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, u32 level)
  77 {
  78         if (level == SUSPEND_POWER_DOWN)
  79                 corgibl_blank(FB_BLANK_POWERDOWN);
  80         return 0;
  81 }
  82
  83 static int corgibl_resume(struct device *dev, u32 level)
  84 {
  85         if (level == RESUME_POWER_ON)
  86                 corgibl_blank(FB_BLANK_UNBLANK);
  87         return 0;
  88 }
  89 #else
  90 #define corgibl_suspend NULL
  91 #define corgibl_resume  NULL
  92 #endif
  93
  94
  95 static int corgibl_set_power(struct backlight_device *bd, int state)
  96 {
  97         corgibl_blank(state);
  98         return 0;
  99 }
 100
 101 static int corgibl_get_power(struct backlight_device *bd)
 102 {
 103         return corgibl_powermode;
 104 }
 105
 106 static int corgibl_set_intensity(struct backlight_device *bd, int intensity)
 107 {
 108         if (intensity > corgibl_data.max_brightness)
 109                 intensity = corgibl_data.max_brightness;
 110         corgibl_send_intensity(intensity);
 111         current_intensity=intensity;
 112         return 0;
 113 }
 114
 115 static int corgibl_get_intensity(struct backlight_device *bd)
 116 {
 117         return current_intensity;
 118 }
 119
 120 /*
 121  * Called when the battery is low to limit the backlight intensity.
 122  * If limit==0 clear any limit, otherwise limit the intensity
 123  */
 124 void corgibl_limit_intensity(int limit)
 125 {
 126         corgibl_limit = (limit ? 1 : 0);
 127         corgibl_send_intensity(current_intensity);
 128 }
 129 EXPORT_SYMBOL(corgibl_limit_intensity);
 130
 131
 132 static struct backlight_properties corgibl_data = {
 133         .owner          = THIS_MODULE,
 134         .get_power      = corgibl_get_power,
 135         .set_power      = corgibl_set_power,
 136         .get_brightness = corgibl_get_intensity,
 137         .set_brightness = corgibl_set_intensity,
 138 };
 139
 140 static struct backlight_device *corgi_backlight_device;
 141
 142 static int __init corgibl_probe(struct device *dev)
 143 {
 144         struct corgibl_machinfo *machinfo = dev->platform_data;
 145
 146         corgibl_data.max_brightness = machinfo->max_intensity;
 147         corgibl_mach_set_intensity = machinfo->set_bl_intensity;
 148
 149         corgi_backlight_device = backlight_device_register ("corgi-bl",
 150                 NULL, &corgibl_data);
 151         if (IS_ERR (corgi_backlight_device))
 152                 return PTR_ERR (corgi_backlight_device);
 153
 154         corgibl_set_intensity(NULL, CORGI_DEFAULT_INTENSITY);
 155         corgibl_limit_intensity(0);
 156
 157         printk("Corgi Backlight Driver Initialized.\n");
 158         return 0;
 159 }
 160
 161 static int corgibl_remove(struct device *dev)
 162 {
 163         backlight_device_unregister(corgi_backlight_device);
 164
 165         corgibl_set_intensity(NULL, 0);
 166
 167         printk("Corgi Backlight Driver Unloaded\n");
 168         return 0;
 169 }
 170
 171 static struct device_driver corgibl_driver = {
 172         .name           = "corgi-bl",
 173         .bus            = &platform_bus_type,
 174         .probe          = corgibl_probe,
 175         .remove         = corgibl_remove,
 176         .suspend        = corgibl_suspend,
 177         .resume         = corgibl_resume,
 178 };
 179
 180 static int __init corgibl_init(void)
 181 {
 182         return driver_register(&corgibl_driver);
 183 }
 184
 185 static void __exit corgibl_exit(void)
 186 {
 187         driver_unregister(&corgibl_driver);
 188 }
 189
 190 module_init(corgibl_init);
 191 module_exit(corgibl_exit);
 192
 193 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 194 MODULE_DESCRIPTION("Corgi Backlight Driver");
 195 MODULE_LICENSE("GPLv2");