--- /dev/null
+/*
+ * Gmux driver for Apple laptops
+ *
+ * Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
+ *
+ * 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.
+ */
+
+#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/acpi.h>
+#include <linux/pnp.h>
+#include <linux/apple_bl.h>
+#include <linux/slab.h>
+#include <acpi/video.h>
+#include <asm/io.h>
+
+struct apple_gmux_data {
+ unsigned long iostart;
+ unsigned long iolen;
+
+ struct backlight_device *bdev;
+};
+
+/*
+ * gmux port offsets. Many of these are not yet used, but may be in the
+ * future, and it's useful to have them documented here anyhow.
+ */
+#define GMUX_PORT_VERSION_MAJOR 0x04
+#define GMUX_PORT_VERSION_MINOR 0x05
+#define GMUX_PORT_VERSION_RELEASE 0x06
+#define GMUX_PORT_SWITCH_DISPLAY 0x10
+#define GMUX_PORT_SWITCH_GET_DISPLAY 0x11
+#define GMUX_PORT_INTERRUPT_ENABLE 0x14
+#define GMUX_PORT_INTERRUPT_STATUS 0x16
+#define GMUX_PORT_SWITCH_DDC 0x28
+#define GMUX_PORT_SWITCH_EXTERNAL 0x40
+#define GMUX_PORT_SWITCH_GET_EXTERNAL 0x41
+#define GMUX_PORT_DISCRETE_POWER 0x50
+#define GMUX_PORT_MAX_BRIGHTNESS 0x70
+#define GMUX_PORT_BRIGHTNESS 0x74
+
+#define GMUX_MIN_IO_LEN (GMUX_PORT_BRIGHTNESS + 4)
+
+#define GMUX_INTERRUPT_ENABLE 0xff
+#define GMUX_INTERRUPT_DISABLE 0x00
+
+#define GMUX_INTERRUPT_STATUS_ACTIVE 0
+#define GMUX_INTERRUPT_STATUS_DISPLAY (1 << 0)
+#define GMUX_INTERRUPT_STATUS_POWER (1 << 2)
+#define GMUX_INTERRUPT_STATUS_HOTPLUG (1 << 3)
+
+#define GMUX_BRIGHTNESS_MASK 0x00ffffff
+#define GMUX_MAX_BRIGHTNESS GMUX_BRIGHTNESS_MASK
+
+static inline u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
+{
+ return inb(gmux_data->iostart + port);
+}
+
+static inline void gmux_write8(struct apple_gmux_data *gmux_data, int port,
+ u8 val)
+{
+ outb(val, gmux_data->iostart + port);
+}
+
+static inline u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
+{
+ return inl(gmux_data->iostart + port);
+}
+
+static int gmux_get_brightness(struct backlight_device *bd)
+{
+ struct apple_gmux_data *gmux_data = bl_get_data(bd);
+ return gmux_read32(gmux_data, GMUX_PORT_BRIGHTNESS) &
+ GMUX_BRIGHTNESS_MASK;
+}
+
+static int gmux_update_status(struct backlight_device *bd)
+{
+ struct apple_gmux_data *gmux_data = bl_get_data(bd);
+ u32 brightness = bd->props.brightness;
+
+ /*
+ * Older gmux versions require writing out lower bytes first then
+ * setting the upper byte to 0 to flush the values. Newer versions
+ * accept a single u32 write, but the old method also works, so we
+ * just use the old method for all gmux versions.
+ */
+ gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS, brightness);
+ gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 1, brightness >> 8);
+ gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 2, brightness >> 16);
+ gmux_write8(gmux_data, GMUX_PORT_BRIGHTNESS + 3, 0);
+
+ return 0;
+}
+
+static const struct backlight_ops gmux_bl_ops = {
+ .get_brightness = gmux_get_brightness,
+ .update_status = gmux_update_status,
+};
+
+static int __devinit gmux_probe(struct pnp_dev *pnp,
+ const struct pnp_device_id *id)
+{
+ struct apple_gmux_data *gmux_data;
+ struct resource *res;
+ struct backlight_properties props;
+ struct backlight_device *bdev;
+ u8 ver_major, ver_minor, ver_release;
+ int ret = -ENXIO;
+
+ gmux_data = kzalloc(sizeof(*gmux_data), GFP_KERNEL);
+ if (!gmux_data)
+ return -ENOMEM;
+ pnp_set_drvdata(pnp, gmux_data);
+
+ res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
+ if (!res) {
+ pr_err("Failed to find gmux I/O resource\n");
+ goto err_free;
+ }
+
+ gmux_data->iostart = res->start;
+ gmux_data->iolen = res->end - res->start;
+
+ if (gmux_data->iolen < GMUX_MIN_IO_LEN) {
+ pr_err("gmux I/O region too small (%lu < %u)\n",
+ gmux_data->iolen, GMUX_MIN_IO_LEN);
+ goto err_free;
+ }
+
+ if (!request_region(gmux_data->iostart, gmux_data->iolen,
+ "Apple gmux")) {
+ pr_err("gmux I/O already in use\n");
+ goto err_free;
+ }
+
+ /*
+ * On some machines the gmux is in ACPI even thought the machine
+ * doesn't really have a gmux. Check for invalid version information
+ * to detect this.
+ */
+ ver_major = gmux_read8(gmux_data, GMUX_PORT_VERSION_MAJOR);
+ ver_minor = gmux_read8(gmux_data, GMUX_PORT_VERSION_MINOR);
+ ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
+ if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
+ pr_info("gmux device not present\n");
+ ret = -ENODEV;
+ goto err_release;
+ }
+
+ pr_info("Found gmux version %d.%d.%d\n", ver_major, ver_minor,
+ ver_release);
+
+ memset(&props, 0, sizeof(props));
+ props.type = BACKLIGHT_PLATFORM;
+ props.max_brightness = gmux_read32(gmux_data, GMUX_PORT_MAX_BRIGHTNESS);
+
+ /*
+ * Currently it's assumed that the maximum brightness is less than
+ * 2^24 for compatibility with old gmux versions. Cap the max
+ * brightness at this value, but print a warning if the hardware
+ * reports something higher so that it can be fixed.
+ */
+ if (WARN_ON(props.max_brightness > GMUX_MAX_BRIGHTNESS))
+ props.max_brightness = GMUX_MAX_BRIGHTNESS;
+
+ bdev = backlight_device_register("gmux_backlight", &pnp->dev,
+ gmux_data, &gmux_bl_ops, &props);
+ if (IS_ERR(bdev)) {
+ ret = PTR_ERR(bdev);
+ goto err_release;
+ }
+
+ gmux_data->bdev = bdev;
+ bdev->props.brightness = gmux_get_brightness(bdev);
+ backlight_update_status(bdev);
+
+ /*
+ * The backlight situation on Macs is complicated. If the gmux is
+ * present it's the best choice, because it always works for
+ * backlight control and supports more levels than other options.
+ * Disable the other backlight choices.
+ */
+ acpi_video_unregister();
+ apple_bl_unregister();
+
+ return 0;
+
+err_release:
+ release_region(gmux_data->iostart, gmux_data->iolen);
+err_free:
+ kfree(gmux_data);
+ return ret;
+}
+
+static void __devexit gmux_remove(struct pnp_dev *pnp)
+{
+ struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+
+ backlight_device_unregister(gmux_data->bdev);
+ release_region(gmux_data->iostart, gmux_data->iolen);
+ kfree(gmux_data);
+
+ acpi_video_register();
+ apple_bl_register();
+}
+
+static const struct pnp_device_id gmux_device_ids[] = {
+ {"APP000B", 0},
+ {"", 0}
+};
+
+static struct pnp_driver gmux_pnp_driver = {
+ .name = "apple-gmux",
+ .probe = gmux_probe,
+ .remove = __devexit_p(gmux_remove),
+ .id_table = gmux_device_ids,
+};
+
+static int __init apple_gmux_init(void)
+{
+ return pnp_register_driver(&gmux_pnp_driver);
+}
+
+static void __exit apple_gmux_exit(void)
+{
+ pnp_unregister_driver(&gmux_pnp_driver);
+}
+
+module_init(apple_gmux_init);
+module_exit(apple_gmux_exit);
+
+MODULE_AUTHOR("Seth Forshee <seth.forshee@canonical.com>");
+MODULE_DESCRIPTION("Apple Gmux Driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pnp, gmux_device_ids);
projects / linux-beck.git / commitdiff