+int sun4i_csi_v4l2_register(struct sun4i_csi *csi)
+{
+	struct video_device *vdev = &csi->vdev;
+	int ret;
+
+	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE_MPLANE | V4L2_CAP_STREAMING;
+	vdev->v4l2_dev = &csi->v4l;
+	vdev->queue = &csi->queue;
+	strscpy(vdev->name, KBUILD_MODNAME, sizeof(vdev->name));
+	vdev->release = video_device_release_empty;
+	vdev->lock = &csi->lock;
+
+	/* Set a default format */
+	csi->v_fmt.pixelformat = CSI_DEFAULT_FORMAT;
+	csi->v_fmt.width = CSI_DEFAULT_WIDTH;
+	csi->v_fmt.height = CSI_DEFAULT_HEIGHT;
+	_csi_try_fmt(csi, &csi->v_fmt, NULL);
+
+	vdev->fops = &csi_fops;
+	vdev->ioctl_ops = &csi_ioctl_ops;
+	video_set_drvdata(vdev, csi);
+
+	ret = video_register_device(&csi->vdev, VFL_TYPE_GRABBER, -1);
+	if (ret)
+		return ret;
+
+	dev_info(csi->dev, "Device registered as %s\n",
+		 video_device_node_name(vdev));
+
+	return 0;
+}
+

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