drivers/video/backlight/corgi_bl.c

   1 /*
   2  *  Backlight Driver for Sharp Corgi
   3  *
   4  *  Copyright (c) 2004-2005 Richard Purdie
   5  *
   6  *  Based on Sharp's 2.4 Backlight Driver
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  *
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/device.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/fb.h>
  20 #include <linux/backlight.h>
  21
  22 #include <asm/mach-types.h>
  23 #include <asm/arch/sharpsl.h>
  24
  25 #define CORGI_DEFAULT_INTENSITY         0x1f
  26 #define CORGI_LIMIT_MASK                0x0b
  27
  28 static int corgibl_powermode = FB_BLANK_UNBLANK;
  29 static int current_intensity = 0;
  30 static int corgibl_limit = 0;
  31 static void (*corgibl_mach_set_intensity)(int intensity);
  32 static spinlock_t bl_lock = SPIN_LOCK_UNLOCKED;
  33 static struct backlight_properties corgibl_data;
  34
  35 static void corgibl_send_intensity(int intensity)
  36 {
  37         unsigned long flags;
  38         void (*corgi_kick_batt)(void);
  39
  40         if (corgibl_powermode != FB_BLANK_UNBLANK) {
  41                 intensity = 0;
  42         } else {
  43                 if (corgibl_limit)
  44                         intensity &= CORGI_LIMIT_MASK;
  45         }
  46
  47         spin_lock_irqsave(&bl_lock, flags);
  48
  49         corgibl_mach_set_intensity(intensity);
  50
  51         spin_unlock_irqrestore(&bl_lock, flags);
  52 }
  53
  54 static void corgibl_blank(int blank)
  55 {
  56         switch(blank) {
  57
  58         case FB_BLANK_NORMAL:
  59         case FB_BLANK_VSYNC_SUSPEND:
  60         case FB_BLANK_HSYNC_SUSPEND:
  61         case FB_BLANK_POWERDOWN:
  62                 if (corgibl_powermode == FB_BLANK_UNBLANK) {
  63                         corgibl_send_intensity(0);
  64                         corgibl_powermode = blank;
  65                 }
  66                 break;
  67         case FB_BLANK_UNBLANK:
  68                 if (corgibl_powermode != FB_BLANK_UNBLANK) {
  69                         corgibl_powermode = blank;
  70                         corgibl_send_intensity(current_intensity);
  71                 }
  72                 break;
  73         }
  74 }
  75
  76 #ifdef CONFIG_PM
  77 static int corgibl_suspend(struct device *dev, pm_message_t state, u32 level)
  78 {
  79         if (level == SUSPEND_POWER_DOWN)
  80                 corgibl_blank(FB_BLANK_POWERDOWN);
  81         return 0;
  82 }
  83
  84 static int corgibl_resume(struct device *dev, u32 level)
  85 {
  86         if (level == RESUME_POWER_ON)
  87                 corgibl_blank(FB_BLANK_UNBLANK);
  88         return 0;
  89 }
  90 #else
  91 #define corgibl_suspend NULL
  92 #define corgibl_resume  NULL
  93 #endif
  94
  95
  96 static int corgibl_set_power(struct backlight_device *bd, int state)
  97 {
  98         corgibl_blank(state);
  99         return 0;
 100 }
 101
 102 static int corgibl_get_power(struct backlight_device *bd)
 103 {
 104         return corgibl_powermode;
 105 }
 106
 107 static int corgibl_set_intensity(struct backlight_device *bd, int intensity)
 108 {
 109         if (intensity > corgibl_data.max_brightness)
 110                 intensity = corgibl_data.max_brightness;
 111         corgibl_send_intensity(intensity);
 112         current_intensity=intensity;
 113         return 0;
 114 }
 115
 116 static int corgibl_get_intensity(struct backlight_device *bd)
 117 {
 118         return current_intensity;
 119 }
 120
 121 /*
 122  * Called when the battery is low to limit the backlight intensity.
 123  * If limit==0 clear any limit, otherwise limit the intensity
 124  */
 125 void corgibl_limit_intensity(int limit)
 126 {
 127         corgibl_limit = (limit ? 1 : 0);
 128         corgibl_send_intensity(current_intensity);
 129 }
 130 EXPORT_SYMBOL(corgibl_limit_intensity);
 131
 132
 133 static struct backlight_properties corgibl_data = {
 134         .owner          = THIS_MODULE,
 135         .get_power      = corgibl_get_power,
 136         .set_power      = corgibl_set_power,
 137         .get_brightness = corgibl_get_intensity,
 138         .set_brightness = corgibl_set_intensity,
 139 };
 140
 141 static struct backlight_device *corgi_backlight_device;
 142
 143 static int __init corgibl_probe(struct device *dev)
 144 {
 145         struct corgibl_machinfo *machinfo = dev->platform_data;
 146
 147         corgibl_data.max_brightness = machinfo->max_intensity;
 148         corgibl_mach_set_intensity = machinfo->set_bl_intensity;
 149
 150         corgi_backlight_device = backlight_device_register ("corgi-bl",
 151                 NULL, &corgibl_data);
 152         if (IS_ERR (corgi_backlight_device))
 153                 return PTR_ERR (corgi_backlight_device);
 154
 155         corgibl_set_intensity(NULL, CORGI_DEFAULT_INTENSITY);
 156         corgibl_limit_intensity(0);
 157
 158         printk("Corgi Backlight Driver Initialized.\n");
 159         return 0;
 160 }
 161
 162 static int corgibl_remove(struct device *dev)
 163 {
 164         backlight_device_unregister(corgi_backlight_device);
 165
 166         corgibl_set_intensity(NULL, 0);
 167
 168         printk("Corgi Backlight Driver Unloaded\n");
 169         return 0;
 170 }
 171
 172 static struct device_driver corgibl_driver = {
 173         .name           = "corgi-bl",
 174         .bus            = &platform_bus_type,
 175         .probe          = corgibl_probe,
 176         .remove         = corgibl_remove,
 177         .suspend        = corgibl_suspend,
 178         .resume         = corgibl_resume,
 179 };
 180
 181 static int __init corgibl_init(void)
 182 {
 183         return driver_register(&corgibl_driver);
 184 }
 185
 186 static void __exit corgibl_exit(void)
 187 {
 188         driver_unregister(&corgibl_driver);
 189 }
 190
 191 module_init(corgibl_init);
 192 module_exit(corgibl_exit);
 193
 194 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 195 MODULE_DESCRIPTION("Corgi Backlight Driver");
 196 MODULE_LICENSE("GPLv2");