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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * LCD Lowlevel Control Abstraction
3 *
4 * Copyright (C) 2003,2004 Hewlett-Packard Company
5 *
6 */
7
8#ifndef _LINUX_LCD_H
9#define _LINUX_LCD_H
10
11#include <linux/device.h>
Richard Purdie28ee0862007-02-08 22:25:09 +000012#include <linux/mutex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/notifier.h>
14
Richard Purdie28ee0862007-02-08 22:25:09 +000015/* Notes on locking:
16 *
Richard Purdie599a52d2007-02-10 23:07:48 +000017 * lcd_device->ops_lock is an internal backlight lock protecting the ops
Richard Purdie28ee0862007-02-08 22:25:09 +000018 * field and no code outside the core should need to touch it.
19 *
20 * Access to set_power() is serialised by the update_lock mutex since
21 * most drivers seem to need this and historically get it wrong.
22 *
23 * Most drivers don't need locking on their get_power() method.
24 * If yours does, you need to implement it in the driver. You can use the
25 * update_lock mutex if appropriate.
26 *
27 * Any other use of the locks below is probably wrong.
28 */
29
Linus Torvalds1da177e2005-04-16 15:20:36 -070030struct lcd_device;
31struct fb_info;
32
Linus Torvalds1da177e2005-04-16 15:20:36 -070033struct lcd_properties {
Richard Purdie599a52d2007-02-10 23:07:48 +000034 /* The maximum value for contrast (read-only) */
35 int max_contrast;
36};
37
38struct lcd_ops {
Linus Torvalds1da177e2005-04-16 15:20:36 -070039 /* Get the LCD panel power status (0: full on, 1..3: controller
40 power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
41 int (*get_power)(struct lcd_device *);
42 /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
43 int (*set_power)(struct lcd_device *, int power);
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 /* Get the current contrast setting (0-max_contrast) */
45 int (*get_contrast)(struct lcd_device *);
46 /* Set LCD panel contrast */
47 int (*set_contrast)(struct lcd_device *, int contrast);
48 /* Check if given framebuffer device is the one LCD is bound to;
49 return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
Ben Dooks0c531362008-07-23 21:31:38 -070050 int (*check_fb)(struct lcd_device *, struct fb_info *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070051};
52
53struct lcd_device {
Richard Purdie599a52d2007-02-10 23:07:48 +000054 struct lcd_properties props;
55 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 registered this device has been unloaded, and if class_get_devdata()
57 points to something in the body of that driver, it is also invalid. */
Richard Purdie599a52d2007-02-10 23:07:48 +000058 struct mutex ops_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 /* If this is NULL, the backing module is unloaded */
Richard Purdie599a52d2007-02-10 23:07:48 +000060 struct lcd_ops *ops;
Richard Purdie28ee0862007-02-08 22:25:09 +000061 /* Serialise access to set_power method */
62 struct mutex update_lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 /* The framebuffer notifier block */
64 struct notifier_block fb_notif;
Richard Purdie655bfd72007-07-09 12:17:24 +010065
66 struct device dev;
Linus Torvalds1da177e2005-04-16 15:20:36 -070067};
68
Richard Purdie28ee0862007-02-08 22:25:09 +000069static inline void lcd_set_power(struct lcd_device *ld, int power)
70{
71 mutex_lock(&ld->update_lock);
Richard Purdie599a52d2007-02-10 23:07:48 +000072 if (ld->ops && ld->ops->set_power)
73 ld->ops->set_power(ld, power);
Richard Purdie28ee0862007-02-08 22:25:09 +000074 mutex_unlock(&ld->update_lock);
75}
76
Linus Torvalds1da177e2005-04-16 15:20:36 -070077extern struct lcd_device *lcd_device_register(const char *name,
Richard Purdie655bfd72007-07-09 12:17:24 +010078 struct device *parent, void *devdata, struct lcd_ops *ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079extern void lcd_device_unregister(struct lcd_device *ld);
80
Richard Purdie655bfd72007-07-09 12:17:24 +010081#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
82
83static inline void * lcd_get_data(struct lcd_device *ld_dev)
84{
85 return dev_get_drvdata(&ld_dev->dev);
86}
87
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
89#endif