root/drivers/input/mouse/elan_i2c_core.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Elan I2C/SMBus Touchpad driver
 *
 * Copyright (c) 2013 ELAN Microelectronics Corp.
 *
 * Author: 林政維 (Duson Lin) <dusonlin@emc.com.tw>
 * Author: KT Liao <kt.liao@emc.com.tw>
 * Version: 1.6.3
 *
 * Based on cyapa driver:
 * copyright (c) 2011-2012 Cypress Semiconductor, Inc.
 * copyright (c) 2011-2012 Google, Inc.
 *
 * Trademarks are the property of their respective owners.
 */

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/firmware.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/input/mt.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string_choices.h>
#include <linux/input.h>
#include <linux/uaccess.h>
#include <linux/jiffies.h>
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/pm_wakeirq.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/unaligned.h>

#include "elan_i2c.h"

#define DRIVER_NAME             "elan_i2c"
#define ELAN_VENDOR_ID          0x04f3
#define ETP_MAX_PRESSURE        255
#define ETP_FWIDTH_REDUCE       90
#define ETP_FINGER_WIDTH        15
#define ETP_RETRY_COUNT         3

/* quirks to control the device */
#define ETP_QUIRK_QUICK_WAKEUP  BIT(0)

/* The main device structure */
struct elan_tp_data {
        struct i2c_client       *client;
        struct input_dev        *input;
        struct input_dev        *tp_input; /* trackpoint input node */
        struct regulator        *vcc;

        const struct elan_transport_ops *ops;

        /* for fw update */
        struct completion       fw_completion;
        bool                    in_fw_update;

        struct mutex            sysfs_mutex;

        unsigned int            max_x;
        unsigned int            max_y;
        unsigned int            width_x;
        unsigned int            width_y;
        unsigned int            x_res;
        unsigned int            y_res;

        u8                      pattern;
        u16                     product_id;
        u8                      fw_version;
        u8                      sm_version;
        u8                      iap_version;
        u16                     fw_checksum;
        unsigned int            report_features;
        unsigned int            report_len;
        int                     pressure_adjustment;
        u8                      mode;
        u16                     ic_type;
        u16                     fw_validpage_count;
        u16                     fw_page_size;
        u32                     fw_signature_address;

        u8                      min_baseline;
        u8                      max_baseline;
        bool                    baseline_ready;
        u8                      clickpad;
        bool                    middle_button;

        u32                     quirks;         /* Various quirks */
};

static u32 elan_i2c_lookup_quirks(u16 ic_type, u16 product_id)
{
        static const struct {
                u16 ic_type;
                u16 product_id;
                u32 quirks;
        } elan_i2c_quirks[] = {
                { 0x0D, ETP_PRODUCT_ID_DELBIN, ETP_QUIRK_QUICK_WAKEUP },
                { 0x0D, ETP_PRODUCT_ID_WHITEBOX, ETP_QUIRK_QUICK_WAKEUP },
                { 0x10, ETP_PRODUCT_ID_VOXEL, ETP_QUIRK_QUICK_WAKEUP },
                { 0x14, ETP_PRODUCT_ID_MAGPIE, ETP_QUIRK_QUICK_WAKEUP },
                { 0x14, ETP_PRODUCT_ID_BOBBA, ETP_QUIRK_QUICK_WAKEUP },
        };
        u32 quirks = 0;
        int i;

        for (i = 0; i < ARRAY_SIZE(elan_i2c_quirks); i++) {
                if (elan_i2c_quirks[i].ic_type == ic_type &&
                    elan_i2c_quirks[i].product_id == product_id) {
                        quirks = elan_i2c_quirks[i].quirks;
                }
        }

        if (ic_type >= 0x0D && product_id >= 0x123)
                quirks |= ETP_QUIRK_QUICK_WAKEUP;

        return quirks;
}

static int elan_get_fwinfo(u16 ic_type, u8 iap_version, u16 *validpage_count,
                           u32 *signature_address, u16 *page_size)
{
        switch (ic_type) {
        case 0x00:
        case 0x06:
        case 0x08:
                *validpage_count = 512;
                break;
        case 0x03:
        case 0x07:
        case 0x09:
        case 0x0A:
        case 0x0B:
        case 0x0C:
                *validpage_count = 768;
                break;
        case 0x0D:
                *validpage_count = 896;
                break;
        case 0x0E:
                *validpage_count = 640;
                break;
        case 0x10:
                *validpage_count = 1024;
                break;
        case 0x11:
                *validpage_count = 1280;
                break;
        case 0x13:
                *validpage_count = 2048;
                break;
        case 0x14:
        case 0x15:
                *validpage_count = 1024;
                break;
        case 0x19:
                *validpage_count = 2032;
                break;
        default:
                /* unknown ic type clear value */
                *validpage_count = 0;
                *signature_address = 0;
                *page_size = 0;
                return -ENXIO;
        }

        *signature_address =
                (*validpage_count * ETP_FW_PAGE_SIZE) - ETP_FW_SIGNATURE_SIZE;

        if ((ic_type == 0x14 || ic_type == 0x15) && iap_version >= 2) {
                *validpage_count /= 8;
                *page_size = ETP_FW_PAGE_SIZE_512;
        } else if (ic_type >= 0x0D && iap_version >= 1) {
                *validpage_count /= 2;
                *page_size = ETP_FW_PAGE_SIZE_128;
        } else {
                *page_size = ETP_FW_PAGE_SIZE;
        }

        return 0;
}

static int elan_set_power(struct elan_tp_data *data, bool on)
{
        int repeat = ETP_RETRY_COUNT;
        int error;

        do {
                error = data->ops->power_control(data->client, on);
                if (error >= 0)
                        return 0;

                msleep(30);
        } while (--repeat > 0);

        dev_err(&data->client->dev, "failed to set power %s: %d\n",
                str_on_off(on), error);
        return error;
}

static int elan_sleep(struct elan_tp_data *data)
{
        int repeat = ETP_RETRY_COUNT;
        int error;

        do {
                error = data->ops->sleep_control(data->client, true);
                if (!error)
                        return 0;

                msleep(30);
        } while (--repeat > 0);

        return error;
}

static int elan_query_product(struct elan_tp_data *data)
{
        int error;

        error = data->ops->get_product_id(data->client, &data->product_id);
        if (error)
                return error;

        error = data->ops->get_pattern(data->client, &data->pattern);
        if (error)
                return error;

        error = data->ops->get_sm_version(data->client, data->pattern,
                                          &data->ic_type, &data->sm_version,
                                          &data->clickpad);
        if (error)
                return error;

        return 0;
}

static int elan_check_ASUS_special_fw(struct elan_tp_data *data)
{
        if (data->ic_type == 0x0E) {
                switch (data->product_id) {
                case 0x05 ... 0x07:
                case 0x09:
                case 0x13:
                        return true;
                }
        } else if (data->ic_type == 0x08 && data->product_id == 0x26) {
                /* ASUS EeeBook X205TA */
                return true;
        }

        return false;
}

static int __elan_initialize(struct elan_tp_data *data, bool skip_reset)
{
        struct i2c_client *client = data->client;
        bool woken_up = false;
        int error;

        if (!skip_reset) {
                error = data->ops->initialize(client);
                if (error) {
                        dev_err(&client->dev, "device initialize failed: %d\n", error);
                        return error;
                }
        }

        error = elan_query_product(data);
        if (error)
                return error;

        /*
         * Some ASUS devices were shipped with firmware that requires
         * touchpads to be woken up first, before attempting to switch
         * them into absolute reporting mode.
         */
        if (elan_check_ASUS_special_fw(data)) {
                error = data->ops->sleep_control(client, false);
                if (error) {
                        dev_err(&client->dev,
                                "failed to wake device up: %d\n", error);
                        return error;
                }

                msleep(200);
                woken_up = true;
        }

        data->mode |= ETP_ENABLE_ABS;
        error = data->ops->set_mode(client, data->mode);
        if (error) {
                dev_err(&client->dev,
                        "failed to switch to absolute mode: %d\n", error);
                return error;
        }

        if (!woken_up) {
                error = data->ops->sleep_control(client, false);
                if (error) {
                        dev_err(&client->dev,
                                "failed to wake device up: %d\n", error);
                        return error;
                }
        }

        return 0;
}

static int elan_initialize(struct elan_tp_data *data, bool skip_reset)
{
        int repeat = ETP_RETRY_COUNT;
        int error;

        do {
                error = __elan_initialize(data, skip_reset);
                if (!error)
                        return 0;

                skip_reset = false;
                msleep(30);
        } while (--repeat > 0);

        return error;
}

static int elan_query_device_info(struct elan_tp_data *data)
{
        int error;

        error = data->ops->get_version(data->client, data->pattern, false,
                                       &data->fw_version);
        if (error)
                return error;

        error = data->ops->get_checksum(data->client, false,
                                        &data->fw_checksum);
        if (error)
                return error;

        error = data->ops->get_version(data->client, data->pattern,
                                       true, &data->iap_version);
        if (error)
                return error;

        error = data->ops->get_pressure_adjustment(data->client,
                                                   &data->pressure_adjustment);
        if (error)
                return error;

        error = data->ops->get_report_features(data->client, data->pattern,
                                               &data->report_features,
                                               &data->report_len);
        if (error)
                return error;

        data->quirks = elan_i2c_lookup_quirks(data->ic_type, data->product_id);

        error = elan_get_fwinfo(data->ic_type, data->iap_version,
                                &data->fw_validpage_count,
                                &data->fw_signature_address,
                                &data->fw_page_size);
        if (error)
                dev_warn(&data->client->dev,
                         "unexpected iap version %#04x (ic type: %#04x), firmware update will not work\n",
                         data->iap_version, data->ic_type);

        return 0;
}

static unsigned int elan_convert_resolution(u8 val, u8 pattern)
{
        /*
         * pattern <= 0x01:
         *      (value from firmware) * 10 + 790 = dpi
         * else
         *      ((value from firmware) + 3) * 100 = dpi
         */
        int res = pattern <= 0x01 ?
                (int)(char)val * 10 + 790 : ((int)(char)val + 3) * 100;
        /*
         * We also have to convert dpi to dots/mm (*10/254 to avoid floating
         * point).
         */
        return res * 10 / 254;
}

static int elan_query_device_parameters(struct elan_tp_data *data)
{
        struct i2c_client *client = data->client;
        unsigned int x_traces, y_traces;
        u32 x_mm, y_mm;
        u8 hw_x_res, hw_y_res;
        int error;

        if (device_property_read_u32(&client->dev,
                                     "touchscreen-size-x", &data->max_x) ||
            device_property_read_u32(&client->dev,
                                     "touchscreen-size-y", &data->max_y)) {
                error = data->ops->get_max(data->client,
                                           &data->max_x,
                                           &data->max_y);
                if (error)
                        return error;
        } else {
                /* size is the maximum + 1 */
                --data->max_x;
                --data->max_y;
        }

        if (device_property_read_u32(&client->dev,
                                     "elan,x_traces",
                                     &x_traces) ||
            device_property_read_u32(&client->dev,
                                     "elan,y_traces",
                                     &y_traces)) {
                error = data->ops->get_num_traces(data->client,
                                                  &x_traces, &y_traces);
                if (error)
                        return error;
        }

        if (!x_traces || !y_traces) {
                dev_warn(&client->dev,
                         "invalid trace numbers: x=%u, y=%u\n",
                         x_traces, y_traces);
                data->width_x = 1;
                data->width_y = 1;
        } else {
                data->width_x = data->max_x / x_traces;
                data->width_y = data->max_y / y_traces;
        }

        if (device_property_read_u32(&client->dev,
                                     "touchscreen-x-mm", &x_mm) ||
            device_property_read_u32(&client->dev,
                                     "touchscreen-y-mm", &y_mm)) {
                error = data->ops->get_resolution(data->client,
                                                  &hw_x_res, &hw_y_res);
                if (error)
                        return error;

                data->x_res = elan_convert_resolution(hw_x_res, data->pattern);
                data->y_res = elan_convert_resolution(hw_y_res, data->pattern);
        } else {
                if (unlikely(x_mm == 0 || y_mm == 0)) {
                        dev_warn(&client->dev,
                                 "invalid physical dimensions: x_mm=%u, y_mm=%u\n",
                                 x_mm, y_mm);
                        data->x_res = 1;
                        data->y_res = 1;
                } else {
                        data->x_res = (data->max_x + 1) / x_mm;
                        data->y_res = (data->max_y + 1) / y_mm;
                }
        }

        if (device_property_read_bool(&client->dev, "elan,clickpad"))
                data->clickpad = 1;

        if (device_property_read_bool(&client->dev, "elan,middle-button"))
                data->middle_button = true;

        return 0;
}

/*
 **********************************************************
 * IAP firmware updater related routines
 **********************************************************
 */
static int elan_write_fw_block(struct elan_tp_data *data, u16 page_size,
                               const u8 *page, u16 checksum, int idx)
{
        int retry = ETP_RETRY_COUNT;
        int error;

        do {
                error = data->ops->write_fw_block(data->client, page_size,
                                                  page, checksum, idx);
                if (!error)
                        return 0;

                dev_dbg(&data->client->dev,
                        "IAP retrying page %d (error: %d)\n", idx, error);
        } while (--retry > 0);

        return error;
}

static int __elan_update_firmware(struct elan_tp_data *data,
                                  const struct firmware *fw)
{
        struct i2c_client *client = data->client;
        struct device *dev = &client->dev;
        int i, j;
        int error;
        u16 iap_start_addr;
        u16 boot_page_count;
        u16 sw_checksum = 0, fw_checksum = 0;

        error = data->ops->prepare_fw_update(client, data->ic_type,
                                             data->iap_version,
                                             data->fw_page_size);
        if (error)
                return error;

        iap_start_addr = get_unaligned_le16(&fw->data[ETP_IAP_START_ADDR * 2]);

        boot_page_count = (iap_start_addr * 2) / data->fw_page_size;
        for (i = boot_page_count; i < data->fw_validpage_count; i++) {
                u16 checksum = 0;
                const u8 *page = &fw->data[i * data->fw_page_size];

                for (j = 0; j < data->fw_page_size; j += 2)
                        checksum += ((page[j + 1] << 8) | page[j]);

                error = elan_write_fw_block(data, data->fw_page_size,
                                            page, checksum, i);
                if (error) {
                        dev_err(dev, "write page %d fail: %d\n", i, error);
                        return error;
                }

                sw_checksum += checksum;
        }

        /* Wait WDT reset and power on reset */
        msleep(600);

        error = data->ops->finish_fw_update(client, &data->fw_completion);
        if (error)
                return error;

        error = data->ops->get_checksum(client, true, &fw_checksum);
        if (error)
                return error;

        if (sw_checksum != fw_checksum) {
                dev_err(dev, "checksum diff sw=[%04X], fw=[%04X]\n",
                        sw_checksum, fw_checksum);
                return -EIO;
        }

        return 0;
}

static int elan_update_firmware(struct elan_tp_data *data,
                                const struct firmware *fw)
{
        struct i2c_client *client = data->client;
        int retval;

        dev_dbg(&client->dev, "Starting firmware update....\n");

        guard(disable_irq)(&client->irq);

        data->in_fw_update = true;

        retval = __elan_update_firmware(data, fw);
        if (retval) {
                dev_err(&client->dev, "firmware update failed: %d\n", retval);
                data->ops->iap_reset(client);
        } else {
                /* Reinitialize TP after fw is updated */
                elan_initialize(data, false);
                elan_query_device_info(data);
        }

        data->in_fw_update = false;

        return retval;
}

/*
 *******************************************************************
 * SYSFS attributes
 *******************************************************************
 */
static ssize_t elan_sysfs_read_fw_checksum(struct device *dev,
                                           struct device_attribute *attr,
                                           char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        return sysfs_emit(buf, "0x%04x\n", data->fw_checksum);
}

static ssize_t elan_sysfs_read_product_id(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        return sysfs_emit(buf, ETP_PRODUCT_ID_FORMAT_STRING "\n",
                          data->product_id);
}

static ssize_t elan_sysfs_read_fw_ver(struct device *dev,
                                      struct device_attribute *attr,
                                      char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        return sysfs_emit(buf, "%d.0\n", data->fw_version);
}

static ssize_t elan_sysfs_read_sm_ver(struct device *dev,
                                      struct device_attribute *attr,
                                      char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        return sysfs_emit(buf, "%d.0\n", data->sm_version);
}

static ssize_t elan_sysfs_read_iap_ver(struct device *dev,
                                       struct device_attribute *attr,
                                       char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        return sysfs_emit(buf, "%d.0\n", data->iap_version);
}

static ssize_t elan_sysfs_update_fw(struct device *dev,
                                    struct device_attribute *attr,
                                    const char *buf, size_t count)
{
        struct elan_tp_data *data = dev_get_drvdata(dev);
        int error;
        const u8 *fw_signature;
        static const u8 signature[] = {0xAA, 0x55, 0xCC, 0x33, 0xFF, 0xFF};

        if (data->fw_validpage_count == 0)
                return -EINVAL;

        /* Look for a firmware with the product id appended. */
        const char *fw_name __free(kfree) =
                kasprintf(GFP_KERNEL, ETP_FW_NAME, data->product_id);
        if (!fw_name) {
                dev_err(dev, "failed to allocate memory for firmware name\n");
                return -ENOMEM;
        }

        dev_info(dev, "requesting fw '%s'\n", fw_name);
        const struct firmware *fw __free(firmware) = NULL;
        error = request_firmware(&fw, fw_name, dev);
        if (error) {
                dev_err(dev, "failed to request firmware: %d\n", error);
                return error;
        }

        if (fw->size < data->fw_signature_address + sizeof(signature)) {
                dev_err(dev, "firmware file too small\n");
                return -EBADF;
        }

        /* Firmware file must match signature data */
        fw_signature = &fw->data[data->fw_signature_address];
        if (memcmp(fw_signature, signature, sizeof(signature)) != 0) {
                dev_err(dev, "signature mismatch (expected %*ph, got %*ph)\n",
                        (int)sizeof(signature), signature,
                        (int)sizeof(signature), fw_signature);
                return -EBADF;
        }

        scoped_cond_guard(mutex_intr, return -EINTR, &data->sysfs_mutex) {
                error = elan_update_firmware(data, fw);
                if (error)
                        return error;
        }

        return count;
}

static int elan_calibrate(struct elan_tp_data *data)
{
        struct i2c_client *client = data->client;
        struct device *dev = &client->dev;
        int tries = 20;
        int retval;
        int error;
        u8 val[ETP_CALIBRATE_MAX_LEN];

        guard(disable_irq)(&client->irq);

        data->mode |= ETP_ENABLE_CALIBRATE;
        retval = data->ops->set_mode(client, data->mode);
        if (retval) {
                data->mode &= ~ETP_ENABLE_CALIBRATE;
                dev_err(dev, "failed to enable calibration mode: %d\n",
                        retval);
                return retval;
        }

        retval = data->ops->calibrate(client);
        if (retval) {
                dev_err(dev, "failed to start calibration: %d\n",
                        retval);
                goto out_disable_calibrate;
        }

        val[0] = 0xff;
        do {
                /* Wait 250ms before checking if calibration has completed. */
                msleep(250);

                retval = data->ops->calibrate_result(client, val);
                if (retval)
                        dev_err(dev, "failed to check calibration result: %d\n",
                                retval);
                else if (val[0] == 0)
                        break; /* calibration done */

        } while (--tries);

        if (tries == 0) {
                dev_err(dev, "failed to calibrate. Timeout.\n");
                retval = -ETIMEDOUT;
        }

out_disable_calibrate:
        data->mode &= ~ETP_ENABLE_CALIBRATE;
        error = data->ops->set_mode(data->client, data->mode);
        if (error) {
                dev_err(dev, "failed to disable calibration mode: %d\n",
                        error);
                if (!retval)
                        retval = error;
        }
        return retval;
}

static ssize_t calibrate_store(struct device *dev,
                               struct device_attribute *attr,
                               const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);
        int error;

        scoped_cond_guard(mutex_intr, return -EINTR, &data->sysfs_mutex) {
                error = elan_calibrate(data);
                if (error)
                        return error;
        }

        return count;
}

static ssize_t elan_sysfs_read_mode(struct device *dev,
                                    struct device_attribute *attr,
                                    char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);
        int error;
        enum tp_mode mode;

        scoped_cond_guard(mutex_intr, return -EINTR, &data->sysfs_mutex) {
                error = data->ops->iap_get_mode(data->client, &mode);
                if (error)
                        return error;
        }

        return sysfs_emit(buf, "%d\n", (int)mode);
}

static DEVICE_ATTR(product_id, S_IRUGO, elan_sysfs_read_product_id, NULL);
static DEVICE_ATTR(firmware_version, S_IRUGO, elan_sysfs_read_fw_ver, NULL);
static DEVICE_ATTR(sample_version, S_IRUGO, elan_sysfs_read_sm_ver, NULL);
static DEVICE_ATTR(iap_version, S_IRUGO, elan_sysfs_read_iap_ver, NULL);
static DEVICE_ATTR(fw_checksum, S_IRUGO, elan_sysfs_read_fw_checksum, NULL);
static DEVICE_ATTR(mode, S_IRUGO, elan_sysfs_read_mode, NULL);
static DEVICE_ATTR(update_fw, S_IWUSR, NULL, elan_sysfs_update_fw);

static DEVICE_ATTR_WO(calibrate);

static struct attribute *elan_sysfs_entries[] = {
        &dev_attr_product_id.attr,
        &dev_attr_firmware_version.attr,
        &dev_attr_sample_version.attr,
        &dev_attr_iap_version.attr,
        &dev_attr_fw_checksum.attr,
        &dev_attr_calibrate.attr,
        &dev_attr_mode.attr,
        &dev_attr_update_fw.attr,
        NULL,
};

static const struct attribute_group elan_sysfs_group = {
        .attrs = elan_sysfs_entries,
};

static int elan_acquire_baseline(struct elan_tp_data *data)
{
        struct i2c_client *client = data->client;
        struct device *dev = &client->dev;
        int retval;
        int error;

        guard(disable_irq)(&client->irq);

        data->baseline_ready = false;

        data->mode |= ETP_ENABLE_CALIBRATE;
        retval = data->ops->set_mode(client, data->mode);
        if (retval) {
                data->mode &= ~ETP_ENABLE_CALIBRATE;
                dev_err(dev, "Failed to enable calibration mode to get baseline: %d\n",
                        retval);
                return retval;
        }

        msleep(250);

        retval = data->ops->get_baseline_data(client, true,
                                              &data->max_baseline);
        if (retval) {
                dev_err(dev, "Failed to read max baseline from device: %d\n",
                        retval);
                goto out_disable_calibrate;
        }

        retval = data->ops->get_baseline_data(client, false,
                                              &data->min_baseline);
        if (retval) {
                dev_err(dev, "Failed to read min baseline from device: %d\n",
                        retval);
                goto out_disable_calibrate;
        }

        data->baseline_ready = true;

out_disable_calibrate:
        data->mode &= ~ETP_ENABLE_CALIBRATE;
        error = data->ops->set_mode(client, data->mode);
        if (error) {
                dev_err(dev, "Failed to disable calibration mode after acquiring baseline: %d\n",
                        error);
                if (!retval)
                        retval = error;
        }

        return retval;
}

static ssize_t acquire_store(struct device *dev, struct device_attribute *attr,
                             const char *buf, size_t count)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);
        int error;

        scoped_cond_guard(mutex_intr, return -EINTR, &data->sysfs_mutex) {
                error = elan_acquire_baseline(data);
                if (error)
                        return error;
        }

        return count;
}

static ssize_t min_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        scoped_guard(mutex_intr, &data->sysfs_mutex) {
                if (!data->baseline_ready)
                        return -ENODATA;

                return sysfs_emit(buf, "%d", data->min_baseline);
        }

        return -EINTR;
}

static ssize_t max_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);

        scoped_guard(mutex_intr, &data->sysfs_mutex) {
                if (!data->baseline_ready)
                        return -ENODATA;

                return sysfs_emit(buf, "%d", data->max_baseline);
        }

        return -EINTR;
}

static DEVICE_ATTR_WO(acquire);
static DEVICE_ATTR_RO(min);
static DEVICE_ATTR_RO(max);

static struct attribute *elan_baseline_sysfs_entries[] = {
        &dev_attr_acquire.attr,
        &dev_attr_min.attr,
        &dev_attr_max.attr,
        NULL,
};

static const struct attribute_group elan_baseline_sysfs_group = {
        .name = "baseline",
        .attrs = elan_baseline_sysfs_entries,
};

static const struct attribute_group *elan_sysfs_groups[] = {
        &elan_sysfs_group,
        &elan_baseline_sysfs_group,
        NULL
};

/*
 ******************************************************************
 * Elan isr functions
 ******************************************************************
 */
static void elan_report_contact(struct elan_tp_data *data, int contact_num,
                                bool contact_valid, bool high_precision,
                                u8 *packet, u8 *finger_data)
{
        struct input_dev *input = data->input;
        unsigned int pos_x, pos_y;
        unsigned int pressure, scaled_pressure;

        if (contact_valid) {
                if (high_precision) {
                        pos_x = get_unaligned_be16(&finger_data[0]);
                        pos_y = get_unaligned_be16(&finger_data[2]);
                } else {
                        pos_x = ((finger_data[0] & 0xf0) << 4) | finger_data[1];
                        pos_y = ((finger_data[0] & 0x0f) << 8) | finger_data[2];
                }

                if (pos_x > data->max_x || pos_y > data->max_y) {
                        dev_dbg(input->dev.parent,
                                "[%d] x=%d y=%d over max (%d, %d)",
                                contact_num, pos_x, pos_y,
                                data->max_x, data->max_y);
                        return;
                }

                pressure = finger_data[4];
                scaled_pressure = pressure + data->pressure_adjustment;
                if (scaled_pressure > ETP_MAX_PRESSURE)
                        scaled_pressure = ETP_MAX_PRESSURE;

                input_mt_slot(input, contact_num);
                input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
                input_report_abs(input, ABS_MT_POSITION_X, pos_x);
                input_report_abs(input, ABS_MT_POSITION_Y, data->max_y - pos_y);
                input_report_abs(input, ABS_MT_PRESSURE, scaled_pressure);

                if (data->report_features & ETP_FEATURE_REPORT_MK) {
                        unsigned int mk_x, mk_y, area_x, area_y;
                        int adj_width_x, adj_width_y;
                        u8 mk_data = high_precision ?
                                packet[ETP_MK_DATA_OFFSET + contact_num] :
                                finger_data[3];

                        mk_x = mk_data & 0x0f;
                        mk_y = mk_data >> 4;

                        /*
                         * To avoid treating large finger as palm, let's reduce
                         * the width x and y per trace.
                         */

                        adj_width_x = data->width_x > ETP_FWIDTH_REDUCE ?
                                        data->width_x - ETP_FWIDTH_REDUCE : 0;
                        adj_width_y = data->width_y > ETP_FWIDTH_REDUCE ?
                                        data->width_y - ETP_FWIDTH_REDUCE : 0;

                        area_x = mk_x * adj_width_x;
                        area_y = mk_y * adj_width_y;

                        input_report_abs(input, ABS_TOOL_WIDTH, mk_x);
                        input_report_abs(input, ABS_MT_TOUCH_MAJOR,
                                         max(area_x, area_y));
                        input_report_abs(input, ABS_MT_TOUCH_MINOR,
                                         min(area_x, area_y));
                }
        } else {
                input_mt_slot(input, contact_num);
                input_mt_report_slot_inactive(input);
        }
}

static void elan_report_absolute(struct elan_tp_data *data, u8 *packet,
                                 bool high_precision)
{
        struct input_dev *input = data->input;
        u8 *finger_data = &packet[ETP_FINGER_DATA_OFFSET];
        int i;
        u8 tp_info = packet[ETP_TOUCH_INFO_OFFSET];
        u8 hover_info = packet[ETP_HOVER_INFO_OFFSET];
        bool contact_valid, hover_event;

        pm_wakeup_event(&data->client->dev, 0);

        hover_event = hover_info & BIT(6);

        for (i = 0; i < ETP_MAX_FINGERS; i++) {
                contact_valid = tp_info & BIT(3 + i);
                elan_report_contact(data, i, contact_valid, high_precision,
                                    packet, finger_data);
                if (contact_valid)
                        finger_data += ETP_FINGER_DATA_LEN;
        }

        input_report_key(input, BTN_LEFT,   tp_info & BIT(0));
        input_report_key(input, BTN_MIDDLE, tp_info & BIT(2));
        input_report_key(input, BTN_RIGHT,  tp_info & BIT(1));
        input_report_abs(input, ABS_DISTANCE, hover_event != 0);
        input_mt_report_pointer_emulation(input, true);
        input_sync(input);
}

static void elan_report_trackpoint(struct elan_tp_data *data, u8 *report)
{
        struct input_dev *input = data->tp_input;
        u8 *packet = &report[ETP_REPORT_ID_OFFSET + 1];
        int x, y;

        pm_wakeup_event(&data->client->dev, 0);

        if (!data->tp_input) {
                dev_warn_once(&data->client->dev,
                              "received a trackpoint report while no trackpoint device has been created. Please report upstream.\n");
                return;
        }

        input_report_key(input, BTN_LEFT, packet[0] & 0x01);
        input_report_key(input, BTN_RIGHT, packet[0] & 0x02);
        input_report_key(input, BTN_MIDDLE, packet[0] & 0x04);

        if ((packet[3] & 0x0F) == 0x06) {
                x = packet[4] - (int)((packet[1] ^ 0x80) << 1);
                y = (int)((packet[2] ^ 0x80) << 1) - packet[5];

                input_report_rel(input, REL_X, x);
                input_report_rel(input, REL_Y, y);
        }

        input_sync(input);
}

static irqreturn_t elan_isr(int irq, void *dev_id)
{
        struct elan_tp_data *data = dev_id;
        int error;
        u8 report[ETP_MAX_REPORT_LEN];

        /*
         * When device is connected to i2c bus, when all IAP page writes
         * complete, the driver will receive interrupt and must read
         * 0000 to confirm that IAP is finished.
        */
        if (data->in_fw_update) {
                complete(&data->fw_completion);
                goto out;
        }

        error = data->ops->get_report(data->client, report, data->report_len);
        if (error)
                goto out;

        switch (report[ETP_REPORT_ID_OFFSET]) {
        case ETP_REPORT_ID:
                elan_report_absolute(data, report, false);
                break;
        case ETP_REPORT_ID2:
                elan_report_absolute(data, report, true);
                break;
        case ETP_TP_REPORT_ID:
        case ETP_TP_REPORT_ID2:
                elan_report_trackpoint(data, report);
                break;
        default:
                dev_err(&data->client->dev, "invalid report id data (%x)\n",
                        report[ETP_REPORT_ID_OFFSET]);
        }

out:
        return IRQ_HANDLED;
}

/*
 ******************************************************************
 * Elan initialization functions
 ******************************************************************
 */

static int elan_setup_trackpoint_input_device(struct elan_tp_data *data)
{
        struct device *dev = &data->client->dev;
        struct input_dev *input;

        input = devm_input_allocate_device(dev);
        if (!input)
                return -ENOMEM;

        input->name = "Elan TrackPoint";
        input->id.bustype = BUS_I2C;
        input->id.vendor = ELAN_VENDOR_ID;
        input->id.product = data->product_id;
        input_set_drvdata(input, data);

        input_set_capability(input, EV_REL, REL_X);
        input_set_capability(input, EV_REL, REL_Y);
        input_set_capability(input, EV_KEY, BTN_LEFT);
        input_set_capability(input, EV_KEY, BTN_RIGHT);
        input_set_capability(input, EV_KEY, BTN_MIDDLE);

        __set_bit(INPUT_PROP_POINTER, input->propbit);
        __set_bit(INPUT_PROP_POINTING_STICK, input->propbit);

        data->tp_input = input;

        return 0;
}

static int elan_setup_input_device(struct elan_tp_data *data)
{
        struct device *dev = &data->client->dev;
        struct input_dev *input;
        unsigned int max_width = max(data->width_x, data->width_y);
        unsigned int min_width = min(data->width_x, data->width_y);
        int error;

        input = devm_input_allocate_device(dev);
        if (!input)
                return -ENOMEM;

        input->name = "Elan Touchpad";
        input->id.bustype = BUS_I2C;
        input->id.vendor = ELAN_VENDOR_ID;
        input->id.product = data->product_id;
        input_set_drvdata(input, data);

        error = input_mt_init_slots(input, ETP_MAX_FINGERS,
                                    INPUT_MT_POINTER | INPUT_MT_DROP_UNUSED);
        if (error) {
                dev_err(dev, "failed to initialize MT slots: %d\n", error);
                return error;
        }

        __set_bit(EV_ABS, input->evbit);
        __set_bit(INPUT_PROP_POINTER, input->propbit);
        if (data->clickpad) {
                __set_bit(INPUT_PROP_BUTTONPAD, input->propbit);
        } else {
                __set_bit(BTN_RIGHT, input->keybit);
                if (data->middle_button)
                        __set_bit(BTN_MIDDLE, input->keybit);
        }
        __set_bit(BTN_LEFT, input->keybit);

        /* Set up ST parameters */
        input_set_abs_params(input, ABS_X, 0, data->max_x, 0, 0);
        input_set_abs_params(input, ABS_Y, 0, data->max_y, 0, 0);
        input_abs_set_res(input, ABS_X, data->x_res);
        input_abs_set_res(input, ABS_Y, data->y_res);
        input_set_abs_params(input, ABS_PRESSURE, 0, ETP_MAX_PRESSURE, 0, 0);
        if (data->report_features & ETP_FEATURE_REPORT_MK)
                input_set_abs_params(input, ABS_TOOL_WIDTH,
                                     0, ETP_FINGER_WIDTH, 0, 0);
        input_set_abs_params(input, ABS_DISTANCE, 0, 1, 0, 0);

        /* And MT parameters */
        input_set_abs_params(input, ABS_MT_POSITION_X, 0, data->max_x, 0, 0);
        input_set_abs_params(input, ABS_MT_POSITION_Y, 0, data->max_y, 0, 0);
        input_abs_set_res(input, ABS_MT_POSITION_X, data->x_res);
        input_abs_set_res(input, ABS_MT_POSITION_Y, data->y_res);
        input_set_abs_params(input, ABS_MT_PRESSURE, 0,
                             ETP_MAX_PRESSURE, 0, 0);
        if (data->report_features & ETP_FEATURE_REPORT_MK) {
                input_set_abs_params(input, ABS_MT_TOUCH_MAJOR,
                                     0, ETP_FINGER_WIDTH * max_width, 0, 0);
                input_set_abs_params(input, ABS_MT_TOUCH_MINOR,
                                     0, ETP_FINGER_WIDTH * min_width, 0, 0);
        }

        data->input = input;

        return 0;
}

static void elan_disable_regulator(void *_data)
{
        struct elan_tp_data *data = _data;

        regulator_disable(data->vcc);
}

static int elan_probe(struct i2c_client *client)
{
        const struct elan_transport_ops *transport_ops;
        struct device *dev = &client->dev;
        struct elan_tp_data *data;
        unsigned long irqflags;
        int error;

        if (IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_I2C) &&
            i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                transport_ops = &elan_i2c_ops;
        } else if (IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) &&
                   i2c_check_functionality(client->adapter,
                                           I2C_FUNC_SMBUS_BYTE_DATA |
                                                I2C_FUNC_SMBUS_BLOCK_DATA |
                                                I2C_FUNC_SMBUS_I2C_BLOCK)) {
                transport_ops = &elan_smbus_ops;
        } else {
                dev_err(dev, "not a supported I2C/SMBus adapter\n");
                return -EIO;
        }

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

        i2c_set_clientdata(client, data);

        data->ops = transport_ops;
        data->client = client;
        init_completion(&data->fw_completion);
        mutex_init(&data->sysfs_mutex);

        data->vcc = devm_regulator_get(dev, "vcc");
        if (IS_ERR(data->vcc))
                return dev_err_probe(dev, PTR_ERR(data->vcc), "Failed to get 'vcc' regulator\n");

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

        error = devm_add_action_or_reset(dev, elan_disable_regulator, data);
        if (error) {
                dev_err(dev, "Failed to add disable regulator action: %d\n",
                        error);
                return error;
        }

        /* Make sure there is something at this address */
        error = i2c_smbus_read_byte(client);
        if (error < 0) {
                dev_dbg(&client->dev, "nothing at this address: %d\n", error);
                return -ENXIO;
        }

        /* Initialize the touchpad. */
        error = elan_initialize(data, false);
        if (error)
                return error;

        error = elan_query_device_info(data);
        if (error)
                return error;

        error = elan_query_device_parameters(data);
        if (error)
                return error;

        dev_info(dev,
                 "Elan Touchpad: Module ID: 0x%04x, Firmware: 0x%04x, Sample: 0x%04x, IAP: 0x%04x\n",
                 data->product_id,
                 data->fw_version,
                 data->sm_version,
                 data->iap_version);

        dev_dbg(dev,
                "Elan Touchpad Extra Information:\n"
                "    Max ABS X,Y:   %d,%d\n"
                "    Width X,Y:   %d,%d\n"
                "    Resolution X,Y:   %d,%d (dots/mm)\n"
                "    ic type: 0x%x\n"
                "    info pattern: 0x%x\n",
                data->max_x, data->max_y,
                data->width_x, data->width_y,
                data->x_res, data->y_res,
                data->ic_type, data->pattern);

        /* Set up input device properties based on queried parameters. */
        error = elan_setup_input_device(data);
        if (error)
                return error;

        if (device_property_read_bool(&client->dev, "elan,trackpoint")) {
                error = elan_setup_trackpoint_input_device(data);
                if (error)
                        return error;
        }

        /*
         * Platform code (ACPI, DTS) should normally set up interrupt
         * for us, but in case it did not let's fall back to using falling
         * edge to be compatible with older Chromebooks.
         */
        irqflags = irq_get_trigger_type(client->irq);
        if (!irqflags)
                irqflags = IRQF_TRIGGER_FALLING;

        error = devm_request_threaded_irq(dev, client->irq, NULL, elan_isr,
                                          irqflags | IRQF_ONESHOT,
                                          client->name, data);
        if (error) {
                dev_err(dev, "cannot register irq=%d\n", client->irq);
                return error;
        }

        error = input_register_device(data->input);
        if (error) {
                dev_err(dev, "failed to register input device: %d\n", error);
                return error;
        }

        if (data->tp_input) {
                error = input_register_device(data->tp_input);
                if (error) {
                        dev_err(&client->dev,
                                "failed to register TrackPoint input device: %d\n",
                                error);
                        return error;
                }
        }

        return 0;
}

static int __elan_suspend(struct elan_tp_data *data)
{
        struct i2c_client *client = data->client;
        int error;

        if (device_may_wakeup(&client->dev))
                return elan_sleep(data);

        /* Touchpad is not a wakeup source */
        error = elan_set_power(data, false);
        if (error)
                return error;

        error = regulator_disable(data->vcc);
        if (error) {
                dev_err(&client->dev,
                        "failed to disable regulator when suspending: %d\n",
                        error);
                /* Attempt to power the chip back up */
                elan_set_power(data, true);
                return error;
        }

        return 0;
}

static int elan_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);
        int error;

        /*
         * We are taking the mutex to make sure sysfs operations are
         * complete before we attempt to bring the device into low[er]
         * power mode.
         */
        scoped_cond_guard(mutex_intr, return -EINTR, &data->sysfs_mutex) {
                disable_irq(client->irq);

                error = __elan_suspend(data);
                if (error) {
                        enable_irq(client->irq);
                        return error;
                }
        }

        return 0;
}

static int elan_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct elan_tp_data *data = i2c_get_clientdata(client);
        int error;

        if (!device_may_wakeup(dev)) {
                error = regulator_enable(data->vcc);
                if (error) {
                        dev_err(dev, "error %d enabling regulator\n", error);
                        goto err;
                }
        }

        error = elan_set_power(data, true);
        if (error) {
                dev_err(dev, "power up when resuming failed: %d\n", error);
                goto err;
        }

        error = elan_initialize(data, data->quirks & ETP_QUIRK_QUICK_WAKEUP);
        if (error)
                dev_err(dev, "initialize when resuming failed: %d\n", error);

err:
        enable_irq(data->client->irq);
        return error;
}

static DEFINE_SIMPLE_DEV_PM_OPS(elan_pm_ops, elan_suspend, elan_resume);

static const struct i2c_device_id elan_id[] = {
        { .name = DRIVER_NAME },
        { }
};
MODULE_DEVICE_TABLE(i2c, elan_id);

#ifdef CONFIG_ACPI
#include <linux/input/elan-i2c-ids.h>
MODULE_DEVICE_TABLE(acpi, elan_acpi_id);
#endif

#ifdef CONFIG_OF
static const struct of_device_id elan_of_match[] = {
        { .compatible = "elan,ekth3000" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, elan_of_match);
#endif

static struct i2c_driver elan_driver = {
        .driver = {
                .name   = DRIVER_NAME,
                .pm     = pm_sleep_ptr(&elan_pm_ops),
                .acpi_match_table = ACPI_PTR(elan_acpi_id),
                .of_match_table = of_match_ptr(elan_of_match),
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
                .dev_groups = elan_sysfs_groups,
        },
        .probe          = elan_probe,
        .id_table       = elan_id,
};

module_i2c_driver(elan_driver);

MODULE_AUTHOR("Duson Lin <dusonlin@emc.com.tw>");
MODULE_DESCRIPTION("Elan I2C/SMBus Touchpad driver");
MODULE_LICENSE("GPL");