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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
15#define LCD_POWER_ON (0)
16#define LCD_POWER_REDUCED (1) // deprecated; don't use in new code
17#define LCD_POWER_REDUCED_VSYNC_SUSPEND (2) // deprecated; don't use in new code
18#define LCD_POWER_OFF (4)
19
20/* Notes on locking:
21 *
22 * lcd_device->ops_lock is an internal backlight lock protecting the ops
23 * field and no code outside the core should need to touch it.
24 *
25 * Access to set_power() is serialised by the update_lock mutex since
26 * most drivers seem to need this and historically get it wrong.
27 *
28 * Most drivers don't need locking on their get_power() method.
29 * If yours does, you need to implement it in the driver. You can use the
30 * update_lock mutex if appropriate.
31 *
32 * Any other use of the locks below is probably wrong.
33 */
34
35struct lcd_device;
36
37struct lcd_properties {
38 /* The maximum value for contrast (read-only) */
39 int max_contrast;
40};
41
42struct lcd_ops {
43 /* Get the LCD panel power status (0: full on, 1..3: controller
44 power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
45 int (*get_power)(struct lcd_device *);
46 /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
47 int (*set_power)(struct lcd_device *, int power);
48 /* Get the current contrast setting (0-max_contrast) */
49 int (*get_contrast)(struct lcd_device *);
50 /* Set LCD panel contrast */
51 int (*set_contrast)(struct lcd_device *, int contrast);
52
53 /*
54 * Set LCD panel mode (resolutions ...)
55 */
56 int (*set_mode)(struct lcd_device *lcd, u32 xres, u32 yres);
57
58 /*
59 * Check if the LCD controls the given display device. This
60 * operation is optional and if not implemented it is assumed that
61 * the display is always the one controlled by the LCD.
62 *
63 * RETURNS:
64 *
65 * If display_dev is NULL or display_dev matches the device controlled by
66 * the LCD, return true. Otherwise return false.
67 */
68 bool (*controls_device)(struct lcd_device *lcd, struct device *display_device);
69};
70
71struct lcd_device {
72 struct lcd_properties props;
73 /* This protects the 'ops' field. If 'ops' is NULL, the driver that
74 registered this device has been unloaded, and if class_get_devdata()
75 points to something in the body of that driver, it is also invalid. */
76 struct mutex ops_lock;
77 /* If this is NULL, the backing module is unloaded */
78 const struct lcd_ops *ops;
79 /* Serialise access to set_power method */
80 struct mutex update_lock;
81
82 /**
83 * @entry: List entry of all registered lcd devices
84 */
85 struct list_head entry;
86
87 struct device dev;
88};
89
90struct lcd_platform_data {
91 /* reset lcd panel device. */
92 int (*reset)(struct lcd_device *ld);
93 /* on or off to lcd panel. if 'enable' is 0 then
94 lcd power off and 1, lcd power on. */
95 int (*power_on)(struct lcd_device *ld, int enable);
96
97 /* it indicates whether lcd panel was enabled
98 from bootloader or not. */
99 int lcd_enabled;
100 /* it means delay for stable time when it becomes low to high
101 or high to low that is dependent on whether reset gpio is
102 low active or high active. */
103 unsigned int reset_delay;
104 /* stable time needing to become lcd power on. */
105 unsigned int power_on_delay;
106 /* stable time needing to become lcd power off. */
107 unsigned int power_off_delay;
108
109 /* it could be used for any purpose. */
110 void *pdata;
111};
112
113static inline void lcd_set_power(struct lcd_device *ld, int power)
114{
115 mutex_lock(&ld->update_lock);
116 if (ld->ops && ld->ops->set_power)
117 ld->ops->set_power(ld, power);
118 mutex_unlock(&ld->update_lock);
119}
120
121extern struct lcd_device *lcd_device_register(const char *name,
122 struct device *parent, void *devdata, const struct lcd_ops *ops);
123extern struct lcd_device *devm_lcd_device_register(struct device *dev,
124 const char *name, struct device *parent,
125 void *devdata, const struct lcd_ops *ops);
126extern void lcd_device_unregister(struct lcd_device *ld);
127extern void devm_lcd_device_unregister(struct device *dev,
128 struct lcd_device *ld);
129
130#if IS_REACHABLE(CONFIG_LCD_CLASS_DEVICE)
131void lcd_notify_blank_all(struct device *display_dev, int power);
132void lcd_notify_mode_change_all(struct device *display_dev,
133 unsigned int width, unsigned int height);
134#else
135static inline void lcd_notify_blank_all(struct device *display_dev, int power)
136{}
137
138static inline void lcd_notify_mode_change_all(struct device *display_dev,
139 unsigned int width, unsigned int height)
140{}
141#endif
142
143#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
144
145static inline void * lcd_get_data(struct lcd_device *ld_dev)
146{
147 return dev_get_drvdata(&ld_dev->dev);
148}
149
150
151#endif