On Wed, 11 Oct 2017, Meghana Madhyastha <meghana.madhyastha@xxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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?
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
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