drivers/video/backlight/hp680_bl.c

   1 /*
   2  *  Backlight Driver for HP Jornada 680
   3  *
   4  *  Copyright (c) 2005 Andriy Skulysh
   5  *
   6  *  Based on Sharp's Corgi Backlight Driver
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/fb.h>
  19 #include <linux/backlight.h>
  20
  21 #include <cpu/dac.h>
  22 #include <mach/hp6xx.h>
  23 #include <asm/hd64461.h>
  24
  25 #define HP680_MAX_INTENSITY 255
  26 #define HP680_DEFAULT_INTENSITY 10
  27
  28 static int hp680bl_suspended;
  29 static int current_intensity = 0;
  30 static DEFINE_SPINLOCK(bl_lock);
  31
  32 static void hp680bl_send_intensity(struct backlight_device *bd)
  33 {
  34         unsigned long flags;
  35         u16 v;
  36         int intensity = bd->props.brightness;
  37
  38         if (bd->props.power != FB_BLANK_UNBLANK)
  39                 intensity = 0;
  40         if (bd->props.fb_blank != FB_BLANK_UNBLANK)
  41                 intensity = 0;
  42         if (hp680bl_suspended)
  43                 intensity = 0;
  44
  45         spin_lock_irqsave(&bl_lock, flags);
  46         if (intensity && current_intensity == 0) {
  47                 sh_dac_enable(DAC_LCD_BRIGHTNESS);
  48                 v = inw(HD64461_GPBDR);
  49                 v &= ~HD64461_GPBDR_LCDOFF;
  50                 outw(v, HD64461_GPBDR);
  51                 sh_dac_output(255-(u8)intensity, DAC_LCD_BRIGHTNESS);
  52         } else if (intensity == 0 && current_intensity != 0) {
  53                 sh_dac_output(255-(u8)intensity, DAC_LCD_BRIGHTNESS);
  54                 sh_dac_disable(DAC_LCD_BRIGHTNESS);
  55                 v = inw(HD64461_GPBDR);
  56                 v |= HD64461_GPBDR_LCDOFF;
  57                 outw(v, HD64461_GPBDR);
  58         } else if (intensity) {
  59                 sh_dac_output(255-(u8)intensity, DAC_LCD_BRIGHTNESS);
  60         }
  61         spin_unlock_irqrestore(&bl_lock, flags);
  62
  63         current_intensity = intensity;
  64 }
  65
  66
  67 #ifdef CONFIG_PM
  68 static int hp680bl_suspend(struct platform_device *pdev, pm_message_t state)
  69 {
  70         struct backlight_device *bd = platform_get_drvdata(pdev);
  71
  72         hp680bl_suspended = 1;
  73         hp680bl_send_intensity(bd);
  74         return 0;
  75 }
  76
  77 static int hp680bl_resume(struct platform_device *pdev)
  78 {
  79         struct backlight_device *bd = platform_get_drvdata(pdev);
  80
  81         hp680bl_suspended = 0;
  82         hp680bl_send_intensity(bd);
  83         return 0;
  84 }
  85 #else
  86 #define hp680bl_suspend NULL
  87 #define hp680bl_resume  NULL
  88 #endif
  89
  90 static int hp680bl_set_intensity(struct backlight_device *bd)
  91 {
  92         hp680bl_send_intensity(bd);
  93         return 0;
  94 }
  95
  96 static int hp680bl_get_intensity(struct backlight_device *bd)
  97 {
  98         return current_intensity;
  99 }
 100
 101 static struct backlight_ops hp680bl_ops = {
 102         .get_brightness = hp680bl_get_intensity,
 103         .update_status  = hp680bl_set_intensity,
 104 };
 105
 106 static int __init hp680bl_probe(struct platform_device *pdev)
 107 {
 108         struct backlight_device *bd;
 109
 110         bd = backlight_device_register ("hp680-bl", &pdev->dev, NULL,
 111                     &hp680bl_ops);
 112         if (IS_ERR(bd))
 113                 return PTR_ERR(bd);
 114
 115         platform_set_drvdata(pdev, bd);
 116
 117         bd->props.max_brightness = HP680_MAX_INTENSITY;
 118         bd->props.brightness = HP680_DEFAULT_INTENSITY;
 119         hp680bl_send_intensity(bd);
 120
 121         return 0;
 122 }
 123
 124 static int hp680bl_remove(struct platform_device *pdev)
 125 {
 126         struct backlight_device *bd = platform_get_drvdata(pdev);
 127
 128         bd->props.brightness = 0;
 129         bd->props.power = 0;
 130         hp680bl_send_intensity(bd);
 131
 132         backlight_device_unregister(bd);
 133
 134         return 0;
 135 }
 136
 137 static struct platform_driver hp680bl_driver = {
 138         .probe          = hp680bl_probe,
 139         .remove         = hp680bl_remove,
 140         .suspend        = hp680bl_suspend,
 141         .resume         = hp680bl_resume,
 142         .driver         = {
 143                 .name   = "hp680-bl",
 144         },
 145 };
 146
 147 static struct platform_device *hp680bl_device;
 148
 149 static int __init hp680bl_init(void)
 150 {
 151         int ret;
 152
 153         ret = platform_driver_register(&hp680bl_driver);
 154         if (ret)
 155                 return ret;
 156         hp680bl_device = platform_device_register_simple("hp680-bl", -1,
 157                                                         NULL, 0);
 158         if (IS_ERR(hp680bl_device)) {
 159                 platform_driver_unregister(&hp680bl_driver);
 160                 return PTR_ERR(hp680bl_device);
 161         }
 162         return 0;
 163 }
 164
 165 static void __exit hp680bl_exit(void)
 166 {
 167         platform_device_unregister(hp680bl_device);
 168         platform_driver_unregister(&hp680bl_driver);
 169 }
 170
 171 module_init(hp680bl_init);
 172 module_exit(hp680bl_exit);
 173
 174 MODULE_AUTHOR("Andriy Skulysh <askulysh@gmail.com>");
 175 MODULE_DESCRIPTION("HP Jornada 680 Backlight Driver");
 176 MODULE_LICENSE("GPL");