// SPDX-License-Identifier: GPL-2.0+
/*
 * This is a driver for the keyboard, touchpad and USB port of the
 * keyboard dock for the Asus TF103C 2-in-1 tablet.
 *
 * This keyboard dock has its own I2C attached embedded controller
 * and the keyboard and touchpad are also connected over I2C,
 * instead of using the usual USB connection. This means that the
 * keyboard dock requires this special driver to function.
 *
 * Copyright (C) 2021 Hans de Goede <hdegoede@redhat.com>
 */

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/machine.h>
#include <linux/hid.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/mod_devicetable.h>
#include <linux/moduleparam.h>
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/workqueue.h>
#include <asm/unaligned.h>

static bool fnlock;
module_param(fnlock, bool, 0644);
MODULE_PARM_DESC(fnlock,
		 "By default the kbd toprow sends multimedia key presses. AltGr "
		 "can be pressed to change this to F1-F12. Set this to 1 to "
		 "change the default. Press AltGr + Esc to toggle at runtime.");

#define TF103C_DOCK_DEV_NAME				"NPCE69A:00"

#define TF103C_DOCK_HPD_DEBOUNCE			msecs_to_jiffies(20)

/*** Touchpad I2C device defines ***/
#define TF103C_DOCK_TP_ADDR				0x15

/*** Keyboard I2C device defines **A*/
#define TF103C_DOCK_KBD_ADDR				0x16

#define TF103C_DOCK_KBD_DATA_REG			0x73
#define TF103C_DOCK_KBD_DATA_MIN_LENGTH			4
#define TF103C_DOCK_KBD_DATA_MAX_LENGTH			11
#define TF103C_DOCK_KBD_DATA_MODIFIERS			3
#define TF103C_DOCK_KBD_DATA_KEYS			5
#define TF103C_DOCK_KBD_CMD_REG				0x75

#define TF103C_DOCK_KBD_CMD_ENABLE			0x0800

/*** EC innterrupt data I2C device defines ***/
#define TF103C_DOCK_INTR_ADDR				0x19
#define TF103C_DOCK_INTR_DATA_REG			0x6a

#define TF103C_DOCK_INTR_DATA1_OBF_MASK			0x01
#define TF103C_DOCK_INTR_DATA1_KEY_MASK			0x04
#define TF103C_DOCK_INTR_DATA1_KBC_MASK			0x08
#define TF103C_DOCK_INTR_DATA1_AUX_MASK			0x20
#define TF103C_DOCK_INTR_DATA1_SCI_MASK			0x40
#define TF103C_DOCK_INTR_DATA1_SMI_MASK			0x80
/* Special values for the OOB data on kbd_client / tp_client */
#define TF103C_DOCK_INTR_DATA1_OOB_VALUE		0xc1
#define TF103C_DOCK_INTR_DATA2_OOB_VALUE		0x04

#define TF103C_DOCK_SMI_AC_EVENT			0x31
#define TF103C_DOCK_SMI_HANDSHAKING			0x50
#define TF103C_DOCK_SMI_EC_WAKEUP			0x53
#define TF103C_DOCK_SMI_BOOTBLOCK_RESET			0x5e
#define TF103C_DOCK_SMI_WATCHDOG_RESET			0x5f
#define TF103C_DOCK_SMI_ADAPTER_CHANGE			0x60
#define TF103C_DOCK_SMI_DOCK_INSERT			0x61
#define TF103C_DOCK_SMI_DOCK_REMOVE			0x62
#define TF103C_DOCK_SMI_PAD_BL_CHANGE			0x63
#define TF103C_DOCK_SMI_HID_STATUS_CHANGED		0x64
#define TF103C_DOCK_SMI_HID_WAKEUP			0x65
#define TF103C_DOCK_SMI_S3				0x83
#define TF103C_DOCK_SMI_S5				0x85
#define TF103C_DOCK_SMI_NOTIFY_SHUTDOWN			0x90
#define TF103C_DOCK_SMI_RESUME				0x91

/*** EC (dockram) I2C device defines ***/
#define TF103C_DOCK_EC_ADDR				0x1b

#define TF103C_DOCK_EC_CMD_REG				0x0a
#define TF103C_DOCK_EC_CMD_LEN				9

enum {
	TF103C_DOCK_FLAG_HID_OPEN,
};

struct tf103c_dock_data {
	struct delayed_work hpd_work;
	struct irq_chip tp_irqchip;
	struct irq_domain *tp_irq_domain;
	struct i2c_client *ec_client;
	struct i2c_client *intr_client;
	struct i2c_client *kbd_client;
	struct i2c_client *tp_client;
	struct gpio_desc *pwr_en;
	struct gpio_desc *irq_gpio;
	struct gpio_desc *hpd_gpio;
	struct input_dev *input;
	struct hid_device *hid;
	unsigned long flags;
	int board_rev;
	int irq;
	int hpd_irq;
	int tp_irq;
	int last_press_0x13;
	int last_press_0x14;
	bool enabled;
	bool tp_enabled;
	bool altgr_pressed;
	bool esc_pressed;
	bool filter_esc;
	u8 kbd_buf[TF103C_DOCK_KBD_DATA_MAX_LENGTH];
};

static struct gpiod_lookup_table tf103c_dock_gpios = {
	.dev_id = "i2c-" TF103C_DOCK_DEV_NAME,
	.table = {
		GPIO_LOOKUP("INT33FC:00",      55, "dock_pwr_en", GPIO_ACTIVE_HIGH),
		GPIO_LOOKUP("INT33FC:02",       1, "dock_irq", GPIO_ACTIVE_HIGH),
		GPIO_LOOKUP("INT33FC:02",      29, "dock_hpd", GPIO_ACTIVE_HIGH),
		GPIO_LOOKUP("gpio_crystalcove", 2, "board_rev", GPIO_ACTIVE_HIGH),
		{}
	},
};

/* Byte 0 is the length of the rest of the packet */
static const u8 tf103c_dock_enable_cmd[9] = { 8, 0x20, 0, 0, 0, 0, 0x20, 0, 0 };
static const u8 tf103c_dock_usb_enable_cmd[9] = { 8, 0, 0, 0, 0, 0, 0, 0x40, 0 };
static const u8 tf103c_dock_suspend_cmd[9] = { 8, 0, 0x20, 0, 0, 0x22, 0, 0, 0 };

/*** keyboard related code ***/

static u8 tf103c_dock_kbd_hid_desc[] = {
	0x05, 0x01,         /*  Usage Page (Desktop),               */
	0x09, 0x06,         /*  Usage (Keyboard),                   */
	0xA1, 0x01,         /*  Collection (Application),           */
	0x85, 0x11,         /*      Report ID (17),                 */
	0x95, 0x08,         /*      Report Count (8),               */
	0x75, 0x01,         /*      Report Size (1),                */
	0x15, 0x00,         /*      Logical Minimum (0),            */
	0x25, 0x01,         /*      Logical Maximum (1),            */
	0x05, 0x07,         /*      Usage Page (Keyboard),          */
	0x19, 0xE0,         /*      Usage Minimum (KB Leftcontrol), */
	0x29, 0xE7,         /*      Usage Maximum (KB Right GUI),   */
	0x81, 0x02,         /*      Input (Variable),               */
	0x95, 0x01,         /*      Report Count (1),               */
	0x75, 0x08,         /*      Report Size (8),                */
	0x81, 0x01,         /*      Input (Constant),               */
	0x95, 0x06,         /*      Report Count (6),               */
	0x75, 0x08,         /*      Report Size (8),                */
	0x15, 0x00,         /*      Logical Minimum (0),            */
	0x26, 0xFF, 0x00,   /*      Logical Maximum (255),          */
	0x05, 0x07,         /*      Usage Page (Keyboard),          */
	0x19, 0x00,         /*      Usage Minimum (None),           */
	0x2A, 0xFF, 0x00,   /*      Usage Maximum (FFh),            */
	0x81, 0x00,         /*      Input,                          */
	0xC0                /*  End Collection                      */
};

static int tf103c_dock_kbd_read(struct tf103c_dock_data *dock)
{
	struct i2c_client *client = dock->kbd_client;
	struct device *dev = &dock->ec_client->dev;
	struct i2c_msg msgs[2];
	u8 reg[2];
	int ret;

	reg[0] = TF103C_DOCK_KBD_DATA_REG & 0xff;
	reg[1] = TF103C_DOCK_KBD_DATA_REG >> 8;

	msgs[0].addr = client->addr;
	msgs[0].flags = 0;
	msgs[0].len = sizeof(reg);
	msgs[0].buf = reg;

	msgs[1].addr = client->addr;
	msgs[1].flags = I2C_M_RD;
	msgs[1].len = TF103C_DOCK_KBD_DATA_MAX_LENGTH;
	msgs[1].buf = dock->kbd_buf;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
	if (ret != ARRAY_SIZE(msgs)) {
		dev_err(dev, "error %d reading kbd data\n", ret);
		return -EIO;
	}

	return 0;
}

static void tf103c_dock_kbd_write(struct tf103c_dock_data *dock, u16 cmd)
{
	struct device *dev = &dock->ec_client->dev;
	u8 buf[4];
	int ret;

	put_unaligned_le16(TF103C_DOCK_KBD_CMD_REG, &buf[0]);
	put_unaligned_le16(cmd, &buf[2]);

	ret = i2c_master_send(dock->kbd_client, buf, sizeof(buf));
	if (ret != sizeof(buf))
		dev_err(dev, "error %d writing kbd cmd\n", ret);
}

/* HID ll_driver functions for forwarding input-reports from the kbd_client */
static int tf103c_dock_hid_parse(struct hid_device *hid)
{
	return hid_parse_report(hid, tf103c_dock_kbd_hid_desc,
				sizeof(tf103c_dock_kbd_hid_desc));
}

static int tf103c_dock_hid_start(struct hid_device *hid)
{
	return 0;
}

static void tf103c_dock_hid_stop(struct hid_device *hid)
{
	hid->claimed = 0;
}

static int tf103c_dock_hid_open(struct hid_device *hid)
{
	struct tf103c_dock_data *dock = hid->driver_data;

	set_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags);
	return 0;
}

static void tf103c_dock_hid_close(struct hid_device *hid)
{
	struct tf103c_dock_data *dock = hid->driver_data;

	clear_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags);
}

/* Mandatory, but not used */
static int tf103c_dock_hid_raw_request(struct hid_device *hid, u8 reportnum,
				       u8 *buf, size_t len, u8 rtype, int reqtype)
{
	return 0;
}

static const struct hid_ll_driver tf103c_dock_hid_ll_driver = {
	.parse = tf103c_dock_hid_parse,
	.start = tf103c_dock_hid_start,
	.stop = tf103c_dock_hid_stop,
	.open = tf103c_dock_hid_open,
	.close = tf103c_dock_hid_close,
	.raw_request = tf103c_dock_hid_raw_request,
};

static const int tf103c_dock_toprow_codes[13][2] = {
	/* Normal,            AltGr pressed */
	{ KEY_POWER,          KEY_F1 },
	{ KEY_RFKILL,         KEY_F2 },
	{ KEY_F21,            KEY_F3 }, /* Touchpad toggle, userspace expects F21 */
	{ KEY_BRIGHTNESSDOWN, KEY_F4 },
	{ KEY_BRIGHTNESSUP,   KEY_F5 },
	{ KEY_CAMERA,         KEY_F6 },
	{ KEY_CONFIG,         KEY_F7 },
	{ KEY_PREVIOUSSONG,   KEY_F8 },
	{ KEY_PLAYPAUSE,      KEY_F9 },
	{ KEY_NEXTSONG,       KEY_F10 },
	{ KEY_MUTE,           KEY_F11 },
	{ KEY_VOLUMEDOWN,     KEY_F12 },
	{ KEY_VOLUMEUP,       KEY_SYSRQ },
};

static void tf103c_dock_report_toprow_kbd_hook(struct tf103c_dock_data *dock)
{
	u8 *esc, *buf = dock->kbd_buf;
	int size;

	/*
	 * Stop AltGr reports from getting reported on the "Asus TF103C Dock
	 * Keyboard" input_dev, since this gets used as "Fn" key for the toprow
	 * keys. Instead we report this on the "Asus TF103C Dock Top Row Keys"
	 * input_dev, when not used to modify the toprow keys.
	 */
	dock->altgr_pressed = buf[TF103C_DOCK_KBD_DATA_MODIFIERS] & 0x40;
	buf[TF103C_DOCK_KBD_DATA_MODIFIERS] &= ~0x40;

	input_report_key(dock->input, KEY_RIGHTALT, dock->altgr_pressed);
	input_sync(dock->input);

	/* Toggle fnlock on AltGr + Esc press */
	buf = buf + TF103C_DOCK_KBD_DATA_KEYS;
	size = TF103C_DOCK_KBD_DATA_MAX_LENGTH - TF103C_DOCK_KBD_DATA_KEYS;
	esc = memchr(buf, 0x29, size);
	if (!dock->esc_pressed && esc) {
		if (dock->altgr_pressed) {
			fnlock = !fnlock;
			dock->filter_esc = true;
		}
	}
	if (esc && dock->filter_esc)
		*esc = 0;
	else
		dock->filter_esc = false;

	dock->esc_pressed = esc != NULL;
}

static void tf103c_dock_toprow_press(struct tf103c_dock_data *dock, int key_code)
{
	/*
	 * Release AltGr before reporting the toprow key, so that userspace
	 * sees e.g. just KEY_SUSPEND and not AltGr + KEY_SUSPEND.
	 */
	if (dock->altgr_pressed) {
		input_report_key(dock->input, KEY_RIGHTALT, false);
		input_sync(dock->input);
	}

	input_report_key(dock->input, key_code, true);
	input_sync(dock->input);
}

static void tf103c_dock_toprow_release(struct tf103c_dock_data *dock, int key_code)
{
	input_report_key(dock->input, key_code, false);
	input_sync(dock->input);

	if (dock->altgr_pressed) {
		input_report_key(dock->input, KEY_RIGHTALT, true);
		input_sync(dock->input);
	}
}

static void tf103c_dock_toprow_event(struct tf103c_dock_data *dock,
					    int toprow_index, int *last_press)
{
	int key_code, fn = dock->altgr_pressed ^ fnlock;

	if (last_press && *last_press) {
		tf103c_dock_toprow_release(dock, *last_press);
		*last_press = 0;
	}

	if (toprow_index < 0)
		return;

	key_code = tf103c_dock_toprow_codes[toprow_index][fn];
	tf103c_dock_toprow_press(dock, key_code);

	if (last_press)
		*last_press = key_code;
	else
		tf103c_dock_toprow_release(dock, key_code);
}

/*
 * The keyboard sends what appears to be standard I2C-HID input-reports,
 * except that a 16 bit register address of where the I2C-HID format
 * input-reports are stored must be send before reading it in a single
 * (I2C repeated-start) I2C transaction.
 *
 * Its unknown how to get the HID descriptors but they are easy to reconstruct:
 *
 * Input report id 0x11 is 8 bytes long and contain standard USB HID intf-class,
 * Boot Interface Subclass reports.
 * Input report id 0x13 is 2 bytes long and sends Consumer Control events
 * Input report id 0x14 is 1 byte long and sends System Control events
 *
 * However the top row keys (where a normal keyboard has F1-F12 + Print-Screen)
 * are a mess, using a mix of the 0x13 and 0x14 input reports as well as EC SCI
 * events; and these need special handling to allow actually sending F1-F12,
 * since the Fn key on the keyboard only works on the cursor keys and the top
 * row keys always send their special "Multimedia hotkey" codes.
 *
 * So only forward the 0x11 reports to HID and handle the top-row keys here.
 */
static void tf103c_dock_kbd_interrupt(struct tf103c_dock_data *dock)
{
	struct device *dev = &dock->ec_client->dev;
	u8 *buf = dock->kbd_buf;
	int size;

	if (tf103c_dock_kbd_read(dock))
		return;

	size = buf[0] | buf[1] << 8;
	if (size < TF103C_DOCK_KBD_DATA_MIN_LENGTH ||
	    size > TF103C_DOCK_KBD_DATA_MAX_LENGTH) {
		dev_err(dev, "error reported kbd pkt size %d is out of range %d-%d\n", size,
			TF103C_DOCK_KBD_DATA_MIN_LENGTH,
			TF103C_DOCK_KBD_DATA_MAX_LENGTH);
		return;
	}

	switch (buf[2]) {
	case 0x11:
		if (size != 11)
			break;

		tf103c_dock_report_toprow_kbd_hook(dock);

		if (test_bit(TF103C_DOCK_FLAG_HID_OPEN, &dock->flags))
			hid_input_report(dock->hid, HID_INPUT_REPORT, buf + 2, size - 2, 1);
		return;
	case 0x13:
		if (size != 5)
			break;

		switch (buf[3] | buf[4] << 8) {
		case 0:
			tf103c_dock_toprow_event(dock, -1, &dock->last_press_0x13);
			return;
		case 0x70:
			tf103c_dock_toprow_event(dock, 3, &dock->last_press_0x13);
			return;
		case 0x6f:
			tf103c_dock_toprow_event(dock, 4, &dock->last_press_0x13);
			return;
		case 0xb6:
			tf103c_dock_toprow_event(dock, 7, &dock->last_press_0x13);
			return;
		case 0xcd:
			tf103c_dock_toprow_event(dock, 8, &dock->last_press_0x13);
			return;
		case 0xb5:
			tf103c_dock_toprow_event(dock, 9, &dock->last_press_0x13);
			return;
		case 0xe2:
			tf103c_dock_toprow_event(dock, 10, &dock->last_press_0x13);
			return;
		case 0xea:
			tf103c_dock_toprow_event(dock, 11, &dock->last_press_0x13);
			return;
		case 0xe9:
			tf103c_dock_toprow_event(dock, 12, &dock->last_press_0x13);
			return;
		}
		break;
	case 0x14:
		if (size != 4)
			break;

		switch (buf[3]) {
		case 0:
			tf103c_dock_toprow_event(dock, -1, &dock->last_press_0x14);
			return;
		case 1:
			tf103c_dock_toprow_event(dock, 0, &dock->last_press_0x14);
			return;
		}
		break;
	}

	dev_warn(dev, "warning unknown kbd data: %*ph\n", size, buf);
}

/*** touchpad related code ***/

static const struct property_entry tf103c_dock_touchpad_props[] = {
	PROPERTY_ENTRY_BOOL("elan,clickpad"),
	{ }
};

static const struct software_node tf103c_dock_touchpad_sw_node = {
	.properties = tf103c_dock_touchpad_props,
};

/*
 * tf103c_enable_touchpad() is only called from the threaded interrupt handler
 * and tf103c_disable_touchpad() is only called after the irq is disabled,
 * so no locking is necessary.
 */
static void tf103c_dock_enable_touchpad(struct tf103c_dock_data *dock)
{
	struct i2c_board_info board_info = { };
	struct device *dev = &dock->ec_client->dev;
	int ret;

	if (dock->tp_enabled) {
		/* Happens after resume, the tp needs to be reinitialized */
		ret = device_reprobe(&dock->tp_client->dev);
		if (ret)
			dev_err_probe(dev, ret, "reprobing tp-client\n");
		return;
	}

	strscpy(board_info.type, "elan_i2c", I2C_NAME_SIZE);
	board_info.addr = TF103C_DOCK_TP_ADDR;
	board_info.dev_name = TF103C_DOCK_DEV_NAME "-tp";
	board_info.irq = dock->tp_irq;
	board_info.swnode = &tf103c_dock_touchpad_sw_node;

	dock->tp_client = i2c_new_client_device(dock->ec_client->adapter, &board_info);
	if (IS_ERR(dock->tp_client)) {
		dev_err(dev, "error %ld creating tp client\n", PTR_ERR(dock->tp_client));
		return;
	}

	dock->tp_enabled = true;
}

static void tf103c_dock_disable_touchpad(struct tf103c_dock_data *dock)
{
	if (!dock->tp_enabled)
		return;

	i2c_unregister_device(dock->tp_client);

	dock->tp_enabled = false;
}

/*** interrupt handling code ***/
static void tf103c_dock_ec_cmd(struct tf103c_dock_data *dock, const u8 *cmd)
{
	struct device *dev = &dock->ec_client->dev;
	int ret;

	ret = i2c_smbus_write_i2c_block_data(dock->ec_client, TF103C_DOCK_EC_CMD_REG,
					     TF103C_DOCK_EC_CMD_LEN, cmd);
	if (ret)
		dev_err(dev, "error %d sending %*ph cmd\n", ret,
			TF103C_DOCK_EC_CMD_LEN, cmd);
}

static void tf103c_dock_sci(struct tf103c_dock_data *dock, u8 val)
{
	struct device *dev = &dock->ec_client->dev;

	switch (val) {
	case 2:
		tf103c_dock_toprow_event(dock, 1, NULL);
		return;
	case 4:
		tf103c_dock_toprow_event(dock, 2, NULL);
		return;
	case 8:
		tf103c_dock_toprow_event(dock, 5, NULL);
		return;
	case 17:
		tf103c_dock_toprow_event(dock, 6, NULL);
		return;
	}

	dev_warn(dev, "warning unknown SCI value: 0x%02x\n", val);
}

static void tf103c_dock_smi(struct tf103c_dock_data *dock, u8 val)
{
	struct device *dev = &dock->ec_client->dev;

	switch (val) {
	case TF103C_DOCK_SMI_EC_WAKEUP:
		tf103c_dock_ec_cmd(dock, tf103c_dock_enable_cmd);
		tf103c_dock_ec_cmd(dock, tf103c_dock_usb_enable_cmd);
		tf103c_dock_kbd_write(dock, TF103C_DOCK_KBD_CMD_ENABLE);
		break;
	case TF103C_DOCK_SMI_PAD_BL_CHANGE:
		/* There is no backlight, but the EC still sends this */
		break;
	case TF103C_DOCK_SMI_HID_STATUS_CHANGED:
		tf103c_dock_enable_touchpad(dock);
		break;
	default:
		dev_warn(dev, "warning unknown SMI value: 0x%02x\n", val);
		break;
	}
}

static irqreturn_t tf103c_dock_irq(int irq, void *data)
{
	struct tf103c_dock_data *dock = data;
	struct device *dev = &dock->ec_client->dev;
	u8 intr_data[8];
	int ret;

	ret = i2c_smbus_read_i2c_block_data(dock->intr_client, TF103C_DOCK_INTR_DATA_REG,
					    sizeof(intr_data), intr_data);
	if (ret != sizeof(intr_data)) {
		dev_err(dev, "error %d reading intr data\n", ret);
		return IRQ_NONE;
	}

	if (!(intr_data[1] & TF103C_DOCK_INTR_DATA1_OBF_MASK))
		return IRQ_NONE;

	/* intr_data[0] is the length of the rest of the packet */
	if (intr_data[0] == 3 && intr_data[1] == TF103C_DOCK_INTR_DATA1_OOB_VALUE &&
				 intr_data[2] == TF103C_DOCK_INTR_DATA2_OOB_VALUE) {
		/* intr_data[3] seems to contain a HID input report id */
		switch (intr_data[3]) {
		case 0x01:
			handle_nested_irq(dock->tp_irq);
			break;
		case 0x11:
		case 0x13:
		case 0x14:
			tf103c_dock_kbd_interrupt(dock);
			break;
		default:
			dev_warn(dev, "warning unknown intr_data[3]: 0x%02x\n", intr_data[3]);
			break;
		}
		return IRQ_HANDLED;
	}

	if (intr_data[1] & TF103C_DOCK_INTR_DATA1_SCI_MASK) {
		tf103c_dock_sci(dock, intr_data[2]);
		return IRQ_HANDLED;
	}

	if (intr_data[1] & TF103C_DOCK_INTR_DATA1_SMI_MASK) {
		tf103c_dock_smi(dock, intr_data[2]);
		return IRQ_HANDLED;
	}

	dev_warn(dev, "warning unknown intr data: %*ph\n", 8, intr_data);
	return IRQ_NONE;
}

/*
 * tf103c_dock_[dis|en]able only run from hpd_work or at times when
 * hpd_work cannot run (hpd_irq disabled), so no locking is necessary.
 */
static void tf103c_dock_enable(struct tf103c_dock_data *dock)
{
	if (dock->enabled)
		return;

	if (dock->board_rev != 2)
		gpiod_set_value(dock->pwr_en, 1);

	msleep(500);
	enable_irq(dock->irq);

	dock->enabled = true;
}

static void tf103c_dock_disable(struct tf103c_dock_data *dock)
{
	if (!dock->enabled)
		return;

	disable_irq(dock->irq);
	tf103c_dock_disable_touchpad(dock);
	if (dock->board_rev != 2)
		gpiod_set_value(dock->pwr_en, 0);

	dock->enabled = false;
}

static void tf103c_dock_hpd_work(struct work_struct *work)
{
	struct tf103c_dock_data *dock =
		container_of(work, struct tf103c_dock_data, hpd_work.work);

	if (gpiod_get_value(dock->hpd_gpio))
		tf103c_dock_enable(dock);
	else
		tf103c_dock_disable(dock);
}

static irqreturn_t tf103c_dock_hpd_irq(int irq, void *data)
{
	struct tf103c_dock_data *dock = data;

	mod_delayed_work(system_long_wq, &dock->hpd_work, TF103C_DOCK_HPD_DEBOUNCE);
	return IRQ_HANDLED;
}

static void tf103c_dock_start_hpd(struct tf103c_dock_data *dock)
{
	enable_irq(dock->hpd_irq);
	/* Sync current HPD status */
	queue_delayed_work(system_long_wq, &dock->hpd_work, TF103C_DOCK_HPD_DEBOUNCE);
}

static void tf103c_dock_stop_hpd(struct tf103c_dock_data *dock)
{
	disable_irq(dock->hpd_irq);
	cancel_delayed_work_sync(&dock->hpd_work);
}

/*** probe ***/

static const struct dmi_system_id tf103c_dock_dmi_ids[] = {
	{
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
			DMI_MATCH(DMI_PRODUCT_NAME, "TF103C"),
		},
	},
	{ }
};

static void tf103c_dock_non_devm_cleanup(void *data)
{
	struct tf103c_dock_data *dock = data;

	if (dock->tp_irq_domain)
		irq_domain_remove(dock->tp_irq_domain);

	if (!IS_ERR_OR_NULL(dock->hid))
		hid_destroy_device(dock->hid);

	i2c_unregister_device(dock->kbd_client);
	i2c_unregister_device(dock->intr_client);
	gpiod_remove_lookup_table(&tf103c_dock_gpios);
}

static int tf103c_dock_probe(struct i2c_client *client)
{
	struct i2c_board_info board_info = { };
	struct device *dev = &client->dev;
	struct gpio_desc *board_rev_gpio;
	struct tf103c_dock_data *dock;
	enum gpiod_flags flags;
	int i, ret;

	/* GPIOs are hardcoded for the Asus TF103C, don't bind on other devs */
	if (!dmi_check_system(tf103c_dock_dmi_ids))
		return -ENODEV;

	dock = devm_kzalloc(dev, sizeof(*dock), GFP_KERNEL);
	if (!dock)
		return -ENOMEM;

	INIT_DELAYED_WORK(&dock->hpd_work, tf103c_dock_hpd_work);

	/* 1. Get GPIOs and their IRQs */
	gpiod_add_lookup_table(&tf103c_dock_gpios);

	ret = devm_add_action_or_reset(dev, tf103c_dock_non_devm_cleanup, dock);
	if (ret)
		return ret;

	/*
	 * The pin is configured as input by default, use ASIS because otherwise
	 * the gpio-crystalcove.c switches off the internal pull-down replacing
	 * it with a pull-up.
	 */
	board_rev_gpio = gpiod_get(dev, "board_rev", GPIOD_ASIS);
	if (IS_ERR(board_rev_gpio))
		return dev_err_probe(dev, PTR_ERR(board_rev_gpio), "requesting board_rev GPIO\n");
	dock->board_rev = gpiod_get_value_cansleep(board_rev_gpio) + 1;
	gpiod_put(board_rev_gpio);

	/*
	 * The Android driver drives the dock-pwr-en pin high at probe for
	 * revision 2 boards and then never touches it again?
	 * This code has only been tested on a revision 1 board, so for now
	 * just mimick what Android does on revision 2 boards.
	 */
	flags = (dock->board_rev == 2) ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
	dock->pwr_en = devm_gpiod_get(dev, "dock_pwr_en", flags);
	if (IS_ERR(dock->pwr_en))
		return dev_err_probe(dev, PTR_ERR(dock->pwr_en), "requesting pwr_en GPIO\n");

	dock->irq_gpio = devm_gpiod_get(dev, "dock_irq", GPIOD_IN);
	if (IS_ERR(dock->irq_gpio))
		return dev_err_probe(dev, PTR_ERR(dock->irq_gpio), "requesting IRQ GPIO\n");

	dock->irq = gpiod_to_irq(dock->irq_gpio);
	if (dock->irq < 0)
		return dev_err_probe(dev, dock->irq, "getting dock IRQ");

	ret = devm_request_threaded_irq(dev, dock->irq, NULL, tf103c_dock_irq,
					IRQF_TRIGGER_LOW | IRQF_ONESHOT | IRQF_NO_AUTOEN,
					"dock_irq", dock);
	if (ret)
		return dev_err_probe(dev, ret, "requesting dock IRQ");

	dock->hpd_gpio = devm_gpiod_get(dev, "dock_hpd", GPIOD_IN);
	if (IS_ERR(dock->hpd_gpio))
		return dev_err_probe(dev, PTR_ERR(dock->hpd_gpio), "requesting HPD GPIO\n");

	dock->hpd_irq = gpiod_to_irq(dock->hpd_gpio);
	if (dock->hpd_irq < 0)
		return dev_err_probe(dev, dock->hpd_irq, "getting HPD IRQ");

	ret = devm_request_irq(dev, dock->hpd_irq, tf103c_dock_hpd_irq,
			       IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_NO_AUTOEN,
			       "dock_hpd", dock);
	if (ret)
		return ret;

	/*
	 * 2. Create I2C clients. The dock uses 4 different i2c addresses,
	 * the ACPI NPCE69A node being probed points to the EC address.
	 */
	dock->ec_client = client;

	strscpy(board_info.type, "tf103c-dock-intr", I2C_NAME_SIZE);
	board_info.addr = TF103C_DOCK_INTR_ADDR;
	board_info.dev_name = TF103C_DOCK_DEV_NAME "-intr";

	dock->intr_client = i2c_new_client_device(client->adapter, &board_info);
	if (IS_ERR(dock->intr_client))
		return dev_err_probe(dev, PTR_ERR(dock->intr_client), "creating intr client\n");

	strscpy(board_info.type, "tf103c-dock-kbd", I2C_NAME_SIZE);
	board_info.addr = TF103C_DOCK_KBD_ADDR;
	board_info.dev_name = TF103C_DOCK_DEV_NAME "-kbd";

	dock->kbd_client = i2c_new_client_device(client->adapter, &board_info);
	if (IS_ERR(dock->kbd_client))
		return dev_err_probe(dev, PTR_ERR(dock->kbd_client), "creating kbd client\n");

	/* 3. Create input_dev for the top row of the keyboard */
	dock->input = devm_input_allocate_device(dev);
	if (!dock->input)
		return -ENOMEM;

	dock->input->name = "Asus TF103C Dock Top Row Keys";
	dock->input->phys = dev_name(dev);
	dock->input->dev.parent = dev;
	dock->input->id.bustype = BUS_I2C;
	dock->input->id.vendor = /* USB_VENDOR_ID_ASUSTEK */
	dock->input->id.product = /* From TF-103-C */
	dock->input->id.version = 0x0100;  /* 1.0 */

	for (i = 0; i < ARRAY_SIZE(tf103c_dock_toprow_codes); i++) {
		input_set_capability(dock->input, EV_KEY, tf103c_dock_toprow_codes[i][0]);
		input_set_capability(dock->input, EV_KEY, tf103c_dock_toprow_codes[i][1]);
	}
	input_set_capability(dock->input, EV_KEY, KEY_RIGHTALT);

	ret = input_register_device(dock->input);
	if (ret)
		return ret;

	/* 4. Create HID device for the keyboard */
	dock->hid = hid_allocate_device();
	if (IS_ERR(dock->hid))
		return dev_err_probe(dev, PTR_ERR(dock->hid), "allocating hid dev\n");

	dock->hid->driver_data = dock;
	dock->hid->ll_driver = &tf103c_dock_hid_ll_driver;
	dock->hid->dev.parent = &client->dev;
	dock->hid->bus = BUS_I2C;
	dock->hid->vendor = 0x0b05;  /* USB_VENDOR_ID_ASUSTEK */
	dock->hid->product = 0x0103; /* From TF-103-C */
	dock->hid->version = 0x0100; /* 1.0 */
	strscpy(dock->hid->name, "Asus TF103C Dock Keyboard", sizeof(dock->hid->name));
	strscpy(dock->hid->phys, dev_name(dev), sizeof(dock->hid->phys));

	ret = hid_add_device(dock->hid);
	if (ret)
		return dev_err_probe(dev, ret, "adding hid dev\n");

	/* 5. Setup irqchip for touchpad IRQ pass-through */
	dock->tp_irqchip.name = KBUILD_MODNAME;

	dock->tp_irq_domain = irq_domain_add_linear(NULL, 1, &irq_domain_simple_ops, NULL);
	if (!dock->tp_irq_domain)
		return -ENOMEM;

	dock->tp_irq = irq_create_mapping(dock->tp_irq_domain, 0);
	if (!dock->tp_irq)
		return -ENOMEM;

	irq_set_chip_data(dock->tp_irq, dock);
	irq_set_chip_and_handler(dock->tp_irq, &dock->tp_irqchip, handle_simple_irq);
	irq_set_nested_thread(dock->tp_irq, true);
	irq_set_noprobe(dock->tp_irq);

	dev_info(dev, "Asus TF103C board-revision: %d\n", dock->board_rev);

	tf103c_dock_start_hpd(dock);

	device_init_wakeup(dev, true);
	i2c_set_clientdata(client, dock);
	return 0;
}

static void tf103c_dock_remove(struct i2c_client *client)
{
	struct tf103c_dock_data *dock = i2c_get_clientdata(client);

	tf103c_dock_stop_hpd(dock);
	tf103c_dock_disable(dock);
}

static int __maybe_unused tf103c_dock_suspend(struct device *dev)
{
	struct tf103c_dock_data *dock = dev_get_drvdata(dev);

	tf103c_dock_stop_hpd(dock);

	if (dock->enabled) {
		tf103c_dock_ec_cmd(dock, tf103c_dock_suspend_cmd);

		if (device_may_wakeup(dev))
			enable_irq_wake(dock->irq);
	}

	return 0;
}

static int __maybe_unused tf103c_dock_resume(struct device *dev)
{
	struct tf103c_dock_data *dock = dev_get_drvdata(dev);

	if (dock->enabled) {
		if (device_may_wakeup(dev))
			disable_irq_wake(dock->irq);

		/* Don't try to resume if the dock was unplugged during suspend */
		if (gpiod_get_value(dock->hpd_gpio))
			tf103c_dock_ec_cmd(dock, tf103c_dock_enable_cmd);
	}

	tf103c_dock_start_hpd(dock);
	return 0;
}

static SIMPLE_DEV_PM_OPS(tf103c_dock_pm_ops, tf103c_dock_suspend, tf103c_dock_resume);

static const struct acpi_device_id tf103c_dock_acpi_match[] = {
	{"NPCE69A"},
	{ }
};
MODULE_DEVICE_TABLE(acpi, tf103c_dock_acpi_match);

static struct i2c_driver tf103c_dock_driver = {
	.driver = {
		.name = "asus-tf103c-dock",
		.pm = &tf103c_dock_pm_ops,
		.acpi_match_table = tf103c_dock_acpi_match,
	},
	.probe = tf103c_dock_probe,
	.remove	= tf103c_dock_remove,
};
module_i2c_driver(tf103c_dock_driver);

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com");
MODULE_DESCRIPTION("X86 Android tablets DSDT fixups driver");
MODULE_LICENSE("GPL");