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Commit 762a936f authored by Thierry Reding's avatar Thierry Reding Committed by Linus Torvalds
Browse files

backlight: add of_find_backlight_by_node() 



This function finds the struct backlight_device for a given device tree
node.  A dummy function is provided so that it safely compiles out if OF
support is disabled.

[akpm@linux-foundation.org: Don't use IS_ENABLED(CONFIG_OF)]
Signed-off-by: default avatarThierry Reding <thierry.reding@avionic-design.de>
Acked-by: default avatarJingoo Han <jg1.han@samsung.com>
Reviewed-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Cc: Thierry Reding <thierry.reding@avionic-design.de>
Reviewed-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Acked-by: default avatarJingoo Han <jg1.han@samsung.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fb08cd9b

drivers/video/backlight/backlight.c

+29 −0
Original line number Diff line number Diff line
@@ -370,6 +370,35 @@ void backlight_device_unregister(struct backlight_device *bd) 
}

EXPORT_SYMBOL(backlight_device_unregister);



#ifdef CONFIG_OF

static int of_parent_match(struct device *dev, void *data)

{

	return dev->parent && dev->parent->of_node == data;

}



/**

 * of_find_backlight_by_node() - find backlight device by device-tree node

 * @node: device-tree node of the backlight device

 *

 * Returns a pointer to the backlight device corresponding to the given DT

 * node or NULL if no such backlight device exists or if the device hasn't

 * been probed yet.

 *

 * This function obtains a reference on the backlight device and it is the

 * caller's responsibility to drop the reference by calling put_device() on

 * the backlight device's .dev field.

 */

struct backlight_device *of_find_backlight_by_node(struct device_node *node)

{

	struct device *dev;



	dev = class_find_device(backlight_class, NULL, node, of_parent_match);



	return dev ? to_backlight_device(dev) : NULL;

}

EXPORT_SYMBOL(of_find_backlight_by_node);

#endif



static void __exit backlight_class_exit(void)

{

	class_destroy(backlight_class);

include/linux/backlight.h

+10 −0
Original line number Diff line number Diff line
@@ -134,4 +134,14 @@ struct generic_bl_info { 
	void (*kick_battery)(void);

};



#ifdef CONFIG_OF

struct backlight_device *of_find_backlight_by_node(struct device_node *node);

#else

static inline struct backlight_device *

of_find_backlight_by_node(struct device_node *node)

{

	return NULL;

}

#endif



#endif