Re: [PATCH v8 3/3] drm/tinydrm: Add devres versions of backlight_get

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 11 Oct 2017, Meghana Madhyastha <meghana.madhyastha@gmail.com> wrote:
> On Wed, Oct 11, 2017 at 04:56:25PM +0300, Jani Nikula wrote:
>> On Wed, 11 Oct 2017, Meghana Madhyastha <meghana.madhyastha@gmail.com> wrote:
>> > Add devm_backlight_get and the corresponding release
>> > function because some drivers use devres versions of functions
>> > for requiring device resources.
>> >
>> > Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
>> > ---
>> > Changes in v8:
>> > -Put the devres version to backlight.c along with backlight_get.
>> >
>> >  drivers/gpu/drm/tinydrm/mi0283qt.c  |  2 +-
>> >  drivers/video/backlight/backlight.c | 31 +++++++++++++++++++++++++++++++
>> >  include/linux/backlight.h           | 16 ++++++++++++++++
>> >  3 files changed, 48 insertions(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/tinydrm/mi0283qt.c b/drivers/gpu/drm/tinydrm/mi0283qt.c
>> > index edf9502..03fec36 100644
>> > --- a/drivers/gpu/drm/tinydrm/mi0283qt.c
>> > +++ b/drivers/gpu/drm/tinydrm/mi0283qt.c
>> > @@ -190,7 +190,7 @@ static int mi0283qt_probe(struct spi_device *spi)
>> >  	if (IS_ERR(mipi->regulator))
>> >  		return PTR_ERR(mipi->regulator);
>> >  
>> > -	mipi->backlight = backlight_get(dev);
>> > +	mipi->backlight = devm_backlight_get(dev);
>> >  	if (IS_ERR(mipi->backlight))
>> >  		return PTR_ERR(mipi->backlight);
>> >  
>> > diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
>> > index 1debb60..9b24dc2 100644
>> > --- a/drivers/video/backlight/backlight.c
>> > +++ b/drivers/video/backlight/backlight.c
>> > @@ -618,6 +618,37 @@ struct backlight_device *backlight_get(struct device *dev)
>> >  	return bd;
>> >  }
>> >  EXPORT_SYMBOL(backlight_get);
>> > +
>> > +static void devm_backlight_get_release(void *data)
>> 
>> I think that's a confusing name because of the "get", maybe just call it
>> devm_backlight_put?
>
> backlight_put is already in use as a helper function so wouldn't
> devm_backlight_put be confusing as there is already a backlight_put?

I'd think not, as it literally is a devm version of the same thing.

BR,
Jani.



>
> Regards,
> Meghana
>  
>> BR,
>> Jani.
>> 
>> 
>> 
>> > +{
>> > +	backlight_put(data);
>> > +}
>> > +
>> > +/**
>> > + * devm_backlight_get - Resource-managed backlight_get()
>> > + * @dev: Device
>> > + *
>> > + * Device managed version of backlight_get(). The reference on the backlight
>> > + * device is automatically dropped on driver detach.
>> > + */
>> > +struct backlight_device *devm_backlight_get(struct device *dev)
>> > +{
>> > +	struct backlight_device *bd;
>> > +	int ret;
>> > +
>> > +	bd = backlight_get(dev);
>> > +	if (!bd)
>> > +		return NULL;
>> > +
>> > +	ret = devm_add_action(dev, devm_backlight_get_release, bd);
>> > +	if (ret) {
>> > +		backlight_put(bd);
>> > +		return ERR_PTR(ret);
>> > +	}
>> > +
>> > +	return bd;
>> > +}
>> > +EXPORT_SYMBOL(devm_backlight_get);
>> >  #endif
>> >  
>> >  static void __exit backlight_class_exit(void)
>> > diff --git a/include/linux/backlight.h b/include/linux/backlight.h
>> > index 1d713b3..0bfadb6 100644
>> > --- a/include/linux/backlight.h
>> > +++ b/include/linux/backlight.h
>> > @@ -183,6 +183,16 @@ static inline int backlight_disable(struct backlight_device *bd)
>> >  	return backlight_update_status(bd);
>> >  }
>> >  
>> > +/**
>> > + ** backlight_put - Drop backlight reference
>> > + ** @bd: the backlight device to put
>> > + **/
>> > +static inline void backlight_put(struct backlight_device *bd)
>> > +{
>> > +	if (bd)
>> > +		put_device(&bd->dev);
>> > +}
>> > +
>> >  struct generic_bl_info {
>> >  	const char *name;
>> >  	int max_intensity;
>> > @@ -204,11 +214,17 @@ of_find_backlight_by_node(struct device_node *node)
>> >  
>> >  #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>> >  struct backlight_device *backlight_get(struct device *dev);
>> > +struct backlight_device *devm_backlight_get(struct device *dev);
>> >  #else
>> >  static inline struct backlight_device *backlight_get(struct device *dev)
>> >  {
>> >  	return NULL;
>> >  }
>> > +
>> > +static inline struct backlight_device *devm_backlight_get(struct device *dev)
>> > +{
>> > +	return NULL;
>> > +}
>> >  #endif
>> >  
>> >  #endif
>> 
>> -- 
>> Jani Nikula, Intel Open Source Technology Center

-- 
Jani Nikula, Intel Open Source Technology Center
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