drivers/platform/x86/dell-laptop.c

/*
 *  Driver for Dell laptop extras
 *
 *  Copyright (c) Red Hat <mjg@redhat.com>
 *  Copyright (c) 2014 Gabriele Mazzotta <gabriele.mzt@gmail.com>
 *  Copyright (c) 2014 Pali Rohár <pali.rohar@gmail.com>
 *
 *  Based on documentation in the libsmbios package:
 *  Copyright (C) 2005-2014 Dell Inc.
 *
 *  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/platform_device.h>
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <linux/rfkill.h>
#include <linux/power_supply.h>
#include <linux/acpi.h>
#include <linux/mm.h>
#include <linux/i8042.h>
#include <linux/debugfs.h>
#include <linux/dell-led.h>
#include <linux/seq_file.h>
#include <acpi/video.h>
#include "dell-rbtn.h"
#include "dell-smbios.h"

struct quirk_entry {
	bool touchpad_led;
	bool kbd_led_levels_off_1;

	bool needs_kbd_timeouts;
	/*
	 * Ordered list of timeouts expressed in seconds.
	 * The list must end with -1
	 */
	int kbd_timeouts[];
};

static struct quirk_entry *quirks;

static struct quirk_entry quirk_dell_vostro_v130 = {
	.touchpad_led = true,
};

static int __init dmi_matched(const struct dmi_system_id *dmi)
{
	quirks = dmi->driver_data;
	return 1;
}

/*
 * These values come from Windows utility provided by Dell. If any other value
 * is used then BIOS silently set timeout to 0 without any error message.
 */
static struct quirk_entry quirk_dell_xps13_9333 = {
	.needs_kbd_timeouts = true,
	.kbd_timeouts = { 0, 5, 15, 60, 5 * 60, 15 * 60, -1 },
};

static struct quirk_entry quirk_dell_latitude_e6410 = {
	.kbd_led_levels_off_1 = true,
};

static struct platform_driver platform_driver = {
	.driver = {
		.name = "dell-laptop",
	}
};

static struct platform_device *platform_device;
static struct backlight_device *dell_backlight_device;
static struct rfkill *wifi_rfkill;
static struct rfkill *bluetooth_rfkill;
static struct rfkill *wwan_rfkill;
static bool force_rfkill;

module_param(force_rfkill, bool, 0444);
MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted models");

static const struct dmi_system_id dell_device_table[] __initconst = {
	{
		.ident = "Dell laptop",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
		},
	},
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "9"), /*Laptop*/
		},
	},
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "10"), /*Notebook*/
		},
	},
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "30"), /*Tablet*/
		},
	},
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "31"), /*Convertible*/
		},
	},
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "32"), /*Detachable*/
		},
	},
	{
		.ident = "Dell Computer Corporation",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
			DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
		},
	},
	{ }
};
MODULE_DEVICE_TABLE(dmi, dell_device_table);

static const struct dmi_system_id dell_quirks[] __initconst = {
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro V130",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V130"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro V131",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro V131"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3350",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3350"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3555",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3555"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron N311z",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron N311z"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron M5110",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron M5110"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3360",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3360"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3460",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3460"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3560",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Vostro 3560"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Vostro 3450",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Dell System Vostro 3450"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 5420",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5420"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 5520",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5520"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 5720",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 5720"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 7420",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7420"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 7520",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7520"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Inspiron 7720",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 7720"),
		},
		.driver_data = &quirk_dell_vostro_v130,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell XPS13 9333",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "XPS13 9333"),
		},
		.driver_data = &quirk_dell_xps13_9333,
	},
	{
		.callback = dmi_matched,
		.ident = "Dell Latitude E6410",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_PRODUCT_NAME, "Latitude E6410"),
		},
		.driver_data = &quirk_dell_latitude_e6410,
	},
	{ }
};

static void dell_fill_request(struct calling_interface_buffer *buffer,
			       u32 arg0, u32 arg1, u32 arg2, u32 arg3)
{
	memset(buffer, 0, sizeof(struct calling_interface_buffer));
	buffer->input[0] = arg0;
	buffer->input[1] = arg1;
	buffer->input[2] = arg2;
	buffer->input[3] = arg3;
}

static int dell_send_request(struct calling_interface_buffer *buffer,
			     u16 class, u16 select)
{
	int ret;

	buffer->cmd_class = class;
	buffer->cmd_select = select;
	ret = dell_smbios_call(buffer);
	if (ret != 0)
		return ret;
	return dell_smbios_error(buffer->output[0]);
}

/*
 * Derived from information in smbios-wireless-ctl:
 *
 * cbSelect 17, Value 11
 *
 * Return Wireless Info
 * cbArg1, byte0 = 0x00
 *
 *     cbRes1 Standard return codes (0, -1, -2)
 *     cbRes2 Info bit flags:
 *
 *     0 Hardware switch supported (1)
 *     1 WiFi locator supported (1)
 *     2 WLAN supported (1)
 *     3 Bluetooth (BT) supported (1)
 *     4 WWAN supported (1)
 *     5 Wireless KBD supported (1)
 *     6 Uw b supported (1)
 *     7 WiGig supported (1)
 *     8 WLAN installed (1)
 *     9 BT installed (1)
 *     10 WWAN installed (1)
 *     11 Uw b installed (1)
 *     12 WiGig installed (1)
 *     13-15 Reserved (0)
 *     16 Hardware (HW) switch is On (1)
 *     17 WLAN disabled (1)
 *     18 BT disabled (1)
 *     19 WWAN disabled (1)
 *     20 Uw b disabled (1)
 *     21 WiGig disabled (1)
 *     20-31 Reserved (0)
 *
 *     cbRes3 NVRAM size in bytes
 *     cbRes4, byte 0 NVRAM format version number
 *
 *
 * Set QuickSet Radio Disable Flag
 *     cbArg1, byte0 = 0x01
 *     cbArg1, byte1
 *     Radio ID     value:
 *     0        Radio Status
 *     1        WLAN ID
 *     2        BT ID
 *     3        WWAN ID
 *     4        UWB ID
 *     5        WIGIG ID
 *     cbArg1, byte2    Flag bits:
 *             0 QuickSet disables radio (1)
 *             1-7 Reserved (0)
 *
 *     cbRes1    Standard return codes (0, -1, -2)
 *     cbRes2    QuickSet (QS) radio disable bit map:
 *     0 QS disables WLAN
 *     1 QS disables BT
 *     2 QS disables WWAN
 *     3 QS disables UWB
 *     4 QS disables WIGIG
 *     5-31 Reserved (0)
 *
 * Wireless Switch Configuration
 *     cbArg1, byte0 = 0x02
 *
 *     cbArg1, byte1
 *     Subcommand:
 *     0 Get config
 *     1 Set config
 *     2 Set WiFi locator enable/disable
 *     cbArg1,byte2
 *     Switch settings (if byte 1==1):
 *     0 WLAN sw itch control (1)
 *     1 BT sw itch control (1)
 *     2 WWAN sw itch control (1)
 *     3 UWB sw itch control (1)
 *     4 WiGig sw itch control (1)
 *     5-7 Reserved (0)
 *    cbArg1, byte2 Enable bits (if byte 1==2):
 *     0 Enable WiFi locator (1)
 *
 *    cbRes1     Standard return codes (0, -1, -2)
 *    cbRes2 QuickSet radio disable bit map:
 *     0 WLAN controlled by sw itch (1)
 *     1 BT controlled by sw itch (1)
 *     2 WWAN controlled by sw itch (1)
 *     3 UWB controlled by sw itch (1)
 *     4 WiGig controlled by sw itch (1)
 *     5-6 Reserved (0)
 *     7 Wireless sw itch config locked (1)
 *     8 WiFi locator enabled (1)
 *     9-14 Reserved (0)
 *     15 WiFi locator setting locked (1)
 *     16-31 Reserved (0)
 *
 * Read Local Config Data (LCD)
 *     cbArg1, byte0 = 0x10
 *     cbArg1, byte1 NVRAM index low byte
 *     cbArg1, byte2 NVRAM index high byte
 *     cbRes1 Standard return codes (0, -1, -2)
 *     cbRes2 4 bytes read from LCD[index]
 *     cbRes3 4 bytes read from LCD[index+4]
 *     cbRes4 4 bytes read from LCD[index+8]
 *
 * Write Local Config Data (LCD)
 *     cbArg1, byte0 = 0x11
 *     cbArg1, byte1 NVRAM index low byte
 *     cbArg1, byte2 NVRAM index high byte
 *     cbArg2 4 bytes to w rite at LCD[index]
 *     cbArg3 4 bytes to w rite at LCD[index+4]
 *     cbArg4 4 bytes to w rite at LCD[index+8]
 *     cbRes1 Standard return codes (0, -1, -2)
 *
 * Populate Local Config Data from NVRAM
 *     cbArg1, byte0 = 0x12
 *     cbRes1 Standard return codes (0, -1, -2)
 *
 * Commit Local Config Data to NVRAM
 *     cbArg1, byte0 = 0x13
 *     cbRes1 Standard return codes (0, -1, -2)
 */

static int dell_rfkill_set(void *data, bool blocked)
{
	int disable = blocked ? 1 : 0;
	unsigned long radio = (unsigned long)data;
	int hwswitch_bit = (unsigned long)data - 1;
	struct calling_interface_buffer buffer;
	int hwswitch;
	int status;
	int ret;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	if (ret)
		return ret;
	status = buffer.output[1];

	dell_fill_request(&buffer, 0x2, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	if (ret)
		return ret;
	hwswitch = buffer.output[1];

	/* If the hardware switch controls this radio, and the hardware
	   switch is disabled, always disable the radio */
	if (ret == 0 && (hwswitch & BIT(hwswitch_bit)) &&
	    (status & BIT(0)) && !(status & BIT(16)))
		disable = 1;

	dell_fill_request(&buffer, 1 | (radio<<8) | (disable << 16), 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	return ret;
}

static void dell_rfkill_update_sw_state(struct rfkill *rfkill, int radio,
					int status)
{
	if (status & BIT(0)) {
		/* Has hw-switch, sync sw_state to BIOS */
		struct calling_interface_buffer buffer;
		int block = rfkill_blocked(rfkill);
		dell_fill_request(&buffer,
				   1 | (radio << 8) | (block << 16), 0, 0, 0);
		dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	} else {
		/* No hw-switch, sync BIOS state to sw_state */
		rfkill_set_sw_state(rfkill, !!(status & BIT(radio + 16)));
	}
}

static void dell_rfkill_update_hw_state(struct rfkill *rfkill, int radio,
					int status, int hwswitch)
{
	if (hwswitch & (BIT(radio - 1)))
		rfkill_set_hw_state(rfkill, !(status & BIT(16)));
}

static void dell_rfkill_query(struct rfkill *rfkill, void *data)
{
	int radio = ((unsigned long)data & 0xF);
	struct calling_interface_buffer buffer;
	int hwswitch;
	int status;
	int ret;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	status = buffer.output[1];

	if (ret != 0 || !(status & BIT(0))) {
		return;
	}

	dell_fill_request(&buffer, 0, 0x2, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	hwswitch = buffer.output[1];

	if (ret != 0)
		return;

	dell_rfkill_update_hw_state(rfkill, radio, status, hwswitch);
}

static const struct rfkill_ops dell_rfkill_ops = {
	.set_block = dell_rfkill_set,
	.query = dell_rfkill_query,
};

static struct dentry *dell_laptop_dir;

static int dell_debugfs_show(struct seq_file *s, void *data)
{
	struct calling_interface_buffer buffer;
	int hwswitch_state;
	int hwswitch_ret;
	int status;
	int ret;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	if (ret)
		return ret;
	status = buffer.output[1];

	dell_fill_request(&buffer, 0, 0x2, 0, 0);
	hwswitch_ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	if (hwswitch_ret)
		return hwswitch_ret;
	hwswitch_state = buffer.output[1];

	seq_printf(s, "return:\t%d\n", ret);
	seq_printf(s, "status:\t0x%X\n", status);
	seq_printf(s, "Bit 0 : Hardware switch supported:   %lu\n",
		   status & BIT(0));
	seq_printf(s, "Bit 1 : Wifi locator supported:      %lu\n",
		  (status & BIT(1)) >> 1);
	seq_printf(s, "Bit 2 : Wifi is supported:           %lu\n",
		  (status & BIT(2)) >> 2);
	seq_printf(s, "Bit 3 : Bluetooth is supported:      %lu\n",
		  (status & BIT(3)) >> 3);
	seq_printf(s, "Bit 4 : WWAN is supported:           %lu\n",
		  (status & BIT(4)) >> 4);
	seq_printf(s, "Bit 5 : Wireless keyboard supported: %lu\n",
		  (status & BIT(5)) >> 5);
	seq_printf(s, "Bit 6 : UWB supported:               %lu\n",
		  (status & BIT(6)) >> 6);
	seq_printf(s, "Bit 7 : WiGig supported:             %lu\n",
		  (status & BIT(7)) >> 7);
	seq_printf(s, "Bit 8 : Wifi is installed:           %lu\n",
		  (status & BIT(8)) >> 8);
	seq_printf(s, "Bit 9 : Bluetooth is installed:      %lu\n",
		  (status & BIT(9)) >> 9);
	seq_printf(s, "Bit 10: WWAN is installed:           %lu\n",
		  (status & BIT(10)) >> 10);
	seq_printf(s, "Bit 11: UWB installed:               %lu\n",
		  (status & BIT(11)) >> 11);
	seq_printf(s, "Bit 12: WiGig installed:             %lu\n",
		  (status & BIT(12)) >> 12);

	seq_printf(s, "Bit 16: Hardware switch is on:       %lu\n",
		  (status & BIT(16)) >> 16);
	seq_printf(s, "Bit 17: Wifi is blocked:             %lu\n",
		  (status & BIT(17)) >> 17);
	seq_printf(s, "Bit 18: Bluetooth is blocked:        %lu\n",
		  (status & BIT(18)) >> 18);
	seq_printf(s, "Bit 19: WWAN is blocked:             %lu\n",
		  (status & BIT(19)) >> 19);
	seq_printf(s, "Bit 20: UWB is blocked:              %lu\n",
		  (status & BIT(20)) >> 20);
	seq_printf(s, "Bit 21: WiGig is blocked:            %lu\n",
		  (status & BIT(21)) >> 21);

	seq_printf(s, "\nhwswitch_return:\t%d\n", hwswitch_ret);
	seq_printf(s, "hwswitch_state:\t0x%X\n", hwswitch_state);
	seq_printf(s, "Bit 0 : Wifi controlled by switch:      %lu\n",
		   hwswitch_state & BIT(0));
	seq_printf(s, "Bit 1 : Bluetooth controlled by switch: %lu\n",
		   (hwswitch_state & BIT(1)) >> 1);
	seq_printf(s, "Bit 2 : WWAN controlled by switch:      %lu\n",
		   (hwswitch_state & BIT(2)) >> 2);
	seq_printf(s, "Bit 3 : UWB controlled by switch:       %lu\n",
		   (hwswitch_state & BIT(3)) >> 3);
	seq_printf(s, "Bit 4 : WiGig controlled by switch:     %lu\n",
		   (hwswitch_state & BIT(4)) >> 4);
	seq_printf(s, "Bit 7 : Wireless switch config locked:  %lu\n",
		   (hwswitch_state & BIT(7)) >> 7);
	seq_printf(s, "Bit 8 : Wifi locator enabled:           %lu\n",
		   (hwswitch_state & BIT(8)) >> 8);
	seq_printf(s, "Bit 15: Wifi locator setting locked:    %lu\n",
		   (hwswitch_state & BIT(15)) >> 15);

	return 0;
}
DEFINE_SHOW_ATTRIBUTE(dell_debugfs);

static void dell_update_rfkill(struct work_struct *ignored)
{
	struct calling_interface_buffer buffer;
	int hwswitch = 0;
	int status;
	int ret;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	status = buffer.output[1];

	if (ret != 0)
		return;

	dell_fill_request(&buffer, 0, 0x2, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);

	if (ret == 0 && (status & BIT(0)))
		hwswitch = buffer.output[1];

	if (wifi_rfkill) {
		dell_rfkill_update_hw_state(wifi_rfkill, 1, status, hwswitch);
		dell_rfkill_update_sw_state(wifi_rfkill, 1, status);
	}
	if (bluetooth_rfkill) {
		dell_rfkill_update_hw_state(bluetooth_rfkill, 2, status,
					    hwswitch);
		dell_rfkill_update_sw_state(bluetooth_rfkill, 2, status);
	}
	if (wwan_rfkill) {
		dell_rfkill_update_hw_state(wwan_rfkill, 3, status, hwswitch);
		dell_rfkill_update_sw_state(wwan_rfkill, 3, status);
	}
}
static DECLARE_DELAYED_WORK(dell_rfkill_work, dell_update_rfkill);

static bool dell_laptop_i8042_filter(unsigned char data, unsigned char str,
			      struct serio *port)
{
	static bool extended;

	if (str & I8042_STR_AUXDATA)
		return false;

	if (unlikely(data == 0xe0)) {
		extended = true;
		return false;
	} else if (unlikely(extended)) {
		switch (data) {
		case 0x8:
			schedule_delayed_work(&dell_rfkill_work,
					      round_jiffies_relative(HZ / 4));
			break;
		}
		extended = false;
	}

	return false;
}

static int (*dell_rbtn_notifier_register_func)(struct notifier_block *);
static int (*dell_rbtn_notifier_unregister_func)(struct notifier_block *);

static int dell_laptop_rbtn_notifier_call(struct notifier_block *nb,
					  unsigned long action, void *data)
{
	schedule_delayed_work(&dell_rfkill_work, 0);
	return NOTIFY_OK;
}

static struct notifier_block dell_laptop_rbtn_notifier = {
	.notifier_call = dell_laptop_rbtn_notifier_call,
};

static int __init dell_setup_rfkill(void)
{
	struct calling_interface_buffer buffer;
	int status, ret, whitelisted;
	const char *product;

	/*
	 * rfkill support causes trouble on various models, mostly Inspirons.
	 * So we whitelist certain series, and don't support rfkill on others.
	 */
	whitelisted = 0;
	product = dmi_get_system_info(DMI_PRODUCT_NAME);
	if (product &&  (strncmp(product, "Latitude", 8) == 0 ||
			 strncmp(product, "Precision", 9) == 0))
		whitelisted = 1;
	if (!force_rfkill && !whitelisted)
		return 0;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_INFO, SELECT_RFKILL);
	status = buffer.output[1];

	/* dell wireless info smbios call is not supported */
	if (ret != 0)
		return 0;

	/* rfkill is only tested on laptops with a hwswitch */
	if (!(status & BIT(0)) && !force_rfkill)
		return 0;

	if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
		wifi_rfkill = rfkill_alloc("dell-wifi", &platform_device->dev,
					   RFKILL_TYPE_WLAN,
					   &dell_rfkill_ops, (void *) 1);
		if (!wifi_rfkill) {
			ret = -ENOMEM;
			goto err_wifi;
		}
		ret = rfkill_register(wifi_rfkill);
		if (ret)
			goto err_wifi;
	}

	if ((status & (1<<3|1<<9)) == (1<<3|1<<9)) {
		bluetooth_rfkill = rfkill_alloc("dell-bluetooth",
						&platform_device->dev,
						RFKILL_TYPE_BLUETOOTH,
						&dell_rfkill_ops, (void *) 2);
		if (!bluetooth_rfkill) {
			ret = -ENOMEM;
			goto err_bluetooth;
		}
		ret = rfkill_register(bluetooth_rfkill);
		if (ret)
			goto err_bluetooth;
	}

	if ((status & (1<<4|1<<10)) == (1<<4|1<<10)) {
		wwan_rfkill = rfkill_alloc("dell-wwan",
					   &platform_device->dev,
					   RFKILL_TYPE_WWAN,
					   &dell_rfkill_ops, (void *) 3);
		if (!wwan_rfkill) {
			ret = -ENOMEM;
			goto err_wwan;
		}
		ret = rfkill_register(wwan_rfkill);
		if (ret)
			goto err_wwan;
	}

	/*
	 * Dell Airplane Mode Switch driver (dell-rbtn) supports ACPI devices
	 * which can receive events from HW slider switch.
	 *
	 * Dell SMBIOS on whitelisted models supports controlling radio devices
	 * but does not support receiving HW button switch events. We can use
	 * i8042 filter hook function to receive keyboard data and handle
	 * keycode for HW button.
	 *
	 * So if it is possible we will use Dell Airplane Mode Switch ACPI
	 * driver for receiving HW events and Dell SMBIOS for setting rfkill
	 * states. If ACPI driver or device is not available we will fallback to
	 * i8042 filter hook function.
	 *
	 * To prevent duplicate rfkill devices which control and do same thing,
	 * dell-rbtn driver will automatically remove its own rfkill devices
	 * once function dell_rbtn_notifier_register() is called.
	 */

	dell_rbtn_notifier_register_func =
		symbol_request(dell_rbtn_notifier_register);
	if (dell_rbtn_notifier_register_func) {
		dell_rbtn_notifier_unregister_func =
			symbol_request(dell_rbtn_notifier_unregister);
		if (!dell_rbtn_notifier_unregister_func) {
			symbol_put(dell_rbtn_notifier_register);
			dell_rbtn_notifier_register_func = NULL;
		}
	}

	if (dell_rbtn_notifier_register_func) {
		ret = dell_rbtn_notifier_register_func(
			&dell_laptop_rbtn_notifier);
		symbol_put(dell_rbtn_notifier_register);
		dell_rbtn_notifier_register_func = NULL;
		if (ret != 0) {
			symbol_put(dell_rbtn_notifier_unregister);
			dell_rbtn_notifier_unregister_func = NULL;
		}
	} else {
		pr_info("Symbols from dell-rbtn acpi driver are not available\n");
		ret = -ENODEV;
	}

	if (ret == 0) {
		pr_info("Using dell-rbtn acpi driver for receiving events\n");
	} else if (ret != -ENODEV) {
		pr_warn("Unable to register dell rbtn notifier\n");
		goto err_filter;
	} else {
		ret = i8042_install_filter(dell_laptop_i8042_filter);
		if (ret) {
			pr_warn("Unable to install key filter\n");
			goto err_filter;
		}
		pr_info("Using i8042 filter function for receiving events\n");
	}

	return 0;
err_filter:
	if (wwan_rfkill)
		rfkill_unregister(wwan_rfkill);
err_wwan:
	rfkill_destroy(wwan_rfkill);
	if (bluetooth_rfkill)
		rfkill_unregister(bluetooth_rfkill);
err_bluetooth:
	rfkill_destroy(bluetooth_rfkill);
	if (wifi_rfkill)
		rfkill_unregister(wifi_rfkill);
err_wifi:
	rfkill_destroy(wifi_rfkill);

	return ret;
}

static void dell_cleanup_rfkill(void)
{
	if (dell_rbtn_notifier_unregister_func) {
		dell_rbtn_notifier_unregister_func(&dell_laptop_rbtn_notifier);
		symbol_put(dell_rbtn_notifier_unregister);
		dell_rbtn_notifier_unregister_func = NULL;
	} else {
		i8042_remove_filter(dell_laptop_i8042_filter);
	}
	cancel_delayed_work_sync(&dell_rfkill_work);
	if (wifi_rfkill) {
		rfkill_unregister(wifi_rfkill);
		rfkill_destroy(wifi_rfkill);
	}
	if (bluetooth_rfkill) {
		rfkill_unregister(bluetooth_rfkill);
		rfkill_destroy(bluetooth_rfkill);
	}
	if (wwan_rfkill) {
		rfkill_unregister(wwan_rfkill);
		rfkill_destroy(wwan_rfkill);
	}
}

static int dell_send_intensity(struct backlight_device *bd)
{
	struct calling_interface_buffer buffer;
	struct calling_interface_token *token;
	int ret;

	token = dell_smbios_find_token(BRIGHTNESS_TOKEN);
	if (!token)
		return -ENODEV;

	dell_fill_request(&buffer,
			   token->location, bd->props.brightness, 0, 0);
	if (power_supply_is_system_supplied() > 0)
		ret = dell_send_request(&buffer,
					CLASS_TOKEN_WRITE, SELECT_TOKEN_AC);
	else
		ret = dell_send_request(&buffer,
					CLASS_TOKEN_WRITE, SELECT_TOKEN_BAT);

	return ret;
}

static int dell_get_intensity(struct backlight_device *bd)
{
	struct calling_interface_buffer buffer;
	struct calling_interface_token *token;
	int ret;

	token = dell_smbios_find_token(BRIGHTNESS_TOKEN);
	if (!token)
		return -ENODEV;

	dell_fill_request(&buffer, token->location, 0, 0, 0);
	if (power_supply_is_system_supplied() > 0)
		ret = dell_send_request(&buffer,
					CLASS_TOKEN_READ, SELECT_TOKEN_AC);
	else
		ret = dell_send_request(&buffer,
					CLASS_TOKEN_READ, SELECT_TOKEN_BAT);

	if (ret == 0)
		ret = buffer.output[1];

	return ret;
}

static const struct backlight_ops dell_ops = {
	.get_brightness = dell_get_intensity,
	.update_status  = dell_send_intensity,
};

static void touchpad_led_on(void)
{
	int command = 0x97;
	char data = 1;
	i8042_command(&data, command | 1 << 12);
}

static void touchpad_led_off(void)
{
	int command = 0x97;
	char data = 2;
	i8042_command(&data, command | 1 << 12);
}

static void touchpad_led_set(struct led_classdev *led_cdev,
	enum led_brightness value)
{
	if (value > 0)
		touchpad_led_on();
	else
		touchpad_led_off();
}

static struct led_classdev touchpad_led = {
	.name = "dell-laptop::touchpad",
	.brightness_set = touchpad_led_set,
	.flags = LED_CORE_SUSPENDRESUME,
};

static int __init touchpad_led_init(struct device *dev)
{
	return led_classdev_register(dev, &touchpad_led);
}

static void touchpad_led_exit(void)
{
	led_classdev_unregister(&touchpad_led);
}

/*
 * Derived from information in smbios-keyboard-ctl:
 *
 * cbClass 4
 * cbSelect 11
 * Keyboard illumination
 * cbArg1 determines the function to be performed
 *
 * cbArg1 0x0 = Get Feature Information
 *  cbRES1         Standard return codes (0, -1, -2)
 *  cbRES2, word0  Bitmap of user-selectable modes
 *     bit 0     Always off (All systems)
 *     bit 1     Always on (Travis ATG, Siberia)
 *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
 *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
 *     bit 4     Auto: Input-activity-based On; input-activity based Off
 *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
 *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
 *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
 *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
 *     bits 9-15 Reserved for future use
 *  cbRES2, byte2  Reserved for future use
 *  cbRES2, byte3  Keyboard illumination type
 *     0         Reserved
 *     1         Tasklight
 *     2         Backlight
 *     3-255     Reserved for future use
 *  cbRES3, byte0  Supported auto keyboard illumination trigger bitmap.
 *     bit 0     Any keystroke
 *     bit 1     Touchpad activity
 *     bit 2     Pointing stick
 *     bit 3     Any mouse
 *     bits 4-7  Reserved for future use
 *  cbRES3, byte1  Supported timeout unit bitmap
 *     bit 0     Seconds
 *     bit 1     Minutes
 *     bit 2     Hours
 *     bit 3     Days
 *     bits 4-7  Reserved for future use
 *  cbRES3, byte2  Number of keyboard light brightness levels
 *  cbRES4, byte0  Maximum acceptable seconds value (0 if seconds not supported).
 *  cbRES4, byte1  Maximum acceptable minutes value (0 if minutes not supported).
 *  cbRES4, byte2  Maximum acceptable hours value (0 if hours not supported).
 *  cbRES4, byte3  Maximum acceptable days value (0 if days not supported)
 *
 * cbArg1 0x1 = Get Current State
 *  cbRES1         Standard return codes (0, -1, -2)
 *  cbRES2, word0  Bitmap of current mode state
 *     bit 0     Always off (All systems)
 *     bit 1     Always on (Travis ATG, Siberia)
 *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
 *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
 *     bit 4     Auto: Input-activity-based On; input-activity based Off
 *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
 *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
 *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
 *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
 *     bits 9-15 Reserved for future use
 *     Note: Only One bit can be set
 *  cbRES2, byte2  Currently active auto keyboard illumination triggers.
 *     bit 0     Any keystroke
 *     bit 1     Touchpad activity
 *     bit 2     Pointing stick
 *     bit 3     Any mouse
 *     bits 4-7  Reserved for future use
 *  cbRES2, byte3  Current Timeout on battery
 *     bits 7:6  Timeout units indicator:
 *     00b       Seconds
 *     01b       Minutes
 *     10b       Hours
 *     11b       Days
 *     bits 5:0  Timeout value (0-63) in sec/min/hr/day
 *     NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte
 *     are set upon return from the [Get feature information] call.
 *  cbRES3, byte0  Current setting of ALS value that turns the light on or off.
 *  cbRES3, byte1  Current ALS reading
 *  cbRES3, byte2  Current keyboard light level.
 *  cbRES3, byte3  Current timeout on AC Power
 *     bits 7:6  Timeout units indicator:
 *     00b       Seconds
 *     01b       Minutes
 *     10b       Hours
 *     11b       Days
 *     Bits 5:0  Timeout value (0-63) in sec/min/hr/day
 *     NOTE: A value of 0 means always on (no timeout) if any bits of RES3 byte2
 *     are set upon return from the upon return from the [Get Feature information] call.
 *
 * cbArg1 0x2 = Set New State
 *  cbRES1         Standard return codes (0, -1, -2)
 *  cbArg2, word0  Bitmap of current mode state
 *     bit 0     Always off (All systems)
 *     bit 1     Always on (Travis ATG, Siberia)
 *     bit 2     Auto: ALS-based On; ALS-based Off (Travis ATG)
 *     bit 3     Auto: ALS- and input-activity-based On; input-activity based Off
 *     bit 4     Auto: Input-activity-based On; input-activity based Off
 *     bit 5     Auto: Input-activity-based On (illumination level 25%); input-activity based Off
 *     bit 6     Auto: Input-activity-based On (illumination level 50%); input-activity based Off
 *     bit 7     Auto: Input-activity-based On (illumination level 75%); input-activity based Off
 *     bit 8     Auto: Input-activity-based On (illumination level 100%); input-activity based Off
 *     bits 9-15 Reserved for future use
 *     Note: Only One bit can be set
 *  cbArg2, byte2  Desired auto keyboard illumination triggers. Must remain inactive to allow
 *                 keyboard to turn off automatically.
 *     bit 0     Any keystroke
 *     bit 1     Touchpad activity
 *     bit 2     Pointing stick
 *     bit 3     Any mouse
 *     bits 4-7  Reserved for future use
 *  cbArg2, byte3  Desired Timeout on battery
 *     bits 7:6  Timeout units indicator:
 *     00b       Seconds
 *     01b       Minutes
 *     10b       Hours
 *     11b       Days
 *     bits 5:0  Timeout value (0-63) in sec/min/hr/day
 *  cbArg3, byte0  Desired setting of ALS value that turns the light on or off.
 *  cbArg3, byte2  Desired keyboard light level.
 *  cbArg3, byte3  Desired Timeout on AC power
 *     bits 7:6  Timeout units indicator:
 *     00b       Seconds
 *     01b       Minutes
 *     10b       Hours
 *     11b       Days
 *     bits 5:0  Timeout value (0-63) in sec/min/hr/day
 */


enum kbd_timeout_unit {
	KBD_TIMEOUT_SECONDS = 0,
	KBD_TIMEOUT_MINUTES,
	KBD_TIMEOUT_HOURS,
	KBD_TIMEOUT_DAYS,
};

enum kbd_mode_bit {
	KBD_MODE_BIT_OFF = 0,
	KBD_MODE_BIT_ON,
	KBD_MODE_BIT_ALS,
	KBD_MODE_BIT_TRIGGER_ALS,
	KBD_MODE_BIT_TRIGGER,
	KBD_MODE_BIT_TRIGGER_25,
	KBD_MODE_BIT_TRIGGER_50,
	KBD_MODE_BIT_TRIGGER_75,
	KBD_MODE_BIT_TRIGGER_100,
};

#define kbd_is_als_mode_bit(bit) \
	((bit) == KBD_MODE_BIT_ALS || (bit) == KBD_MODE_BIT_TRIGGER_ALS)
#define kbd_is_trigger_mode_bit(bit) \
	((bit) >= KBD_MODE_BIT_TRIGGER_ALS && (bit) <= KBD_MODE_BIT_TRIGGER_100)
#define kbd_is_level_mode_bit(bit) \
	((bit) >= KBD_MODE_BIT_TRIGGER_25 && (bit) <= KBD_MODE_BIT_TRIGGER_100)

struct kbd_info {
	u16 modes;
	u8 type;
	u8 triggers;
	u8 levels;
	u8 seconds;
	u8 minutes;
	u8 hours;
	u8 days;
};

struct kbd_state {
	u8 mode_bit;
	u8 triggers;
	u8 timeout_value;
	u8 timeout_unit;
	u8 timeout_value_ac;
	u8 timeout_unit_ac;
	u8 als_setting;
	u8 als_value;
	u8 level;
};

static const int kbd_tokens[] = {
	KBD_LED_OFF_TOKEN,
	KBD_LED_AUTO_25_TOKEN,
	KBD_LED_AUTO_50_TOKEN,
	KBD_LED_AUTO_75_TOKEN,
	KBD_LED_AUTO_100_TOKEN,
	KBD_LED_ON_TOKEN,
};

static u16 kbd_token_bits;

static struct kbd_info kbd_info;
static bool kbd_als_supported;
static bool kbd_triggers_supported;
static bool kbd_timeout_ac_supported;

static u8 kbd_mode_levels[16];
static int kbd_mode_levels_count;

static u8 kbd_previous_level;
static u8 kbd_previous_mode_bit;

static bool kbd_led_present;
static DEFINE_MUTEX(kbd_led_mutex);
static enum led_brightness kbd_led_level;

/*
 * NOTE: there are three ways to set the keyboard backlight level.
 * First, via kbd_state.mode_bit (assigning KBD_MODE_BIT_TRIGGER_* value).
 * Second, via kbd_state.level (assigning numerical value <= kbd_info.levels).
 * Third, via SMBIOS tokens (KBD_LED_* in kbd_tokens)
 *
 * There are laptops which support only one of these methods. If we want to
 * support as many machines as possible we need to implement all three methods.
 * The first two methods use the kbd_state structure. The third uses SMBIOS
 * tokens. If kbd_info.levels == 0, the machine does not support setting the
 * keyboard backlight level via kbd_state.level.
 */

static int kbd_get_info(struct kbd_info *info)
{
	struct calling_interface_buffer buffer;
	u8 units;
	int ret;

	dell_fill_request(&buffer, 0, 0, 0, 0);
	ret = dell_send_request(&buffer,
				CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT);
	if (ret)
		return ret;

	info->modes = buffer.output[1] & 0xFFFF;
	info->type = (buffer.output[1] >> 24) & 0xFF;
	info->triggers = buffer.output[2] & 0xFF;
	units = (buffer.output[2] >> 8) & 0xFF;
	info->levels = (buffer.output[2] >> 16) & 0xFF;

	if (quirks && quirks->kbd_led_levels_off_1 && info->levels)
		info->levels--;

	if (units & BIT(0))
		info->seconds = (buffer.output[3] >> 0) & 0xFF;
	if (units & BIT(1))
		info->minutes = (buffer.output[3] >> 8) & 0xFF;
	if (units & BIT(2))
		info->hours = (buffer.output[3] >> 16) & 0xFF;
	if (units & BIT(3))
		info->days = (buffer.output[3] >> 24) & 0xFF;

	return ret;
}

static unsigned int kbd_get_max_level(void)
{
	if (kbd_info.levels != 0)
		return kbd_info.levels;
	if (kbd_mode_levels_count > 0)
		return kbd_mode_levels_count - 1;
	return 0;
}

static int kbd_get_level(struct kbd_state *state)
{
	int i;

	if (kbd_info.levels != 0)
		return state->level;

	if (kbd_mode_levels_count > 0) {
		for (i = 0; i < kbd_mode_levels_count; ++i)
			if (kbd_mode_levels[i] == state->mode_bit)
				return i;
		return 0;
	}

	return -EINVAL;
}

static int kbd_set_level(struct kbd_state *state, u8 level)
{
	if (kbd_info.levels != 0) {
		if (level != 0)
			kbd_previous_level = level;
		if (state->level == level)
			return 0;
		state->level = level;
		if (level != 0 && state->mode_bit == KBD_MODE_BIT_OFF)
			state->mode_bit = kbd_previous_mode_bit;
		else if (level == 0 && state->mode_bit != KBD_MODE_BIT_OFF) {
			kbd_previous_mode_bit = state->mode_bit;
			state->mode_bit = KBD_MODE_BIT_OFF;
		}
		return 0;
	}

	if (kbd_mode_levels_count > 0 && level < kbd_mode_levels_count) {
		if (level != 0)
			kbd_previous_level = level;
		state->mode_bit = kbd_mode_levels[level];
		return 0;
	}

	return -EINVAL;
}

static int kbd_get_state(struct kbd_state *state)
{
	struct calling_interface_buffer buffer;
	int ret;

	dell_fill_request(&buffer, 0x1, 0, 0, 0);
	ret = dell_send_request(&buffer,
				CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT);
	if (ret)
		return ret;

	state->mode_bit = ffs(buffer.output[1] & 0xFFFF);
	if (state->mode_bit != 0)
		state->mode_bit--;

	state->triggers = (buffer.output[1] >> 16) & 0xFF;
	state->timeout_value = (buffer.output[1] >> 24) & 0x3F;
	state->timeout_unit = (buffer.output[1] >> 30) & 0x3;
	state->als_setting = buffer.output[2] & 0xFF;
	state->als_value = (buffer.output[2] >> 8) & 0xFF;
	state->level = (buffer.output[2] >> 16) & 0xFF;
	state->timeout_value_ac = (buffer.output[2] >> 24) & 0x3F;
	state->timeout_unit_ac = (buffer.output[2] >> 30) & 0x3;

	return ret;
}

static int kbd_set_state(struct kbd_state *state)
{
	struct calling_interface_buffer buffer;
	int ret;
	u32 input1;
	u32 input2;

	input1 = BIT(state->mode_bit) & 0xFFFF;
	input1 |= (state->triggers & 0xFF) << 16;
	input1 |= (state->timeout_value & 0x3F) << 24;
	input1 |= (state->timeout_unit & 0x3) << 30;
	input2 = state->als_setting & 0xFF;
	input2 |= (state->level & 0xFF) << 16;
	input2 |= (state->timeout_value_ac & 0x3F) << 24;
	input2 |= (state->timeout_unit_ac & 0x3) << 30;
	dell_fill_request(&buffer, 0x2, input1, input2, 0);
	ret = dell_send_request(&buffer,
				CLASS_KBD_BACKLIGHT, SELECT_KBD_BACKLIGHT);

	return ret;
}

static int kbd_set_state_safe(struct kbd_state *state, struct kbd_state *old)
{
	int ret;

	ret = kbd_set_state(state);
	if (ret == 0)
		return 0;

	/*
	 * When setting the new state fails,try to restore the previous one.
	 * This is needed on some machines where BIOS sets a default state when
	 * setting a new state fails. This default state could be all off.
	 */

	if (kbd_set_state(old))
		pr_err("Setting old previous keyboard state failed\n");

	return ret;
}

static int kbd_set_token_bit(u8 bit)
{
	struct calling_interface_buffer buffer;
	struct calling_interface_token *token;
	int ret;

	if (bit >= ARRAY_SIZE(kbd_tokens))
		return -EINVAL;

	token = dell_smbios_find_token(kbd_tokens[bit]);
	if (!token)
		return -EINVAL;

	dell_fill_request(&buffer, token->location, token->value, 0, 0);
	ret = dell_send_request(&buffer, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD);

	return ret;
}

static int kbd_get_token_bit(u8 bit)
{
	struct calling_interface_buffer buffer;
	struct calling_interface_token *token;
	int ret;
	int val;

	if (bit >= ARRAY_SIZE(kbd_tokens))
		return -EINVAL;

	token = dell_smbios_find_token(kbd_tokens[bit]);
	if (!token)
		return -EINVAL;

	dell_fill_request(&buffer, token->location, 0, 0, 0);
	ret = dell_send_request(&buffer, CLASS_TOKEN_READ, SELECT_TOKEN_STD);
	val = buffer.output[1];

	if (ret)
		return ret;

	return (val == token->value);
}

static int kbd_get_first_active_token_bit(void)
{
	int i;
	int ret;

	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i) {
		ret = kbd_get_token_bit(i);
		if (ret == 1)
			return i;
	}

	return ret;
}

static int kbd_get_valid_token_counts(void)
{
	return hweight16(kbd_token_bits);
}

static inline int kbd_init_info(void)
{
	struct kbd_state state;
	int ret;
	int i;

	ret = kbd_get_info(&kbd_info);
	if (ret)
		return ret;

	/* NOTE: Old models without KBD_LED_AC_TOKEN token supports only one
	 *       timeout value which is shared for both battery and AC power
	 *       settings. So do not try to set AC values on old models.
	 */
	if (dell_smbios_find_token(KBD_LED_AC_TOKEN))
		kbd_timeout_ac_supported = true;

	kbd_get_state(&state);

	/* NOTE: timeout value is stored in 6 bits so max value is 63 */
	if (kbd_info.seconds > 63)
		kbd_info.seconds = 63;
	if (kbd_info.minutes > 63)
		kbd_info.minutes = 63;
	if (kbd_info.hours > 63)
		kbd_info.hours = 63;
	if (kbd_info.days > 63)
		kbd_info.days = 63;

	/* NOTE: On tested machines ON mode did not work and caused
	 *       problems (turned backlight off) so do not use it
	 */
	kbd_info.modes &= ~BIT(KBD_MODE_BIT_ON);

	kbd_previous_level = kbd_get_level(&state);
	kbd_previous_mode_bit = state.mode_bit;

	if (kbd_previous_level == 0 && kbd_get_max_level() != 0)
		kbd_previous_level = 1;

	if (kbd_previous_mode_bit == KBD_MODE_BIT_OFF) {
		kbd_previous_mode_bit =
			ffs(kbd_info.modes & ~BIT(KBD_MODE_BIT_OFF));
		if (kbd_previous_mode_bit != 0)
			kbd_previous_mode_bit--;
	}

	if (kbd_info.modes & (BIT(KBD_MODE_BIT_ALS) |
			      BIT(KBD_MODE_BIT_TRIGGER_ALS)))
		kbd_als_supported = true;

	if (kbd_info.modes & (
	    BIT(KBD_MODE_BIT_TRIGGER_ALS) | BIT(KBD_MODE_BIT_TRIGGER) |
	    BIT(KBD_MODE_BIT_TRIGGER_25) | BIT(KBD_MODE_BIT_TRIGGER_50) |
	    BIT(KBD_MODE_BIT_TRIGGER_75) | BIT(KBD_MODE_BIT_TRIGGER_100)
	   ))
		kbd_triggers_supported = true;

	/* kbd_mode_levels[0] is reserved, see below */
	for (i = 0; i < 16; ++i)
		if (kbd_is_level_mode_bit(i) && (BIT(i) & kbd_info.modes))
			kbd_mode_levels[1 + kbd_mode_levels_count++] = i;

	/*
	 * Find the first supported mode and assign to kbd_mode_levels[0].
	 * This should be 0 (off), but we cannot depend on the BIOS to
	 * support 0.
	 */
	if (kbd_mode_levels_count > 0) {
		for (i = 0; i < 16; ++i) {
			if (BIT(i) & kbd_info.modes) {
				kbd_mode_levels[0] = i;
				break;
			}
		}
		kbd_mode_levels_count++;
	}

	return 0;

}

static inline void kbd_init_tokens(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(kbd_tokens); ++i)
		if (dell_smbios_find_token(kbd_tokens[i]))
			kbd_token_bits |= BIT(i);
}

static void kbd_init(void)
{
	int ret;

	ret = kbd_init_info();
	kbd_init_tokens();

	/*
	 * Only supports keyboard backlight when it has at least two modes.
	 */
	if ((ret == 0 && (kbd_info.levels != 0 || kbd_mode_levels_count >= 2))
	    || kbd_get_valid_token_counts() >= 2)
		kbd_led_present = true;
}

static ssize_t kbd_led_timeout_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct kbd_state new_state;
	struct kbd_state state;
	bool convert;
	int value;
	int ret;
	char ch;
	u8 unit;
	int i;

	ret = sscanf(buf, "%d %c", &value, &ch);
	if (ret < 1)
		return -EINVAL;
	else if (ret == 1)
		ch = 's';

	if (value < 0)
		return -EINVAL;

	convert = false;

	switch (ch) {
	case 's':
		if (value > kbd_info.seconds)
			convert = true;
		unit = KBD_TIMEOUT_SECONDS;
		break;
	case 'm':
		if (value > kbd_info.minutes)
			convert = true;
		unit = KBD_TIMEOUT_MINUTES;
		break;
	case 'h':
		if (value > kbd_info.hours)
			convert = true;
		unit = KBD_TIMEOUT_HOURS;
		break;
	case 'd':
		if (value > kbd_info.days)
			convert = true;
		unit = KBD_TIMEOUT_DAYS;
		break;
	default:
		return -EINVAL;
	}

	if (quirks && quirks->needs_kbd_timeouts)
		convert = true;

	if (convert) {
		/* Convert value from current units to seconds */
		switch (unit) {
		case KBD_TIMEOUT_DAYS:
			value *= 24;
		case KBD_TIMEOUT_HOURS:
			value *= 60;
		case KBD_TIMEOUT_MINUTES:
			value *= 60;
			unit = KBD_TIMEOUT_SECONDS;
		}

		if (quirks && quirks->needs_kbd_timeouts) {
			for (i = 0; quirks->kbd_timeouts[i] != -1; i++) {
				if (value <= quirks->kbd_timeouts[i]) {
					value = quirks->kbd_timeouts[i];
					break;
				}
			}
		}

		if (value <= kbd_info.seconds && kbd_info.seconds) {
			unit = KBD_TIMEOUT_SECONDS;
		} else if (value / 60 <= kbd_info.minutes && kbd_info.minutes) {
			value /= 60;
			unit = KBD_TIMEOUT_MINUTES;
		} else if (value / (60 * 60) <= kbd_info.hours && kbd_info.hours) {
			value /= (60 * 60);
			unit = KBD_TIMEOUT_HOURS;
		} else if (value / (60 * 60 * 24) <= kbd_info.days && kbd_info.days) {
			value /= (60 * 60 * 24);
			unit = KBD_TIMEOUT_DAYS;
		} else {
			return -EINVAL;
		}
	}

	mutex_lock(&kbd_led_mutex);

	ret = kbd_get_state(&state);
	if (ret)
		goto out;

	new_state = state;

	if (kbd_timeout_ac_supported && power_supply_is_system_supplied() > 0) {
		new_state.timeout_value_ac = value;
		new_state.timeout_unit_ac = unit;
	} else {
		new_state.timeout_value = value;
		new_state.timeout_unit = unit;
	}

	ret = kbd_set_state_safe(&new_state, &state);
	if (ret)
		goto out;

	ret = count;
out:
	mutex_unlock(&kbd_led_mutex);
	return ret;
}

static ssize_t kbd_led_timeout_show(struct device *dev,
				    struct device_attribute *attr, char *buf)
{
	struct kbd_state state;
	int value;
	int ret;
	int len;
	u8 unit;

	ret = kbd_get_state(&state);
	if (ret)
		return ret;

	if (kbd_timeout_ac_supported && power_supply_is_system_supplied() > 0) {
		value = state.timeout_value_ac;
		unit = state.timeout_unit_ac;
	} else {
		value = state.timeout_value;
		unit = state.timeout_unit;
	}

	len = sprintf(buf, "%d", value);

	switch (unit) {
	case KBD_TIMEOUT_SECONDS:
		return len + sprintf(buf+len, "s\n");
	case KBD_TIMEOUT_MINUTES:
		return len + sprintf(buf+len, "m\n");
	case KBD_TIMEOUT_HOURS:
		return len + sprintf(buf+len, "h\n");
	case KBD_TIMEOUT_DAYS:
		return len + sprintf(buf+len, "d\n");
	default:
		return -EINVAL;
	}

	return len;
}

static DEVICE_ATTR(stop_timeout, S_IRUGO | S_IWUSR,
		   kbd_led_timeout_show, kbd_led_timeout_store);

static const char * const kbd_led_triggers[] = {
	"keyboard",
	"touchpad",
	/*"trackstick"*/ NULL, /* NOTE: trackstick is just alias for touchpad */
	"mouse",
};

static ssize_t kbd_led_triggers_store(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
{
	struct kbd_state new_state;
	struct kbd_state state;
	bool triggers_enabled = false;
	int trigger_bit = -1;
	char trigger[21];
	int i, ret;

	ret = sscanf(buf, "%20s", trigger);
	if (ret != 1)
		return -EINVAL;

	if (trigger[0] != '+' && trigger[0] != '-')
		return -EINVAL;

	mutex_lock(&kbd_led_mutex);

	ret = kbd_get_state(&state);
	if (ret)
		goto out;

	if (kbd_triggers_supported)
		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);

	if (kbd_triggers_supported) {
		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
			if (!(kbd_info.triggers & BIT(i)))
				continue;
			if (!kbd_led_triggers[i])
				continue;
			if (strcmp(trigger+1, kbd_led_triggers[i]) != 0)
				continue;
			if (trigger[0] == '+' &&
			    triggers_enabled && (state.triggers & BIT(i))) {
				ret = count;
				goto out;
			}
			if (trigger[0] == '-' &&
			    (!triggers_enabled || !(state.triggers & BIT(i)))) {
				ret = count;
				goto out;
			}
			trigger_bit = i;
			break;
		}
	}

	if (trigger_bit == -1) {
		ret = -EINVAL;
		goto out;
	}

	new_state = state;
	if (trigger[0] == '+')
		new_state.triggers |= BIT(trigger_bit);
	else {
		new_state.triggers &= ~BIT(trigger_bit);
		/*
		 * NOTE: trackstick bit (2) must be disabled when
		 *       disabling touchpad bit (1), otherwise touchpad
		 *       bit (1) will not be disabled
		 */
		if (trigger_bit == 1)
			new_state.triggers &= ~BIT(2);
	}
	if ((kbd_info.triggers & new_state.triggers) !=
	    new_state.triggers) {
		ret = -EINVAL;
		goto out;
	}
	if (new_state.triggers && !triggers_enabled) {
		new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
		kbd_set_level(&new_state, kbd_previous_level);
	} else if (new_state.triggers == 0) {
		kbd_set_level(&new_state, 0);
	}
	if (!(kbd_info.modes & BIT(new_state.mode_bit))) {
		ret = -EINVAL;
		goto out;
	}
	ret = kbd_set_state_safe(&new_state, &state);
	if (ret)
		goto out;
	if (new_state.mode_bit != KBD_MODE_BIT_OFF)
		kbd_previous_mode_bit = new_state.mode_bit;
	ret = count;
out:
	mutex_unlock(&kbd_led_mutex);
	return ret;
}

static ssize_t kbd_led_triggers_show(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct kbd_state state;
	bool triggers_enabled;
	int level, i, ret;
	int len = 0;

	ret = kbd_get_state(&state);
	if (ret)
		return ret;

	len = 0;

	if (kbd_triggers_supported) {
		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);
		level = kbd_get_level(&state);
		for (i = 0; i < ARRAY_SIZE(kbd_led_triggers); ++i) {
			if (!(kbd_info.triggers & BIT(i)))
				continue;
			if (!kbd_led_triggers[i])
				continue;
			if ((triggers_enabled || level <= 0) &&
			    (state.triggers & BIT(i)))
				buf[len++] = '+';
			else
				buf[len++] = '-';
			len += sprintf(buf+len, "%s ", kbd_led_triggers[i]);
		}
	}

	if (len)
		buf[len - 1] = '\n';

	return len;
}

static DEVICE_ATTR(start_triggers, S_IRUGO | S_IWUSR,
		   kbd_led_triggers_show, kbd_led_triggers_store);

static ssize_t kbd_led_als_enabled_store(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	struct kbd_state new_state;
	struct kbd_state state;
	bool triggers_enabled = false;
	int enable;
	int ret;

	ret = kstrtoint(buf, 0, &enable);
	if (ret)
		return ret;

	mutex_lock(&kbd_led_mutex);

	ret = kbd_get_state(&state);
	if (ret)
		goto out;

	if (enable == kbd_is_als_mode_bit(state.mode_bit)) {
		ret = count;
		goto out;
	}

	new_state = state;

	if (kbd_triggers_supported)
		triggers_enabled = kbd_is_trigger_mode_bit(state.mode_bit);

	if (enable) {
		if (triggers_enabled)
			new_state.mode_bit = KBD_MODE_BIT_TRIGGER_ALS;
		else
			new_state.mode_bit = KBD_MODE_BIT_ALS;
	} else {
		if (triggers_enabled) {
			new_state.mode_bit = KBD_MODE_BIT_TRIGGER;
			kbd_set_level(&new_state, kbd_previous_level);
		} else {
			new_state.mode_bit = KBD_MODE_BIT_ON;
		}
	}
	if (!(kbd_info.modes & BIT(new_state.mode_bit)))  {
		ret = -EINVAL;
		goto out;
	}

	ret = kbd_set_state_safe(&new_state, &state);
	if (ret)
		goto out;
	kbd_previous_mode_bit = new_state.mode_bit;

	ret = count;
out:
	mutex_unlock(&kbd_led_mutex);
	return ret;
}

static ssize_t kbd_led_als_enabled_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct kbd_state state;
	bool enabled = false;
	int ret;

	ret = kbd_get_state(&state);
	if (ret)
		return ret;
	enabled = kbd_is_als_mode_bit(state.mode_bit);

	return sprintf(buf, "%d\n", enabled ? 1 : 0);
}

static DEVICE_ATTR(als_enabled, S_IRUGO | S_IWUSR,
		   kbd_led_als_enabled_show, kbd_led_als_enabled_store);

static ssize_t kbd_led_als_setting_store(struct device *dev,
					 struct device_attribute *attr,
					 const char *buf, size_t count)
{
	struct kbd_state state;
	struct kbd_state new_state;
	u8 setting;
	int ret;

	ret = kstrtou8(buf, 10, &setting);
	if (ret)
		return ret;

	mutex_lock(&kbd_led_mutex);

	ret = kbd_get_state(&state);
	if (ret)
		goto out;

	new_state = state;
	new_state.als_setting = setting;

	ret = kbd_set_state_safe(&new_state, &state);
	if (ret)
		goto out;

	ret = count;
out:
	mutex_unlock(&kbd_led_mutex);
	return ret;
}

static ssize_t kbd_led_als_setting_show(struct device *dev,
					struct device_attribute *attr,
					char *buf)
{
	struct kbd_state state;
	int ret;

	ret = kbd_get_state(&state);
	if (ret)
		return ret;

	return sprintf(buf, "%d\n", state.als_setting);
}

static DEVICE_ATTR(als_setting, S_IRUGO | S_IWUSR,
		   kbd_led_als_setting_show, kbd_led_als_setting_store);

static struct attribute *kbd_led_attrs[] = {
	&dev_attr_stop_timeout.attr,
	&dev_attr_start_triggers.attr,
	NULL,
};

static const struct attribute_group kbd_led_group = {
	.attrs = kbd_led_attrs,
};

static struct attribute *kbd_led_als_attrs[] = {
	&dev_attr_als_enabled.attr,
	&dev_attr_als_setting.attr,
	NULL,
};

static const struct attribute_group kbd_led_als_group = {
	.attrs = kbd_led_als_attrs,
};

static const struct attribute_group *kbd_led_groups[] = {
	&kbd_led_group,
	&kbd_led_als_group,
	NULL,
};

static enum led_brightness kbd_led_level_get(struct led_classdev *led_cdev)
{
	int ret;
	u16 num;
	struct kbd_state state;

	if (kbd_get_max_level()) {
		ret = kbd_get_state(&state);
		if (ret)
			return 0;
		ret = kbd_get_level(&state);
		if (ret < 0)
			return 0;
		return ret;
	}

	if (kbd_get_valid_token_counts()) {
		ret = kbd_get_first_active_token_bit();
		if (ret < 0)
			return 0;
		for (num = kbd_token_bits; num != 0 && ret > 0; --ret)
			num &= num - 1; /* clear the first bit set */
		if (num == 0)
			return 0;
		return ffs(num) - 1;
	}

	pr_warn("Keyboard brightness level control not supported\n");
	return 0;
}

static int kbd_led_level_set(struct led_classdev *led_cdev,
			     enum led_brightness value)
{
	enum led_brightness new_value = value;
	struct kbd_state state;
	struct kbd_state new_state;
	u16 num;
	int ret;

	mutex_lock(&kbd_led_mutex);

	if (kbd_get_max_level()) {
		ret = kbd_get_state(&state);
		if (ret)
			goto out;
		new_state = state;
		ret = kbd_set_level(&new_state, value);
		if (ret)
			goto out;
		ret = kbd_set_state_safe(&new_state, &state);
	} else if (kbd_get_valid_token_counts()) {
		for (num = kbd_token_bits; num != 0 && value > 0; --value)
			num &= num - 1; /* clear the first bit set */
		if (num == 0)
			ret = 0;
		else
			ret = kbd_set_token_bit(ffs(num) - 1);
	} else {
		pr_warn("Keyboard brightness level control not supported\n");
		ret = -ENXIO;
	}

out:
	if (ret == 0)
		kbd_led_level = new_value;

	mutex_unlock(&kbd_led_mutex);
	return ret;
}

static struct led_classdev kbd_led = {
	.name           = "dell::kbd_backlight",
	.flags		= LED_BRIGHT_HW_CHANGED,
	.brightness_set_blocking = kbd_led_level_set,
	.brightness_get = kbd_led_level_get,
	.groups         = kbd_led_groups,
};

static int __init kbd_led_init(struct device *dev)
{
	int ret;

	kbd_init();
	if (!kbd_led_present)
		return -ENODEV;
	if (!kbd_als_supported)
		kbd_led_groups[1] = NULL;
	kbd_led.max_brightness = kbd_get_max_level();
	if (!kbd_led.max_brightness) {
		kbd_led.max_brightness = kbd_get_valid_token_counts();
		if (kbd_led.max_brightness)
			kbd_led.max_brightness--;
	}

	kbd_led_level = kbd_led_level_get(NULL);

	ret = led_classdev_register(dev, &kbd_led);
	if (ret)
		kbd_led_present = false;

	return ret;
}

static void brightness_set_exit(struct led_classdev *led_cdev,
				enum led_brightness value)
{
	/* Don't change backlight level on exit */
};

static void kbd_led_exit(void)
{
	if (!kbd_led_present)
		return;
	kbd_led.brightness_set = brightness_set_exit;
	led_classdev_unregister(&kbd_led);
}

static int dell_laptop_notifier_call(struct notifier_block *nb,
				     unsigned long action, void *data)
{
	bool changed = false;
	enum led_brightness new_kbd_led_level;

	switch (action) {
	case DELL_LAPTOP_KBD_BACKLIGHT_BRIGHTNESS_CHANGED:
		if (!kbd_led_present)
			break;

		mutex_lock(&kbd_led_mutex);
		new_kbd_led_level = kbd_led_level_get(&kbd_led);
		if (kbd_led_level != new_kbd_led_level) {
			kbd_led_level = new_kbd_led_level;
			changed = true;
		}
		mutex_unlock(&kbd_led_mutex);

		if (changed)
			led_classdev_notify_brightness_hw_changed(&kbd_led,
								kbd_led_level);
		break;
	}

	return NOTIFY_OK;
}

static struct notifier_block dell_laptop_notifier = {
	.notifier_call = dell_laptop_notifier_call,
};

int dell_micmute_led_set(int state)
{
	struct calling_interface_buffer buffer;
	struct calling_interface_token *token;

	if (state == 0)
		token = dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE);
	else if (state == 1)
		token = dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE);
	else
		return -EINVAL;

	if (!token)
		return -ENODEV;

	dell_fill_request(&buffer, token->location, token->value, 0, 0);
	dell_send_request(&buffer, CLASS_TOKEN_WRITE, SELECT_TOKEN_STD);

	return state;
}
EXPORT_SYMBOL_GPL(dell_micmute_led_set);

static int __init dell_init(void)
{
	struct calling_interface_token *token;
	int max_intensity = 0;
	int ret;

	if (!dmi_check_system(dell_device_table))
		return -ENODEV;

	quirks = NULL;
	/* find if this machine support other functions */
	dmi_check_system(dell_quirks);

	ret = platform_driver_register(&platform_driver);
	if (ret)
		goto fail_platform_driver;
	platform_device = platform_device_alloc("dell-laptop", -1);
	if (!platform_device) {
		ret = -ENOMEM;
		goto fail_platform_device1;
	}
	ret = platform_device_add(platform_device);
	if (ret)
		goto fail_platform_device2;

	ret = dell_setup_rfkill();

	if (ret) {
		pr_warn("Unable to setup rfkill\n");
		goto fail_rfkill;
	}

	if (quirks && quirks->touchpad_led)
		touchpad_led_init(&platform_device->dev);

	kbd_led_init(&platform_device->dev);

	dell_laptop_dir = debugfs_create_dir("dell_laptop", NULL);
	if (dell_laptop_dir != NULL)
		debugfs_create_file("rfkill", 0444, dell_laptop_dir, NULL,
				    &dell_debugfs_fops);

	dell_laptop_register_notifier(&dell_laptop_notifier);

	if (acpi_video_get_backlight_type() != acpi_backlight_vendor)
		return 0;

	token = dell_smbios_find_token(BRIGHTNESS_TOKEN);
	if (token) {
		struct calling_interface_buffer buffer;

		dell_fill_request(&buffer, token->location, 0, 0, 0);
		ret = dell_send_request(&buffer,
					CLASS_TOKEN_READ, SELECT_TOKEN_AC);
		if (ret)
			max_intensity = buffer.output[3];
	}

	if (max_intensity) {
		struct backlight_properties props;
		memset(&props, 0, sizeof(struct backlight_properties));
		props.type = BACKLIGHT_PLATFORM;
		props.max_brightness = max_intensity;
		dell_backlight_device = backlight_device_register("dell_backlight",
								  &platform_device->dev,
								  NULL,
								  &dell_ops,
								  &props);

		if (IS_ERR(dell_backlight_device)) {
			ret = PTR_ERR(dell_backlight_device);
			dell_backlight_device = NULL;
			goto fail_backlight;
		}

		dell_backlight_device->props.brightness =
			dell_get_intensity(dell_backlight_device);
		if (dell_backlight_device->props.brightness < 0) {
			ret = dell_backlight_device->props.brightness;
			goto fail_get_brightness;
		}
		backlight_update_status(dell_backlight_device);
	}

	return 0;

fail_get_brightness:
	backlight_device_unregister(dell_backlight_device);
fail_backlight:
	dell_cleanup_rfkill();
fail_rfkill:
	platform_device_del(platform_device);
fail_platform_device2:
	platform_device_put(platform_device);
fail_platform_device1:
	platform_driver_unregister(&platform_driver);
fail_platform_driver:
	return ret;
}

static void __exit dell_exit(void)
{
	dell_laptop_unregister_notifier(&dell_laptop_notifier);
	debugfs_remove_recursive(dell_laptop_dir);
	if (quirks && quirks->touchpad_led)
		touchpad_led_exit();
	kbd_led_exit();
	backlight_device_unregister(dell_backlight_device);
	dell_cleanup_rfkill();
	if (platform_device) {
		platform_device_unregister(platform_device);
		platform_driver_unregister(&platform_driver);
	}
}

/* dell-rbtn.c driver export functions which will not work correctly (and could
 * cause kernel crash) if they are called before dell-rbtn.c init code. This is
 * not problem when dell-rbtn.c is compiled as external module. When both files
 * (dell-rbtn.c and dell-laptop.c) are compiled statically into kernel, then we
 * need to ensure that dell_init() will be called after initializing dell-rbtn.
 * This can be achieved by late_initcall() instead module_init().
 */
late_initcall(dell_init);
module_exit(dell_exit);

MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
MODULE_AUTHOR("Gabriele Mazzotta <gabriele.mzt@gmail.com>");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_DESCRIPTION("Dell laptop driver");
MODULE_LICENSE("GPL");