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