drivers/video/backlight/apple_bl.c

   1 /*
   2  *  Backlight Driver for Intel-based Apples
   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/backlight.h>
  23 #include <linux/err.h>
  24 #include <linux/io.h>
  25 #include <linux/pci.h>
  26 #include <linux/acpi.h>
  27
  28 static struct backlight_device *apple_backlight_device;
  29
  30 struct hw_data {
  31         /* I/O resource to allocate. */
  32         unsigned long iostart;
  33         unsigned long iolen;
  34         /* Backlight operations structure. */
  35         const struct backlight_ops backlight_ops;
  36         void (*set_brightness)(int);
  37 };
  38
  39 static const struct hw_data *hw_data;
  40
  41 #define DRIVER "apple_backlight: "
  42
  43 /* Module parameters. */
  44 static int debug;
  45 module_param_named(debug, debug, int, 0644);
  46 MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");
  47
  48 /*
  49  * Implementation for machines with Intel chipset.
  50  */
  51 static void intel_chipset_set_brightness(int intensity)
  52 {
  53         outb(0x04 | (intensity << 4), 0xb3);
  54         outb(0xbf, 0xb2);
  55 }
  56
  57 static int intel_chipset_send_intensity(struct backlight_device *bd)
  58 {
  59         int intensity = bd->props.brightness;
  60
  61         if (debug)
  62                 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
  63                        intensity);
  64
  65         intel_chipset_set_brightness(intensity);
  66         return 0;
  67 }
  68
  69 static int intel_chipset_get_intensity(struct backlight_device *bd)
  70 {
  71         int intensity;
  72
  73         outb(0x03, 0xb3);
  74         outb(0xbf, 0xb2);
  75         intensity = inb(0xb3) >> 4;
  76
  77         if (debug)
  78                 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
  79                        intensity);
  80
  81         return intensity;
  82 }
  83
  84 static const struct hw_data intel_chipset_data = {
  85         .iostart = 0xb2,
  86         .iolen = 2,
  87         .backlight_ops  = {
  88                 .options        = BL_CORE_SUSPENDRESUME,
  89                 .get_brightness = intel_chipset_get_intensity,
  90                 .update_status  = intel_chipset_send_intensity,
  91         },
  92         .set_brightness = intel_chipset_set_brightness,
  93 };
  94
  95 /*
  96  * Implementation for machines with Nvidia chipset.
  97  */
  98 static void nvidia_chipset_set_brightness(int intensity)
  99 {
 100         outb(0x04 | (intensity << 4), 0x52f);
 101         outb(0xbf, 0x52e);
 102 }
 103
 104 static int nvidia_chipset_send_intensity(struct backlight_device *bd)
 105 {
 106         int intensity = bd->props.brightness;
 107
 108         if (debug)
 109                 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
 110                        intensity);
 111
 112         nvidia_chipset_set_brightness(intensity);
 113         return 0;
 114 }
 115
 116 static int nvidia_chipset_get_intensity(struct backlight_device *bd)
 117 {
 118         int intensity;
 119
 120         outb(0x03, 0x52f);
 121         outb(0xbf, 0x52e);
 122         intensity = inb(0x52f) >> 4;
 123
 124         if (debug)
 125                 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
 126                        intensity);
 127
 128         return intensity;
 129 }
 130
 131 static const struct hw_data nvidia_chipset_data = {
 132         .iostart = 0x52e,
 133         .iolen = 2,
 134         .backlight_ops          = {
 135                 .options        = BL_CORE_SUSPENDRESUME,
 136                 .get_brightness = nvidia_chipset_get_intensity,
 137                 .update_status  = nvidia_chipset_send_intensity
 138         },
 139         .set_brightness = nvidia_chipset_set_brightness,
 140 };
 141
 142 static int __devinit apple_bl_add(struct acpi_device *dev)
 143 {
 144         struct backlight_properties props;
 145         struct pci_dev *host;
 146         int intensity;
 147
 148         host = pci_get_bus_and_slot(0, 0);
 149
 150         if (!host) {
 151                 printk(KERN_ERR DRIVER "unable to find PCI host\n");
 152                 return -ENODEV;
 153         }
 154
 155         if (host->vendor == PCI_VENDOR_ID_INTEL)
 156                 hw_data = &intel_chipset_data;
 157         else if (host->vendor == PCI_VENDOR_ID_NVIDIA)
 158                 hw_data = &nvidia_chipset_data;
 159
 160         pci_dev_put(host);
 161
 162         if (!hw_data) {
 163                 printk(KERN_ERR DRIVER "unknown hardware\n");
 164                 return -ENODEV;
 165         }
 166
 167         /* Check that the hardware responds - this may not work under EFI */
 168
 169         intensity = hw_data->backlight_ops.get_brightness(NULL);
 170
 171         if (!intensity) {
 172                 hw_data->set_brightness(1);
 173                 if (!hw_data->backlight_ops.get_brightness(NULL))
 174                         return -ENODEV;
 175
 176                 hw_data->set_brightness(0);
 177         }
 178
 179         if (!request_region(hw_data->iostart, hw_data->iolen,
 180                             "Apple backlight"))
 181                 return -ENXIO;
 182
 183         memset(&props, 0, sizeof(struct backlight_properties));
 184         props.type = BACKLIGHT_PLATFORM;
 185         props.max_brightness = 15;
 186         apple_backlight_device = backlight_device_register("apple_backlight",
 187                                   NULL, NULL, &hw_data->backlight_ops, &props);
 188
 189         if (IS_ERR(apple_backlight_device)) {
 190                 release_region(hw_data->iostart, hw_data->iolen);
 191                 return PTR_ERR(apple_backlight_device);
 192         }
 193
 194         apple_backlight_device->props.brightness =
 195                 hw_data->backlight_ops.get_brightness(apple_backlight_device);
 196         backlight_update_status(apple_backlight_device);
 197
 198         return 0;
 199 }
 200
 201 static int __devexit apple_bl_remove(struct acpi_device *dev, int type)
 202 {
 203         backlight_device_unregister(apple_backlight_device);
 204
 205         release_region(hw_data->iostart, hw_data->iolen);
 206         hw_data = NULL;
 207         return 0;
 208 }
 209
 210 static const struct acpi_device_id apple_bl_ids[] = {
 211         {"APP0002", 0},
 212         {"", 0},
 213 };
 214
 215 static struct acpi_driver apple_bl_driver = {
 216         .name = "Apple backlight",
 217         .ids = apple_bl_ids,
 218         .ops = {
 219                 .add = apple_bl_add,
 220                 .remove = apple_bl_remove,
 221         },
 222 };
 223
 224 static int __init apple_bl_init(void)
 225 {
 226         return acpi_bus_register_driver(&apple_bl_driver);
 227 }
 228
 229 static void __exit apple_bl_exit(void)
 230 {
 231         acpi_bus_unregister_driver(&apple_bl_driver);
 232 }
 233
 234 module_init(apple_bl_init);
 235 module_exit(apple_bl_exit);
 236
 237 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 238 MODULE_DESCRIPTION("Apple Backlight Driver");
 239 MODULE_LICENSE("GPL");
 240 MODULE_DEVICE_TABLE(acpi, apple_bl_ids);
 241 MODULE_ALIAS("mbp_nvidia_bl");