LXR linux/include/linux/lcd.h

   1/*
   2 * LCD Lowlevel Control Abstraction
   3 *
   4 * Copyright (C) 2003,2004 Hewlett-Packard Company
   5 *
   6 */
   7
   8#ifndef _LINUX_LCD_H
   9#define _LINUX_LCD_H
  10
  11#include <linux/device.h>
  12#include <linux/mutex.h>
  13#include <linux/notifier.h>
  14#include <linux/fb.h>
  15
  16/* Notes on locking:
  17 *
  18 * lcd_device->ops_lock is an internal backlight lock protecting the ops
  19 * field and no code outside the core should need to touch it.
  20 *
  21 * Access to set_power() is serialised by the update_lock mutex since
  22 * most drivers seem to need this and historically get it wrong.
  23 *
  24 * Most drivers don't need locking on their get_power() method.
  25 * If yours does, you need to implement it in the driver. You can use the
  26 * update_lock mutex if appropriate.
  27 *
  28 * Any other use of the locks below is probably wrong.
  29 */
  30
  31struct lcd_device;
  32struct fb_info;
  33
  34struct lcd_properties {
  35        /* The maximum value for contrast (read-only) */
  36        int max_contrast;
  37};
  38
  39struct lcd_ops {
  40        /* Get the LCD panel power status (0: full on, 1..3: controller
  41           power on, flat panel power off, 4: full off), see FB_BLANK_XXX */
  42        int (*get_power)(struct lcd_device *);
  43        /*
  44         * Enable or disable power to the LCD(0: on; 4: off, see FB_BLANK_XXX)
  45         * and this callback would be called proir to fb driver's callback.
  46         *
  47         * P.S. note that if early_set_power is not NULL then early fb notifier
  48         *      would be registered.
  49         */
  50        int (*early_set_power)(struct lcd_device *, int power);
  51        /* revert the effects of the early blank event. */
  52        int (*r_early_set_power)(struct lcd_device *, int power);
  53        /* Enable or disable power to the LCD (0: on; 4: off, see FB_BLANK_XXX) */
  54        int (*set_power)(struct lcd_device *, int power);
  55        /* Get the current contrast setting (0-max_contrast) */
  56        int (*get_contrast)(struct lcd_device *);
  57        /* Set LCD panel contrast */
  58        int (*set_contrast)(struct lcd_device *, int contrast);
  59        /* Set LCD panel mode (resolutions ...) */
  60        int (*set_mode)(struct lcd_device *, struct fb_videomode *);
  61        /* Check if given framebuffer device is the one LCD is bound to;
  62           return 0 if not, !=0 if it is. If NULL, lcd always matches the fb. */
  63        int (*check_fb)(struct lcd_device *, struct fb_info *);
  64};
  65
  66struct lcd_device {
  67        struct lcd_properties props;
  68        /* This protects the 'ops' field. If 'ops' is NULL, the driver that
  69           registered this device has been unloaded, and if class_get_devdata()
  70           points to something in the body of that driver, it is also invalid. */
  71        struct mutex ops_lock;
  72        /* If this is NULL, the backing module is unloaded */
  73        struct lcd_ops *ops;
  74        /* Serialise access to set_power method */
  75        struct mutex update_lock;
  76        /* The framebuffer notifier block */
  77        struct notifier_block fb_notif;
  78
  79        struct device dev;
  80};
  81
  82struct lcd_platform_data {
  83        /* reset lcd panel device. */
  84        int (*reset)(struct lcd_device *ld);
  85        /* on or off to lcd panel. if 'enable' is 0 then
  86           lcd power off and 1, lcd power on. */
  87        int (*power_on)(struct lcd_device *ld, int enable);
  88
  89        /* it indicates whether lcd panel was enabled
  90           from bootloader or not. */
  91        int lcd_enabled;
  92        /* it means delay for stable time when it becomes low to high
  93           or high to low that is dependent on whether reset gpio is
  94           low active or high active. */
  95        unsigned int reset_delay;
  96        /* stable time needing to become lcd power on. */
  97        unsigned int power_on_delay;
  98        /* stable time needing to become lcd power off. */
  99        unsigned int power_off_delay;
 100
 101        /* it could be used for any purpose. */
 102        void *pdata;
 103};
 104
 105static inline void lcd_set_power(struct lcd_device *ld, int power)
 106{
 107        mutex_lock(&ld->update_lock);
 108        if (ld->ops && ld->ops->set_power)
 109                ld->ops->set_power(ld, power);
 110        mutex_unlock(&ld->update_lock);
 111}
 112
 113extern struct lcd_device *lcd_device_register(const char *name,
 114        struct device *parent, void *devdata, struct lcd_ops *ops);
 115extern void lcd_device_unregister(struct lcd_device *ld);
 116
 117#define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
 118
 119static inline void * lcd_get_data(struct lcd_device *ld_dev)
 120{
 121        return dev_get_drvdata(&ld_dev->dev);
 122}
 123
 124
 125#endif
 126