[v3] media: dvb: Provide 4 devm variants

  Provide devm variants for automatic resource release on device removal.
Makes error-handling in probe() simpler, thus less error-prone.
Once all resources are devmanaged, remove() is no longer needed.

Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
---
Changes from v2:
x Handle dvb_register_adapter() return code correctly
Changes from v1:
x Simplify devm_dvb_register_adapter() implementation
x Add 3 more devm APIs
x Document them in devres.rst
---
 Documentation/driver-model/devres.rst |  6 ++++++
 drivers/media/dvb-core/dmxdev.c       | 13 +++++++++++++
 drivers/media/dvb-core/dvb_demux.c    | 13 +++++++++++++
 drivers/media/dvb-core/dvb_frontend.c | 13 +++++++++++++
 drivers/media/dvb-core/dvbdev.c       | 12 ++++++++++++
 include/media/dmxdev.h                |  3 +++
 include/media/dvb_demux.h             |  2 ++
 include/media/dvb_frontend.h          |  3 +++
 include/media/dvbdev.h                |  3 +++
 9 files changed, 68 insertions(+)
  

Hi Marc,

Thanks for your patch.

On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
> Provide devm variants for automatic resource release on device removal.
> Makes error-handling in probe() simpler, thus less error-prone.
> Once all resources are devmanaged, remove() is no longer needed.
> 

I think it would be better to add this API as part of a series
that also uses it.

Regards,
Eze
  

On 21/07/2019 17:02, Ezequiel Garcia wrote:

> On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
>
>> Provide devm variants for automatic resource release on device removal.
>> Makes error-handling in probe() simpler, thus less error-prone.
>> Once all resources are devmanaged, remove() is no longer needed.
> 
> I think it would be better to add this API as part of a series
> that also uses it.

I have an outstanding RFC for a new driver:

	https://patchwork.kernel.org/patch/11040435/

Locally, I've updated the probe function to use the proposed devm functions.

I was mainly hoping to get initial feedback from the maintainers.
1) See if they're OK with devm APIs
2) See if they're OK with the way I implemented devm APIs
3) See what's missing to get an Ack

static int tsif_probe(struct platform_device *pdev)
{
	int err, virq;
	struct tsif *tsif;
	struct resource *res;
	struct dvb_frontend *fe;
	struct dvb_adapter *adap;
	struct device *dev = &pdev->dev;
	short num = DVB_UNSET;

	fe = dvb_get_demod_fe(dev->of_node);
	if (!fe)
		return -ENXIO;

	tsif = devm_kzalloc(dev, sizeof(*tsif), GFP_KERNEL);
	if (!tsif)
		return -ENOMEM;

	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsif0");
	tsif->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(tsif->base))
		return PTR_ERR(tsif->base);

	virq = platform_get_irq_byname(pdev, "tsif0");
	err = devm_request_irq(dev, virq, tsif_isr, IRQF_SHARED, "tsif", tsif);
	if (err)
		return err;

	tsif->clk = devm_clk_get(dev, "iface");
	if (IS_ERR(tsif->clk))
		return PTR_ERR(tsif->clk);

	err = devm_clk_prepare_enable(dev, tsif->clk);
	if (err)
		return err;

	adap = &tsif->adapter;
	err = devm_dvb_register_adapter(dev, adap, "tsif", THIS_MODULE, &num);
	if (err) return err;

	/* Not sure the diff between filter and feed? */
	tsif->demux.filternum = 16; /*** Dunno what to put here ***/
	tsif->demux.feednum = 16;	/*** Dunno what to put here ***/
	tsif->demux.start_feed = noop;
	tsif->demux.stop_feed = noop;
	err = devm_dvb_dmx_init(dev, &tsif->demux);
	if (err) return err;

	/* What relation to dvb_demux.filternum??? */
	/* Do I need this object?? */
	tsif->dmxdev.filternum = 16;
	tsif->dmxdev.demux = &tsif->demux.dmx;
	err = devm_dvb_dmxdev_init(dev, &tsif->dmxdev, adap);
	if (err) return err;

	err = devm_dvb_register_frontend(dev, adap, fe);
	if (err) return err;

	writel_relaxed(TSIF_START + ENABLE_IRQ, tsif->base + TSIF_STS_CTL);
	devm_add_action(dev, stop_tsif, tsif);
	INIT_WORK(&tsif->work, handle_pkt);

	return 0;
}
  

On Mon, Jul 22, 2019 at 10:13:56AM +0200, Marc Gonzalez wrote:
> On 21/07/2019 17:02, Ezequiel Garcia wrote:
> 
> > On Thu, 2019-07-18 at 15:03 +0200, Marc Gonzalez wrote:
> >
> >> Provide devm variants for automatic resource release on device removal.
> >> Makes error-handling in probe() simpler, thus less error-prone.
> >> Once all resources are devmanaged, remove() is no longer needed.
> > 
> > I think it would be better to add this API as part of a series
> > that also uses it.
> 
> I have an outstanding RFC for a new driver:
> 
> 	https://patchwork.kernel.org/patch/11040435/
> 
> Locally, I've updated the probe function to use the proposed devm functions.
> 
> I was mainly hoping to get initial feedback from the maintainers.
> 1) See if they're OK with devm APIs

devm_ has some lifetime issues, wrt to disconnect. However, for a platform
device it is fine.

> 2) See if they're OK with the way I implemented devm APIs

Looks good to me.

> 3) See what's missing to get an Ack

Please submit both this patch and a the driver as a series.

Thanks,

Sean

> 
> static int tsif_probe(struct platform_device *pdev)
> {
> 	int err, virq;
> 	struct tsif *tsif;
> 	struct resource *res;
> 	struct dvb_frontend *fe;
> 	struct dvb_adapter *adap;
> 	struct device *dev = &pdev->dev;
> 	short num = DVB_UNSET;
> 
> 	fe = dvb_get_demod_fe(dev->of_node);
> 	if (!fe)
> 		return -ENXIO;
> 
> 	tsif = devm_kzalloc(dev, sizeof(*tsif), GFP_KERNEL);
> 	if (!tsif)
> 		return -ENOMEM;
> 
> 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "tsif0");
> 	tsif->base = devm_ioremap_resource(dev, res);
> 	if (IS_ERR(tsif->base))
> 		return PTR_ERR(tsif->base);
> 
> 	virq = platform_get_irq_byname(pdev, "tsif0");
> 	err = devm_request_irq(dev, virq, tsif_isr, IRQF_SHARED, "tsif", tsif);
> 	if (err)
> 		return err;
> 
> 	tsif->clk = devm_clk_get(dev, "iface");
> 	if (IS_ERR(tsif->clk))
> 		return PTR_ERR(tsif->clk);
> 
> 	err = devm_clk_prepare_enable(dev, tsif->clk);
> 	if (err)
> 		return err;
> 
> 	adap = &tsif->adapter;
> 	err = devm_dvb_register_adapter(dev, adap, "tsif", THIS_MODULE, &num);
> 	if (err) return err;
> 
> 	/* Not sure the diff between filter and feed? */
> 	tsif->demux.filternum = 16; /*** Dunno what to put here ***/
> 	tsif->demux.feednum = 16;	/*** Dunno what to put here ***/
> 	tsif->demux.start_feed = noop;
> 	tsif->demux.stop_feed = noop;
> 	err = devm_dvb_dmx_init(dev, &tsif->demux);
> 	if (err) return err;
> 
> 	/* What relation to dvb_demux.filternum??? */
> 	/* Do I need this object?? */
> 	tsif->dmxdev.filternum = 16;
> 	tsif->dmxdev.demux = &tsif->demux.dmx;
> 	err = devm_dvb_dmxdev_init(dev, &tsif->dmxdev, adap);
> 	if (err) return err;
> 
> 	err = devm_dvb_register_frontend(dev, adap, fe);
> 	if (err) return err;
> 
> 	writel_relaxed(TSIF_START + ENABLE_IRQ, tsif->base + TSIF_STS_CTL);
> 	devm_add_action(dev, stop_tsif, tsif);
> 	INIT_WORK(&tsif->work, handle_pkt);
> 
> 	return 0;
> }