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
32struct lcd_device;
33struct fb_info;
34
35struct lcd_properties {
36	/* The maximum value for contrast (read-only) */
37	int max_contrast;
38};
39
40struct 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
57struct 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
73struct 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
96static 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(&ld->update_lock);
102}
103
104extern struct lcd_device *lcd_device_register(const char *name,
105	struct device *parent, void *devdata, struct lcd_ops *ops);
106extern struct lcd_device *devm_lcd_device_register(struct device *dev,
107	const char *name, struct device *parent,
108	void *devdata, struct lcd_ops *ops);
109extern void lcd_device_unregister(struct lcd_device *ld);
110extern 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
115static inline void * lcd_get_data(struct lcd_device *ld_dev)
116{
117	return dev_get_drvdata(&ld_dev->dev);
118}
119
120
121#endif
122