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-pxa/corgi.h>
  23 #include <asm/hardware/scoop.h>
  24
  25 #define CORGI_MAX_INTENSITY             0x3e
  26 #define CORGI_DEFAULT_INTENSITY         0x1f
  27 #define CORGI_LIMIT_MASK                        0x0b
  28
  29 static int corgibl_powermode = FB_BLANK_UNBLANK;
  30 static int current_intensity = 0;
  31 static int corgibl_limit = 0;
  32 static spinlock_t bl_lock = SPIN_LOCK_UNLOCKED;
  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         /* Skip 0x20 as it will blank the display */
  47         if (intensity >= 0x20)
  48                 intensity++;
  49
  50         spin_lock_irqsave(&bl_lock, flags);
  51         /* Bits 0-4 are accessed via the SSP interface */
  52         corgi_ssp_blduty_set(intensity & 0x1f);
  53         /* Bit 5 is via SCOOP */
  54         if (intensity & 0x0020)
  55                 set_scoop_gpio(&corgiscoop_device.dev, CORGI_SCP_BACKLIGHT_CONT);
  56         else
  57                 reset_scoop_gpio(&corgiscoop_device.dev, CORGI_SCP_BACKLIGHT_CONT);
  58         spin_unlock_irqrestore(&bl_lock, flags);
  59 }
  60
  61 static void corgibl_blank(int blank)
  62 {
  63         switch(blank) {
  64
  65         case FB_BLANK_NORMAL:
  66         case FB_BLANK_VSYNC_SUSPEND:
  67         case FB_BLANK_HSYNC_SUSPEND:
  68         case FB_BLANK_POWERDOWN:
  69                 if (corgibl_powermode == FB_BLANK_UNBLANK) {
  70                         corgibl_send_intensity(0);
  71                         corgibl_powermode = blank;
  72                 }
  73                 break;
  74         case FB_BLANK_UNBLANK:
  75                 if (corgibl_powermode != FB_BLANK_UNBLANK) {
  76                         corgibl_powermode = blank;
  77                         corgibl_send_intensity(current_intensity);
  78                 }
  79                 break;
  80         }
  81 }
  82
  83 #ifdef CONFIG_PM
  84 static int corgibl_suspend(struct device *dev, u32 state, u32 level)
  85 {
  86         if (level == SUSPEND_POWER_DOWN)
  87                 corgibl_blank(FB_BLANK_POWERDOWN);
  88         return 0;
  89 }
  90
  91 static int corgibl_resume(struct device *dev, u32 level)
  92 {
  93         if (level == RESUME_POWER_ON)
  94                 corgibl_blank(FB_BLANK_UNBLANK);
  95         return 0;
  96 }
  97 #else
  98 #define corgibl_suspend NULL
  99 #define corgibl_resume  NULL
 100 #endif
 101
 102
 103 static int corgibl_set_power(struct backlight_device *bd, int state)
 104 {
 105         corgibl_blank(state);
 106         return 0;
 107 }
 108
 109 static int corgibl_get_power(struct backlight_device *bd)
 110 {
 111         return corgibl_powermode;
 112 }
 113
 114 static int corgibl_set_intensity(struct backlight_device *bd, int intensity)
 115 {
 116         if (intensity > CORGI_MAX_INTENSITY)
 117                 intensity = CORGI_MAX_INTENSITY;
 118         corgibl_send_intensity(intensity);
 119         current_intensity=intensity;
 120         return 0;
 121 }
 122
 123 static int corgibl_get_intensity(struct backlight_device *bd)
 124 {
 125         return current_intensity;
 126 }
 127
 128 /*
 129  * Called when the battery is low to limit the backlight intensity.
 130  * If limit==0 clear any limit, otherwise limit the intensity
 131  */
 132 void corgibl_limit_intensity(int limit)
 133 {
 134         corgibl_limit = (limit ? 1 : 0);
 135         corgibl_send_intensity(current_intensity);
 136 }
 137 EXPORT_SYMBOL(corgibl_limit_intensity);
 138
 139
 140 static struct backlight_properties corgibl_data = {
 141         .owner          = THIS_MODULE,
 142         .get_power      = corgibl_get_power,
 143         .set_power      = corgibl_set_power,
 144         .max_brightness = CORGI_MAX_INTENSITY,
 145         .get_brightness = corgibl_get_intensity,
 146         .set_brightness = corgibl_set_intensity,
 147 };
 148
 149 static struct backlight_device *corgi_backlight_device;
 150
 151 static int __init corgibl_probe(struct device *dev)
 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
 160         printk("Corgi Backlight Driver Initialized.\n");
 161         return 0;
 162 }
 163
 164 static int corgibl_remove(struct device *dev)
 165 {
 166         backlight_device_unregister(corgi_backlight_device);
 167
 168         corgibl_set_intensity(NULL, 0);
 169
 170         printk("Corgi Backlight Driver Unloaded\n");
 171         return 0;
 172 }
 173
 174 static struct device_driver corgibl_driver = {
 175         .name           = "corgi-bl",
 176         .bus            = &platform_bus_type,
 177         .probe          = corgibl_probe,
 178         .remove         = corgibl_remove,
 179         .suspend        = corgibl_suspend,
 180         .resume         = corgibl_resume,
 181 };
 182
 183 static int __init corgibl_init(void)
 184 {
 185         return driver_register(&corgibl_driver);
 186 }
 187
 188 static void __exit corgibl_exit(void)
 189 {
 190         driver_unregister(&corgibl_driver);
 191 }
 192
 193 module_init(corgibl_init);
 194 module_exit(corgibl_exit);
 195
 196 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 197 MODULE_DESCRIPTION("Corgi Backlight Driver");
 198 MODULE_LICENSE("GPLv2");