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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Backlight Driver for Intel-based Apples4 *5 * Copyright (c) Red Hat <mjg@redhat.com>6 * Based on code from Pommed:7 * Copyright (C) 2006 Nicolas Boichat <nicolas @boichat.ch>8 * Copyright (C) 2006 Felipe Alfaro Solana <felipe_alfaro @linuxmail.org>9 * Copyright (C) 2007 Julien BLACHE <jb@jblache.org>10 *11 * This driver triggers SMIs which cause the firmware to change the12 * backlight brightness. This is icky in many ways, but it's impractical to13 * get at the firmware code in order to figure out what it's actually doing.14 */15 16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt17 18#include <linux/module.h>19#include <linux/kernel.h>20#include <linux/init.h>21#include <linux/backlight.h>22#include <linux/err.h>23#include <linux/io.h>24#include <linux/pci.h>25#include <linux/acpi.h>26#include <linux/atomic.h>27#include <acpi/video.h>28 29static struct backlight_device *apple_backlight_device;30 31struct 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 40static const struct hw_data *hw_data;41 42/* Module parameters. */43static int debug;44module_param_named(debug, debug, int, 0644);45MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");46 47/*48 * Implementation for machines with Intel chipset.49 */50static void intel_chipset_set_brightness(int intensity)51{52 outb(0x04 | (intensity << 4), 0xb3);53 outb(0xbf, 0xb2);54}55 56static int intel_chipset_send_intensity(struct backlight_device *bd)57{58 int intensity = bd->props.brightness;59 60 if (debug)61 pr_debug("setting brightness to %d\n", intensity);62 63 intel_chipset_set_brightness(intensity);64 return 0;65}66 67static int intel_chipset_get_intensity(struct backlight_device *bd)68{69 int intensity;70 71 outb(0x03, 0xb3);72 outb(0xbf, 0xb2);73 intensity = inb(0xb3) >> 4;74 75 if (debug)76 pr_debug("read brightness of %d\n", intensity);77 78 return intensity;79}80 81static const struct hw_data intel_chipset_data = {82 .iostart = 0xb2,83 .iolen = 2,84 .backlight_ops = {85 .options = BL_CORE_SUSPENDRESUME,86 .get_brightness = intel_chipset_get_intensity,87 .update_status = intel_chipset_send_intensity,88 },89 .set_brightness = intel_chipset_set_brightness,90};91 92/*93 * Implementation for machines with Nvidia chipset.94 */95static void nvidia_chipset_set_brightness(int intensity)96{97 outb(0x04 | (intensity << 4), 0x52f);98 outb(0xbf, 0x52e);99}100 101static int nvidia_chipset_send_intensity(struct backlight_device *bd)102{103 int intensity = bd->props.brightness;104 105 if (debug)106 pr_debug("setting brightness to %d\n", intensity);107 108 nvidia_chipset_set_brightness(intensity);109 return 0;110}111 112static int nvidia_chipset_get_intensity(struct backlight_device *bd)113{114 int intensity;115 116 outb(0x03, 0x52f);117 outb(0xbf, 0x52e);118 intensity = inb(0x52f) >> 4;119 120 if (debug)121 pr_debug("read brightness of %d\n", intensity);122 123 return intensity;124}125 126static const struct hw_data nvidia_chipset_data = {127 .iostart = 0x52e,128 .iolen = 2,129 .backlight_ops = {130 .options = BL_CORE_SUSPENDRESUME,131 .get_brightness = nvidia_chipset_get_intensity,132 .update_status = nvidia_chipset_send_intensity133 },134 .set_brightness = nvidia_chipset_set_brightness,135};136 137static int apple_bl_add(struct acpi_device *dev)138{139 struct backlight_properties props;140 struct pci_dev *host;141 int intensity;142 143 host = pci_get_domain_bus_and_slot(0, 0, 0);144 145 if (!host) {146 pr_err("unable to find PCI host\n");147 return -ENODEV;148 }149 150 if (host->vendor == PCI_VENDOR_ID_INTEL)151 hw_data = &intel_chipset_data;152 else if (host->vendor == PCI_VENDOR_ID_NVIDIA)153 hw_data = &nvidia_chipset_data;154 155 pci_dev_put(host);156 157 if (!hw_data) {158 pr_err("unknown hardware\n");159 return -ENODEV;160 }161 162 /* Check that the hardware responds - this may not work under EFI */163 164 intensity = hw_data->backlight_ops.get_brightness(NULL);165 166 if (!intensity) {167 hw_data->set_brightness(1);168 if (!hw_data->backlight_ops.get_brightness(NULL))169 return -ENODEV;170 171 hw_data->set_brightness(0);172 }173 174 if (!request_region(hw_data->iostart, hw_data->iolen,175 "Apple backlight"))176 return -ENXIO;177 178 memset(&props, 0, sizeof(struct backlight_properties));179 props.type = BACKLIGHT_PLATFORM;180 props.max_brightness = 15;181 apple_backlight_device = backlight_device_register("apple_backlight",182 NULL, NULL, &hw_data->backlight_ops, &props);183 184 if (IS_ERR(apple_backlight_device)) {185 release_region(hw_data->iostart, hw_data->iolen);186 return PTR_ERR(apple_backlight_device);187 }188 189 apple_backlight_device->props.brightness =190 hw_data->backlight_ops.get_brightness(apple_backlight_device);191 backlight_update_status(apple_backlight_device);192 193 return 0;194}195 196static void apple_bl_remove(struct acpi_device *dev)197{198 backlight_device_unregister(apple_backlight_device);199 200 release_region(hw_data->iostart, hw_data->iolen);201 hw_data = NULL;202}203 204static const struct acpi_device_id apple_bl_ids[] = {205 {"APP0002", 0},206 {"", 0},207};208 209static struct acpi_driver apple_bl_driver = {210 .name = "Apple backlight",211 .ids = apple_bl_ids,212 .ops = {213 .add = apple_bl_add,214 .remove = apple_bl_remove,215 },216};217 218static int __init apple_bl_init(void)219{220 /*221 * Use ACPI video detection code to see if this driver should register222 * or if another driver, e.g. the apple-gmux driver should be used.223 */224 if (acpi_video_get_backlight_type() != acpi_backlight_vendor)225 return -ENODEV;226 227 return acpi_bus_register_driver(&apple_bl_driver);228}229 230static void __exit apple_bl_exit(void)231{232 acpi_bus_unregister_driver(&apple_bl_driver);233}234 235module_init(apple_bl_init);236module_exit(apple_bl_exit);237 238MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");239MODULE_DESCRIPTION("Apple Backlight Driver");240MODULE_LICENSE("GPL");241MODULE_DEVICE_TABLE(acpi, apple_bl_ids);242MODULE_ALIAS("mbp_nvidia_bl");243