2 * LCD Lowlevel Control Abstraction
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
11 #include <linux/device.h>
12 #include <linux/mutex.h>
13 #include <linux/notifier.h>
18 * lcd_device->ops_lock is an internal backlight lock protecting the ops
19 * field and no code outside the core should need to touch it.
21 * Access to set_power() is serialised by the update_lock mutex since
22 * most drivers seem to need this and historically get it wrong.
24 * Most drivers don't need locking on their get_power() method.
25 * If yours does, you need to implement it in the driver. You can use the
26 * update_lock mutex if appropriate.
28 * Any other use of the locks below is probably wrong.
34 struct lcd_properties
{
35 /* The maximum value for contrast (read-only) */
40 /* Get the LCD panel power status (0: full on, 1..3: controller
41 power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
42 int (*get_power
)(struct lcd_device
*);
43 /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
44 int (*set_power
)(struct lcd_device
*, int power
);
45 /* Get the current contrast setting (0-max_contrast) */
46 int (*get_contrast
)(struct lcd_device
*);
47 /* Set LCD panel contrast */
48 int (*set_contrast
)(struct lcd_device
*, int contrast
);
49 /* Set LCD panel mode (resolutions ...) */
50 int (*set_mode
)(struct lcd_device
*, struct fb_videomode
*);
51 /* Check if given framebuffer device is the one LCD is bound to;
52 return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
53 int (*check_fb
)(struct lcd_device
*, struct fb_info
*);
57 struct lcd_properties props
;
58 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
59 registered this device has been unloaded, and if class_get_devdata()
60 points to something in the body of that driver, it is also invalid. */
61 struct mutex ops_lock
;
62 /* If this is NULL, the backing module is unloaded */
64 /* Serialise access to set_power method */
65 struct mutex update_lock
;
66 /* The framebuffer notifier block */
67 struct notifier_block fb_notif
;
72 static inline void lcd_set_power(struct lcd_device
*ld
, int power
)
74 mutex_lock(&ld
->update_lock
);
75 if (ld
->ops
&& ld
->ops
->set_power
)
76 ld
->ops
->set_power(ld
, power
);
77 mutex_unlock(&ld
->update_lock
);
80 extern struct lcd_device
*lcd_device_register(const char *name
,
81 struct device
*parent
, void *devdata
, struct lcd_ops
*ops
);
82 extern void lcd_device_unregister(struct lcd_device
*ld
);
84 #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
86 static inline void * lcd_get_data(struct lcd_device
*ld_dev
)
88 return dev_get_drvdata(&ld_dev
->dev
);
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