[PATCH v12 3/3] drm/tinydrm: Add devres versions of backlight_get

[Noralf Trønnes]

Den 12.10.2017 17.57, skrev Meghana Madhyastha:
> 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 v12:
>   -Move backlight_put() to the patch 2/3 from patch 3/3.
>
>   drivers/gpu/drm/tinydrm/mi0283qt.c  |  2 +-
>   drivers/video/backlight/backlight.c | 25 +++++++++++++++++++++++++
>   include/linux/backlight.h           | 16 ++++++++++++++++
>   3 files changed, 42 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 f3e95b3..3663f26 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -623,6 +623,31 @@ static inline void backlight_put(struct backlight_device *bd)
>   		put_device(&bd->dev);
>   }
>   
> +/**
> + ** 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);

How can this even compile? Where is devm_backlight_get_release?
Or didn't it change name to devm_backlight_put or something?

> +	if (ret) {
> +		backlight_put(bd);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return bd;
> +}
> +EXPORT_SYMBOL(devm_backlight_get);
> +
>   static void __exit backlight_class_exit(void)
>   {
>   	class_destroy(backlight_class);
> 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);
> +}
> +

This is the one that should be moved to to previous patch.

>   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