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
  31 struct lcd_device;
  32 struct fb_info;
  33
  34 struct lcd_properties {
  35         /* The maximum value for contrast (read-only) */
  36         int max_contrast;
  37 };
  38
  39 struct 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
  66 struct 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
  82 struct 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
 105 static 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
 113 extern struct lcd_device *lcd_device_register(const char *name,
 114         struct device *parent, void *devdata, struct lcd_ops *ops);
 115 extern void lcd_device_unregister(struct lcd_device *ld);
 116
 117 #define to_lcd_device(obj) container_of(obj, struct lcd_device, dev)
 118
 119 static inline void * lcd_get_data(struct lcd_device *ld_dev)
 120 {
 121         return dev_get_drvdata(&ld_dev->dev);
 122 }
 123
 124
 125 #endif