/*
 * Cypress APA trackpad with I2C interface
 *
 * Author: Dudley Du <dudl@cypress.com>
 * Further cleanup and restructuring by:
 *   Daniel Kurtz <djkurtz@chromium.org>
 *   Benson Leung <bleung@chromium.org>
 *
 * Copyright (C) 2011-2015 Cypress Semiconductor, Inc.
 * Copyright (C) 2011-2012 Google, Inc.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/pm_runtime.h>
#include <linux/acpi.h>
#include <linux/of.h>
#include "cyapa.h"


#define CYAPA_ADAPTER_FUNC_NONE   0
#define CYAPA_ADAPTER_FUNC_I2C    1
#define CYAPA_ADAPTER_FUNC_SMBUS  2
#define CYAPA_ADAPTER_FUNC_BOTH   3

#define CYAPA_FW_NAME		"cyapa.bin"

const char product_id[] = "CYTRA";

static int cyapa_reinitialize(struct cyapa *cyapa);

bool cyapa_is_pip_bl_mode(struct cyapa *cyapa)
{
	if (cyapa->gen == CYAPA_GEN6 && cyapa->state == CYAPA_STATE_GEN6_BL)
		return true;

	if (cyapa->gen == CYAPA_GEN5 && cyapa->state == CYAPA_STATE_GEN5_BL)
		return true;

	return false;
}

bool cyapa_is_pip_app_mode(struct cyapa *cyapa)
{
	if (cyapa->gen == CYAPA_GEN6 && cyapa->state == CYAPA_STATE_GEN6_APP)
		return true;

	if (cyapa->gen == CYAPA_GEN5 && cyapa->state == CYAPA_STATE_GEN5_APP)
		return true;

	return false;
}

static bool cyapa_is_bootloader_mode(struct cyapa *cyapa)
{
	if (cyapa_is_pip_bl_mode(cyapa))
		return true;

	if (cyapa->gen == CYAPA_GEN3 &&
		cyapa->state >= CYAPA_STATE_BL_BUSY &&
		cyapa->state <= CYAPA_STATE_BL_ACTIVE)
		return true;

	return false;
}

static inline bool cyapa_is_operational_mode(struct cyapa *cyapa)
{
	if (cyapa_is_pip_app_mode(cyapa))
		return true;

	if (cyapa->gen == CYAPA_GEN3 && cyapa->state == CYAPA_STATE_OP)
		return true;

	return false;
}

/* Returns 0 on success, else negative errno on failure. */
static ssize_t cyapa_i2c_read(struct cyapa *cyapa, u8 reg, size_t len,
					u8 *values)
{
	struct i2c_client *client = cyapa->client;
	struct i2c_msg msgs[] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = 1,
			.buf = &reg,
		},
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = len,
			.buf = values,
		},
	};
	int ret;

	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));

	if (ret != ARRAY_SIZE(msgs))
		return ret < 0 ? ret : -EIO;

	return 0;
}

/**
 * cyapa_i2c_write - Execute i2c block data write operation
 * @cyapa: Handle to this driver
 * @ret: Offset of the data to written in the register map
 * @len: number of bytes to write
 * @values: Data to be written
 *
 * Return negative errno code on error; return zero when success.
 */
static int cyapa_i2c_write(struct cyapa *cyapa, u8 reg,
					 size_t len, const void *values)
{
	struct i2c_client *client = cyapa->client;
	char buf[32];
	int ret;

	if (len > sizeof(buf) - 1)
		return -ENOMEM;

	buf[0] = reg;
	memcpy(&buf[1], values, len);

	ret = i2c_master_send(client, buf, len + 1);
	if (ret != len + 1)
		return ret < 0 ? ret : -EIO;

	return 0;
}

static u8 cyapa_check_adapter_functionality(struct i2c_client *client)
{
	u8 ret = CYAPA_ADAPTER_FUNC_NONE;

	if (i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
		ret |= CYAPA_ADAPTER_FUNC_I2C;
	if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
				     I2C_FUNC_SMBUS_BLOCK_DATA |
				     I2C_FUNC_SMBUS_I2C_BLOCK))
		ret |= CYAPA_ADAPTER_FUNC_SMBUS;
	return ret;
}

/*
 * Query device for its current operating state.
 */
static int cyapa_get_state(struct cyapa *cyapa)
{
	u8 status[BL_STATUS_SIZE];
	u8 cmd[32];
	/* The i2c address of gen4 and gen5 trackpad device must be even. */
	bool even_addr = ((cyapa->client->addr & 0x0001) == 0);
	bool smbus = false;
	int retries = 2;
	int error;

	cyapa->state = CYAPA_STATE_NO_DEVICE;

	/*
	 * Get trackpad status by reading 3 registers starting from 0.
	 * If the device is in the bootloader, this will be BL_HEAD.
	 * If the device is in operation mode, this will be the DATA regs.
	 *
	 */
	error = cyapa_i2c_reg_read_block(cyapa, BL_HEAD_OFFSET, BL_STATUS_SIZE,
				       status);

	/*
	 * On smbus systems in OP mode, the i2c_reg_read will fail with
	 * -ETIMEDOUT.  In this case, try again using the smbus equivalent
	 * command.  This should return a BL_HEAD indicating CYAPA_STATE_OP.
	 */
	if (cyapa->smbus && (error == -ETIMEDOUT || error == -ENXIO)) {
		if (!even_addr)
			error = cyapa_read_block(cyapa,
					CYAPA_CMD_BL_STATUS, status);
		smbus = true;
	}

	if (error != BL_STATUS_SIZE)
		goto error;

	/*
	 * Detect trackpad protocol based on characteristic registers and bits.
	 */
	do {
		cyapa->status[REG_OP_STATUS] = status[REG_OP_STATUS];
		cyapa->status[REG_BL_STATUS] = status[REG_BL_STATUS];
		cyapa->status[REG_BL_ERROR] = status[REG_BL_ERROR];

		if (cyapa->gen == CYAPA_GEN_UNKNOWN ||
				cyapa->gen == CYAPA_GEN3) {
			error = cyapa_gen3_ops.state_parse(cyapa,
					status, BL_STATUS_SIZE);
			if (!error)
				goto out_detected;
		}
		if (cyapa->gen == CYAPA_GEN_UNKNOWN ||
				cyapa->gen == CYAPA_GEN6 ||
				cyapa->gen == CYAPA_GEN5) {
			error = cyapa_pip_state_parse(cyapa,
					status, BL_STATUS_SIZE);
			if (!error)
				goto out_detected;
		}
		/* For old Gen5 trackpads detecting. */
		if ((cyapa->gen == CYAPA_GEN_UNKNOWN ||
				cyapa->gen == CYAPA_GEN5) &&
			!smbus && even_addr) {
			error = cyapa_gen5_ops.state_parse(cyapa,
					status, BL_STATUS_SIZE);
			if (!error)
				goto out_detected;
		}

		/*
		 * Write 0x00 0x00 to trackpad device to force update its
		 * status, then redo the detection again.
		 */
		if (!smbus) {
			cmd[0] = 0x00;
			cmd[1] = 0x00;
			error = cyapa_i2c_write(cyapa, 0, 2, cmd);
			if (error)
				goto error;

			msleep(50);

			error = cyapa_i2c_read(cyapa, BL_HEAD_OFFSET,
					BL_STATUS_SIZE, status);
			if (error)
				goto error;
		}
	} while (--retries > 0 && !smbus);

	goto error;

out_detected:
	if (cyapa->state <= CYAPA_STATE_BL_BUSY)
		return -EAGAIN;
	return 0;

error:
	return (error < 0) ? error : -EAGAIN;
}

/*
 * Poll device for its status in a loop, waiting up to timeout for a response.
 *
 * When the device switches state, it usually takes ~300 ms.
 * However, when running a new firmware image, the device must calibrate its
 * sensors, which can take as long as 2 seconds.
 *
 * Note: The timeout has granularity of the polling rate, which is 100 ms.
 *
 * Returns:
 *   0 when the device eventually responds with a valid non-busy state.
 *   -ETIMEDOUT if device never responds (too many -EAGAIN)
 *   -EAGAIN    if bootload is busy, or unknown state.
 *   < 0        other errors
 */
int cyapa_poll_state(struct cyapa *cyapa, unsigned int timeout)
{
	int error;
	int tries = timeout / 100;

	do {
		error = cyapa_get_state(cyapa);
		if (!error && cyapa->state > CYAPA_STATE_BL_BUSY)
			return 0;

		msleep(100);
	} while (tries--);

	return (error == -EAGAIN || error == -ETIMEDOUT) ? -ETIMEDOUT : error;
}

/*
 * Check if device is operational.
 *
 * An operational device is responding, has exited bootloader, and has
 * firmware supported by this driver.
 *
 * Returns:
 *   -ENODEV no device
 *   -EBUSY  no device or in bootloader
 *   -EIO    failure while reading from device
 *   -ETIMEDOUT timeout failure for bus idle or bus no response
 *   -EAGAIN device is still in bootloader
 *           if ->state = CYAPA_STATE_BL_IDLE, device has invalid firmware
 *   -EINVAL device is in operational mode, but not supported by this driver
 *   0       device is supported
 */
static int cyapa_check_is_operational(struct cyapa *cyapa)
{
	int error;

	error = cyapa_poll_state(cyapa, 4000);
	if (error)
		return error;

	switch (cyapa->gen) {
	case CYAPA_GEN6:
		cyapa->ops = &cyapa_gen6_ops;
		break;
	case CYAPA_GEN5:
		cyapa->ops = &cyapa_gen5_ops;
		break;
	case CYAPA_GEN3:
		cyapa->ops = &cyapa_gen3_ops;
		break;
	default:
		return -ENODEV;
	}

	error = cyapa->ops->operational_check(cyapa);
	if (!error && cyapa_is_operational_mode(cyapa))
		cyapa->operational = true;
	else
		cyapa->operational = false;

	return error;
}


/*
 * Returns 0 on device detected, negative errno on no device detected.
 * And when the device is detected and operational, it will be reset to
 * full power active mode automatically.
 */
static int cyapa_detect(struct cyapa *cyapa)
{
	struct device *dev = &cyapa->client->dev;
	int error;

	error = cyapa_check_is_operational(cyapa);
	if (error) {
		if (error != -ETIMEDOUT && error != -ENODEV &&
			cyapa_is_bootloader_mode(cyapa)) {
			dev_warn(dev, "device detected but not operational\n");
			return 0;
		}

		dev_err(dev, "no device detected: %d\n", error);
		return error;
	}

	return 0;
}

static int cyapa_open(struct input_dev *input)
{
	struct cyapa *cyapa = input_get_drvdata(input);
	struct i2c_client *client = cyapa->client;
	struct device *dev = &client->dev;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	if (cyapa->operational) {
		/*
		 * though failed to set active power mode,
		 * but still may be able to work in lower scan rate
		 * when in operational mode.
		 */
		error = cyapa->ops->set_power_mode(cyapa,
				PWR_MODE_FULL_ACTIVE, 0, false);
		if (error) {
			dev_warn(dev, "set active power failed: %d\n", error);
			goto out;
		}
	} else {
		error = cyapa_reinitialize(cyapa);
		if (error || !cyapa->operational) {
			error = error ? error : -EAGAIN;
			goto out;
		}
	}

	enable_irq(client->irq);
	if (!pm_runtime_enabled(dev)) {
		pm_runtime_set_active(dev);
		pm_runtime_enable(dev);
	}

	pm_runtime_get_sync(dev);
	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_sync_autosuspend(dev);
out:
	mutex_unlock(&cyapa->state_sync_lock);
	return error;
}

static void cyapa_close(struct input_dev *input)
{
	struct cyapa *cyapa = input_get_drvdata(input);
	struct i2c_client *client = cyapa->client;
	struct device *dev = &cyapa->client->dev;

	mutex_lock(&cyapa->state_sync_lock);

	disable_irq(client->irq);
	if (pm_runtime_enabled(dev))
		pm_runtime_disable(dev);
	pm_runtime_set_suspended(dev);

	if (cyapa->operational)
		cyapa->ops->set_power_mode(cyapa, PWR_MODE_OFF, 0, false);

	mutex_unlock(&cyapa->state_sync_lock);
}

static int cyapa_create_input_dev(struct cyapa *cyapa)
{
	struct device *dev = &cyapa->client->dev;
	struct input_dev *input;
	int error;

	if (!cyapa->physical_size_x || !cyapa->physical_size_y)
		return -EINVAL;

	input = devm_input_allocate_device(dev);
	if (!input) {
		dev_err(dev, "failed to allocate memory for input device.\n");
		return -ENOMEM;
	}

	input->name = CYAPA_NAME;
	input->phys = cyapa->phys;
	input->id.bustype = BUS_I2C;
	input->id.version = 1;
	input->id.product = 0;  /* Means any product in eventcomm. */
	input->dev.parent = &cyapa->client->dev;

	input->open = cyapa_open;
	input->close = cyapa_close;

	input_set_drvdata(input, cyapa);

	__set_bit(EV_ABS, input->evbit);

	/* Finger position */
	input_set_abs_params(input, ABS_MT_POSITION_X, 0, cyapa->max_abs_x, 0,
			     0);
	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, cyapa->max_abs_y, 0,
			     0);
	input_set_abs_params(input, ABS_MT_PRESSURE, 0, cyapa->max_z, 0, 0);
	if (cyapa->gen > CYAPA_GEN3) {
		input_set_abs_params(input, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
		input_set_abs_params(input, ABS_MT_TOUCH_MINOR, 0, 255, 0, 0);
		/*
		 * Orientation is the angle between the vertical axis and
		 * the major axis of the contact ellipse.
		 * The range is -127 to 127.
		 * the positive direction is clockwise form the vertical axis.
		 * If the ellipse of contact degenerates into a circle,
		 * orientation is reported as 0.
		 *
		 * Also, for Gen5 trackpad the accurate of this orientation
		 * value is value + (-30 ~ 30).
		 */
		input_set_abs_params(input, ABS_MT_ORIENTATION,
				-127, 127, 0, 0);
	}
	if (cyapa->gen >= CYAPA_GEN5) {
		input_set_abs_params(input, ABS_MT_WIDTH_MAJOR, 0, 255, 0, 0);
		input_set_abs_params(input, ABS_MT_WIDTH_MINOR, 0, 255, 0, 0);
		input_set_abs_params(input, ABS_DISTANCE, 0, 1, 0, 0);
	}

	input_abs_set_res(input, ABS_MT_POSITION_X,
			  cyapa->max_abs_x / cyapa->physical_size_x);
	input_abs_set_res(input, ABS_MT_POSITION_Y,
			  cyapa->max_abs_y / cyapa->physical_size_y);

	if (cyapa->btn_capability & CAPABILITY_LEFT_BTN_MASK)
		__set_bit(BTN_LEFT, input->keybit);
	if (cyapa->btn_capability & CAPABILITY_MIDDLE_BTN_MASK)
		__set_bit(BTN_MIDDLE, input->keybit);
	if (cyapa->btn_capability & CAPABILITY_RIGHT_BTN_MASK)
		__set_bit(BTN_RIGHT, input->keybit);

	if (cyapa->btn_capability == CAPABILITY_LEFT_BTN_MASK)
		__set_bit(INPUT_PROP_BUTTONPAD, input->propbit);

	/* Handle pointer emulation and unused slots in core */
	error = input_mt_init_slots(input, CYAPA_MAX_MT_SLOTS,
				    INPUT_MT_POINTER | INPUT_MT_DROP_UNUSED);
	if (error) {
		dev_err(dev, "failed to initialize MT slots: %d\n", error);
		return error;
	}

	/* Register the device in input subsystem */
	error = input_register_device(input);
	if (error) {
		dev_err(dev, "failed to register input device: %d\n", error);
		return error;
	}

	cyapa->input = input;
	return 0;
}

static void cyapa_enable_irq_for_cmd(struct cyapa *cyapa)
{
	struct input_dev *input = cyapa->input;

	if (!input || !input->users) {
		/*
		 * When input is NULL, TP must be in deep sleep mode.
		 * In this mode, later non-power I2C command will always failed
		 * if not bring it out of deep sleep mode firstly,
		 * so must command TP to active mode here.
		 */
		if (!input || cyapa->operational)
			cyapa->ops->set_power_mode(cyapa,
				PWR_MODE_FULL_ACTIVE, 0, false);
		/* Gen3 always using polling mode for command. */
		if (cyapa->gen >= CYAPA_GEN5)
			enable_irq(cyapa->client->irq);
	}
}

static void cyapa_disable_irq_for_cmd(struct cyapa *cyapa)
{
	struct input_dev *input = cyapa->input;

	if (!input || !input->users) {
		if (cyapa->gen >= CYAPA_GEN5)
			disable_irq(cyapa->client->irq);
		if (!input || cyapa->operational)
			cyapa->ops->set_power_mode(cyapa,
						   PWR_MODE_OFF, 0, false);
	}
}

/*
 * cyapa_sleep_time_to_pwr_cmd and cyapa_pwr_cmd_to_sleep_time
 *
 * These are helper functions that convert to and from integer idle
 * times and register settings to write to the PowerMode register.
 * The trackpad supports between 20ms to 1000ms scan intervals.
 * The time will be increased in increments of 10ms from 20ms to 100ms.
 * From 100ms to 1000ms, time will be increased in increments of 20ms.
 *
 * When Idle_Time < 100, the format to convert Idle_Time to Idle_Command is:
 *   Idle_Command = Idle Time / 10;
 * When Idle_Time >= 100, the format to convert Idle_Time to Idle_Command is:
 *   Idle_Command = Idle Time / 20 + 5;
 */
u8 cyapa_sleep_time_to_pwr_cmd(u16 sleep_time)
{
	u16 encoded_time;

	sleep_time = clamp_val(sleep_time, 20, 1000);
	encoded_time = sleep_time < 100 ? sleep_time / 10 : sleep_time / 20 + 5;
	return (encoded_time << 2) & PWR_MODE_MASK;
}

u16 cyapa_pwr_cmd_to_sleep_time(u8 pwr_mode)
{
	u8 encoded_time = pwr_mode >> 2;

	return (encoded_time < 10) ? encoded_time * 10
				   : (encoded_time - 5) * 20;
}

/* 0 on driver initialize and detected successfully, negative on failure. */
static int cyapa_initialize(struct cyapa *cyapa)
{
	int error = 0;

	cyapa->state = CYAPA_STATE_NO_DEVICE;
	cyapa->gen = CYAPA_GEN_UNKNOWN;
	mutex_init(&cyapa->state_sync_lock);

	/*
	 * Set to hard code default, they will be updated with trackpad set
	 * default values after probe and initialized.
	 */
	cyapa->suspend_power_mode = PWR_MODE_SLEEP;
	cyapa->suspend_sleep_time =
		cyapa_pwr_cmd_to_sleep_time(cyapa->suspend_power_mode);

	/* ops.initialize() is aimed to prepare for module communications. */
	error = cyapa_gen3_ops.initialize(cyapa);
	if (!error)
		error = cyapa_gen5_ops.initialize(cyapa);
	if (!error)
		error = cyapa_gen6_ops.initialize(cyapa);
	if (error)
		return error;

	error = cyapa_detect(cyapa);
	if (error)
		return error;

	/* Power down the device until we need it. */
	if (cyapa->operational)
		cyapa->ops->set_power_mode(cyapa, PWR_MODE_OFF, 0, false);

	return 0;
}

static int cyapa_reinitialize(struct cyapa *cyapa)
{
	struct device *dev = &cyapa->client->dev;
	struct input_dev *input = cyapa->input;
	int error;

	if (pm_runtime_enabled(dev))
		pm_runtime_disable(dev);

	/* Avoid command failures when TP was in OFF state. */
	if (cyapa->operational)
		cyapa->ops->set_power_mode(cyapa,
					   PWR_MODE_FULL_ACTIVE, 0, false);

	error = cyapa_detect(cyapa);
	if (error)
		goto out;

	if (!input && cyapa->operational) {
		error = cyapa_create_input_dev(cyapa);
		if (error) {
			dev_err(dev, "create input_dev instance failed: %d\n",
					error);
			goto out;
		}
	}

out:
	if (!input || !input->users) {
		/* Reset to power OFF state to save power when no user open. */
		if (cyapa->operational)
			cyapa->ops->set_power_mode(cyapa,
						   PWR_MODE_OFF, 0, false);
	} else if (!error && cyapa->operational) {
		/*
		 * Make sure only enable runtime PM when device is
		 * in operational mode and input->users > 0.
		 */
		pm_runtime_set_active(dev);
		pm_runtime_enable(dev);

		pm_runtime_get_sync(dev);
		pm_runtime_mark_last_busy(dev);
		pm_runtime_put_sync_autosuspend(dev);
	}

	return error;
}

static irqreturn_t cyapa_irq(int irq, void *dev_id)
{
	struct cyapa *cyapa = dev_id;
	struct device *dev = &cyapa->client->dev;
	int error;

	if (device_may_wakeup(dev))
		pm_wakeup_event(dev, 0);

	/* Interrupt event can be caused by host command to trackpad device. */
	if (cyapa->ops->irq_cmd_handler(cyapa)) {
		/*
		 * Interrupt event maybe from trackpad device input reporting.
		 */
		if (!cyapa->input) {
			/*
			 * Still in probing or in firmware image
			 * updating or reading.
			 */
			cyapa->ops->sort_empty_output_data(cyapa,
					NULL, NULL, NULL);
			goto out;
		}

		if (cyapa->operational) {
			error = cyapa->ops->irq_handler(cyapa);

			/*
			 * Apply runtime power management to touch report event
			 * except the events caused by the command responses.
			 * Note:
			 * It will introduce about 20~40 ms additional delay
			 * time in receiving for first valid touch report data.
			 * The time is used to execute device runtime resume
			 * process.
			 */
			pm_runtime_get_sync(dev);
			pm_runtime_mark_last_busy(dev);
			pm_runtime_put_sync_autosuspend(dev);
		}

		if (!cyapa->operational || error) {
			if (!mutex_trylock(&cyapa->state_sync_lock)) {
				cyapa->ops->sort_empty_output_data(cyapa,
					NULL, NULL, NULL);
				goto out;
			}
			cyapa_reinitialize(cyapa);
			mutex_unlock(&cyapa->state_sync_lock);
		}
	}

out:
	return IRQ_HANDLED;
}

/*
 **************************************************************
 * sysfs interface
 **************************************************************
*/
#ifdef CONFIG_PM_SLEEP
static ssize_t cyapa_show_suspend_scanrate(struct device *dev,
					   struct device_attribute *attr,
					   char *buf)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	u8 pwr_cmd = cyapa->suspend_power_mode;
	u16 sleep_time;
	int len;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	pwr_cmd = cyapa->suspend_power_mode;
	sleep_time = cyapa->suspend_sleep_time;

	mutex_unlock(&cyapa->state_sync_lock);

	switch (pwr_cmd) {
	case PWR_MODE_BTN_ONLY:
		len = scnprintf(buf, PAGE_SIZE, "%s\n", BTN_ONLY_MODE_NAME);
		break;

	case PWR_MODE_OFF:
		len = scnprintf(buf, PAGE_SIZE, "%s\n", OFF_MODE_NAME);
		break;

	default:
		len = scnprintf(buf, PAGE_SIZE, "%u\n",
				cyapa->gen == CYAPA_GEN3 ?
					cyapa_pwr_cmd_to_sleep_time(pwr_cmd) :
					sleep_time);
		break;
	}

	return len;
}

static ssize_t cyapa_update_suspend_scanrate(struct device *dev,
					     struct device_attribute *attr,
					     const char *buf, size_t count)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	u16 sleep_time;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	if (sysfs_streq(buf, BTN_ONLY_MODE_NAME)) {
		cyapa->suspend_power_mode = PWR_MODE_BTN_ONLY;
	} else if (sysfs_streq(buf, OFF_MODE_NAME)) {
		cyapa->suspend_power_mode = PWR_MODE_OFF;
	} else if (!kstrtou16(buf, 10, &sleep_time)) {
		cyapa->suspend_sleep_time = min_t(u16, sleep_time, 1000);
		cyapa->suspend_power_mode =
			cyapa_sleep_time_to_pwr_cmd(cyapa->suspend_sleep_time);
	} else {
		count = -EINVAL;
	}

	mutex_unlock(&cyapa->state_sync_lock);

	return count;
}

static DEVICE_ATTR(suspend_scanrate_ms, S_IRUGO|S_IWUSR,
		   cyapa_show_suspend_scanrate,
		   cyapa_update_suspend_scanrate);

static struct attribute *cyapa_power_wakeup_entries[] = {
	&dev_attr_suspend_scanrate_ms.attr,
	NULL,
};

static const struct attribute_group cyapa_power_wakeup_group = {
	.name = power_group_name,
	.attrs = cyapa_power_wakeup_entries,
};

static void cyapa_remove_power_wakeup_group(void *data)
{
	struct cyapa *cyapa = data;

	sysfs_unmerge_group(&cyapa->client->dev.kobj,
				&cyapa_power_wakeup_group);
}

static int cyapa_prepare_wakeup_controls(struct cyapa *cyapa)
{
	struct i2c_client *client = cyapa->client;
	struct device *dev = &client->dev;
	int error;

	if (device_can_wakeup(dev)) {
		error = sysfs_merge_group(&client->dev.kobj,
					&cyapa_power_wakeup_group);
		if (error) {
			dev_err(dev, "failed to add power wakeup group: %d\n",
				error);
			return error;
		}

		error = devm_add_action(dev,
				cyapa_remove_power_wakeup_group, cyapa);
		if (error) {
			cyapa_remove_power_wakeup_group(cyapa);
			dev_err(dev, "failed to add power cleanup action: %d\n",
				error);
			return error;
		}
	}

	return 0;
}
#else
static inline int cyapa_prepare_wakeup_controls(struct cyapa *cyapa)
{
	return 0;
}
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM
static ssize_t cyapa_show_rt_suspend_scanrate(struct device *dev,
					      struct device_attribute *attr,
					      char *buf)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	u8 pwr_cmd;
	u16 sleep_time;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	pwr_cmd = cyapa->runtime_suspend_power_mode;
	sleep_time = cyapa->runtime_suspend_sleep_time;

	mutex_unlock(&cyapa->state_sync_lock);

	return scnprintf(buf, PAGE_SIZE, "%u\n",
			 cyapa->gen == CYAPA_GEN3 ?
				cyapa_pwr_cmd_to_sleep_time(pwr_cmd) :
				sleep_time);
}

static ssize_t cyapa_update_rt_suspend_scanrate(struct device *dev,
						struct device_attribute *attr,
						const char *buf, size_t count)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	u16 time;
	int error;

	if (buf == NULL || count == 0 || kstrtou16(buf, 10, &time)) {
		dev_err(dev, "invalid runtime suspend scanrate ms parameter\n");
		return -EINVAL;
	}

	/*
	 * When the suspend scanrate is changed, pm_runtime_get to resume
	 * a potentially suspended device, update to the new pwr_cmd
	 * and then pm_runtime_put to suspend into the new power mode.
	 */
	pm_runtime_get_sync(dev);

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	cyapa->runtime_suspend_sleep_time = min_t(u16, time, 1000);
	cyapa->runtime_suspend_power_mode =
		cyapa_sleep_time_to_pwr_cmd(cyapa->runtime_suspend_sleep_time);

	mutex_unlock(&cyapa->state_sync_lock);

	pm_runtime_put_sync_autosuspend(dev);

	return count;
}

static DEVICE_ATTR(runtime_suspend_scanrate_ms, S_IRUGO|S_IWUSR,
		   cyapa_show_rt_suspend_scanrate,
		   cyapa_update_rt_suspend_scanrate);

static struct attribute *cyapa_power_runtime_entries[] = {
	&dev_attr_runtime_suspend_scanrate_ms.attr,
	NULL,
};

static const struct attribute_group cyapa_power_runtime_group = {
	.name = power_group_name,
	.attrs = cyapa_power_runtime_entries,
};

static void cyapa_remove_power_runtime_group(void *data)
{
	struct cyapa *cyapa = data;

	sysfs_unmerge_group(&cyapa->client->dev.kobj,
				&cyapa_power_runtime_group);
}

static int cyapa_start_runtime(struct cyapa *cyapa)
{
	struct device *dev = &cyapa->client->dev;
	int error;

	cyapa->runtime_suspend_power_mode = PWR_MODE_IDLE;
	cyapa->runtime_suspend_sleep_time =
		cyapa_pwr_cmd_to_sleep_time(cyapa->runtime_suspend_power_mode);

	error = sysfs_merge_group(&dev->kobj, &cyapa_power_runtime_group);
	if (error) {
		dev_err(dev,
			"failed to create power runtime group: %d\n", error);
		return error;
	}

	error = devm_add_action(dev, cyapa_remove_power_runtime_group, cyapa);
	if (error) {
		cyapa_remove_power_runtime_group(cyapa);
		dev_err(dev,
			"failed to add power runtime cleanup action: %d\n",
			error);
		return error;
	}

	/* runtime is enabled until device is operational and opened. */
	pm_runtime_set_suspended(dev);
	pm_runtime_use_autosuspend(dev);
	pm_runtime_set_autosuspend_delay(dev, AUTOSUSPEND_DELAY);

	return 0;
}
#else
static inline int cyapa_start_runtime(struct cyapa *cyapa)
{
	return 0;
}
#endif /* CONFIG_PM */

static ssize_t cyapa_show_fm_ver(struct device *dev,
				 struct device_attribute *attr, char *buf)
{
	int error;
	struct cyapa *cyapa = dev_get_drvdata(dev);

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;
	error = scnprintf(buf, PAGE_SIZE, "%d.%d\n", cyapa->fw_maj_ver,
			 cyapa->fw_min_ver);
	mutex_unlock(&cyapa->state_sync_lock);
	return error;
}

static ssize_t cyapa_show_product_id(struct device *dev,
				     struct device_attribute *attr, char *buf)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	int size;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;
	size = scnprintf(buf, PAGE_SIZE, "%s\n", cyapa->product_id);
	mutex_unlock(&cyapa->state_sync_lock);
	return size;
}

static int cyapa_firmware(struct cyapa *cyapa, const char *fw_name)
{
	struct device *dev = &cyapa->client->dev;
	const struct firmware *fw;
	int error;

	error = request_firmware(&fw, fw_name, dev);
	if (error) {
		dev_err(dev, "Could not load firmware from %s: %d\n",
			fw_name, error);
		return error;
	}

	error = cyapa->ops->check_fw(cyapa, fw);
	if (error) {
		dev_err(dev, "Invalid CYAPA firmware image: %s\n",
				fw_name);
		goto done;
	}

	/*
	 * Resume the potentially suspended device because doing FW
	 * update on a device not in the FULL mode has a chance to
	 * fail.
	 */
	pm_runtime_get_sync(dev);

	/* Require IRQ support for firmware update commands. */
	cyapa_enable_irq_for_cmd(cyapa);

	error = cyapa->ops->bl_enter(cyapa);
	if (error) {
		dev_err(dev, "bl_enter failed, %d\n", error);
		goto err_detect;
	}

	error = cyapa->ops->bl_activate(cyapa);
	if (error) {
		dev_err(dev, "bl_activate failed, %d\n", error);
		goto err_detect;
	}

	error = cyapa->ops->bl_initiate(cyapa, fw);
	if (error) {
		dev_err(dev, "bl_initiate failed, %d\n", error);
		goto err_detect;
	}

	error = cyapa->ops->update_fw(cyapa, fw);
	if (error) {
		dev_err(dev, "update_fw failed, %d\n", error);
		goto err_detect;
	}

err_detect:
	cyapa_disable_irq_for_cmd(cyapa);
	pm_runtime_put_noidle(dev);

done:
	release_firmware(fw);
	return error;
}

static ssize_t cyapa_update_fw_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	char fw_name[NAME_MAX];
	int ret, error;

	if (count >= NAME_MAX) {
		dev_err(dev, "File name too long\n");
		return -EINVAL;
	}

	memcpy(fw_name, buf, count);
	if (fw_name[count - 1] == '\n')
		fw_name[count - 1] = '\0';
	else
		fw_name[count] = '\0';

	if (cyapa->input) {
		/*
		 * Force the input device to be registered after the firmware
		 * image is updated, so if the corresponding parameters updated
		 * in the new firmware image can taken effect immediately.
		 */
		input_unregister_device(cyapa->input);
		cyapa->input = NULL;
	}

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error) {
		/*
		 * Whatever, do reinitialize to try to recover TP state to
		 * previous state just as it entered fw update entrance.
		 */
		cyapa_reinitialize(cyapa);
		return error;
	}

	error = cyapa_firmware(cyapa, fw_name);
	if (error)
		dev_err(dev, "firmware update failed: %d\n", error);
	else
		dev_dbg(dev, "firmware update successfully done.\n");

	/*
	 * Re-detect trackpad device states because firmware update process
	 * will reset trackpad device into bootloader mode.
	 */
	ret = cyapa_reinitialize(cyapa);
	if (ret) {
		dev_err(dev, "failed to re-detect after updated: %d\n", ret);
		error = error ? error : ret;
	}

	mutex_unlock(&cyapa->state_sync_lock);

	return error ? error : count;
}

static ssize_t cyapa_calibrate_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	if (cyapa->operational) {
		cyapa_enable_irq_for_cmd(cyapa);
		error = cyapa->ops->calibrate_store(dev, attr, buf, count);
		cyapa_disable_irq_for_cmd(cyapa);
	} else {
		error = -EBUSY;  /* Still running in bootloader mode. */
	}

	mutex_unlock(&cyapa->state_sync_lock);
	return error < 0 ? error : count;
}

static ssize_t cyapa_show_baseline(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	ssize_t error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	if (cyapa->operational) {
		cyapa_enable_irq_for_cmd(cyapa);
		error = cyapa->ops->show_baseline(dev, attr, buf);
		cyapa_disable_irq_for_cmd(cyapa);
	} else {
		error = -EBUSY;  /* Still running in bootloader mode. */
	}

	mutex_unlock(&cyapa->state_sync_lock);
	return error;
}

static char *cyapa_state_to_string(struct cyapa *cyapa)
{
	switch (cyapa->state) {
	case CYAPA_STATE_BL_BUSY:
		return "bootloader busy";
	case CYAPA_STATE_BL_IDLE:
		return "bootloader idle";
	case CYAPA_STATE_BL_ACTIVE:
		return "bootloader active";
	case CYAPA_STATE_GEN5_BL:
	case CYAPA_STATE_GEN6_BL:
		return "bootloader";
	case CYAPA_STATE_OP:
	case CYAPA_STATE_GEN5_APP:
	case CYAPA_STATE_GEN6_APP:
		return "operational";  /* Normal valid state. */
	default:
		return "invalid mode";
	}
}

static ssize_t cyapa_show_mode(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	int size;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	size = scnprintf(buf, PAGE_SIZE, "gen%d %s\n",
			cyapa->gen, cyapa_state_to_string(cyapa));

	mutex_unlock(&cyapa->state_sync_lock);
	return size;
}

static DEVICE_ATTR(firmware_version, S_IRUGO, cyapa_show_fm_ver, NULL);
static DEVICE_ATTR(product_id, S_IRUGO, cyapa_show_product_id, NULL);
static DEVICE_ATTR(update_fw, S_IWUSR, NULL, cyapa_update_fw_store);
static DEVICE_ATTR(baseline, S_IRUGO, cyapa_show_baseline, NULL);
static DEVICE_ATTR(calibrate, S_IWUSR, NULL, cyapa_calibrate_store);
static DEVICE_ATTR(mode, S_IRUGO, cyapa_show_mode, NULL);

static struct attribute *cyapa_sysfs_entries[] = {
	&dev_attr_firmware_version.attr,
	&dev_attr_product_id.attr,
	&dev_attr_update_fw.attr,
	&dev_attr_baseline.attr,
	&dev_attr_calibrate.attr,
	&dev_attr_mode.attr,
	NULL,
};

static const struct attribute_group cyapa_sysfs_group = {
	.attrs = cyapa_sysfs_entries,
};

static void cyapa_remove_sysfs_group(void *data)
{
	struct cyapa *cyapa = data;

	sysfs_remove_group(&cyapa->client->dev.kobj, &cyapa_sysfs_group);
}

static void cyapa_disable_regulator(void *data)
{
	struct cyapa *cyapa = data;

	regulator_disable(cyapa->vcc);
}

static int cyapa_probe(struct i2c_client *client,
		       const struct i2c_device_id *dev_id)
{
	struct device *dev = &client->dev;
	struct cyapa *cyapa;
	u8 adapter_func;
	union i2c_smbus_data dummy;
	int error;

	adapter_func = cyapa_check_adapter_functionality(client);
	if (adapter_func == CYAPA_ADAPTER_FUNC_NONE) {
		dev_err(dev, "not a supported I2C/SMBus adapter\n");
		return -EIO;
	}

	/* Make sure there is something at this address */
	if (i2c_smbus_xfer(client->adapter, client->addr, 0,
			I2C_SMBUS_READ, 0, I2C_SMBUS_BYTE, &dummy) < 0)
		return -ENODEV;

	cyapa = devm_kzalloc(dev, sizeof(struct cyapa), GFP_KERNEL);
	if (!cyapa)
		return -ENOMEM;

	/* i2c isn't supported, use smbus */
	if (adapter_func == CYAPA_ADAPTER_FUNC_SMBUS)
		cyapa->smbus = true;

	cyapa->client = client;
	i2c_set_clientdata(client, cyapa);
	sprintf(cyapa->phys, "i2c-%d-%04x/input0", client->adapter->nr,
		client->addr);

	cyapa->vcc = devm_regulator_get(dev, "vcc");
	if (IS_ERR(cyapa->vcc)) {
		error = PTR_ERR(cyapa->vcc);
		dev_err(dev, "failed to get vcc regulator: %d\n", error);
		return error;
	}

	error = regulator_enable(cyapa->vcc);
	if (error) {
		dev_err(dev, "failed to enable regulator: %d\n", error);
		return error;
	}

	error = devm_add_action(dev, cyapa_disable_regulator, cyapa);
	if (error) {
		cyapa_disable_regulator(cyapa);
		dev_err(dev, "failed to add disable regulator action: %d\n",
			error);
		return error;
	}

	error = cyapa_initialize(cyapa);
	if (error) {
		dev_err(dev, "failed to detect and initialize tp device.\n");
		return error;
	}

	error = sysfs_create_group(&client->dev.kobj, &cyapa_sysfs_group);
	if (error) {
		dev_err(dev, "failed to create sysfs entries: %d\n", error);
		return error;
	}

	error = devm_add_action(dev, cyapa_remove_sysfs_group, cyapa);
	if (error) {
		cyapa_remove_sysfs_group(cyapa);
		dev_err(dev, "failed to add sysfs cleanup action: %d\n", error);
		return error;
	}

	error = cyapa_prepare_wakeup_controls(cyapa);
	if (error) {
		dev_err(dev, "failed to prepare wakeup controls: %d\n", error);
		return error;
	}

	error = cyapa_start_runtime(cyapa);
	if (error) {
		dev_err(dev, "failed to start pm_runtime: %d\n", error);
		return error;
	}

	error = devm_request_threaded_irq(dev, client->irq,
					  NULL, cyapa_irq,
					  IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
					  "cyapa", cyapa);
	if (error) {
		dev_err(dev, "failed to request threaded irq: %d\n", error);
		return error;
	}

	/* Disable IRQ until the device is opened */
	disable_irq(client->irq);

	/*
	 * Register the device in the input subsystem when it's operational.
	 * Otherwise, keep in this driver, so it can be be recovered or updated
	 * through the sysfs mode and update_fw interfaces by user or apps.
	 */
	if (cyapa->operational) {
		error = cyapa_create_input_dev(cyapa);
		if (error) {
			dev_err(dev, "create input_dev instance failed: %d\n",
					error);
			return error;
		}
	}

	return 0;
}

static int __maybe_unused cyapa_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct cyapa *cyapa = i2c_get_clientdata(client);
	u8 power_mode;
	int error;

	error = mutex_lock_interruptible(&cyapa->state_sync_lock);
	if (error)
		return error;

	/*
	 * Runtime PM is enable only when device is in operational mode and
	 * users in use, so need check it before disable it to
	 * avoid unbalance warning.
	 */
	if (pm_runtime_enabled(dev))
		pm_runtime_disable(dev);
	disable_irq(client->irq);

	/*
	 * Set trackpad device to idle mode if wakeup is allowed,
	 * otherwise turn off.
	 */
	if (cyapa->operational) {
		power_mode = device_may_wakeup(dev) ? cyapa->suspend_power_mode
						    : PWR_MODE_OFF;
		error = cyapa->ops->set_power_mode(cyapa, power_mode,
				cyapa->suspend_sleep_time, true);
		if (error)
			dev_err(dev, "suspend set power mode failed: %d\n",
					error);
	}

	/*
	 * Disable proximity interrupt when system idle, want true touch to
	 * wake the system.
	 */
	if (cyapa->dev_pwr_mode != PWR_MODE_OFF)
		cyapa->ops->set_proximity(cyapa, false);

	if (device_may_wakeup(dev))
		cyapa->irq_wake = (enable_irq_wake(client->irq) == 0);

	mutex_unlock(&cyapa->state_sync_lock);
	return 0;
}

static int __maybe_unused cyapa_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct cyapa *cyapa = i2c_get_clientdata(client);
	int error;

	mutex_lock(&cyapa->state_sync_lock);

	if (device_may_wakeup(dev) && cyapa->irq_wake) {
		disable_irq_wake(client->irq);
		cyapa->irq_wake = false;
	}

	/*
	 * Update device states and runtime PM states.
	 * Re-Enable proximity interrupt after enter operational mode.
	 */
	error = cyapa_reinitialize(cyapa);
	if (error)
		dev_warn(dev, "failed to reinitialize TP device: %d\n", error);

	enable_irq(client->irq);

	mutex_unlock(&cyapa->state_sync_lock);
	return 0;
}

static int __maybe_unused cyapa_runtime_suspend(struct device *dev)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	int error;

	error = cyapa->ops->set_power_mode(cyapa,
			cyapa->runtime_suspend_power_mode,
			cyapa->runtime_suspend_sleep_time,
			false);
	if (error)
		dev_warn(dev, "runtime suspend failed: %d\n", error);

	return 0;
}

static int __maybe_unused cyapa_runtime_resume(struct device *dev)
{
	struct cyapa *cyapa = dev_get_drvdata(dev);
	int error;

	error = cyapa->ops->set_power_mode(cyapa,
					   PWR_MODE_FULL_ACTIVE, 0, false);
	if (error)
		dev_warn(dev, "runtime resume failed: %d\n", error);

	return 0;
}

static const struct dev_pm_ops cyapa_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(cyapa_suspend, cyapa_resume)
	SET_RUNTIME_PM_OPS(cyapa_runtime_suspend, cyapa_runtime_resume, NULL)
};

static const struct i2c_device_id cyapa_id_table[] = {
	{ "cyapa", 0 },
	{ },
};
MODULE_DEVICE_TABLE(i2c, cyapa_id_table);

#ifdef CONFIG_ACPI
static const struct acpi_device_id cyapa_acpi_id[] = {
	{ "CYAP0000", 0 },  /* Gen3 trackpad with 0x67 I2C address. */
	{ "CYAP0001", 0 },  /* Gen5 trackpad with 0x24 I2C address. */
	{ "CYAP0002", 0 },  /* Gen6 trackpad with 0x24 I2C address. */
	{ }
};
MODULE_DEVICE_TABLE(acpi, cyapa_acpi_id);
#endif

#ifdef CONFIG_OF
static const struct of_device_id cyapa_of_match[] = {
	{ .compatible = "cypress,cyapa" },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, cyapa_of_match);
#endif

static struct i2c_driver cyapa_driver = {
	.driver = {
		.name = "cyapa",
		.pm = &cyapa_pm_ops,
		.acpi_match_table = ACPI_PTR(cyapa_acpi_id),
		.of_match_table = of_match_ptr(cyapa_of_match),
	},

	.probe = cyapa_probe,
	.id_table = cyapa_id_table,
};

module_i2c_driver(cyapa_driver);

MODULE_DESCRIPTION("Cypress APA I2C Trackpad Driver");
MODULE_AUTHOR("Dudley Du <dudl@cypress.com>");
MODULE_LICENSE("GPL");