1 /*
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>
12 #include <linux/mutex.h>
13 #include <linux/notifier.h>
14 #include <linux/fb.h>
15
16 /* Notes on locking:
17 *
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.
20 *
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.
23 *
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.
27 *
28 * Any other use of the locks below is probably wrong.
29 */
30
31 struct lcd_device;
32 struct fb_info;
33
34 struct lcd_properties {
35 /* The maximum value for contrast (read-only) */
36 int max_contrast;
37 };
38
39 struct lcd_ops {
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 *);
54 };
55
56 struct lcd_device {
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 */
63 struct lcd_ops *ops;
64 /* Serialise access to set_power method */
65 struct mutex update_lock;
66 /* The framebuffer notifier block */
67 struct notifier_block fb_notif;
68
69 struct device dev;
70 };
71
72 struct lcd_platform_data {
73 /* reset lcd panel device. */
74 int (*reset)(struct lcd_device *ld);
75 /* on or off to lcd panel. if 'enable' is 0 then
76 lcd power off and 1, lcd power on. */
77 int (*power_on)(struct lcd_device *ld, int enable);
78
79 /* it indicates whether lcd panel was enabled
80 from bootloader or not. */
81 int lcd_enabled;
82 /* it means delay for stable time when it becomes low to high
83 or high to low that is dependent on whether reset gpio is
84 low active or high active. */
85 unsigned int reset_delay;
86 /* stable time needing to become lcd power on. */
87 unsigned int power_on_delay;
88 /* stable time needing to become lcd power off. */
89 unsigned int power_off_delay;
90
91 /* it could be used for any purpose. */
92 void *pdata;
93 };
94
lcd_set_power(struct lcd_device * ld,int power)95 static inline void lcd_set_power(struct lcd_device *ld, int power)
96 {
97 mutex_lock(&ld->update_lock);
98 if (ld->ops && ld->ops->set_power)
99 ld->ops->set_power(ld, power);
100 mutex_unlock(&ld->update_lock);
101 }
102
103 extern struct lcd_device *lcd_device_register(const char *name,
104 struct device *parent, void *devdata, struct lcd_ops *ops);
105 extern void lcd_device_unregister(struct lcd_device *ld);
106
107 #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
108
lcd_get_data(struct lcd_device * ld_dev)109 static inline void * lcd_get_data(struct lcd_device *ld_dev)
110 {
111 return dev_get_drvdata(&ld_dev->dev);
112 }
113
114
115 #endif
116