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"); 242