LXR linux/drivers/video/backlight/generic

   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
  20static int genericbl_intensity;
  21static struct backlight_device *generic_backlight_device;
  22static struct generic_bl_info *bl_machinfo;
  23
  24/* Flag to signal when the battery is low */
  25#define GENERICBL_BATTLOW       BL_CORE_DRIVER1
  26
  27static 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
  50static int genericbl_get_intensity(struct backlight_device *bd)
  51{
  52        return genericbl_intensity;
  53}
  54
  55static 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
  61static 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
  95static 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
 107static struct platform_driver genericbl_driver = {
 108        .probe          = genericbl_probe,
 109        .remove         = genericbl_remove,
 110        .driver         = {
 111                .name   = "generic-bl",
 112        },
 113};
 114
 115module_platform_driver(genericbl_driver);
 116
 117MODULE_AUTHOR("Richard Purdie <rpurdie@rpsys.net>");
 118MODULE_DESCRIPTION("Generic Backlight Driver");
 119MODULE_LICENSE("GPL");
 120