2 * Backlight Driver for Intel-based Apples
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>
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.
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.
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>
25 #include <linux/pci.h>
26 #include <linux/acpi.h>
28 static struct backlight_device *apple_backlight_device;
31 /* I/O resource to allocate. */
32 unsigned long iostart;
34 /* Backlight operations structure. */
35 const struct backlight_ops backlight_ops;
36 void (*set_brightness)(int);
39 static const struct hw_data *hw_data;
41 #define DRIVER "apple_backlight: "
43 /* Module parameters. */
45 module_param_named(debug, debug, int, 0644);
46 MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");
49 * Implementation for machines with Intel chipset.
51 static void intel_chipset_set_brightness(int intensity)
53 outb(0x04 | (intensity << 4), 0xb3);
57 static int intel_chipset_send_intensity(struct backlight_device *bd)
59 int intensity = bd->props.brightness;
62 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
65 intel_chipset_set_brightness(intensity);
69 static int intel_chipset_get_intensity(struct backlight_device *bd)
75 intensity = inb(0xb3) >> 4;
78 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
84 static const struct hw_data intel_chipset_data = {
88 .options = BL_CORE_SUSPENDRESUME,
89 .get_brightness = intel_chipset_get_intensity,
90 .update_status = intel_chipset_send_intensity,
92 .set_brightness = intel_chipset_set_brightness,
96 * Implementation for machines with Nvidia chipset.
98 static void nvidia_chipset_set_brightness(int intensity)
100 outb(0x04 | (intensity << 4), 0x52f);
104 static int nvidia_chipset_send_intensity(struct backlight_device *bd)
106 int intensity = bd->props.brightness;
109 printk(KERN_DEBUG DRIVER "setting brightness to %d\n",
112 nvidia_chipset_set_brightness(intensity);
116 static int nvidia_chipset_get_intensity(struct backlight_device *bd)
122 intensity = inb(0x52f) >> 4;
125 printk(KERN_DEBUG DRIVER "read brightness of %d\n",
131 static const struct hw_data nvidia_chipset_data = {
135 .options = BL_CORE_SUSPENDRESUME,
136 .get_brightness = nvidia_chipset_get_intensity,
137 .update_status = nvidia_chipset_send_intensity
139 .set_brightness = nvidia_chipset_set_brightness,
142 static int __devinit apple_bl_add(struct acpi_device *dev)
144 struct backlight_properties props;
145 struct pci_dev *host;
148 host = pci_get_bus_and_slot(0, 0);
151 printk(KERN_ERR DRIVER "unable to find PCI host\n");
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;
163 printk(KERN_ERR DRIVER "unknown hardware\n");
167 /* Check that the hardware responds - this may not work under EFI */
169 intensity = hw_data->backlight_ops.get_brightness(NULL);
172 hw_data->set_brightness(1);
173 if (!hw_data->backlight_ops.get_brightness(NULL))
176 hw_data->set_brightness(0);
179 if (!request_region(hw_data->iostart, hw_data->iolen,
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);
189 if (IS_ERR(apple_backlight_device)) {
190 release_region(hw_data->iostart, hw_data->iolen);
191 return PTR_ERR(apple_backlight_device);
194 apple_backlight_device->props.brightness =
195 hw_data->backlight_ops.get_brightness(apple_backlight_device);
196 backlight_update_status(apple_backlight_device);
201 static int __devexit apple_bl_remove(struct acpi_device *dev, int type)
203 backlight_device_unregister(apple_backlight_device);
205 release_region(hw_data->iostart, hw_data->iolen);
210 static const struct acpi_device_id apple_bl_ids[] = {
215 static struct acpi_driver apple_bl_driver = {
216 .name = "Apple backlight",
220 .remove = apple_bl_remove,
224 static int __init apple_bl_init(void)
226 return acpi_bus_register_driver(&apple_bl_driver);
229 static void __exit apple_bl_exit(void)
231 acpi_bus_unregister_driver(&apple_bl_driver);
234 module_init(apple_bl_init);
235 module_exit(apple_bl_exit);
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");