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>
27 #include <linux/atomic.h>
29 static struct backlight_device
*apple_backlight_device
;
32 /* I/O resource to allocate. */
33 unsigned long iostart
;
35 /* Backlight operations structure. */
36 const struct backlight_ops backlight_ops
;
37 void (*set_brightness
)(int);
40 static const struct hw_data
*hw_data
;
42 #define DRIVER "apple_backlight: "
44 /* Module parameters. */
46 module_param_named(debug
, debug
, int, 0644);
47 MODULE_PARM_DESC(debug
, "Set to one to enable debugging messages.");
50 * Implementation for machines with Intel chipset.
52 static void intel_chipset_set_brightness(int intensity
)
54 outb(0x04 | (intensity
<< 4), 0xb3);
58 static int intel_chipset_send_intensity(struct backlight_device
*bd
)
60 int intensity
= bd
->props
.brightness
;
63 printk(KERN_DEBUG DRIVER
"setting brightness to %d\n",
66 intel_chipset_set_brightness(intensity
);
70 static int intel_chipset_get_intensity(struct backlight_device
*bd
)
76 intensity
= inb(0xb3) >> 4;
79 printk(KERN_DEBUG DRIVER
"read brightness of %d\n",
85 static const struct hw_data intel_chipset_data
= {
89 .options
= BL_CORE_SUSPENDRESUME
,
90 .get_brightness
= intel_chipset_get_intensity
,
91 .update_status
= intel_chipset_send_intensity
,
93 .set_brightness
= intel_chipset_set_brightness
,
97 * Implementation for machines with Nvidia chipset.
99 static void nvidia_chipset_set_brightness(int intensity
)
101 outb(0x04 | (intensity
<< 4), 0x52f);
105 static int nvidia_chipset_send_intensity(struct backlight_device
*bd
)
107 int intensity
= bd
->props
.brightness
;
110 printk(KERN_DEBUG DRIVER
"setting brightness to %d\n",
113 nvidia_chipset_set_brightness(intensity
);
117 static int nvidia_chipset_get_intensity(struct backlight_device
*bd
)
123 intensity
= inb(0x52f) >> 4;
126 printk(KERN_DEBUG DRIVER
"read brightness of %d\n",
132 static const struct hw_data nvidia_chipset_data
= {
136 .options
= BL_CORE_SUSPENDRESUME
,
137 .get_brightness
= nvidia_chipset_get_intensity
,
138 .update_status
= nvidia_chipset_send_intensity
140 .set_brightness
= nvidia_chipset_set_brightness
,
143 static int __devinit
apple_bl_add(struct acpi_device
*dev
)
145 struct backlight_properties props
;
146 struct pci_dev
*host
;
149 host
= pci_get_bus_and_slot(0, 0);
152 printk(KERN_ERR DRIVER
"unable to find PCI host\n");
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
;
164 printk(KERN_ERR DRIVER
"unknown hardware\n");
168 /* Check that the hardware responds - this may not work under EFI */
170 intensity
= hw_data
->backlight_ops
.get_brightness(NULL
);
173 hw_data
->set_brightness(1);
174 if (!hw_data
->backlight_ops
.get_brightness(NULL
))
177 hw_data
->set_brightness(0);
180 if (!request_region(hw_data
->iostart
, hw_data
->iolen
,
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
);
190 if (IS_ERR(apple_backlight_device
)) {
191 release_region(hw_data
->iostart
, hw_data
->iolen
);
192 return PTR_ERR(apple_backlight_device
);
195 apple_backlight_device
->props
.brightness
=
196 hw_data
->backlight_ops
.get_brightness(apple_backlight_device
);
197 backlight_update_status(apple_backlight_device
);
202 static int __devexit
apple_bl_remove(struct acpi_device
*dev
, int type
)
204 backlight_device_unregister(apple_backlight_device
);
206 release_region(hw_data
->iostart
, hw_data
->iolen
);
211 static const struct acpi_device_id apple_bl_ids
[] = {
216 static struct acpi_driver apple_bl_driver
= {
217 .name
= "Apple backlight",
221 .remove
= apple_bl_remove
,
225 static atomic_t apple_bl_registered
= ATOMIC_INIT(0);
227 int apple_bl_register(void)
229 if (atomic_xchg(&apple_bl_registered
, 1) == 0)
230 return acpi_bus_register_driver(&apple_bl_driver
);
234 EXPORT_SYMBOL_GPL(apple_bl_register
);
236 void apple_bl_unregister(void)
238 if (atomic_xchg(&apple_bl_registered
, 0) == 1)
239 acpi_bus_unregister_driver(&apple_bl_driver
);
241 EXPORT_SYMBOL_GPL(apple_bl_unregister
);
243 static int __init
apple_bl_init(void)
245 return apple_bl_register();
248 static void __exit
apple_bl_exit(void)
250 apple_bl_unregister();
253 module_init(apple_bl_init
);
254 module_exit(apple_bl_exit
);
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");