root/include/linux/backlight.h

INCLUDED FROM

DEFINITIONS

1. backlight_update_status
2. bl_get_data
3. of_find_backlight_by_node

/*
 * Backlight Lowlevel Control Abstraction
 *
 * Copyright (C) 2003,2004 Hewlett-Packard Company
 *
 */

#ifndef _LINUX_BACKLIGHT_H
#define _LINUX_BACKLIGHT_H

#include <linux/device.h>
#include <linux/fb.h>
#include <linux/mutex.h>
#include <linux/notifier.h>

/* Notes on locking:
 *
 * backlight_device->ops_lock is an internal backlight lock protecting the
 * ops pointer and no code outside the core should need to touch it.
 *
 * Access to update_status() is serialised by the update_lock mutex since
 * most drivers seem to need this and historically get it wrong.
 *
 * Most drivers don't need locking on their get_brightness() method.
 * If yours does, you need to implement it in the driver. You can use the
 * update_lock mutex if appropriate.
 *
 * Any other use of the locks below is probably wrong.
 */

enum backlight_update_reason {
        BACKLIGHT_UPDATE_HOTKEY,
        BACKLIGHT_UPDATE_SYSFS,
};

enum backlight_type {
        BACKLIGHT_RAW = 1,
        BACKLIGHT_PLATFORM,
        BACKLIGHT_FIRMWARE,
        BACKLIGHT_TYPE_MAX,
};

enum backlight_notification {
        BACKLIGHT_REGISTERED,
        BACKLIGHT_UNREGISTERED,
};

struct backlight_device;
struct fb_info;

struct backlight_ops {
        unsigned int options;

#define BL_CORE_SUSPENDRESUME   (1 << 0)

        /* Notify the backlight driver some property has changed */
        int (*update_status)(struct backlight_device *);
        /* Return the current backlight brightness (accounting for power,
           fb_blank etc.) */
        int (*get_brightness)(struct backlight_device *);
        /* Check if given framebuffer device is the one bound to this backlight;
           return 0 if not, !=0 if it is. If NULL, backlight always matches the fb. */
        int (*check_fb)(struct backlight_device *, struct fb_info *);
};

/* This structure defines all the properties of a backlight */
struct backlight_properties {
        /* Current User requested brightness (0 - max_brightness) */
        int brightness;
        /* Maximal value for brightness (read-only) */
        int max_brightness;
        /* Current FB Power mode (0: full on, 1..3: power saving
           modes; 4: full off), see FB_BLANK_XXX */
        int power;
        /* FB Blanking active? (values as for power) */
        /* Due to be removed, please use (state & BL_CORE_FBBLANK) */
        int fb_blank;
        /* Backlight type */
        enum backlight_type type;
        /* Flags used to signal drivers of state changes */
        /* Upper 4 bits are reserved for driver internal use */
        unsigned int state;

#define BL_CORE_SUSPENDED       (1 << 0)        /* backlight is suspended */
#define BL_CORE_FBBLANK         (1 << 1)        /* backlight is under an fb blank event */
#define BL_CORE_DRIVER4         (1 << 28)       /* reserved for driver specific use */
#define BL_CORE_DRIVER3         (1 << 29)       /* reserved for driver specific use */
#define BL_CORE_DRIVER2         (1 << 30)       /* reserved for driver specific use */
#define BL_CORE_DRIVER1         (1 << 31)       /* reserved for driver specific use */

};

struct backlight_device {
        /* Backlight properties */
        struct backlight_properties props;

        /* Serialise access to update_status method */
        struct mutex update_lock;

        /* This protects the 'ops' field. If 'ops' is NULL, the driver that
           registered this device has been unloaded, and if class_get_devdata()
           points to something in the body of that driver, it is also invalid. */
        struct mutex ops_lock;
        const struct backlight_ops *ops;

        /* The framebuffer notifier block */
        struct notifier_block fb_notif;

        /* list entry of all registered backlight devices */
        struct list_head entry;

        struct device dev;

        /* Multiple framebuffers may share one backlight device */
        bool fb_bl_on[FB_MAX];

        int use_count;
};

static inline void backlight_update_status(struct backlight_device *bd)
{
        mutex_lock(&bd->update_lock);
        if (bd->ops && bd->ops->update_status)
                bd->ops->update_status(bd);
        mutex_unlock(&bd->update_lock);
}

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);
extern struct backlight_device *devm_backlight_device_register(
        struct device *dev, const char *name, struct device *parent,
        void *devdata, const struct backlight_ops *ops,
        const struct backlight_properties *props);
extern void backlight_device_unregister(struct backlight_device *bd);
extern void devm_backlight_device_unregister(struct device *dev,
                                        struct backlight_device *bd);
extern void backlight_force_update(struct backlight_device *bd,
                                   enum backlight_update_reason reason);
extern bool backlight_device_registered(enum backlight_type type);
extern int backlight_register_notifier(struct notifier_block *nb);
extern int backlight_unregister_notifier(struct notifier_block *nb);

#define to_backlight_device(obj) container_of(obj, struct backlight_device, dev)

static inline void * bl_get_data(struct backlight_device *bl_dev)
{
        return dev_get_drvdata(&bl_dev->dev);
}

struct generic_bl_info {
        const char *name;
        int max_intensity;
        int default_intensity;
        int limit_mask;
        void (*set_bl_intensity)(int intensity);
        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