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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
16#define LCD_POWER_ON (0)
17#define LCD_POWER_REDUCED (1) // deprecated; don't use in new code
18#define LCD_POWER_REDUCED_VSYNC_SUSPEND (2) // deprecated; don't use in new code
19#define LCD_POWER_OFF (4)
20
21/* Notes on locking:
22 *
23 * lcd_device->ops_lock is an internal backlight lock protecting the ops
24 * field and no code outside the core should need to touch it.
25 *
26 * Access to set_power() is serialised by the update_lock mutex since
27 * most drivers seem to need this and historically get it wrong.
28 *
29 * Most drivers don't need locking on their get_power() method.
30 * If yours does, you need to implement it in the driver. You can use the
31 * update_lock mutex if appropriate.
32 *
33 * Any other use of the locks below is probably wrong.
34 */
35
36struct lcd_device;
37
38struct lcd_properties {
39 /* The maximum value for contrast (read-only) */
40 int max_contrast;
41};
42
43struct lcd_ops {
44 /* Get the LCD panel power status (0: full on, 1..3: controller
45 power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
46 int (*get_power)(struct lcd_device *);
47 /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
48 int (*set_power)(struct lcd_device *, int power);
49 /* Get the current contrast setting (0-max_contrast) */
50 int (*get_contrast)(struct lcd_device *);
51 /* Set LCD panel contrast */
52 int (*set_contrast)(struct lcd_device *, int contrast);
53
54 /*
55 * Set LCD panel mode (resolutions ...)
56 */
57 int (*set_mode)(struct lcd_device *lcd, u32 xres, u32 yres);
58
59 /*
60 * Check if the LCD controls the given display device. This
61 * operation is optional and if not implemented it is assumed that
62 * the display is always the one controlled by the LCD.
63 *
64 * RETURNS:
65 *
66 * If display_dev is NULL or display_dev matches the device controlled by
67 * the LCD, return true. Otherwise return false.
68 */
69 bool (*controls_device)(struct lcd_device *lcd, struct device *display_device);
70};
71
72struct lcd_device {
73 struct lcd_properties props;
74 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
75 registered this device has been unloaded, and if class_get_devdata()
76 points to something in the body of that driver, it is also invalid. */
77 struct mutex ops_lock;
78 /* If this is NULL, the backing module is unloaded */
79 const struct lcd_ops *ops;
80 /* Serialise access to set_power method */
81 struct mutex update_lock;
82 /* The framebuffer notifier block */
83 struct notifier_block fb_notif;
84
85 struct device dev;
86};
87
88struct lcd_platform_data {
89 /* reset lcd panel device. */
90 int (*reset)(struct lcd_device *ld);
91 /* on or off to lcd panel. if 'enable' is 0 then
92 lcd power off and 1, lcd power on. */
93 int (*power_on)(struct lcd_device *ld, int enable);
94
95 /* it indicates whether lcd panel was enabled
96 from bootloader or not. */
97 int lcd_enabled;
98 /* it means delay for stable time when it becomes low to high
99 or high to low that is dependent on whether reset gpio is
100 low active or high active. */
101 unsigned int reset_delay;
102 /* stable time needing to become lcd power on. */
103 unsigned int power_on_delay;
104 /* stable time needing to become lcd power off. */
105 unsigned int power_off_delay;
106
107 /* it could be used for any purpose. */
108 void *pdata;
109};
110
111static inline void lcd_set_power(struct lcd_device *ld, int power)
112{
113 mutex_lock(&ld->update_lock);
114 if (ld->ops && ld->ops->set_power)
115 ld->ops->set_power(ld, power);
116 mutex_unlock(&ld->update_lock);
117}
118
119extern struct lcd_device *lcd_device_register(const char *name,
120 struct device *parent, void *devdata, const struct lcd_ops *ops);
121extern struct lcd_device *devm_lcd_device_register(struct device *dev,
122 const char *name, struct device *parent,
123 void *devdata, const struct lcd_ops *ops);
124extern void lcd_device_unregister(struct lcd_device *ld);
125extern void devm_lcd_device_unregister(struct device *dev,
126 struct lcd_device *ld);
127
128#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
129
130static inline void * lcd_get_data(struct lcd_device *ld_dev)
131{
132 return dev_get_drvdata(&ld_dev->dev);
133}
134
135
136#endif