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