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 #include <linux/atomic.h>
  28
  29 static struct backlight_device *apple_backlight_device;
  30
  31 struct hw_data {
  32         /* I/O resource to allocate. */
  33         unsigned long iostart;
  34         unsigned long iolen;
  35         /* Backlight operations structure. */
  36         const struct backlight_ops backlight_ops;
  37         void (*set_brightness)(int);
  38 };
  39
  40 static const struct hw_data *hw_data;
  41
  42 #define DRIVER "apple_backlight: "
  43
  44 /* Module parameters. */
  45 static int debug;
  46 module_param_named(debug, debug, int, 0644);
  47 MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");
  48
  49 /*
  50  * Implementation for machines with Intel chipset.
  51  */
  52 static void intel_chipset_set_brightness(int intensity)
  53 {
  54         outb(0x04 | (intensity << 4), 0xb3);
  55         outb(0xbf, 0xb2);
  56 }
  57
  58 static int intel_chipset_send_intensity(struct backlight_device *bd)
  59 {
  60         int intensity = bd->props.brightness;
  61
  62         if (debug)
  63                 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
  64                        intensity);
  65
  66         intel_chipset_set_brightness(intensity);
  67         return 0;
  68 }
  69
  70 static int intel_chipset_get_intensity(struct backlight_device *bd)
  71 {
  72         int intensity;
  73
  74         outb(0x03, 0xb3);
  75         outb(0xbf, 0xb2);
  76         intensity = inb(0xb3) >> 4;
  77
  78         if (debug)
  79                 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
  80                        intensity);
  81
  82         return intensity;
  83 }
  84
  85 static const struct hw_data intel_chipset_data = {
  86         .iostart = 0xb2,
  87         .iolen = 2,
  88         .backlight_ops  = {
  89                 .options        = BL_CORE_SUSPENDRESUME,
  90                 .get_brightness = intel_chipset_get_intensity,
  91                 .update_status  = intel_chipset_send_intensity,
  92         },
  93         .set_brightness = intel_chipset_set_brightness,
  94 };
  95
  96 /*
  97  * Implementation for machines with Nvidia chipset.
  98  */
  99 static void nvidia_chipset_set_brightness(int intensity)
 100 {
 101         outb(0x04 | (intensity << 4), 0x52f);
 102         outb(0xbf, 0x52e);
 103 }
 104
 105 static int nvidia_chipset_send_intensity(struct backlight_device *bd)
 106 {
 107         int intensity = bd->props.brightness;
 108
 109         if (debug)
 110                 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
 111                        intensity);
 112
 113         nvidia_chipset_set_brightness(intensity);
 114         return 0;
 115 }
 116
 117 static int nvidia_chipset_get_intensity(struct backlight_device *bd)
 118 {
 119         int intensity;
 120
 121         outb(0x03, 0x52f);
 122         outb(0xbf, 0x52e);
 123         intensity = inb(0x52f) >> 4;
 124
 125         if (debug)
 126                 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
 127                        intensity);
 128
 129         return intensity;
 130 }
 131
 132 static const struct hw_data nvidia_chipset_data = {
 133         .iostart = 0x52e,
 134         .iolen = 2,
 135         .backlight_ops          = {
 136                 .options        = BL_CORE_SUSPENDRESUME,
 137                 .get_brightness = nvidia_chipset_get_intensity,
 138                 .update_status  = nvidia_chipset_send_intensity
 139         },
 140         .set_brightness = nvidia_chipset_set_brightness,
 141 };
 142
 143 static int __devinit apple_bl_add(struct acpi_device *dev)
 144 {
 145         struct backlight_properties props;
 146         struct pci_dev *host;
 147         int intensity;
 148
 149         host = pci_get_bus_and_slot(0, 0);
 150
 151         if (!host) {
 152                 printk(KERN_ERR DRIVER "unable to find PCI host\n");
 153                 return -ENODEV;
 154         }
 155
 156         if (host->vendor == PCI_VENDOR_ID_INTEL)
 157                 hw_data = &intel_chipset_data;
 158         else if (host->vendor == PCI_VENDOR_ID_NVIDIA)
 159                 hw_data = &nvidia_chipset_data;
 160
 161         pci_dev_put(host);
 162
 163         if (!hw_data) {
 164                 printk(KERN_ERR DRIVER "unknown hardware\n");
 165                 return -ENODEV;
 166         }
 167
 168         /* Check that the hardware responds - this may not work under EFI */
 169
 170         intensity = hw_data->backlight_ops.get_brightness(NULL);
 171
 172         if (!intensity) {
 173                 hw_data->set_brightness(1);
 174                 if (!hw_data->backlight_ops.get_brightness(NULL))
 175                         return -ENODEV;
 176
 177                 hw_data->set_brightness(0);
 178         }
 179
 180         if (!request_region(hw_data->iostart, hw_data->iolen,
 181                             "Apple backlight"))
 182                 return -ENXIO;
 183
 184         memset(&props, 0, sizeof(struct backlight_properties));
 185         props.type = BACKLIGHT_PLATFORM;
 186         props.max_brightness = 15;
 187         apple_backlight_device = backlight_device_register("apple_backlight",
 188                                   NULL, NULL, &hw_data->backlight_ops, &props);
 189
 190         if (IS_ERR(apple_backlight_device)) {
 191                 release_region(hw_data->iostart, hw_data->iolen);
 192                 return PTR_ERR(apple_backlight_device);
 193         }
 194
 195         apple_backlight_device->props.brightness =
 196                 hw_data->backlight_ops.get_brightness(apple_backlight_device);
 197         backlight_update_status(apple_backlight_device);
 198
 199         return 0;
 200 }
 201
 202 static int __devexit apple_bl_remove(struct acpi_device *dev, int type)
 203 {
 204         backlight_device_unregister(apple_backlight_device);
 205
 206         release_region(hw_data->iostart, hw_data->iolen);
 207         hw_data = NULL;
 208         return 0;
 209 }
 210
 211 static const struct acpi_device_id apple_bl_ids[] = {
 212         {"APP0002", 0},
 213         {"", 0},
 214 };
 215
 216 static struct acpi_driver apple_bl_driver = {
 217         .name = "Apple backlight",
 218         .ids = apple_bl_ids,
 219         .ops = {
 220                 .add = apple_bl_add,
 221                 .remove = apple_bl_remove,
 222         },
 223 };
 224
 225 static atomic_t apple_bl_registered = ATOMIC_INIT(0);
 226
 227 int apple_bl_register(void)
 228 {
 229         if (atomic_xchg(&apple_bl_registered, 1) == 0)
 230                 return acpi_bus_register_driver(&apple_bl_driver);
 231
 232         return 0;
 233 }
 234 EXPORT_SYMBOL_GPL(apple_bl_register);
 235
 236 void apple_bl_unregister(void)
 237 {
 238         if (atomic_xchg(&apple_bl_registered, 0) == 1)
 239                 acpi_bus_unregister_driver(&apple_bl_driver);
 240 }
 241 EXPORT_SYMBOL_GPL(apple_bl_unregister);
 242
 243 static int __init apple_bl_init(void)
 244 {
 245         return apple_bl_register();
 246 }
 247
 248 static void __exit apple_bl_exit(void)
 249 {
 250         apple_bl_unregister();
 251 }
 252
 253 module_init(apple_bl_init);
 254 module_exit(apple_bl_exit);
 255
 256 MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
 257 MODULE_DESCRIPTION("Apple Backlight Driver");
 258 MODULE_LICENSE("GPL");
 259 MODULE_DEVICE_TABLE(acpi, apple_bl_ids);
 260 MODULE_ALIAS("mbp_nvidia_bl");