diff options
Diffstat (limited to 'drivers/video/backlight/apple_bl.c')
| -rw-r--r-- | drivers/video/backlight/apple_bl.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/video/backlight/apple_bl.c b/drivers/video/backlight/apple_bl.c new file mode 100644 index 000000000..c0d9339cf --- /dev/null +++ b/drivers/video/backlight/apple_bl.c @@ -0,0 +1,254 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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 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); +} + +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; +} + +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; +} + +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); +} + +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; +} + +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; +} + +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_domain_bus_and_slot(0, 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; +} + +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; +} + +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; +} +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); +} +EXPORT_SYMBOL_GPL(apple_bl_unregister); + +static int __init apple_bl_init(void) +{ + return apple_bl_register(); +} + +static void __exit apple_bl_exit(void) +{ + apple_bl_unregister(); +} + +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"); |