/*
 * 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
 * @reg: 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, CYAPA_PM_ACTIVE);
                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, CYAPA_PM_DEACTIVE);

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

/*
 * 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, CYAPA_PM_ACTIVE);

        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, CYAPA_PM_ACTIVE);

        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_device_enabled(input)) {
                /* 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, CYAPA_PM_DEACTIVE);
        } 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;
        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(&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_or_reset(dev,
                                cyapa_remove_power_wakeup_group, cyapa);
                if (error) {
                        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_or_reset(dev, cyapa_remove_power_runtime_group,
                                         cyapa);
        if (error) {
                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_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_or_reset(dev, cyapa_disable_regulator, cyapa);
        if (error) {
                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 = devm_device_add_group(dev, &cyapa_sysfs_group);
        if (error) {
                dev_err(dev, "failed to create sysfs entries: %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, CYAPA_PM_SUSPEND);
                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,
                        CYAPA_PM_RUNTIME_SUSPEND);
        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, CYAPA_PM_RUNTIME_RESUME);
        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");