--- /dev/null
+/*
+ * 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);
+}
+
+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_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;
+}
+
+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");
Code Review / kvmfornfv.git / blobdiff