drivers/video/backlight/mbp_nvidia_bl.c

   1 /*
   2  *  Backlight Driver for Nvidia 8600 in Macbook Pro
   3  *
   4  *  Copyright (c) Red Hat <mjg@redhat.com>
   5  *  Based on code from Pommed:
   6  *  Copyright (C) 2006 Nicolas Boichat <nicolas @boichat.ch>
   7  *  Copyright (C) 2006 Felipe Alfaro Solana <felipe_alfaro @linuxmail.org>
   8  *  Copyright (C) 2007 Julien BLACHE <jb@jblache.org>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2 as
  12  *  published by the Free Software Foundation.
  13  *
  14  *  This driver triggers SMIs which cause the firmware to change the
  15  *  backlight brightness. This is icky in many ways, but it's impractical to
  16  *  get at the firmware code in order to figure out what it's actually doing.
  17  */
  18
  19 #include <linux/module.h>
  20 #include <linux/kernel.h>
  21 #include <linux/init.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/backlight.h>
  24 #include <linux/err.h>
  25 #include <linux/dmi.h>
  26 #include <linux/io.h>
  27
  28 static struct backlight_device *mbp_backlight_device;
  29
  30 static struct dmi_system_id __initdata mbp_device_table[] = {
  31         {
  32                 .ident = "3,1",
  33                 .matches = {
  34                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
  35                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,1"),
  36                 },
  37         },
  38         {
  39                 .ident = "3,2",
  40                 .matches = {
  41                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
  42                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,2"),
  43                 },
  44         },
  45         {
  46                 .ident = "4,1",
  47                 .matches = {
  48                         DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
  49                         DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro4,1"),
  50                 },
  51         },
  52         { }
  53 };
  54
  55 static int mbp_send_intensity(struct backlight_device *bd)
  56 {
  57         int intensity = bd->props.brightness;
  58
  59         outb(0x04 | (intensity << 4), 0xb3);
  60         outb(0xbf, 0xb2);
  61
  62         return 0;
  63 }
  64
  65 static int mbp_get_intensity(struct backlight_device *bd)
  66 {
  67         outb(0x03, 0xb3);
  68         outb(0xbf, 0xb2);
  69         return inb(0xb3) >> 4;
  70 }
  71
  72 static struct backlight_ops mbp_ops = {
  73         .options = BL_CORE_SUSPENDRESUME,
  74         .get_brightness = mbp_get_intensity,
  75         .update_status  = mbp_send_intensity,
  76 };
  77
  78 static int __init mbp_init(void)
  79 {
  80         if (!dmi_check_system(mbp_device_table))
  81                 return -ENODEV;
  82
  83         if (!request_region(0xb2, 2, "Macbook Pro backlight"))
  84                 return -ENXIO;
  85
  86         mbp_backlight_device = backlight_device_register("mbp_backlight",
  87                                                          NULL, NULL,
  88                                                          &mbp_ops);
  89         if (IS_ERR(mbp_backlight_device)) {
  90                 release_region(0xb2, 2);
  91                 return PTR_ERR(mbp_backlight_device);
  92         }
  93
  94         mbp_backlight_device->props.max_brightness = 15;
  95         mbp_backlight_device->props.brightness =
  96                 mbp_get_intensity(mbp_backlight_device);
  97         backlight_update_status(mbp_backlight_device);
  98
  99         return 0;
 100 }
 101
 102 static void __exit mbp_exit(void)
 103 {
 104         backlight_device_unregister(mbp_backlight_device);
 105
 106         release_region(0xb2, 2);
 107 }
 108
 109 module_init(mbp_init);
 110 module_exit(mbp_exit);
 111
 112 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 113 MODULE_DESCRIPTION("Nvidia-based Macbook Pro Backlight Driver");
 114 MODULE_LICENSE("GPL");
 115 MODULE_DEVICE_TABLE(dmi, mbp_device_table);