kernel/drivers/video/backlight/generic_bl.c

   1 /*
   2  *  Generic Backlight Driver
   3  *
   4  *  Copyright (c) 2004-2008 Richard Purdie
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License version 2 as
   8  *  published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/mutex.h>
  17 #include <linux/fb.h>
  18 #include <linux/backlight.h>
  19
  20 static int genericbl_intensity;
  21 static struct backlight_device *generic_backlight_device;
  22 static struct generic_bl_info *bl_machinfo;
  23
  24 /* Flag to signal when the battery is low */
  25 #define GENERICBL_BATTLOW       BL_CORE_DRIVER1
  26
  27 static int genericbl_send_intensity(struct backlight_device *bd)
  28 {
  29         int intensity = bd->props.brightness;
  30
  31         if (bd->props.power != FB_BLANK_UNBLANK)
  32                 intensity = 0;
  33         if (bd->props.state & BL_CORE_FBBLANK)
  34                 intensity = 0;
  35         if (bd->props.state & BL_CORE_SUSPENDED)
  36                 intensity = 0;
  37         if (bd->props.state & GENERICBL_BATTLOW)
  38                 intensity &= bl_machinfo->limit_mask;
  39
  40         bl_machinfo->set_bl_intensity(intensity);
  41
  42         genericbl_intensity = intensity;
  43
  44         if (bl_machinfo->kick_battery)
  45                 bl_machinfo->kick_battery();
  46
  47         return 0;
  48 }
  49
  50 static int genericbl_get_intensity(struct backlight_device *bd)
  51 {
  52         return genericbl_intensity;
  53 }
  54
  55 static const struct backlight_ops genericbl_ops = {
  56         .options = BL_CORE_SUSPENDRESUME,
  57         .get_brightness = genericbl_get_intensity,
  58         .update_status  = genericbl_send_intensity,
  59 };
  60
  61 static int genericbl_probe(struct platform_device *pdev)
  62 {
  63         struct backlight_properties props;
  64         struct generic_bl_info *machinfo = dev_get_platdata(&pdev->dev);
  65         const char *name = "generic-bl";
  66         struct backlight_device *bd;
  67
  68         bl_machinfo = machinfo;
  69         if (!machinfo->limit_mask)
  70                 machinfo->limit_mask = -1;
  71
  72         if (machinfo->name)
  73                 name = machinfo->name;
  74
  75         memset(&props, 0, sizeof(struct backlight_properties));
  76         props.type = BACKLIGHT_RAW;
  77         props.max_brightness = machinfo->max_intensity;
  78         bd = devm_backlight_device_register(&pdev->dev, name, &pdev->dev,
  79                                         NULL, &genericbl_ops, &props);
  80         if (IS_ERR(bd))
  81                 return PTR_ERR(bd);
  82
  83         platform_set_drvdata(pdev, bd);
  84
  85         bd->props.power = FB_BLANK_UNBLANK;
  86         bd->props.brightness = machinfo->default_intensity;
  87         backlight_update_status(bd);
  88
  89         generic_backlight_device = bd;
  90
  91         dev_info(&pdev->dev, "Generic Backlight Driver Initialized.\n");
  92         return 0;
  93 }
  94
  95 static int genericbl_remove(struct platform_device *pdev)
  96 {
  97         struct backlight_device *bd = platform_get_drvdata(pdev);
  98
  99         bd->props.power = 0;
 100         bd->props.brightness = 0;
 101         backlight_update_status(bd);
 102
 103         dev_info(&pdev->dev, "Generic Backlight Driver Unloaded\n");
 104         return 0;
 105 }
 106
 107 static struct platform_driver genericbl_driver = {
 108         .probe          = genericbl_probe,
 109         .remove         = genericbl_remove,
 110         .driver         = {
 111                 .name   = "generic-bl",
 112         },
 113 };
 114
 115 module_platform_driver(genericbl_driver);
 116
 117 MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 118 MODULE_DESCRIPTION("Generic Backlight Driver");
 119 MODULE_LICENSE("GPL");