[RFC,media] blackfin: add video display driver

  This is a bridge driver for blackfin diplay device.
It can work with ppi or eppi interface. DV timings
are supported.

Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com>
---
 drivers/media/platform/blackfin/Kconfig        |   15 +-
 drivers/media/platform/blackfin/Makefile       |    1 +
 drivers/media/platform/blackfin/bfin_display.c | 1151 ++++++++++++++++++++++++
 include/media/blackfin/bfin_display.h          |   38 +
 4 files changed, 1203 insertions(+), 2 deletions(-)
 create mode 100644 drivers/media/platform/blackfin/bfin_display.c
 create mode 100644 include/media/blackfin/bfin_display.h
  

Hello,

On 04/13/2013 01:52 AM, Scott Jiang wrote:
> This is a bridge driver for blackfin diplay device.
> It can work with ppi or eppi interface. DV timings
> are supported.
>
> Signed-off-by: Scott Jiang<scott.jiang.linux@gmail.com>
> ---
>   drivers/media/platform/blackfin/Kconfig        |   15 +-
>   drivers/media/platform/blackfin/Makefile       |    1 +
>   drivers/media/platform/blackfin/bfin_display.c | 1151 ++++++++++++++++++++++++
>   include/media/blackfin/bfin_display.h          |   38 +
>   4 files changed, 1203 insertions(+), 2 deletions(-)
>   create mode 100644 drivers/media/platform/blackfin/bfin_display.c
>   create mode 100644 include/media/blackfin/bfin_display.h
>
> diff --git a/drivers/media/platform/blackfin/Kconfig b/drivers/media/platform/blackfin/Kconfig
> index cc23997..8a8fd75 100644
> --- a/drivers/media/platform/blackfin/Kconfig
> +++ b/drivers/media/platform/blackfin/Kconfig
> @@ -9,7 +9,18 @@ config VIDEO_BLACKFIN_CAPTURE
>   	  To compile this driver as a module, choose M here: the
>   	  module will be called bfin_capture.
>
> +config VIDEO_BLACKFIN_DISPLAY
> +	tristate "Blackfin Video Display Driver"
> +	depends on VIDEO_V4L2&&  BLACKFIN&&  I2C
> +	select VIDEOBUF2_DMA_CONTIG
> +	help
> +	  V4L2 bridge driver for Blackfin video display device.

Shouldn't it just be "V4L2 output driver", why are you calling it "bridge" ?

> +	  Choose PPI or EPPI as its interface.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called bfin_display.
> +
>   config VIDEO_BLACKFIN_PPI
>   	tristate
> -	depends on VIDEO_BLACKFIN_CAPTURE
> -	default VIDEO_BLACKFIN_CAPTURE
> +	depends on VIDEO_BLACKFIN_CAPTURE || VIDEO_BLACKFIN_DISPLAY
> +	default VIDEO_BLACKFIN_CAPTURE || VIDEO_BLACKFIN_DISPLAY
> diff --git a/drivers/media/platform/blackfin/Makefile b/drivers/media/platform/blackfin/Makefile
> index 30421bc..015c8f0 100644
> --- a/drivers/media/platform/blackfin/Makefile
> +++ b/drivers/media/platform/blackfin/Makefile
> @@ -1,2 +1,3 @@
>   obj-$(CONFIG_VIDEO_BLACKFIN_CAPTURE) += bfin_capture.o
> +obj-$(CONFIG_VIDEO_BLACKFIN_DISPLAY) += bfin_display.o
>   obj-$(CONFIG_VIDEO_BLACKFIN_PPI)     += ppi.o
> diff --git a/drivers/media/platform/blackfin/bfin_display.c b/drivers/media/platform/blackfin/bfin_display.c
> new file mode 100644
> index 0000000..d971d7b
> --- /dev/null
> +++ b/drivers/media/platform/blackfin/bfin_display.c
> @@ -0,0 +1,1151 @@
> +/*
> + * Analog Devices video display driver

Sounds a bit too generic.

> + *
> + * Copyright (c) 2011 Analog Devices Inc.

2011 - 2013 ?

> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include<linux/completion.h>
> +#include<linux/delay.h>
> +#include<linux/errno.h>
> +#include<linux/fs.h>
> +#include<linux/i2c.h>
> +#include<linux/init.h>
> +#include<linux/interrupt.h>
> +#include<linux/io.h>
> +#include<linux/mm.h>
> +#include<linux/module.h>
> +#include<linux/platform_device.h>
> +#include<linux/slab.h>
> +#include<linux/time.h>
> +#include<linux/types.h>
> +
> +#include<media/v4l2-chip-ident.h>
> +#include<media/v4l2-common.h>
> +#include<media/v4l2-ctrls.h>
> +#include<media/v4l2-device.h>
> +#include<media/v4l2-ioctl.h>
> +#include<media/videobuf2-dma-contig.h>
> +
> +#include<asm/dma.h>
> +
> +#include<media/blackfin/bfin_display.h>
> +#include<media/blackfin/ppi.h>
> +
> +#define DISPLAY_DRV_NAME        "bfin_display"
> +#define DISP_MIN_NUM_BUF        2
> +
> +struct disp_format {
> +	char *desc;
> +	u32 pixelformat;
> +	enum v4l2_mbus_pixelcode mbus_code;
> +	int bpp; /* bits per pixel */
> +	int dlen; /* data length for ppi in bits */
> +};
> +
> +struct disp_buffer {
> +	struct vb2_buffer vb;
> +	struct list_head list;
> +};
> +
> +struct disp_device {
> +	/* capture device instance */

Shouldn't it be "output device..." ?

> +	struct v4l2_device v4l2_dev;
> +	/* v4l2 control handler */
> +	struct v4l2_ctrl_handler ctrl_handler;

This handler seems to be unused, I couldn't find any code adding controls
to it. Any initialization of this handler is a dead code now. You probably
want to move that bits to a patch actually adding any controls.

> +	/* device node data */
> +	struct video_device *video_dev;
> +	/* sub device instance */
> +	struct v4l2_subdev *sd;
> +	/* capture config */
> +	struct bfin_display_config *cfg;
> +	/* ppi interface */
> +	struct ppi_if *ppi;
> +	/* current output */
> +	unsigned int cur_output;
> +	/* current selected standard */
> +	v4l2_std_id std;
> +	/* current selected dv_timings */
> +	struct v4l2_dv_timings dv_timings;
> +	/* used to store pixel format */
> +	struct v4l2_pix_format fmt;
> +	/* bits per pixel*/
> +	int bpp;
> +	/* data length for ppi in bits */
> +	int dlen;
> +	/* used to store encoder supported format */
> +	struct disp_format *enc_formats;
> +	/* number of encoder formats array */
> +	int num_enc_formats;
> +	/* pointing to current video buffer */
> +	struct disp_buffer *cur_frm;
> +	/* buffer queue used in videobuf2 */
> +	struct vb2_queue buffer_queue;
> +	/* allocator-specific contexts for each plane */
> +	struct vb2_alloc_ctx *alloc_ctx;
> +	/* queue of filled frames */
> +	struct list_head dma_queue;
> +	/* used in videobuf2 callback */
> +	spinlock_t lock;
> +	/* used to access display device */
> +	struct mutex mutex;
> +};
> +
> +struct disp_fh {
> +	struct v4l2_fh fh;
> +	/* indicates whether this file handle is doing IO */
> +	bool io_allowed;
> +};

This structure should not be needed when you use the vb2 helpers. Please 
see
below for more details.

> +static const struct disp_format disp_formats[] = {
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved UYVY 8bits",
> +		.pixelformat = V4L2_PIX_FMT_UYVY,
> +		.mbus_code   = V4L2_MBUS_FMT_UYVY8_2X8,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved YUYV 8bits",
> +		.pixelformat = V4L2_PIX_FMT_YUYV,
> +		.mbus_code   = V4L2_MBUS_FMT_YUYV8_2X8,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved UYVY 16bits",
> +		.pixelformat = V4L2_PIX_FMT_UYVY,
> +		.mbus_code   = V4L2_MBUS_FMT_UYVY8_1X16,
> +		.bpp         = 16,
> +		.dlen        = 16,
> +	},
> +	{
> +		.desc        = "RGB 565",
> +		.pixelformat = V4L2_PIX_FMT_RGB565,
> +		.mbus_code   = V4L2_MBUS_FMT_RGB565_2X8_LE,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "RGB 444",
> +		.pixelformat = V4L2_PIX_FMT_RGB444,
> +		.mbus_code   = V4L2_MBUS_FMT_RGB444_2X8_PADHI_LE,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +
> +};
> +#define DISP_MAX_FMTS ARRAY_SIZE(disp_formats)
> +
> +static irqreturn_t disp_isr(int irq, void *dev_id);

Couldn't the functions be reordered so this declaration can be avoided ?

> +static int disp_open(struct file *file)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct video_device *vfd = disp->video_dev;
> +	struct disp_fh *disp_fh;
> +
> +	if (!disp->sd) {
> +		v4l2_err(&disp->v4l2_dev, "No sub device registered\n");
> +		return -ENODEV;
> +	}
> +
> +	disp_fh = kzalloc(sizeof(*disp_fh), GFP_KERNEL);
> +	if (!disp_fh) {
> +		v4l2_err(&disp->v4l2_dev,
> +			 "unable to allocate memory for file handle object\n");

k*alloc functions already log any errors, you could just return -ENOMEM,
without printing anything. There is similar occurrence in disp_probe.

Also it might be a good idea to make your function and data structure names
more specific to this device, e.g. s/disp_*/bfin_disp_*.

> +		return -ENOMEM;
> +	}
> +
> +	v4l2_fh_init(&disp_fh->fh, vfd);
> +
> +	/* store pointer to v4l2_fh in private_data member of file */
> +	file->private_data =&disp_fh->fh;
> +	v4l2_fh_add(&disp_fh->fh);
> +	disp_fh->io_allowed = false;
> +	return 0;
> +}

> +static int disp_reqbufs(struct file *file, void *priv,
> +			struct v4l2_requestbuffers *req_buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct vb2_queue *vq =&disp->buffer_queue;
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (vb2_is_busy(vq))
> +		return -EBUSY;
> +
> +	disp_fh->io_allowed = true;
> +
> +	return vb2_reqbufs(vq, req_buf);
> +}
> +
> +static int disp_querybuf(struct file *file, void *priv,
> +				struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return vb2_querybuf(&disp->buffer_queue, buf);
> +}
> +
> +static int disp_qbuf(struct file *file, void *priv,
> +			struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (!disp_fh->io_allowed)
> +		return -EBUSY;
> +
> +	return vb2_qbuf(&disp->buffer_queue, buf);
> +}
> +
> +static int disp_dqbuf(struct file *file, void *priv,
> +			struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (!disp_fh->io_allowed)
> +		return -EBUSY;
> +
> +	return vb2_dqbuf(&disp->buffer_queue,
> +				buf, file->f_flags&  O_NONBLOCK);
> +}

I would suggest you have a look at the videobuf2 ioctl/fop helpers. Lots of
boilerplate code can be removed when you use them. For an example see:

http://git.linuxtv.org/snawrocki/samsung.git/commitdiff/38b7d67224965bf09eaa3ce147bbebc7fa089411

> +static int disp_probe(struct platform_device *pdev)
> +{
> +	struct disp_device *disp;
> +	struct video_device *vfd;
> +	struct i2c_adapter *i2c_adap;
> +	struct bfin_display_config *config;
> +	struct vb2_queue *q;
> +	struct disp_route *route;
> +	int ret;
> +
> +	config = pdev->dev.platform_data;
> +	if (!config) {
> +		v4l2_err(pdev->dev.driver, "Unable to get board config\n");
> +		return -ENODEV;
> +	}
> +
> +	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
> +	if (!disp) {
> +		v4l2_err(pdev->dev.driver, "Unable to alloc disp\n");
> +		return -ENOMEM;
> +	}
> +
> +	disp->cfg = config;
> +
> +	disp->ppi = ppi_create_instance(config->ppi_info);
> +	if (!disp->ppi) {
> +		v4l2_err(pdev->dev.driver, "Unable to create ppi\n");
> +		ret = -ENODEV;
> +		goto err_free_dev;
> +	}
> +	disp->ppi->priv = disp;
> +
> +	disp->alloc_ctx = vb2_dma_contig_init_ctx(&pdev->dev);
> +	if (IS_ERR(disp->alloc_ctx)) {
> +		ret = PTR_ERR(disp->alloc_ctx);
> +		goto err_free_ppi;
> +	}
> +
> +	vfd = video_device_alloc();

Instead of this allocation you could embed struct video_device instance
in struct disp_device...

> +	if (!vfd) {
> +		ret = -ENOMEM;
> +		v4l2_err(pdev->dev.driver, "Unable to alloc video device\n");
> +		goto err_cleanup_ctx;
> +	}
> +
> +	/* initialize field of video device */
> +	vfd->release    = video_device_release;

..and make this
	vfd->release    = video_device_release_empty;

> +	vfd->fops       =&disp_fops;
> +	vfd->ioctl_ops  =&disp_ioctl_ops;
> +	vfd->tvnorms    = 0;
> +	vfd->v4l2_dev   =&disp->v4l2_dev;
> +	vfd->vfl_dir    = VFL_DIR_TX;
> +	set_bit(V4L2_FL_USE_FH_PRIO,&vfd->flags);
> +	strncpy(vfd->name, DISPLAY_DRV_NAME, sizeof(vfd->name));
> +	disp->video_dev = vfd;
> +
> +	ret = v4l2_device_register(&pdev->dev,&disp->v4l2_dev);
> +	if (ret) {
> +		v4l2_err(pdev->dev.driver,
> +				"Unable to register v4l2 device\n");
> +		goto err_release_vdev;
> +	}
> +	v4l2_info(&disp->v4l2_dev, "v4l2 device registered\n");
> +
> +	disp->v4l2_dev.ctrl_handler =&disp->ctrl_handler;
> +	ret = v4l2_ctrl_handler_init(&disp->ctrl_handler, 0);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to init control handler\n");
> +		goto err_unreg_v4l2;
> +	}
> +
> +	spin_lock_init(&disp->lock);
> +	/* initialize queue */
> +	q =&disp->buffer_queue;
> +	q->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
> +	q->io_modes = VB2_MMAP;
> +	q->drv_priv = disp;
> +	q->buf_struct_size = sizeof(struct disp_buffer);
> +	q->ops =&disp_video_qops;
> +	q->mem_ops =&vb2_dma_contig_memops;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to init videobuf2 queue\n");
> +		goto err_free_handler;
> +	}
> +
> +	mutex_init(&disp->mutex);
> +
> +	/* init video dma queues */
> +	INIT_LIST_HEAD(&disp->dma_queue);
> +
> +	vfd->lock =&disp->mutex;
> +
> +	/* register video device */
> +	ret = video_register_device(disp->video_dev, VFL_TYPE_GRABBER, -1);

The video device should be registered as a last step, only when all
resources it uses are already initialized.

> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to register video device\n");
> +		goto err_free_handler;
> +	}
> +	video_set_drvdata(disp->video_dev, disp);
> +	v4l2_info(&disp->v4l2_dev, "video device registered as: %s\n",
> +			video_device_node_name(vfd));
> +
> +	/* load up the subdevice */
> +	i2c_adap = i2c_get_adapter(config->i2c_adapter_id);
> +	if (!i2c_adap) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to find i2c adapter\n");
> +		goto err_unreg_vdev;
> +
> +	}
> +	disp->sd = v4l2_i2c_new_subdev_board(&disp->v4l2_dev,
> +						 i2c_adap,
> +						&config->board_info,
> +						 NULL);

nit: I bit strange indentation, you could probably just fit it in 2 lines.

> +	if (disp->sd) {
> +		int i;
> +		if (!config->num_outputs) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to work without output\n");
> +			goto err_unreg_vdev;
> +		}
> +
> +		/* update tvnorms from the sub devices */
> +		for (i = 0; i<  config->num_outputs; i++)
> +			vfd->tvnorms |= config->outputs[i].std;
> +	} else {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to register sub device\n");
> +		goto err_unreg_vdev;
> +	}
> +
> +	v4l2_info(&disp->v4l2_dev, "v4l2 sub device registered\n");
> +
> +	/*
> +	 * explicitly set output, otherwise some boards
> +	 * may not work at the state as we expected
> +	 */
> +	route =&config->routes[0];
> +	ret = v4l2_subdev_call(disp->sd, video, s_routing,
> +				route->output, route->output, 0);
> +	if ((ret<  0)&&  (ret != -ENOIOCTLCMD)) {
> +		v4l2_err(&disp->v4l2_dev, "Failed to set output\n");
> +		goto err_unreg_vdev;
> +	}
> +	disp->cur_output = 0;
> +	/* if this route has specific config, update ppi control */
> +	if (route->ppi_control)
> +		config->ppi_control = route->ppi_control;
> +
> +	/* now we can probe the default state */
> +	if (config->outputs[0].capabilities&  V4L2_IN_CAP_STD) {
> +		v4l2_std_id std;
> +		ret = v4l2_subdev_call(disp->sd, core, g_std,&std);
> +		if (ret) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to get std\n");
> +			goto err_unreg_vdev;
> +		}
> +		disp->std = std;
> +	}
> +	if (config->outputs[0].capabilities&  V4L2_IN_CAP_CUSTOM_TIMINGS) {
> +		struct v4l2_dv_timings dv_timings;
> +		ret = v4l2_subdev_call(disp->sd, video,
> +				g_dv_timings,&dv_timings);
> +		if (ret) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to get dv timings\n");
> +			goto err_unreg_vdev;
> +		}
> +		disp->dv_timings = dv_timings;
> +	}
> +	ret = disp_init_encoder_formats(disp);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to create encoder formats table\n");
> +		goto err_unreg_vdev;
> +	}
> +	return 0;
> +err_unreg_vdev:
> +	video_unregister_device(disp->video_dev);
> +	disp->video_dev = NULL;
> +err_free_handler:
> +	v4l2_ctrl_handler_free(&disp->ctrl_handler);
> +err_unreg_v4l2:
> +	v4l2_device_unregister(&disp->v4l2_dev);
> +err_release_vdev:
> +	if (disp->video_dev)
> +		video_device_release(disp->video_dev);
> +err_cleanup_ctx:
> +	vb2_dma_contig_cleanup_ctx(disp->alloc_ctx);
> +err_free_ppi:
> +	ppi_delete_instance(disp->ppi);
> +err_free_dev:
> +	kfree(disp);
> +	return ret;
> +}


Regards,
Sylwester
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Hi Scott!

On Sat April 13 2013 01:52:58 Scott Jiang wrote:
> This is a bridge driver for blackfin diplay device.
> It can work with ppi or eppi interface. DV timings
> are supported.

Thanks for the patch. There are a number of comments below. For the most
part you can save a lot of code by making a few fairly small changes.

> 
> Signed-off-by: Scott Jiang <scott.jiang.linux@gmail.com>
> ---
>  drivers/media/platform/blackfin/Kconfig        |   15 +-
>  drivers/media/platform/blackfin/Makefile       |    1 +
>  drivers/media/platform/blackfin/bfin_display.c | 1151 ++++++++++++++++++++++++
>  include/media/blackfin/bfin_display.h          |   38 +
>  4 files changed, 1203 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/media/platform/blackfin/bfin_display.c
>  create mode 100644 include/media/blackfin/bfin_display.h
> 
> diff --git a/drivers/media/platform/blackfin/Kconfig b/drivers/media/platform/blackfin/Kconfig
> index cc23997..8a8fd75 100644
> --- a/drivers/media/platform/blackfin/Kconfig
> +++ b/drivers/media/platform/blackfin/Kconfig
> @@ -9,7 +9,18 @@ config VIDEO_BLACKFIN_CAPTURE
>  	  To compile this driver as a module, choose M here: the
>  	  module will be called bfin_capture.
>  
> +config VIDEO_BLACKFIN_DISPLAY
> +	tristate "Blackfin Video Display Driver"
> +	depends on VIDEO_V4L2 && BLACKFIN && I2C
> +	select VIDEOBUF2_DMA_CONTIG
> +	help
> +	  V4L2 bridge driver for Blackfin video display device.
> +	  Choose PPI or EPPI as its interface.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called bfin_display.
> +
>  config VIDEO_BLACKFIN_PPI
>  	tristate
> -	depends on VIDEO_BLACKFIN_CAPTURE
> -	default VIDEO_BLACKFIN_CAPTURE
> +	depends on VIDEO_BLACKFIN_CAPTURE || VIDEO_BLACKFIN_DISPLAY
> +	default VIDEO_BLACKFIN_CAPTURE || VIDEO_BLACKFIN_DISPLAY
> diff --git a/drivers/media/platform/blackfin/Makefile b/drivers/media/platform/blackfin/Makefile
> index 30421bc..015c8f0 100644
> --- a/drivers/media/platform/blackfin/Makefile
> +++ b/drivers/media/platform/blackfin/Makefile
> @@ -1,2 +1,3 @@
>  obj-$(CONFIG_VIDEO_BLACKFIN_CAPTURE) += bfin_capture.o
> +obj-$(CONFIG_VIDEO_BLACKFIN_DISPLAY) += bfin_display.o
>  obj-$(CONFIG_VIDEO_BLACKFIN_PPI)     += ppi.o
> diff --git a/drivers/media/platform/blackfin/bfin_display.c b/drivers/media/platform/blackfin/bfin_display.c
> new file mode 100644
> index 0000000..d971d7b
> --- /dev/null
> +++ b/drivers/media/platform/blackfin/bfin_display.c
> @@ -0,0 +1,1151 @@
> +/*
> + * Analog Devices video display driver
> + *
> + * Copyright (c) 2011 Analog Devices Inc.

Analog Devices? What has this to do with Analog Devices?

> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/errno.h>
> +#include <linux/fs.h>
> +#include <linux/i2c.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/time.h>
> +#include <linux/types.h>
> +
> +#include <media/v4l2-chip-ident.h>
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#include <asm/dma.h>
> +
> +#include <media/blackfin/bfin_display.h>
> +#include <media/blackfin/ppi.h>
> +
> +#define DISPLAY_DRV_NAME        "bfin_display"
> +#define DISP_MIN_NUM_BUF        2
> +
> +struct disp_format {
> +	char *desc;
> +	u32 pixelformat;
> +	enum v4l2_mbus_pixelcode mbus_code;
> +	int bpp; /* bits per pixel */
> +	int dlen; /* data length for ppi in bits */
> +};
> +
> +struct disp_buffer {
> +	struct vb2_buffer vb;
> +	struct list_head list;
> +};
> +
> +struct disp_device {
> +	/* capture device instance */
> +	struct v4l2_device v4l2_dev;
> +	/* v4l2 control handler */
> +	struct v4l2_ctrl_handler ctrl_handler;
> +	/* device node data */
> +	struct video_device *video_dev;
> +	/* sub device instance */
> +	struct v4l2_subdev *sd;
> +	/* capture config */
> +	struct bfin_display_config *cfg;
> +	/* ppi interface */
> +	struct ppi_if *ppi;
> +	/* current output */
> +	unsigned int cur_output;
> +	/* current selected standard */
> +	v4l2_std_id std;
> +	/* current selected dv_timings */
> +	struct v4l2_dv_timings dv_timings;
> +	/* used to store pixel format */
> +	struct v4l2_pix_format fmt;
> +	/* bits per pixel*/
> +	int bpp;
> +	/* data length for ppi in bits */
> +	int dlen;
> +	/* used to store encoder supported format */
> +	struct disp_format *enc_formats;
> +	/* number of encoder formats array */
> +	int num_enc_formats;
> +	/* pointing to current video buffer */
> +	struct disp_buffer *cur_frm;
> +	/* buffer queue used in videobuf2 */
> +	struct vb2_queue buffer_queue;
> +	/* allocator-specific contexts for each plane */
> +	struct vb2_alloc_ctx *alloc_ctx;
> +	/* queue of filled frames */
> +	struct list_head dma_queue;
> +	/* used in videobuf2 callback */
> +	spinlock_t lock;
> +	/* used to access display device */
> +	struct mutex mutex;
> +};
> +
> +struct disp_fh {
> +	struct v4l2_fh fh;
> +	/* indicates whether this file handle is doing IO */
> +	bool io_allowed;
> +};
> +
> +static const struct disp_format disp_formats[] = {
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved UYVY 8bits",
> +		.pixelformat = V4L2_PIX_FMT_UYVY,
> +		.mbus_code   = V4L2_MBUS_FMT_UYVY8_2X8,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved YUYV 8bits",
> +		.pixelformat = V4L2_PIX_FMT_YUYV,
> +		.mbus_code   = V4L2_MBUS_FMT_YUYV8_2X8,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "YCbCr 4:2:2 Interleaved UYVY 16bits",
> +		.pixelformat = V4L2_PIX_FMT_UYVY,
> +		.mbus_code   = V4L2_MBUS_FMT_UYVY8_1X16,
> +		.bpp         = 16,
> +		.dlen        = 16,
> +	},
> +	{
> +		.desc        = "RGB 565",
> +		.pixelformat = V4L2_PIX_FMT_RGB565,
> +		.mbus_code   = V4L2_MBUS_FMT_RGB565_2X8_LE,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +	{
> +		.desc        = "RGB 444",
> +		.pixelformat = V4L2_PIX_FMT_RGB444,
> +		.mbus_code   = V4L2_MBUS_FMT_RGB444_2X8_PADHI_LE,
> +		.bpp         = 16,
> +		.dlen        = 8,
> +	},
> +
> +};
> +#define DISP_MAX_FMTS ARRAY_SIZE(disp_formats)
> +
> +static irqreturn_t disp_isr(int irq, void *dev_id);
> +
> +static struct disp_buffer *to_disp_vb(struct vb2_buffer *vb)
> +{
> +	return container_of(vb, struct disp_buffer, vb);
> +}
> +
> +static int disp_init_encoder_formats(struct disp_device *disp)
> +{
> +	enum v4l2_mbus_pixelcode code;
> +	struct disp_format *df;
> +	unsigned int num_formats = 0;
> +	int i, j;
> +
> +	while (!v4l2_subdev_call(disp->sd, video,
> +				enum_mbus_fmt, num_formats, &code))
> +		num_formats++;
> +	if (!num_formats)
> +		return -ENXIO;
> +
> +	df = kzalloc(num_formats * sizeof(*df), GFP_KERNEL);
> +	if (!df)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_formats; i++) {
> +		v4l2_subdev_call(disp->sd, video,
> +				enum_mbus_fmt, i, &code);
> +		for (j = 0; j < DISP_MAX_FMTS; j++)
> +			if (code == disp_formats[j].mbus_code)
> +				break;
> +		if (j == DISP_MAX_FMTS) {
> +			/* we don't allow this encoder working with our bridge */
> +			kfree(df);
> +			return -EINVAL;
> +		}
> +		df[i] = disp_formats[j];
> +	}
> +	disp->enc_formats = df;
> +	disp->num_enc_formats = num_formats;
> +	return 0;
> +}
> +
> +static void disp_free_encoder_formats(struct disp_device *disp)
> +{
> +	disp->num_enc_formats = 0;
> +	kfree(disp->enc_formats);
> +	disp->enc_formats = NULL;
> +}
> +
> +static int disp_open(struct file *file)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct video_device *vfd = disp->video_dev;
> +	struct disp_fh *disp_fh;
> +
> +	if (!disp->sd) {
> +		v4l2_err(&disp->v4l2_dev, "No sub device registered\n");
> +		return -ENODEV;

You know at probe time whether there are subdevices or not. If not, 
then just don't register the video node at all.

> +	}
> +
> +	disp_fh = kzalloc(sizeof(*disp_fh), GFP_KERNEL);
> +	if (!disp_fh) {
> +		v4l2_err(&disp->v4l2_dev,
> +			 "unable to allocate memory for file handle object\n");
> +		return -ENOMEM;
> +	}
> +
> +	v4l2_fh_init(&disp_fh->fh, vfd);
> +
> +	/* store pointer to v4l2_fh in private_data member of file */
> +	file->private_data = &disp_fh->fh;
> +	v4l2_fh_add(&disp_fh->fh);
> +	disp_fh->io_allowed = false;
> +	return 0;
> +}
> +
> +static int disp_release(struct file *file)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	/* if this instance is doing IO */
> +	if (disp_fh->io_allowed)
> +		vb2_queue_release(&disp->buffer_queue);
> +
> +	file->private_data = NULL;
> +	v4l2_fh_del(&disp_fh->fh);
> +	v4l2_fh_exit(&disp_fh->fh);
> +	kfree(disp_fh);
> +	return 0;
> +}
> +
> +static int disp_mmap(struct file *file, struct vm_area_struct *vma)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +
> +	if (mutex_lock_interruptible(&disp->mutex))
> +		return -ERESTARTSYS;
> +	ret = vb2_mmap(&disp->buffer_queue, vma);
> +	mutex_unlock(&disp->mutex);
> +	return ret;
> +}
> +
> +#ifndef CONFIG_MMU
> +static unsigned long disp_get_unmapped_area(struct file *file,
> +					    unsigned long addr,
> +					    unsigned long len,
> +					    unsigned long pgoff,
> +					    unsigned long flags)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +
> +	if (mutex_lock_interruptible(&disp->mutex))
> +		return -ERESTARTSYS;
> +	ret = vb2_get_unmapped_area(&disp->buffer_queue,
> +				    addr,
> +				    len,
> +				    pgoff,
> +				    flags);
> +	mutex_unlock(&disp->mutex);
> +	return ret;
> +}
> +#endif
> +
> +static unsigned int disp_poll(struct file *file, poll_table *wait)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +
> +	mutex_lock(&disp->mutex);
> +	ret = vb2_poll(&disp->buffer_queue, file, wait);
> +	mutex_unlock(&disp->mutex);
> +	return ret;
> +}

Use the helper functions in media/videobuf2-core.h for these file ops.

> +
> +static int disp_queue_setup(struct vb2_queue *vq,
> +				const struct v4l2_format *fmt,
> +				unsigned int *nbuffers, unsigned int *nplanes,
> +				unsigned int sizes[], void *alloc_ctxs[])
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vq);
> +
> +	if (*nbuffers < DISP_MIN_NUM_BUF)
> +		*nbuffers = DISP_MIN_NUM_BUF;
> +
> +	*nplanes = 1;
> +	sizes[0] = disp->fmt.sizeimage;
> +	alloc_ctxs[0] = disp->alloc_ctx;
> +
> +	return 0;
> +}
> +
> +static int disp_buffer_init(struct vb2_buffer *vb)
> +{
> +	struct disp_buffer *buf = to_disp_vb(vb);
> +
> +	INIT_LIST_HEAD(&buf->list);
> +	return 0;
> +}
> +
> +static int disp_buffer_prepare(struct vb2_buffer *vb)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vb->vb2_queue);
> +	struct disp_buffer *buf = to_disp_vb(vb);
> +	unsigned long size;
> +
> +	size = disp->fmt.sizeimage;
> +	if (vb2_plane_size(vb, 0) < size) {
> +		v4l2_err(&disp->v4l2_dev, "buffer too small (%lu < %lu)\n",
> +				vb2_plane_size(vb, 0), size);
> +		return -EINVAL;
> +	}
> +	vb2_set_plane_payload(&buf->vb, 0, size);
> +
> +	return 0;
> +}
> +
> +static void disp_buffer_queue(struct vb2_buffer *vb)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vb->vb2_queue);
> +	struct disp_buffer *buf = to_disp_vb(vb);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&disp->lock, flags);
> +	list_add_tail(&buf->list, &disp->dma_queue);
> +	spin_unlock_irqrestore(&disp->lock, flags);
> +}
> +
> +static void disp_buffer_cleanup(struct vb2_buffer *vb)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vb->vb2_queue);
> +	struct disp_buffer *buf = to_disp_vb(vb);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&disp->lock, flags);
> +	list_del_init(&buf->list);
> +	spin_unlock_irqrestore(&disp->lock, flags);
> +}
> +
> +static void disp_lock(struct vb2_queue *vq)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vq);
> +	mutex_lock(&disp->mutex);
> +}
> +
> +static void disp_unlock(struct vb2_queue *vq)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vq);
> +	mutex_unlock(&disp->mutex);
> +}

Use helper functions for this.

> +
> +static int disp_start_streaming(struct vb2_queue *vq, unsigned int count)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vq);
> +	struct ppi_if *ppi = disp->ppi;
> +	struct ppi_params params;
> +	int ret;
> +
> +	/* enable streamon on the sub device */
> +	ret = v4l2_subdev_call(disp->sd, video, s_stream, 1);
> +	if (ret && (ret != -ENOIOCTLCMD)) {
> +		v4l2_err(&disp->v4l2_dev, "stream on failed in subdev\n");
> +		return ret;
> +	}
> +
> +	/* set ppi params */
> +	params.width = disp->fmt.width;
> +	params.height = disp->fmt.height;
> +	params.bpp = disp->bpp;
> +	params.dlen = disp->dlen;
> +	params.ppi_control = disp->cfg->ppi_control;
> +	params.int_mask = disp->cfg->int_mask;
> +	if (disp->cfg->outputs[disp->cur_output].capabilities
> +			& V4L2_IN_CAP_CUSTOM_TIMINGS) {

_CUSTOM_TIMINGS has been renamed to _DV_TIMINGS.

> +		struct v4l2_bt_timings *bt = &disp->dv_timings.bt;
> +
> +		params.hdelay = bt->hsync + bt->hbackporch;
> +		params.vdelay = bt->vsync + bt->vbackporch;
> +		params.line = bt->hfrontporch + bt->hsync
> +				+ bt->hbackporch + bt->width;
> +		params.frame = bt->vfrontporch + bt->vsync
> +				+ bt->vbackporch + bt->height;
> +		if (bt->interlaced)
> +			params.frame += bt->il_vfrontporch + bt->il_vsync
> +					+ bt->il_vbackporch;
> +		params.hsync = bt->hsync;
> +		params.vsync = bt->vsync;
> +	} else if (disp->cfg->outputs[disp->cur_output].capabilities
> +			& V4L2_IN_CAP_STD) {
> +		params.hdelay = 0;
> +		params.vdelay = 0;
> +		if (disp->std & V4L2_STD_525_60) {
> +			params.line = 858;
> +			params.frame = 525;
> +		} else {
> +			params.line = 864;
> +			params.frame = 625;
> +		}
> +	} else {
> +		params.hdelay = 0;
> +		params.vdelay = 0;
> +		params.line = params.width + disp->cfg->blank_pixels;
> +		params.frame = params.height;
> +	}
> +	ret = ppi->ops->set_params(ppi, &params);
> +	if (ret < 0) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Error in setting ppi params\n");
> +		return ret;
> +	}
> +
> +	/* attach ppi DMA irq handler */
> +	ret = ppi->ops->attach_irq(ppi, disp_isr);
> +	if (ret < 0) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Error in attaching interrupt handler\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int disp_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct disp_device *disp = vb2_get_drv_priv(vq);
> +	struct ppi_if *ppi = disp->ppi;
> +	unsigned long flags;
> +	int ret;
> +
> +	if (!vb2_is_streaming(vq))
> +		return 0;
> +
> +	ppi->ops->stop(ppi);
> +	ppi->ops->detach_irq(ppi);
> +	ret = v4l2_subdev_call(disp->sd, video, s_stream, 0);
> +	if (ret && (ret != -ENOIOCTLCMD))
> +		v4l2_err(&disp->v4l2_dev,
> +				"stream off failed in subdev\n");
> +
> +	spin_lock_irqsave(&disp->lock, flags);
> +	/* release all active buffers */
> +	while (!list_empty(&disp->dma_queue)) {
> +		disp->cur_frm = list_entry(disp->dma_queue.next,
> +						struct disp_buffer, list);
> +		list_del(&disp->cur_frm->list);
> +		vb2_buffer_done(&disp->cur_frm->vb, VB2_BUF_STATE_ERROR);
> +	}
> +	spin_unlock_irqrestore(&disp->lock, flags);
> +	return 0;
> +}
> +
> +static struct vb2_ops disp_video_qops = {
> +	.queue_setup            = disp_queue_setup,
> +	.buf_init               = disp_buffer_init,
> +	.buf_prepare            = disp_buffer_prepare,
> +	.buf_cleanup            = disp_buffer_cleanup,
> +	.buf_queue              = disp_buffer_queue,
> +	.wait_prepare           = disp_unlock,
> +	.wait_finish            = disp_lock,
> +	.start_streaming        = disp_start_streaming,
> +	.stop_streaming         = disp_stop_streaming,
> +};
> +
> +static int disp_reqbufs(struct file *file, void *priv,
> +			struct v4l2_requestbuffers *req_buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct vb2_queue *vq = &disp->buffer_queue;
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (vb2_is_busy(vq))
> +		return -EBUSY;
> +
> +	disp_fh->io_allowed = true;

There is no need for io_allowed. The vb2_is_busy() function does the same
thing. It saves a lot of code since you now can just use v4l2_fh instead of
disp_fh, which allows you to use even more helper functions (v4l2_fh_open and
v4l2_fh_release for starters).

In fact, you can use all the vb2 ioctl helpers saving you a lot of code.

> +
> +	return vb2_reqbufs(vq, req_buf);
> +}
> +
> +static int disp_querybuf(struct file *file, void *priv,
> +				struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return vb2_querybuf(&disp->buffer_queue, buf);
> +}
> +
> +static int disp_qbuf(struct file *file, void *priv,
> +			struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (!disp_fh->io_allowed)
> +		return -EBUSY;
> +
> +	return vb2_qbuf(&disp->buffer_queue, buf);
> +}
> +
> +static int disp_dqbuf(struct file *file, void *priv,
> +			struct v4l2_buffer *buf)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_fh *fh = file->private_data;
> +	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
> +
> +	if (!disp_fh->io_allowed)
> +		return -EBUSY;
> +
> +	return vb2_dqbuf(&disp->buffer_queue,
> +				buf, file->f_flags & O_NONBLOCK);
> +}
> +
> +static irqreturn_t disp_isr(int irq, void *dev_id)
> +{
> +	struct ppi_if *ppi = dev_id;
> +	struct disp_device *disp = ppi->priv;
> +	struct timeval timevalue;
> +	struct vb2_buffer *vb = &disp->cur_frm->vb;
> +	dma_addr_t addr;
> +
> +	spin_lock(&disp->lock);
> +
> +	if (!list_empty(&disp->dma_queue)) {
> +		do_gettimeofday(&timevalue);
> +		vb->v4l2_buf.timestamp = timevalue;

NACK. Use v4l2_get_timestamp and set vb2_queue's 'timestamp_type' field to
V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC.

> +		vb2_buffer_done(vb, VB2_BUF_STATE_DONE);
> +		disp->cur_frm = list_entry(disp->dma_queue.next,
> +				struct disp_buffer, list);
> +		list_del(&disp->cur_frm->list);
> +	}
> +
> +	clear_dma_irqstat(ppi->info->dma_ch);
> +
> +	addr = vb2_dma_contig_plane_dma_addr(&disp->cur_frm->vb, 0);
> +	ppi->ops->update_addr(ppi, (unsigned long)addr);
> +	ppi->ops->start(ppi);
> +
> +	spin_unlock(&disp->lock);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int disp_streamon(struct file *file, void *priv,
> +				enum v4l2_buf_type buf_type)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct disp_fh *fh = file->private_data;
> +	struct ppi_if *ppi = disp->ppi;
> +	dma_addr_t addr;
> +	int ret;
> +
> +	if (!fh->io_allowed)
> +		return -EBUSY;
> +
> +	/* call streamon to start streaming in videobuf */
> +	ret = vb2_streamon(&disp->buffer_queue, buf_type);
> +	if (ret)
> +		return ret;
> +
> +	/* if dma queue is empty, return error */
> +	if (list_empty(&disp->dma_queue)) {
> +		v4l2_err(&disp->v4l2_dev, "dma queue is empty\n");
> +		ret = -EINVAL;
> +		goto err;
> +	}
> +
> +	/* get the next frame from the dma queue */
> +	disp->cur_frm = list_entry(disp->dma_queue.next,
> +					struct disp_buffer, list);
> +	/* remove buffer from the dma queue */
> +	list_del(&disp->cur_frm->list);
> +	addr = vb2_dma_contig_plane_dma_addr(&disp->cur_frm->vb, 0);
> +	/* update DMA address */
> +	ppi->ops->update_addr(ppi, (unsigned long)addr);
> +	/* enable ppi */
> +	ppi->ops->start(ppi);

All this belongs in the start_streaming vb2_op.

> +
> +	return 0;
> +err:
> +	vb2_streamoff(&disp->buffer_queue, buf_type);
> +	return ret;
> +}
> +
> +static int disp_streamoff(struct file *file, void *priv,
> +				enum v4l2_buf_type buf_type)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct disp_fh *fh = file->private_data;
> +
> +	if (!fh->io_allowed)
> +		return -EBUSY;
> +
> +	return vb2_streamoff(&disp->buffer_queue, buf_type);
> +}
> +
> +static int disp_g_std(struct file *file, void *priv, v4l2_std_id *std)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +

Check if the current output supports STD and if not, return -ENODATA. Ditto for S_STD.

> +	*std = disp->std;
> +	return 0;
> +}
> +
> +static int disp_s_std(struct file *file, void *priv, v4l2_std_id *std)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +
> +	if (vb2_is_busy(&disp->buffer_queue))
> +		return -EBUSY;
> +
> +	ret = v4l2_subdev_call(disp->sd, video, s_std_output, *std);
> +	if (ret < 0)
> +		return ret;
> +
> +	disp->std = *std;
> +	return 0;
> +}
> +
> +static int disp_g_dv_timings(struct file *file, void *priv,
> +				struct v4l2_dv_timings *timings)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +

Check if this output supports DV_TIMINGS, and if not return -ENODATA. Ditto for s_dv_timings.

> +	ret = v4l2_subdev_call(disp->sd, video,
> +				g_dv_timings, timings);
> +	if (ret < 0)
> +		return ret;
> +
> +	disp->dv_timings = *timings;
> +	return 0;
> +}
> +
> +static int disp_s_dv_timings(struct file *file, void *priv,
> +				struct v4l2_dv_timings *timings)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	int ret;
> +	if (vb2_is_busy(&disp->buffer_queue))
> +		return -EBUSY;
> +
> +	ret = v4l2_subdev_call(disp->sd, video, s_dv_timings, timings);
> +	if (ret < 0)
> +		return ret;
> +
> +	disp->dv_timings = *timings;
> +	return 0;
> +}
> +
> +static int disp_enum_output(struct file *file, void *priv,
> +				struct v4l2_output *output)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct bfin_display_config *config = disp->cfg;
> +
> +	if (output->index >= config->num_outputs)
> +		return -EINVAL;
> +
> +	*output = config->outputs[output->index];
> +	return 0;
> +}
> +
> +static int disp_g_output(struct file *file, void *priv, unsigned int *index)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	*index = disp->cur_output;
> +	return 0;
> +}
> +
> +static int disp_s_output(struct file *file, void *priv, unsigned int index)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct bfin_display_config *config = disp->cfg;
> +	struct disp_route *route;
> +	int ret;
> +
> +	if (vb2_is_busy(&disp->buffer_queue))
> +		return -EBUSY;
> +
> +	if (index >= config->num_outputs)
> +		return -EINVAL;
> +
> +	route = &config->routes[index];
> +	ret = v4l2_subdev_call(disp->sd, video, s_routing,
> +				0, route->output, route->config);
> +	if ((ret < 0) && (ret != -ENOIOCTLCMD)) {
> +		v4l2_err(&disp->v4l2_dev, "Failed to set output\n");
> +		return ret;
> +	}
> +	disp->cur_output = index;
> +	/* if this route has specific config, update ppi control */
> +	if (route->ppi_control)
> +		config->ppi_control = route->ppi_control;
> +	return 0;
> +}
> +
> +static int disp_try_format(struct disp_device *disp,
> +				struct v4l2_pix_format *pixfmt,
> +				struct disp_format *disp_fmt)
> +{
> +	struct disp_format *df = disp->enc_formats;
> +	struct disp_format *fmt = NULL;
> +	struct v4l2_mbus_framefmt mbus_fmt;
> +	int ret, i;
> +
> +	for (i = 0; i < disp->num_enc_formats; i++) {
> +		fmt = &df[i];
> +		if (pixfmt->pixelformat == fmt->pixelformat)
> +			break;
> +	}
> +	if (i == disp->num_enc_formats)
> +		fmt = &df[0];
> +
> +	v4l2_fill_mbus_format(&mbus_fmt, pixfmt, fmt->mbus_code);
> +	ret = v4l2_subdev_call(disp->sd, video,
> +				try_mbus_fmt, &mbus_fmt);
> +	if (ret < 0)
> +		return ret;
> +	v4l2_fill_pix_format(pixfmt, &mbus_fmt);
> +	if (disp_fmt) {
> +		for (i = 0; i < disp->num_enc_formats; i++) {
> +			fmt = &df[i];
> +			if (mbus_fmt.code == fmt->mbus_code)
> +				break;
> +		}
> +		*disp_fmt = *fmt;
> +	}
> +	pixfmt->bytesperline = pixfmt->width * fmt->bpp / 8;
> +	pixfmt->sizeimage = pixfmt->bytesperline * pixfmt->height;
> +	return 0;
> +}
> +
> +static int disp_enum_fmt_vid_out(struct file *file, void  *priv,
> +					struct v4l2_fmtdesc *fmt)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct disp_format *df = disp->enc_formats;
> +
> +	if (fmt->index >= disp->num_enc_formats)
> +		return -EINVAL;
> +
> +	fmt->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;

Not necessary, type will always be V4L2_BUF_TYPE_VIDEO_OUTPUT.

> +	strlcpy(fmt->description,
> +		df[fmt->index].desc,
> +		sizeof(fmt->description));
> +	fmt->pixelformat = df[fmt->index].pixelformat;
> +	return 0;
> +}
> +
> +static int disp_try_fmt_vid_out(struct file *file, void *priv,
> +					struct v4l2_format *fmt)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_pix_format *pixfmt = &fmt->fmt.pix;
> +
> +	return disp_try_format(disp, pixfmt, NULL);
> +}
> +
> +static int disp_g_fmt_vid_out(struct file *file, void *priv,
> +				struct v4l2_format *fmt)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	fmt->fmt.pix = disp->fmt;
> +	return 0;
> +}
> +
> +static int disp_s_fmt_vid_out(struct file *file, void *priv,
> +				struct v4l2_format *fmt)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	struct v4l2_mbus_framefmt mbus_fmt;
> +	struct disp_format disp_fmt;
> +	struct v4l2_pix_format *pixfmt = &fmt->fmt.pix;
> +	int ret;
> +
> +	if (vb2_is_busy(&disp->buffer_queue))
> +		return -EBUSY;
> +
> +	/* see if format works */
> +	ret = disp_try_format(disp, pixfmt, &disp_fmt);
> +	if (ret < 0)
> +		return ret;
> +
> +	v4l2_fill_mbus_format(&mbus_fmt, pixfmt, disp_fmt.mbus_code);
> +	ret = v4l2_subdev_call(disp->sd, video, s_mbus_fmt, &mbus_fmt);
> +	if (ret < 0)
> +		return ret;
> +	disp->fmt = *pixfmt;
> +	disp->bpp = disp_fmt.bpp;
> +	disp->dlen = disp_fmt.dlen;
> +	return 0;
> +}
> +
> +static int disp_querycap(struct file *file, void  *priv,
> +				struct v4l2_capability *cap)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	cap->capabilities = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
> +	strlcpy(cap->driver, DISPLAY_DRV_NAME, sizeof(cap->driver));
> +	strlcpy(cap->bus_info, "Blackfin Platform", sizeof(cap->bus_info));
> +	strlcpy(cap->card, disp->cfg->card_name, sizeof(cap->card));

Please set cap->device_caps:

	cap->device_caps = V4L2_CAP_VIDEO_OUTPUT | V4L2_CAP_STREAMING;
	cap->capabilities = cap->device_caps | V4L2_CAP_DEVICE_CAPS;

> +	return 0;
> +}
> +
> +static int disp_g_parm(struct file *file, void *fh,
> +				struct v4l2_streamparm *a)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return v4l2_subdev_call(disp->sd, video, g_parm, a);
> +}
> +
> +static int disp_s_parm(struct file *file, void *fh,
> +				struct v4l2_streamparm *a)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return v4l2_subdev_call(disp->sd, video, s_parm, a);
> +}
> +
> +static int disp_g_chip_ident(struct file *file, void *priv,
> +		struct v4l2_dbg_chip_ident *chip)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	chip->ident = V4L2_IDENT_NONE;
> +	chip->revision = 0;
> +	if (chip->match.type != V4L2_CHIP_MATCH_I2C_DRIVER &&
> +			chip->match.type != V4L2_CHIP_MATCH_I2C_ADDR)
> +		return -EINVAL;
> +
> +	return v4l2_subdev_call(disp->sd, core,
> +			g_chip_ident, chip);
> +}

You can drop chip_ident: it's no longer needed since VIDIOC_DBG_G_CHIP_INFO
was added.

> +
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +static int disp_dbg_g_register(struct file *file, void *priv,
> +		struct v4l2_dbg_register *reg)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return v4l2_subdev_call(disp->sd, core,
> +			g_register, reg);
> +}
> +
> +static int disp_dbg_s_register(struct file *file, void *priv,
> +		struct v4l2_dbg_register *reg)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +
> +	return v4l2_subdev_call(disp->sd, core,
> +			s_register, reg);
> +}
> +#endif

Ditto for these g/s_register calls. The core now takes care of that.

> +
> +static int disp_log_status(struct file *file, void *priv)
> +{
> +	struct disp_device *disp = video_drvdata(file);
> +	/* status for sub devices */
> +	v4l2_device_call_all(&disp->v4l2_dev, 0, core, log_status);
> +	return 0;
> +}
> +
> +static const struct v4l2_ioctl_ops disp_ioctl_ops = {
> +	.vidioc_querycap         = disp_querycap,
> +	.vidioc_g_fmt_vid_out    = disp_g_fmt_vid_out,
> +	.vidioc_enum_fmt_vid_out = disp_enum_fmt_vid_out,
> +	.vidioc_s_fmt_vid_out    = disp_s_fmt_vid_out,
> +	.vidioc_try_fmt_vid_out  = disp_try_fmt_vid_out,
> +	.vidioc_enum_output      = disp_enum_output,
> +	.vidioc_g_output         = disp_g_output,
> +	.vidioc_s_output         = disp_s_output,
> +	.vidioc_s_std            = disp_s_std,
> +	.vidioc_g_std            = disp_g_std,
> +	.vidioc_s_dv_timings     = disp_s_dv_timings,
> +	.vidioc_g_dv_timings     = disp_g_dv_timings,
> +	.vidioc_reqbufs          = disp_reqbufs,
> +	.vidioc_querybuf         = disp_querybuf,
> +	.vidioc_qbuf             = disp_qbuf,
> +	.vidioc_dqbuf            = disp_dqbuf,
> +	.vidioc_streamon         = disp_streamon,
> +	.vidioc_streamoff        = disp_streamoff,
> +	.vidioc_g_parm           = disp_g_parm,
> +	.vidioc_s_parm           = disp_s_parm,
> +	.vidioc_g_chip_ident     = disp_g_chip_ident,
> +#ifdef CONFIG_VIDEO_ADV_DEBUG
> +	.vidioc_g_register       = disp_dbg_g_register,
> +	.vidioc_s_register       = disp_dbg_s_register,
> +#endif
> +	.vidioc_log_status       = disp_log_status,
> +};
> +
> +static struct v4l2_file_operations disp_fops = {
> +	.owner = THIS_MODULE,
> +	.open = disp_open,
> +	.release = disp_release,
> +	.unlocked_ioctl = video_ioctl2,
> +	.mmap = disp_mmap,
> +#ifndef CONFIG_MMU
> +	.get_unmapped_area = disp_get_unmapped_area,
> +#endif
> +	.poll = disp_poll
> +};
> +
> +static int disp_probe(struct platform_device *pdev)
> +{
> +	struct disp_device *disp;
> +	struct video_device *vfd;
> +	struct i2c_adapter *i2c_adap;
> +	struct bfin_display_config *config;
> +	struct vb2_queue *q;
> +	struct disp_route *route;
> +	int ret;
> +
> +	config = pdev->dev.platform_data;
> +	if (!config) {
> +		v4l2_err(pdev->dev.driver, "Unable to get board config\n");
> +		return -ENODEV;
> +	}
> +
> +	disp = kzalloc(sizeof(*disp), GFP_KERNEL);
> +	if (!disp) {
> +		v4l2_err(pdev->dev.driver, "Unable to alloc disp\n");
> +		return -ENOMEM;
> +	}
> +
> +	disp->cfg = config;
> +
> +	disp->ppi = ppi_create_instance(config->ppi_info);
> +	if (!disp->ppi) {
> +		v4l2_err(pdev->dev.driver, "Unable to create ppi\n");
> +		ret = -ENODEV;
> +		goto err_free_dev;
> +	}
> +	disp->ppi->priv = disp;
> +
> +	disp->alloc_ctx = vb2_dma_contig_init_ctx(&pdev->dev);
> +	if (IS_ERR(disp->alloc_ctx)) {
> +		ret = PTR_ERR(disp->alloc_ctx);
> +		goto err_free_ppi;
> +	}
> +
> +	vfd = video_device_alloc();
> +	if (!vfd) {
> +		ret = -ENOMEM;
> +		v4l2_err(pdev->dev.driver, "Unable to alloc video device\n");
> +		goto err_cleanup_ctx;
> +	}
> +
> +	/* initialize field of video device */
> +	vfd->release    = video_device_release;
> +	vfd->fops       = &disp_fops;
> +	vfd->ioctl_ops  = &disp_ioctl_ops;
> +	vfd->tvnorms    = 0;
> +	vfd->v4l2_dev   = &disp->v4l2_dev;
> +	vfd->vfl_dir    = VFL_DIR_TX;
> +	set_bit(V4L2_FL_USE_FH_PRIO, &vfd->flags);
> +	strncpy(vfd->name, DISPLAY_DRV_NAME, sizeof(vfd->name));
> +	disp->video_dev = vfd;
> +
> +	ret = v4l2_device_register(&pdev->dev, &disp->v4l2_dev);
> +	if (ret) {
> +		v4l2_err(pdev->dev.driver,
> +				"Unable to register v4l2 device\n");
> +		goto err_release_vdev;
> +	}
> +	v4l2_info(&disp->v4l2_dev, "v4l2 device registered\n");
> +
> +	disp->v4l2_dev.ctrl_handler = &disp->ctrl_handler;
> +	ret = v4l2_ctrl_handler_init(&disp->ctrl_handler, 0);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to init control handler\n");
> +		goto err_unreg_v4l2;
> +	}
> +
> +	spin_lock_init(&disp->lock);
> +	/* initialize queue */
> +	q = &disp->buffer_queue;
> +	q->type = V4L2_BUF_TYPE_VIDEO_OUTPUT;
> +	q->io_modes = VB2_MMAP;
> +	q->drv_priv = disp;
> +	q->buf_struct_size = sizeof(struct disp_buffer);
> +	q->ops = &disp_video_qops;
> +	q->mem_ops = &vb2_dma_contig_memops;
> +
> +	ret = vb2_queue_init(q);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to init videobuf2 queue\n");
> +		goto err_free_handler;
> +	}
> +
> +	mutex_init(&disp->mutex);
> +
> +	/* init video dma queues */
> +	INIT_LIST_HEAD(&disp->dma_queue);
> +
> +	vfd->lock = &disp->mutex;
> +
> +	/* register video device */
> +	ret = video_register_device(disp->video_dev, VFL_TYPE_GRABBER, -1);

This should be done last after everything else is set up.

> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to register video device\n");
> +		goto err_free_handler;
> +	}
> +	video_set_drvdata(disp->video_dev, disp);
> +	v4l2_info(&disp->v4l2_dev, "video device registered as: %s\n",
> +			video_device_node_name(vfd));
> +
> +	/* load up the subdevice */
> +	i2c_adap = i2c_get_adapter(config->i2c_adapter_id);
> +	if (!i2c_adap) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to find i2c adapter\n");
> +		goto err_unreg_vdev;
> +
> +	}
> +	disp->sd = v4l2_i2c_new_subdev_board(&disp->v4l2_dev,
> +						 i2c_adap,
> +						 &config->board_info,
> +						 NULL);
> +	if (disp->sd) {
> +		int i;
> +		if (!config->num_outputs) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to work without output\n");
> +			goto err_unreg_vdev;
> +		}
> +
> +		/* update tvnorms from the sub devices */
> +		for (i = 0; i < config->num_outputs; i++)
> +			vfd->tvnorms |= config->outputs[i].std;

No. vfd->tvnorms should be the std value for the current output, not that of
all outputs combined.

> +	} else {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to register sub device\n");
> +		goto err_unreg_vdev;
> +	}
> +
> +	v4l2_info(&disp->v4l2_dev, "v4l2 sub device registered\n");
> +
> +	/*
> +	 * explicitly set output, otherwise some boards
> +	 * may not work at the state as we expected
> +	 */
> +	route = &config->routes[0];
> +	ret = v4l2_subdev_call(disp->sd, video, s_routing,
> +				route->output, route->output, 0);
> +	if ((ret < 0) && (ret != -ENOIOCTLCMD)) {
> +		v4l2_err(&disp->v4l2_dev, "Failed to set output\n");
> +		goto err_unreg_vdev;
> +	}
> +	disp->cur_output = 0;
> +	/* if this route has specific config, update ppi control */
> +	if (route->ppi_control)
> +		config->ppi_control = route->ppi_control;
> +
> +	/* now we can probe the default state */
> +	if (config->outputs[0].capabilities & V4L2_IN_CAP_STD) {
> +		v4l2_std_id std;
> +		ret = v4l2_subdev_call(disp->sd, core, g_std, &std);
> +		if (ret) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to get std\n");
> +			goto err_unreg_vdev;
> +		}
> +		disp->std = std;
> +	}
> +	if (config->outputs[0].capabilities & V4L2_IN_CAP_CUSTOM_TIMINGS) {
> +		struct v4l2_dv_timings dv_timings;
> +		ret = v4l2_subdev_call(disp->sd, video,
> +				g_dv_timings, &dv_timings);
> +		if (ret) {
> +			v4l2_err(&disp->v4l2_dev,
> +					"Unable to get dv timings\n");
> +			goto err_unreg_vdev;
> +		}
> +		disp->dv_timings = dv_timings;
> +	}
> +	ret = disp_init_encoder_formats(disp);
> +	if (ret) {
> +		v4l2_err(&disp->v4l2_dev,
> +				"Unable to create encoder formats table\n");
> +		goto err_unreg_vdev;
> +	}
> +	return 0;
> +err_unreg_vdev:
> +	video_unregister_device(disp->video_dev);
> +	disp->video_dev = NULL;
> +err_free_handler:
> +	v4l2_ctrl_handler_free(&disp->ctrl_handler);
> +err_unreg_v4l2:
> +	v4l2_device_unregister(&disp->v4l2_dev);
> +err_release_vdev:
> +	if (disp->video_dev)
> +		video_device_release(disp->video_dev);
> +err_cleanup_ctx:
> +	vb2_dma_contig_cleanup_ctx(disp->alloc_ctx);
> +err_free_ppi:
> +	ppi_delete_instance(disp->ppi);
> +err_free_dev:
> +	kfree(disp);
> +	return ret;
> +}
> +
> +static int disp_remove(struct platform_device *pdev)
> +{
> +	struct v4l2_device *v4l2_dev = platform_get_drvdata(pdev);
> +	struct disp_device *disp = container_of(v4l2_dev,
> +						struct disp_device, v4l2_dev);
> +
> +	disp_free_encoder_formats(disp);
> +	video_unregister_device(disp->video_dev);
> +	v4l2_ctrl_handler_free(&disp->ctrl_handler);
> +	v4l2_device_unregister(v4l2_dev);
> +	vb2_dma_contig_cleanup_ctx(disp->alloc_ctx);
> +	ppi_delete_instance(disp->ppi);
> +	kfree(disp);
> +	return 0;
> +}
> +
> +static struct platform_driver disp_driver = {
> +	.driver = {
> +		.name  = DISPLAY_DRV_NAME,
> +		.owner = THIS_MODULE,
> +	},
> +	.probe = disp_probe,
> +	.remove = disp_remove,
> +};
> +module_platform_driver(disp_driver);
> +
> +MODULE_DESCRIPTION("Analog Devices blackfin video display driver");
> +MODULE_AUTHOR("Scott Jiang <Scott.Jiang.Linux@gmail.com>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/media/blackfin/bfin_display.h b/include/media/blackfin/bfin_display.h
> new file mode 100644
> index 0000000..6eb1d5a
> --- /dev/null
> +++ b/include/media/blackfin/bfin_display.h
> @@ -0,0 +1,38 @@
> +#ifndef _BFIN_DISPLAY_H_
> +#define _BFIN_DISPLAY_H_
> +
> +#include <linux/i2c.h>
> +
> +struct v4l2_output;
> +struct ppi_info;
> +
> +struct disp_route {
> +	u32 output;
> +	u32 config;
> +	u32 ppi_control;
> +};
> +
> +struct bfin_display_config {
> +	/* card name */
> +	char *card_name;
> +	/* outputs available at the sub device */
> +	struct v4l2_output *outputs;
> +	/* number of outputs supported */
> +	int num_outputs;
> +	/* routing information for each output */
> +	struct disp_route *routes;
> +	/* i2c bus adapter no */
> +	int i2c_adapter_id;
> +	/* i2c subdevice board info */
> +	struct i2c_board_info board_info;
> +	/* ppi board info */
> +	const struct ppi_info *ppi_info;
> +	/* ppi control */
> +	u32 ppi_control;
> +	/* ppi interrupt mask */
> +	u32 int_mask;
> +	/* horizontal blanking pixels */
> +	int blank_pixels;
> +};
> +
> +#endif
> 

Regards,

	Hans
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Hi Hans,

>> +/*
>> + * Analog Devices video display driver
>> + *
>> + * Copyright (c) 2011 Analog Devices Inc.
>
> Analog Devices? What has this to do with Analog Devices?
>
I wrote this driver for Analog Devices Blackfin.


>> +
>> +static int disp_mmap(struct file *file, struct vm_area_struct *vma)
>> +{
>> +     struct disp_device *disp = video_drvdata(file);
>> +     int ret;
>> +
>> +     if (mutex_lock_interruptible(&disp->mutex))
>> +             return -ERESTARTSYS;
>> +     ret = vb2_mmap(&disp->buffer_queue, vma);
>> +     mutex_unlock(&disp->mutex);
>> +     return ret;
>> +}
>> +
>> +#ifndef CONFIG_MMU
>> +static unsigned long disp_get_unmapped_area(struct file *file,
>> +                                         unsigned long addr,
>> +                                         unsigned long len,
>> +                                         unsigned long pgoff,
>> +                                         unsigned long flags)
>> +{
>> +     struct disp_device *disp = video_drvdata(file);
>> +     int ret;
>> +
>> +     if (mutex_lock_interruptible(&disp->mutex))
>> +             return -ERESTARTSYS;
>> +     ret = vb2_get_unmapped_area(&disp->buffer_queue,
>> +                                 addr,
>> +                                 len,
>> +                                 pgoff,
>> +                                 flags);
>> +     mutex_unlock(&disp->mutex);
>> +     return ret;
>> +}
>> +#endif
>> +
>> +static unsigned int disp_poll(struct file *file, poll_table *wait)
>> +{
>> +     struct disp_device *disp = video_drvdata(file);
>> +     int ret;
>> +
>> +     mutex_lock(&disp->mutex);
>> +     ret = vb2_poll(&disp->buffer_queue, file, wait);
>> +     mutex_unlock(&disp->mutex);
>> +     return ret;
>> +}
>
> Use the helper functions in media/videobuf2-core.h for these file ops.
>
OK, I will use vb2_fop_mmap. But I'm not sure if I need to lock it.

>> +static int disp_reqbufs(struct file *file, void *priv,
>> +                     struct v4l2_requestbuffers *req_buf)
>> +{
>> +     struct disp_device *disp = video_drvdata(file);
>> +     struct vb2_queue *vq = &disp->buffer_queue;
>> +     struct v4l2_fh *fh = file->private_data;
>> +     struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
>> +
>> +     if (vb2_is_busy(vq))
>> +             return -EBUSY;
>> +
>> +     disp_fh->io_allowed = true;
>
> There is no need for io_allowed. The vb2_is_busy() function does the same
> thing. It saves a lot of code since you now can just use v4l2_fh instead of
> disp_fh, which allows you to use even more helper functions (v4l2_fh_open and
> v4l2_fh_release for starters).
>
> In fact, you can use all the vb2 ioctl helpers saving you a lot of code.
>
I don't think so. vb2_is_busy can't check if this file instance has
the right to stream off output.
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Hi Sylwester ,

>> @@ -9,7 +9,18 @@ config VIDEO_BLACKFIN_CAPTURE
>>           To compile this driver as a module, choose M here: the
>>           module will be called bfin_capture.
>>
>> +config VIDEO_BLACKFIN_DISPLAY
>> +       tristate "Blackfin Video Display Driver"
>> +       depends on VIDEO_V4L2&&  BLACKFIN&&  I2C
>> +       select VIDEOBUF2_DMA_CONTIG
>> +       help
>> +         V4L2 bridge driver for Blackfin video display device.
>
>
> Shouldn't it just be "V4L2 output driver", why are you calling it "bridge" ?
>
Hmm, capture<->display, input<->output, right?
The kernel docs called it bridge, may "host" sounds better.

>> +/*
>> + * Analog Devices video display driver
>
>
> Sounds a bit too generic.
>
>> + *
>> + * Copyright (c) 2011 Analog Devices Inc.
>
>
> 2011 - 2013 ?
>
Written in 2011.

>> +struct disp_fh {
>> +       struct v4l2_fh fh;
>> +       /* indicates whether this file handle is doing IO */
>> +       bool io_allowed;
>> +};
>
>
> This structure should not be needed when you use the vb2 helpers. Please see
> below for more details.
>
The only question is how the core deal with the permission that which
file handle can
stream off the output. I want to impose a rule that only IO handle can stop IO.
I refer to priority, but current kernel driver export this to user
space and let user decide it.
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Hi Scott,

On 04/17/2013 08:57 AM, Scott Jiang wrote:
> Hi Sylwester ,
>
>>> @@ -9,7 +9,18 @@ config VIDEO_BLACKFIN_CAPTURE
>>>            To compile this driver as a module, choose M here: the
>>>            module will be called bfin_capture.
>>>
>>> +config VIDEO_BLACKFIN_DISPLAY
>>> +       tristate "Blackfin Video Display Driver"
>>> +       depends on VIDEO_V4L2&&   BLACKFIN&&   I2C
>>> +       select VIDEOBUF2_DMA_CONTIG
>>> +       help
>>> +         V4L2 bridge driver for Blackfin video display device.
>>
>>
>> Shouldn't it just be "V4L2 output driver", why are you calling it "bridge" ?
>>
> Hmm, capture<->display, input<->output, right?

Yes, input/output from user space POV.

> The kernel docs called it bridge, may "host" sounds better.

I suggested "output" as referring to the "V4L2 output interface" [1].
I guess bridge/host could just be skipped and we could simply put it as:

"V4L2 driver for Blackfin video display (E)PPI interface."

>>> +/*
>>> + * Analog Devices video display driver
>>
>>
>> Sounds a bit too generic.
>>
>>> + *
>>> + * Copyright (c) 2011 Analog Devices Inc.
>>
>>
>> 2011 - 2013 ?
>>
> Written in 2011.

Since you're still actively working on it I would say it makes sense
to put it as 2011 - 2013. At least this is what most people do AFAICS.
But I don't really mind, it's up to you!

>>> +struct disp_fh {
>>> +       struct v4l2_fh fh;
>>> +       /* indicates whether this file handle is doing IO */
>>> +       bool io_allowed;
>>> +};
>>
>>
>> This structure should not be needed when you use the vb2 helpers. Please see
>> below for more details.
>>
> The only question is how the core deal with the permission that which
> file handle can
> stream off the output. I want to impose a rule that only IO handle can stop IO.
> I refer to priority, but current kernel driver export this to user
> space and let user decide it.

As far as I can see there would be no change in behaviour if you used the
helpers. For instance, vidioc_streamon/streamoff ioctls

/* From videobuf2-core.c */

/* The queue is busy if there is a owner and you are not that owner. */
static inline bool vb2_queue_is_busy(struct video_device *vdev, struct 
file *file)
{
	return vdev->queue->owner && vdev->queue->owner != file->private_data;
}

/* vb2 ioctl helpers */

int vb2_ioctl_reqbufs(struct file *file, void *priv,
			  struct v4l2_requestbuffers *p)
{
	struct video_device *vdev = video_devdata(file);
	int res = __verify_memory_type(vdev->queue, p->memory, p->type);

	if (res)
		return res;
	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	res = __reqbufs(vdev->queue, p);
	/* If count == 0, then the owner has released all buffers and he
	   is no longer owner of the queue. Otherwise we have a new owner. */
	if (res == 0)
		vdev->queue->owner = p->count ? file->private_data : NULL;
	return res;
}

int vb2_ioctl_streamon(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_streamon(vdev->queue, i);
}

int vb2_ioctl_streamoff(struct file *file, void *priv, enum v4l2_buf_type i)
{
	struct video_device *vdev = video_devdata(file);

	if (vb2_queue_is_busy(vdev, file))
		return -EBUSY;
	return vb2_streamoff(vdev->queue, i);
}

And in your code:


+static int disp_reqbufs(struct file *file, void *priv,
+			struct v4l2_requestbuffers *req_buf)
+{
+	struct disp_device *disp = video_drvdata(file);
+	struct vb2_queue *vq = &disp->buffer_queue;
+	struct v4l2_fh *fh = file->private_data;
+	struct disp_fh *disp_fh = container_of(fh, struct disp_fh, fh);
+
+	if (vb2_is_busy(vq))
+		return -EBUSY;
+
+	disp_fh->io_allowed = true;
+
+	return vb2_reqbufs(vq, req_buf);
+}

+static int disp_streamon(struct file *file, void *priv,
+				enum v4l2_buf_type buf_type)
+{
+	struct disp_device *disp = video_drvdata(file);
+	struct disp_fh *fh = file->private_data;
+	struct ppi_if *ppi = disp->ppi;
+	dma_addr_t addr;
+	int ret;
+
+	if (!fh->io_allowed)
+		return -EBUSY;
+
+	/* call streamon to start streaming in videobuf */
+	ret = vb2_streamon(&disp->buffer_queue, buf_type);
+	if (ret)
+		return ret;
+
	...
+}

+static int disp_streamoff(struct file *file, void *priv,
+				enum v4l2_buf_type buf_type)
+{
+	struct disp_device *disp = video_drvdata(file);
+	struct disp_fh *fh = file->private_data;
+
+	if (!fh->io_allowed)
+		return -EBUSY;
+
+	return vb2_streamoff(&disp->buffer_queue, buf_type);
+}

Please note that you really should be setting io_allowed to true only if
vb2_reqbufs() succeeds.

Hence I wouldn't hesitate to use the core implementation. This way we get
more consistent behaviour across all drivers, which is in line with
what you have currently implemented AFAICT.

[1] http://linuxtv.org/downloads/v4l-dvb-apis/devices.html#output


Thanks,
Sylwester
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Hi Sylwester,

>
>> +       struct v4l2_device v4l2_dev;
>> +       /* v4l2 control handler */
>> +       struct v4l2_ctrl_handler ctrl_handler;
>
>
> This handler seems to be unused, I couldn't find any code adding controls
> to it. Any initialization of this handler is a dead code now. You probably
> want to move that bits to a patch actually adding any controls.
>

This host driver doesn't support any control but without it subdev
controls can't be accessed.
v4l2_ctrl_add_handler should just return 0 if v4l2_dev->ctrl_handler is NULL.
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Hi Scott,

On 04/24/2013 11:26 AM, Scott Jiang wrote:
>>
>>> +       struct v4l2_device v4l2_dev;
>>> +       /* v4l2 control handler */
>>> +       struct v4l2_ctrl_handler ctrl_handler;
>>
>>
>> This handler seems to be unused, I couldn't find any code adding controls
>> to it. Any initialization of this handler is a dead code now. You probably
>> want to move that bits to a patch actually adding any controls.
>>
>
> This host driver doesn't support any control but without it subdev
> controls can't be accessed.
> v4l2_ctrl_add_handler should just return 0 if v4l2_dev->ctrl_handler is NULL.

You're right, I missed the point that a video device could expose just 
controls
inherited from subdevs. And for that its control handler need to be 
initialized.
So I didn't help you too much with that comment, please just ignore it.

Regards,
Sylwester
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