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

[Meghana Madhyastha]

On Wed, Oct 11, 2017 at 04:56:25PM +0300, Jani Nikula wrote:
> On Wed, 11 Oct 2017, Meghana Madhyastha <meghana.madhyastha at 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 at 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?

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