1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * LCD Lowlevel Control Abstraction |
4 | * |
5 | * Copyright (C) 2003,2004 Hewlett-Packard Company |
6 | * |
7 | */ |
8 | |
9 | #ifndef _LINUX_LCD_H |
10 | #define _LINUX_LCD_H |
11 | |
12 | #include <linux/device.h> |
13 | #include <linux/mutex.h> |
14 | #include <linux/notifier.h> |
15 | #include <linux/fb.h> |
16 | |
17 | /* Notes on locking: |
18 | * |
19 | * lcd_device->ops_lock is an internal backlight lock protecting the ops |
20 | * field and no code outside the core should need to touch it. |
21 | * |
22 | * Access to set_power() is serialised by the update_lock mutex since |
23 | * most drivers seem to need this and historically get it wrong. |
24 | * |
25 | * Most drivers don't need locking on their get_power() method. |
26 | * If yours does, you need to implement it in the driver. You can use the |
27 | * update_lock mutex if appropriate. |
28 | * |
29 | * Any other use of the locks below is probably wrong. |
30 | */ |
31 | |
32 | struct lcd_device; |
33 | struct fb_info; |
34 | |
35 | struct lcd_properties { |
36 | /* The maximum value for contrast (read-only) */ |
37 | int max_contrast; |
38 | }; |
39 | |
40 | struct lcd_ops { |
41 | /* Get the LCD panel power status (0: full on, 1..3: controller |
42 | power on, flat panel power off, 4: full off), see FB_BLANK_XXX */ |
43 | int (*get_power)(struct lcd_device *); |
44 | /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */ |
45 | int (*set_power)(struct lcd_device *, int power); |
46 | /* Get the current contrast setting (0-max_contrast) */ |
47 | int (*get_contrast)(struct lcd_device *); |
48 | /* Set LCD panel contrast */ |
49 | int (*set_contrast)(struct lcd_device *, int contrast); |
50 | /* Set LCD panel mode (resolutions ...) */ |
51 | int (*set_mode)(struct lcd_device *, struct fb_videomode *); |
52 | /* Check if given framebuffer device is the one LCD is bound to; |
53 | return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */ |
54 | int (*check_fb)(struct lcd_device *, struct fb_info *); |
55 | }; |
56 | |
57 | struct lcd_device { |
58 | struct lcd_properties props; |
59 | /* This protects the 'ops' field. If 'ops' is NULL, the driver that |
60 | registered this device has been unloaded, and if class_get_devdata() |
61 | points to something in the body of that driver, it is also invalid. */ |
62 | struct mutex ops_lock; |
63 | /* If this is NULL, the backing module is unloaded */ |
64 | struct lcd_ops *ops; |
65 | /* Serialise access to set_power method */ |
66 | struct mutex update_lock; |
67 | /* The framebuffer notifier block */ |
68 | struct notifier_block fb_notif; |
69 | |
70 | struct device dev; |
71 | }; |
72 | |
73 | struct lcd_platform_data { |
74 | /* reset lcd panel device. */ |
75 | int (*reset)(struct lcd_device *ld); |
76 | /* on or off to lcd panel. if 'enable' is 0 then |
77 | lcd power off and 1, lcd power on. */ |
78 | int (*power_on)(struct lcd_device *ld, int enable); |
79 | |
80 | /* it indicates whether lcd panel was enabled |
81 | from bootloader or not. */ |
82 | int lcd_enabled; |
83 | /* it means delay for stable time when it becomes low to high |
84 | or high to low that is dependent on whether reset gpio is |
85 | low active or high active. */ |
86 | unsigned int reset_delay; |
87 | /* stable time needing to become lcd power on. */ |
88 | unsigned int power_on_delay; |
89 | /* stable time needing to become lcd power off. */ |
90 | unsigned int power_off_delay; |
91 | |
92 | /* it could be used for any purpose. */ |
93 | void *pdata; |
94 | }; |
95 | |
96 | static inline void lcd_set_power(struct lcd_device *ld, int power) |
97 | { |
98 | mutex_lock(&ld->update_lock); |
99 | if (ld->ops && ld->ops->set_power) |
100 | ld->ops->set_power(ld, power); |
101 | mutex_unlock(lock: &ld->update_lock); |
102 | } |
103 | |
104 | extern struct lcd_device *lcd_device_register(const char *name, |
105 | struct device *parent, void *devdata, struct lcd_ops *ops); |
106 | extern struct lcd_device *devm_lcd_device_register(struct device *dev, |
107 | const char *name, struct device *parent, |
108 | void *devdata, struct lcd_ops *ops); |
109 | extern void lcd_device_unregister(struct lcd_device *ld); |
110 | extern void devm_lcd_device_unregister(struct device *dev, |
111 | struct lcd_device *ld); |
112 | |
113 | #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev) |
114 | |
115 | static inline void * lcd_get_data(struct lcd_device *ld_dev) |
116 | { |
117 | return dev_get_drvdata(dev: &ld_dev->dev); |
118 | } |
119 | |
120 | |
121 | #endif |
122 | |