599a52d126
Per device data such as brightness belongs to the indivdual device and should therefore be separate from the the backlight operation function pointers. This patch splits the two types of data and allows simplifcation of some code. Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
91 lines
2.8 KiB
C
91 lines
2.8 KiB
C
/*
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* Backlight Lowlevel Control Abstraction
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*
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* Copyright (C) 2003,2004 Hewlett-Packard Company
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*
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*/
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#ifndef _LINUX_BACKLIGHT_H
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#define _LINUX_BACKLIGHT_H
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#include <linux/device.h>
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#include <linux/mutex.h>
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#include <linux/notifier.h>
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/* Notes on locking:
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*
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* backlight_device->ops_lock is an internal backlight lock protecting the
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* ops pointer and no code outside the core should need to touch it.
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*
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* Access to update_status() is serialised by the update_lock mutex since
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* most drivers seem to need this and historically get it wrong.
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*
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* Most drivers don't need locking on their get_brightness() method.
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* If yours does, you need to implement it in the driver. You can use the
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* update_lock mutex if appropriate.
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*
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* Any other use of the locks below is probably wrong.
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*/
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struct backlight_device;
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struct fb_info;
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struct backlight_ops {
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/* Notify the backlight driver some property has changed */
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int (*update_status)(struct backlight_device *);
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/* Return the current backlight brightness (accounting for power,
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fb_blank etc.) */
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int (*get_brightness)(struct backlight_device *);
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/* Check if given framebuffer device is the one bound to this backlight;
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return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
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int (*check_fb)(struct fb_info *);
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};
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/* This structure defines all the properties of a backlight */
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struct backlight_properties {
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/* Current User requested brightness (0 - max_brightness) */
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int brightness;
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/* Maximal value for brightness (read-only) */
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int max_brightness;
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/* Current FB Power mode (0: full on, 1..3: power saving
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modes; 4: full off), see FB_BLANK_XXX */
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int power;
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/* FB Blanking active? (values as for power) */
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int fb_blank;
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};
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struct backlight_device {
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/* Backlight properties */
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struct backlight_properties props;
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/* Serialise access to update_status method */
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struct mutex update_lock;
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/* This protects the 'ops' field. If 'ops' is NULL, the driver that
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registered this device has been unloaded, and if class_get_devdata()
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points to something in the body of that driver, it is also invalid. */
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struct mutex ops_lock;
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struct backlight_ops *ops;
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/* The framebuffer notifier block */
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struct notifier_block fb_notif;
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/* The class device structure */
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struct class_device class_dev;
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};
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static inline void backlight_update_status(struct backlight_device *bd)
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{
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mutex_lock(&bd->update_lock);
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if (bd->ops && bd->ops->update_status)
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bd->ops->update_status(bd);
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mutex_unlock(&bd->update_lock);
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}
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extern struct backlight_device *backlight_device_register(const char *name,
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struct device *dev, void *devdata, struct backlight_ops *ops);
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extern void backlight_device_unregister(struct backlight_device *bd);
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#define to_backlight_device(obj) container_of(obj, struct backlight_device, class_dev)
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#endif
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