diff options
Diffstat (limited to 'drivers/platform/x86/apple-gmux.c')
| -rw-r--r-- | drivers/platform/x86/apple-gmux.c | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c new file mode 100644 index 000000000000..8a582bdfdc76 --- /dev/null +++ b/drivers/platform/x86/apple-gmux.c @@ -0,0 +1,244 @@ +/* + * 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); |