lcd.h

  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