cregit-Linux how code gets into the kernel

Release 4.14 drivers/video/backlight/apple_bl.c

/*
 *  Backlight Driver for Intel-based Apples
 *
 *  Copyright (c) Red Hat <mjg@redhat.com>
 *  Based on code from Pommed:
 *  Copyright (C) 2006 Nicolas Boichat <nicolas @boichat.ch>
 *  Copyright (C) 2006 Felipe Alfaro Solana <felipe_alfaro @linuxmail.org>
 *  Copyright (C) 2007 Julien BLACHE <jb@jblache.org>
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 *
 *  This driver triggers SMIs which cause the firmware to change the
 *  backlight brightness. This is icky in many ways, but it's impractical to
 *  get at the firmware code in order to figure out what it's actually doing.
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/atomic.h>
#include <linux/apple_bl.h>


static struct backlight_device *apple_backlight_device;


struct hw_data {
	/* I/O resource to allocate. */
	
unsigned long iostart;
	
unsigned long iolen;
	/* Backlight operations structure. */
	
const struct backlight_ops backlight_ops;
	
void (*set_brightness)(int);
};


static const struct hw_data *hw_data;

/* Module parameters. */

static int debug;
module_param_named(debug, debug, int, 0644);
MODULE_PARM_DESC(debug, "Set to one to enable debugging messages.");

/*
 * Implementation for machines with Intel chipset.
 */

static void intel_chipset_set_brightness(int intensity) { outb(0x04 | (intensity << 4), 0xb3); outb(0xbf, 0xb2); }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett29100.00%1100.00%
Total29100.00%1100.00%


static int intel_chipset_send_intensity(struct backlight_device *bd) { int intensity = bd->props.brightness; if (debug) pr_debug("setting brightness to %d\n", intensity); intel_chipset_set_brightness(intensity); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Schwalbe2871.79%240.00%
Matthew Garrett820.51%240.00%
Jingoo Han37.69%120.00%
Total39100.00%5100.00%


static int intel_chipset_get_intensity(struct backlight_device *bd) { int intensity; outb(0x03, 0xb3); outb(0xbf, 0xb2); intensity = inb(0xb3) >> 4; if (debug) pr_debug("read brightness of %d\n", intensity); return intensity; }

Contributors

PersonTokensPropCommitsCommitProp
Mario Schwalbe4078.43%240.00%
Matthew Garrett815.69%240.00%
Jingoo Han35.88%120.00%
Total51100.00%5100.00%

static const struct hw_data intel_chipset_data = { .iostart = 0xb2, .iolen = 2, .backlight_ops = { .options = BL_CORE_SUSPENDRESUME, .get_brightness = intel_chipset_get_intensity, .update_status = intel_chipset_send_intensity, }, .set_brightness = intel_chipset_set_brightness, }; /* * Implementation for machines with Nvidia chipset. */
static void nvidia_chipset_set_brightness(int intensity) { outb(0x04 | (intensity << 4), 0x52f); outb(0xbf, 0x52e); }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett29100.00%1100.00%
Total29100.00%1100.00%


static int nvidia_chipset_send_intensity(struct backlight_device *bd) { int intensity = bd->props.brightness; if (debug) pr_debug("setting brightness to %d\n", intensity); nvidia_chipset_set_brightness(intensity); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett2871.79%240.00%
Mario Schwalbe820.51%240.00%
Jingoo Han37.69%120.00%
Total39100.00%5100.00%


static int nvidia_chipset_get_intensity(struct backlight_device *bd) { int intensity; outb(0x03, 0x52f); outb(0xbf, 0x52e); intensity = inb(0x52f) >> 4; if (debug) pr_debug("read brightness of %d\n", intensity); return intensity; }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett2956.86%240.00%
Mario Schwalbe1937.25%240.00%
Jingoo Han35.88%120.00%
Total51100.00%5100.00%

static const struct hw_data nvidia_chipset_data = { .iostart = 0x52e, .iolen = 2, .backlight_ops = { .options = BL_CORE_SUSPENDRESUME, .get_brightness = nvidia_chipset_get_intensity, .update_status = nvidia_chipset_send_intensity }, .set_brightness = nvidia_chipset_set_brightness, };
static int apple_bl_add(struct acpi_device *dev) { struct backlight_properties props; struct pci_dev *host; int intensity; host = pci_get_bus_and_slot(0, 0); if (!host) { pr_err("unable to find PCI host\n"); return -ENODEV; } if (host->vendor == PCI_VENDOR_ID_INTEL) hw_data = &intel_chipset_data; else if (host->vendor == PCI_VENDOR_ID_NVIDIA) hw_data = &nvidia_chipset_data; pci_dev_put(host); if (!hw_data) { pr_err("unknown hardware\n"); return -ENODEV; } /* Check that the hardware responds - this may not work under EFI */ intensity = hw_data->backlight_ops.get_brightness(NULL); if (!intensity) { hw_data->set_brightness(1); if (!hw_data->backlight_ops.get_brightness(NULL)) return -ENODEV; hw_data->set_brightness(0); } if (!request_region(hw_data->iostart, hw_data->iolen, "Apple backlight")) return -ENXIO; memset(&props, 0, sizeof(struct backlight_properties)); props.type = BACKLIGHT_PLATFORM; props.max_brightness = 15; apple_backlight_device = backlight_device_register("apple_backlight", NULL, NULL, &hw_data->backlight_ops, &props); if (IS_ERR(apple_backlight_device)) { release_region(hw_data->iostart, hw_data->iolen); return PTR_ERR(apple_backlight_device); } apple_backlight_device->props.brightness = hw_data->backlight_ops.get_brightness(apple_backlight_device); backlight_update_status(apple_backlight_device); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett21884.17%562.50%
Mario Schwalbe2610.04%112.50%
Evan McClain114.25%112.50%
Jingoo Han41.54%112.50%
Total259100.00%8100.00%


static int apple_bl_remove(struct acpi_device *dev) { backlight_device_unregister(apple_backlight_device); release_region(hw_data->iostart, hw_data->iolen); hw_data = NULL; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett3088.24%375.00%
Mario Schwalbe411.76%125.00%
Total34100.00%4100.00%

static const struct acpi_device_id apple_bl_ids[] = { {"APP0002", 0}, {"", 0}, }; static struct acpi_driver apple_bl_driver = { .name = "Apple backlight", .ids = apple_bl_ids, .ops = { .add = apple_bl_add, .remove = apple_bl_remove, }, }; static atomic_t apple_bl_registered = ATOMIC_INIT(0);
int apple_bl_register(void) { if (atomic_xchg(&apple_bl_registered, 1) == 0) return acpi_bus_register_driver(&apple_bl_driver); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Seth Forshee1655.17%133.33%
Matthew Garrett1344.83%266.67%
Total29100.00%3100.00%

EXPORT_SYMBOL_GPL(apple_bl_register);
void apple_bl_unregister(void) { if (atomic_xchg(&apple_bl_registered, 0) == 1) acpi_bus_unregister_driver(&apple_bl_driver); }

Contributors

PersonTokensPropCommitsCommitProp
Seth Forshee1352.00%125.00%
Matthew Garrett1248.00%375.00%
Total25100.00%4100.00%

EXPORT_SYMBOL_GPL(apple_bl_unregister);
static int __init apple_bl_init(void) { return apple_bl_register(); }

Contributors

PersonTokensPropCommitsCommitProp
Seth Forshee13100.00%1100.00%
Total13100.00%1100.00%


static void __exit apple_bl_exit(void) { apple_bl_unregister(); }

Contributors

PersonTokensPropCommitsCommitProp
Seth Forshee12100.00%1100.00%
Total12100.00%1100.00%

module_init(apple_bl_init); module_exit(apple_bl_exit); MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>"); MODULE_DESCRIPTION("Apple Backlight Driver"); MODULE_LICENSE("GPL"); MODULE_DEVICE_TABLE(acpi, apple_bl_ids); MODULE_ALIAS("mbp_nvidia_bl");

Overall Contributors

PersonTokensPropCommitsCommitProp
Matthew Garrett57863.52%535.71%
Mario Schwalbe21223.30%214.29%
Seth Forshee758.24%17.14%
Jingoo Han232.53%17.14%
Evan McClain111.21%17.14%
Richard Purdie50.55%17.14%
H Hartley Sweeten30.33%17.14%
David Woodhouse20.22%17.14%
Emese Revfy10.11%17.14%
Total910100.00%14100.00%
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