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SubjectRe: [PATCH v17 03/10] video: backlight: Add of_find_backlight helper in backlight.c
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Den 19.01.2018 11.42, skrev Meghana Madhyastha:
> Add of_find_backlight, a helper function which is a generic version
> of tinydrm_of_find_backlight that can be used by other drivers to avoid
> repetition of code and simplify things.
>
> Signed-off-by: Meghana Madhyastha <meghana.madhyastha@gmail.com>
> ---

Reviewed-by: Noralf Trønnes <noralf@tronnes.org>

> changes in v17:
> -rebase with drm-misc-next
> -convert st7735r callers from tinydrm specific helpers
> to new generic backlight helpers
> -remove select BACKLIGHT_LCD_SUPPORT
> and select BACKLIGHT_CLASS_DEVICE from
> tinydrm/Kconfig
>
> drivers/video/backlight/backlight.c | 43 +++++++++++++++++++++++++++++++++++++
> include/linux/backlight.h | 19 ++++++++++++++++
> 2 files changed, 62 insertions(+)
>
> diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c
> index 8049e7656..553bf5c48 100644
> --- a/drivers/video/backlight/backlight.c
> +++ b/drivers/video/backlight/backlight.c
> @@ -580,6 +580,49 @@ struct backlight_device *of_find_backlight_by_node(struct device_node *node)
> EXPORT_SYMBOL(of_find_backlight_by_node);
> #endif
>
> +/**
> + * of_find_backlight - Get backlight device
> + * @dev: Device
> + *
> + * This function looks for a property named 'backlight' on the DT node
> + * connected to @dev and looks up the backlight device.
> + *
> + * Call backlight_put() to drop the reference on the backlight device.
> + *
> + * Returns:
> + * A pointer to the backlight device if found.
> + * Error pointer -EPROBE_DEFER if the DT property is set, but no backlight
> + * device is found.
> + * NULL if there's no backlight property.
> + */
> +struct backlight_device *of_find_backlight(struct device *dev)
> +{
> + struct backlight_device *bd = NULL;
> + struct device_node *np;
> +
> + if (!dev)
> + return NULL;
> +
> + if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
> + np = of_parse_phandle(dev->of_node, "backlight", 0);
> + if (np) {
> + bd = of_find_backlight_by_node(np);
> + of_node_put(np);
> + if (!bd)
> + return ERR_PTR(-EPROBE_DEFER);
> + /*
> + * Note: gpio_backlight uses brightness as
> + * power state during probe
> + */
> + if (!bd->props.brightness)
> + bd->props.brightness = bd->props.max_brightness;
> + }
> + }
> +
> + return bd;
> +}
> +EXPORT_SYMBOL(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 ace825e2c..ddc9bade4 100644
> --- a/include/linux/backlight.h
> +++ b/include/linux/backlight.h
> @@ -162,6 +162,16 @@ 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);
> +}
> +
> extern struct backlight_device *backlight_device_register(const char *name,
> struct device *dev, void *devdata, const struct backlight_ops *ops,
> const struct backlight_properties *props);
> @@ -205,4 +215,13 @@ of_find_backlight_by_node(struct device_node *node)
> }
> #endif
>
> +#if IS_ENABLED(CONFIG_BACKLIGHT_CLASS_DEVICE)
> +struct backlight_device *of_find_backlight(struct device *dev);
> +#else
> +static inline struct backlight_device *of_find_backlight(struct device *dev)
> +{
> + return NULL;
> +}
> +#endif
> +
> #endif

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