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 /* 45 * Enable or disable power to the LCD(0: on; 4: off, see FB_BLANK_XXX) 46 * and this callback would be called proir to fb driver's callback. 47 * 48 * P.S. note that if early_set_power is not NULL then early fb notifier 49 * would be registered. 50 */ 51 int (*early_set_power)(struct lcd_device *, int power); 52 /* revert the effects of the early blank event. */ 53 int (*r_early_set_power)(struct lcd_device *, int power); 54 /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */ 55 int (*set_power)(struct lcd_device *, int power); 56 /* Get the current contrast setting (0-max_contrast) */ 57 int (*get_contrast)(struct lcd_device *); 58 /* Set LCD panel contrast */ 59 int (*set_contrast)(struct lcd_device *, int contrast); 60 /* Set LCD panel mode (resolutions ...) */ 61 int (*set_mode)(struct lcd_device *, struct fb_videomode *); 62 /* Check if given framebuffer device is the one LCD is bound to; 63 return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */ 64 int (*check_fb)(struct lcd_device *, struct fb_info *); 65}; 66 67struct lcd_device { 68 struct lcd_properties props; 69 /* This protects the 'ops' field. If 'ops' is NULL, the driver that 70 registered this device has been unloaded, and if class_get_devdata() 71 points to something in the body of that driver, it is also invalid. */ 72 struct mutex ops_lock; 73 /* If this is NULL, the backing module is unloaded */ 74 struct lcd_ops *ops; 75 /* Serialise access to set_power method */ 76 struct mutex update_lock; 77 /* The framebuffer notifier block */ 78 struct notifier_block fb_notif; 79 80 struct device dev; 81}; 82 83struct lcd_platform_data { 84 /* reset lcd panel device. */ 85 int (*reset)(struct lcd_device *ld); 86 /* on or off to lcd panel. if 'enable' is 0 then 87 lcd power off and 1, lcd power on. */ 88 int (*power_on)(struct lcd_device *ld, int enable); 89 90 /* it indicates whether lcd panel was enabled 91 from bootloader or not. */ 92 int lcd_enabled; 93 /* it means delay for stable time when it becomes low to high 94 or high to low that is dependent on whether reset gpio is 95 low active or high active. */ 96 unsigned int reset_delay; 97 /* stable time needing to become lcd power on. */ 98 unsigned int power_on_delay; 99 /* stable time needing to become lcd power off. */ 100 unsigned int power_off_delay; 101 102 /* it could be used for any purpose. */ 103 void *pdata; 104}; 105 106static inline void lcd_set_power(struct lcd_device *ld, int power) 107{ 108 mutex_lock(&ld->update_lock); 109 if (ld->ops && ld->ops->set_power) 110 ld->ops->set_power(ld, power); 111 mutex_unlock(&ld->update_lock); 112} 113 114extern struct lcd_device *lcd_device_register(const char *name, 115 struct device *parent, void *devdata, struct lcd_ops *ops); 116extern struct lcd_device *devm_lcd_device_register(struct device *dev, 117 const char *name, struct device *parent, 118 void *devdata, struct lcd_ops *ops); 119extern void lcd_device_unregister(struct lcd_device *ld); 120extern void devm_lcd_device_unregister(struct device *dev, 121 struct lcd_device *ld); 122 123#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev) 124 125static inline void * lcd_get_data(struct lcd_device *ld_dev) 126{ 127 return dev_get_drvdata(&ld_dev->dev); 128} 129 130 131#endif 132