Re: [PATCH v17 05/10] video: backlight: Add devres versions of of_find_backlight

[Daniel Thompson]

On Fri, Jan 19, 2018 at 10:44:33AM +0000, Meghana Madhyastha wrote:
> Add devm_of_find_backlight and the corresponding release
> function because some drivers use devres versions of functions
> for acquiring device resources.
> 
> Signed-off-by: Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx>

Acked-by: Daniel Thompson <daniel.thompson@xxxxxxxxxx>


> ---
> changes in v17:
> -fix checkpath errors/warnings
> -rename devm_backlight_put to 
>  devm_backlight_release
> 
>  drivers/video/backlight/backlight.c | 30 ++++++++++++++++++++++++++++++
>  include/linux/backlight.h           |  7 +++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> index 553bf5c48..deb824bef 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -623,6 +623,36 @@ struct backlight_device *of_find_backlight(struct device *dev)
>  }
>  EXPORT_SYMBOL(of_find_backlight);
>  
> +static void devm_backlight_release(void *data)
> +{
> +	backlight_put(data);
> +}
> +
> +/**
> + * devm_of_find_backlight - Resource-managed of_find_backlight()
> + * @dev: Device
> + *
> + * Device managed version of of_find_backlight().
> + * The reference on the backlight device is automatically
> + * dropped on driver detach.
> + */
> +struct backlight_device *devm_of_find_backlight(struct device *dev)
> +{
> +	struct backlight_device *bd;
> +	int ret;
> +
> +	bd = of_find_backlight(dev);
> +	if (IS_ERR_OR_NULL(bd))
> +		return bd;
> +	ret = devm_add_action(dev, devm_backlight_release, bd);
> +	if (ret) {
> +		backlight_put(bd);
> +		return ERR_PTR(ret);
> +	}
> +	return bd;
> +}
> +EXPORT_SYMBOL(devm_of_find_backlight);
> +
>  static void __exit backlight_class_exit(void)
>  {
>  	class_destroy(backlight_class);
> diff --git a/include/linux/backlight.h b/include/linux/backlight.h
> index ddc9bade4..2baab6f38 100644
> --- a/include/linux/backlight.h
> +++ b/include/linux/backlight.h
> @@ -217,11 +217,18 @@ of_find_backlight_by_node(struct device_node *node)
>  
>  #if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
>  struct backlight_device *of_find_backlight(struct device *dev);
> +struct backlight_device *devm_of_find_backlight(struct device *dev);
>  #else
>  static inline struct backlight_device *of_find_backlight(struct device *dev)
>  {
>  	return NULL;
>  }
> +
> +static inline struct backlight_device *
> +devm_of_find_backlight(struct device *dev)
> +{
> +	return NULL;
> +}
>  #endif
>  
>  #endif
> -- 
> 2.11.0
>