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