// SPDX-License-Identifier: GPL-2.0-only
/*
 * Elan I2C/SMBus Touchpad driver - I2C interface
 *
 * Copyright (c) 2013 ELAN Microelectronics Corp.
 *
 * Author: 林政維 (Duson Lin) <dusonlin@emc.com.tw>
 *
 * 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/completion.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/unaligned.h>

#include "elan_i2c.h"

/* Elan i2c commands */
#define ETP_I2C_RESET                   0x0100
#define ETP_I2C_WAKE_UP                 0x0800
#define ETP_I2C_SLEEP                   0x0801
#define ETP_I2C_DESC_CMD                0x0001
#define ETP_I2C_REPORT_DESC_CMD         0x0002
#define ETP_I2C_STAND_CMD               0x0005
#define ETP_I2C_PATTERN_CMD             0x0100
#define ETP_I2C_UNIQUEID_CMD            0x0101
#define ETP_I2C_FW_VERSION_CMD          0x0102
#define ETP_I2C_IC_TYPE_CMD             0x0103
#define ETP_I2C_OSM_VERSION_CMD         0x0103
#define ETP_I2C_NSM_VERSION_CMD         0x0104
#define ETP_I2C_XY_TRACENUM_CMD         0x0105
#define ETP_I2C_MAX_X_AXIS_CMD          0x0106
#define ETP_I2C_MAX_Y_AXIS_CMD          0x0107
#define ETP_I2C_RESOLUTION_CMD          0x0108
#define ETP_I2C_PRESSURE_CMD            0x010A
#define ETP_I2C_IAP_VERSION_CMD         0x0110
#define ETP_I2C_IC_TYPE_P0_CMD          0x0110
#define ETP_I2C_IAP_VERSION_P0_CMD      0x0111
#define ETP_I2C_SET_CMD                 0x0300
#define ETP_I2C_POWER_CMD               0x0307
#define ETP_I2C_FW_CHECKSUM_CMD         0x030F
#define ETP_I2C_IAP_CTRL_CMD            0x0310
#define ETP_I2C_IAP_CMD                 0x0311
#define ETP_I2C_IAP_RESET_CMD           0x0314
#define ETP_I2C_IAP_CHECKSUM_CMD        0x0315
#define ETP_I2C_CALIBRATE_CMD           0x0316
#define ETP_I2C_MAX_BASELINE_CMD        0x0317
#define ETP_I2C_MIN_BASELINE_CMD        0x0318
#define ETP_I2C_IAP_TYPE_REG            0x0040
#define ETP_I2C_IAP_TYPE_CMD            0x0304

#define ETP_I2C_REPORT_LEN              34
#define ETP_I2C_REPORT_LEN_ID2          39
#define ETP_I2C_REPORT_MAX_LEN          39
#define ETP_I2C_DESC_LENGTH             30
#define ETP_I2C_REPORT_DESC_LENGTH      158
#define ETP_I2C_INF_LENGTH              2
#define ETP_I2C_IAP_PASSWORD            0x1EA5
#define ETP_I2C_IAP_RESET               0xF0F0
#define ETP_I2C_MAIN_MODE_ON            (1 << 9)
#define ETP_I2C_IAP_REG_L               0x01
#define ETP_I2C_IAP_REG_H               0x06

static int elan_i2c_read_block(struct i2c_client *client,
                               u16 reg, u8 *val, u16 len)
{
        __le16 buf[] = {
                cpu_to_le16(reg),
        };
        struct i2c_msg msgs[] = {
                {
                        .addr = client->addr,
                        .flags = client->flags & I2C_M_TEN,
                        .len = sizeof(buf),
                        .buf = (u8 *)buf,
                },
                {
                        .addr = client->addr,
                        .flags = (client->flags & I2C_M_TEN) | I2C_M_RD,
                        .len = len,
                        .buf = val,
                }
        };
        int ret;

        ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
        return ret == ARRAY_SIZE(msgs) ? 0 : (ret < 0 ? ret : -EIO);
}

static int elan_i2c_read_cmd(struct i2c_client *client, u16 reg, u8 *val)
{
        int retval;

        retval = elan_i2c_read_block(client, reg, val, ETP_I2C_INF_LENGTH);
        if (retval < 0) {
                dev_err(&client->dev, "reading cmd (0x%04x) fail.\n", reg);
                return retval;
        }

        return 0;
}

static int elan_i2c_write_cmd(struct i2c_client *client, u16 reg, u16 cmd)
{
        __le16 buf[] = {
                cpu_to_le16(reg),
                cpu_to_le16(cmd),
        };
        struct i2c_msg msg = {
                .addr = client->addr,
                .flags = client->flags & I2C_M_TEN,
                .len = sizeof(buf),
                .buf = (u8 *)buf,
        };
        int ret;

        ret = i2c_transfer(client->adapter, &msg, 1);
        if (ret != 1) {
                if (ret >= 0)
                        ret = -EIO;
                dev_err(&client->dev, "writing cmd (0x%04x) failed: %d\n",
                        reg, ret);
                return ret;
        }

        return 0;
}

static int elan_i2c_initialize(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        int error;
        u8 val[256];

        error = elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD, ETP_I2C_RESET);
        if (error) {
                dev_err(dev, "device reset failed: %d\n", error);
                return error;
        }

        /* Wait for the device to reset */
        msleep(100);

        /* get reset acknowledgement 0000 */
        error = i2c_master_recv(client, val, ETP_I2C_INF_LENGTH);
        if (error < 0) {
                dev_err(dev, "failed to read reset response: %d\n", error);
                return error;
        }

        error = elan_i2c_read_block(client, ETP_I2C_DESC_CMD,
                                    val, ETP_I2C_DESC_LENGTH);
        if (error) {
                dev_err(dev, "cannot get device descriptor: %d\n", error);
                return error;
        }

        error = elan_i2c_read_block(client, ETP_I2C_REPORT_DESC_CMD,
                                    val, ETP_I2C_REPORT_DESC_LENGTH);
        if (error) {
                dev_err(dev, "fetching report descriptor failed.: %d\n", error);
                return error;
        }

        return 0;
}

static int elan_i2c_sleep_control(struct i2c_client *client, bool sleep)
{
        return elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD,
                                  sleep ? ETP_I2C_SLEEP : ETP_I2C_WAKE_UP);
}

static int elan_i2c_power_control(struct i2c_client *client, bool enable)
{
        u8 val[2];
        u16 reg;
        int error;

        error = elan_i2c_read_cmd(client, ETP_I2C_POWER_CMD, val);
        if (error) {
                dev_err(&client->dev,
                        "failed to read current power state: %d\n",
                        error);
                return error;
        }

        reg = le16_to_cpup((__le16 *)val);
        if (enable)
                reg &= ~ETP_DISABLE_POWER;
        else
                reg |= ETP_DISABLE_POWER;

        error = elan_i2c_write_cmd(client, ETP_I2C_POWER_CMD, reg);
        if (error) {
                dev_err(&client->dev,
                        "failed to write current power state: %d\n",
                        error);
                return error;
        }

        return 0;
}

static int elan_i2c_set_mode(struct i2c_client *client, u8 mode)
{
        return elan_i2c_write_cmd(client, ETP_I2C_SET_CMD, mode);
}


static int elan_i2c_calibrate(struct i2c_client *client)
{
        return elan_i2c_write_cmd(client, ETP_I2C_CALIBRATE_CMD, 1);
}

static int elan_i2c_calibrate_result(struct i2c_client *client, u8 *val)
{
        return elan_i2c_read_block(client, ETP_I2C_CALIBRATE_CMD, val, 1);
}

static int elan_i2c_get_baseline_data(struct i2c_client *client,
                                      bool max_baseline, u8 *value)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client,
                                  max_baseline ? ETP_I2C_MAX_BASELINE_CMD :
                                                 ETP_I2C_MIN_BASELINE_CMD,
                                  val);
        if (error)
                return error;

        *value = le16_to_cpup((__le16 *)val);

        return 0;
}

static int elan_i2c_get_pattern(struct i2c_client *client, u8 *pattern)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_PATTERN_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get pattern: %d\n", error);
                return error;
        }

        /*
         * Not all versions of firmware implement "get pattern" command.
         * When this command is not implemented the device will respond
         * with 0xFF 0xFF, which we will treat as "old" pattern 0.
         */
        *pattern = val[0] == 0xFF && val[1] == 0xFF ? 0 : val[1];

        return 0;
}

static int elan_i2c_get_version(struct i2c_client *client,
                                u8 pattern, bool iap, u8 *version)
{
        int error;
        u16 cmd;
        u8 val[3];

        if (!iap)
                cmd = ETP_I2C_FW_VERSION_CMD;
        else if (pattern == 0)
                cmd = ETP_I2C_IAP_VERSION_P0_CMD;
        else
                cmd = ETP_I2C_IAP_VERSION_CMD;

        error = elan_i2c_read_cmd(client, cmd, val);
        if (error) {
                dev_err(&client->dev, "failed to get %s version: %d\n",
                        iap ? "IAP" : "FW", error);
                return error;
        }

        if (pattern >= 0x01)
                *version = iap ? val[1] : val[0];
        else
                *version = val[0];
        return 0;
}

static int elan_i2c_get_sm_version(struct i2c_client *client, u8 pattern,
                                   u16 *ic_type, u8 *version, u8 *clickpad)
{
        int error;
        u8 val[3];

        if (pattern >= 0x01) {
                error = elan_i2c_read_cmd(client, ETP_I2C_IC_TYPE_CMD, val);
                if (error) {
                        dev_err(&client->dev, "failed to get ic type: %d\n",
                                error);
                        return error;
                }
                *ic_type = be16_to_cpup((__be16 *)val);

                error = elan_i2c_read_cmd(client, ETP_I2C_NSM_VERSION_CMD,
                                          val);
                if (error) {
                        dev_err(&client->dev, "failed to get SM version: %d\n",
                                error);
                        return error;
                }
                *version = val[1];
                *clickpad = val[0] & 0x10;
        } else {
                error = elan_i2c_read_cmd(client, ETP_I2C_OSM_VERSION_CMD, val);
                if (error) {
                        dev_err(&client->dev, "failed to get SM version: %d\n",
                                error);
                        return error;
                }
                *version = val[0];

                error = elan_i2c_read_cmd(client, ETP_I2C_IC_TYPE_P0_CMD, val);
                if (error) {
                        dev_err(&client->dev, "failed to get ic type: %d\n",
                                error);
                        return error;
                }
                *ic_type = val[0];

                error = elan_i2c_read_cmd(client, ETP_I2C_NSM_VERSION_CMD,
                                          val);
                if (error) {
                        dev_err(&client->dev, "failed to get SM version: %d\n",
                                error);
                        return error;
                }
                *clickpad = val[0] & 0x10;
        }

        return 0;
}

static int elan_i2c_get_product_id(struct i2c_client *client, u16 *id)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_UNIQUEID_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get product ID: %d\n", error);
                return error;
        }

        *id = le16_to_cpup((__le16 *)val);
        return 0;
}

static int elan_i2c_get_checksum(struct i2c_client *client,
                                 bool iap, u16 *csum)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client,
                                  iap ? ETP_I2C_IAP_CHECKSUM_CMD :
                                        ETP_I2C_FW_CHECKSUM_CMD,
                                  val);
        if (error) {
                dev_err(&client->dev, "failed to get %s checksum: %d\n",
                        iap ? "IAP" : "FW", error);
                return error;
        }

        *csum = le16_to_cpup((__le16 *)val);
        return 0;
}

static int elan_i2c_get_max(struct i2c_client *client,
                            unsigned int *max_x, unsigned int *max_y)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_MAX_X_AXIS_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get X dimension: %d\n", error);
                return error;
        }

        *max_x = le16_to_cpup((__le16 *)val);

        error = elan_i2c_read_cmd(client, ETP_I2C_MAX_Y_AXIS_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get Y dimension: %d\n", error);
                return error;
        }

        *max_y = le16_to_cpup((__le16 *)val);

        return 0;
}

static int elan_i2c_get_resolution(struct i2c_client *client,
                                   u8 *hw_res_x, u8 *hw_res_y)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_RESOLUTION_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get resolution: %d\n", error);
                return error;
        }

        *hw_res_x = val[0];
        *hw_res_y = val[1];

        return 0;
}

static int elan_i2c_get_num_traces(struct i2c_client *client,
                                   unsigned int *x_traces,
                                   unsigned int *y_traces)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_XY_TRACENUM_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get trace info: %d\n", error);
                return error;
        }

        *x_traces = val[0];
        *y_traces = val[1];

        return 0;
}

static int elan_i2c_get_pressure_adjustment(struct i2c_client *client,
                                            int *adjustment)
{
        int error;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_PRESSURE_CMD, val);
        if (error) {
                dev_err(&client->dev, "failed to get pressure format: %d\n",
                        error);
                return error;
        }

        if ((val[0] >> 4) & 0x1)
                *adjustment = 0;
        else
                *adjustment = ETP_PRESSURE_OFFSET;

        return 0;
}

static int elan_i2c_iap_get_mode(struct i2c_client *client, enum tp_mode *mode)
{
        int error;
        u16 constant;
        u8 val[3];

        error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CTRL_CMD, val);
        if (error) {
                dev_err(&client->dev,
                        "failed to read iap control register: %d\n",
                        error);
                return error;
        }

        constant = le16_to_cpup((__le16 *)val);
        dev_dbg(&client->dev, "iap control reg: 0x%04x.\n", constant);

        *mode = (constant & ETP_I2C_MAIN_MODE_ON) ? MAIN_MODE : IAP_MODE;

        return 0;
}

static int elan_i2c_iap_reset(struct i2c_client *client)
{
        int error;

        error = elan_i2c_write_cmd(client, ETP_I2C_IAP_RESET_CMD,
                                   ETP_I2C_IAP_RESET);
        if (error) {
                dev_err(&client->dev, "cannot reset IC: %d\n", error);
                return error;
        }

        return 0;
}

static int elan_i2c_set_flash_key(struct i2c_client *client)
{
        int error;

        error = elan_i2c_write_cmd(client, ETP_I2C_IAP_CMD,
                                   ETP_I2C_IAP_PASSWORD);
        if (error) {
                dev_err(&client->dev, "cannot set flash key: %d\n", error);
                return error;
        }

        return 0;
}

static int elan_read_write_iap_type(struct i2c_client *client, u16 fw_page_size)
{
        int error;
        u16 constant;
        u8 val[3];
        int retry = 3;

        do {
                error = elan_i2c_write_cmd(client, ETP_I2C_IAP_TYPE_CMD,
                                           fw_page_size / 2);
                if (error) {
                        dev_err(&client->dev,
                                "cannot write iap type: %d\n", error);
                        return error;
                }

                error = elan_i2c_read_cmd(client, ETP_I2C_IAP_TYPE_CMD, val);
                if (error) {
                        dev_err(&client->dev,
                                "failed to read iap type register: %d\n",
                                error);
                        return error;
                }
                constant = le16_to_cpup((__le16 *)val);
                dev_dbg(&client->dev, "iap type reg: 0x%04x\n", constant);

                if (constant == fw_page_size / 2)
                        return 0;

        } while (--retry > 0);

        dev_err(&client->dev, "cannot set iap type\n");
        return -EIO;
}

static int elan_i2c_prepare_fw_update(struct i2c_client *client, u16 ic_type,
                                      u8 iap_version, u16 fw_page_size)
{
        struct device *dev = &client->dev;
        int error;
        enum tp_mode mode;
        u8 val[3];
        u16 password;

        /* Get FW in which mode (IAP_MODE/MAIN_MODE)  */
        error = elan_i2c_iap_get_mode(client, &mode);
        if (error)
                return error;

        if (mode == IAP_MODE) {
                /* Reset IC */
                error = elan_i2c_iap_reset(client);
                if (error)
                        return error;

                msleep(30);
        }

        /* Set flash key*/
        error = elan_i2c_set_flash_key(client);
        if (error)
                return error;

        /* Wait for F/W IAP initialization */
        msleep(mode == MAIN_MODE ? 100 : 30);

        /* Check if we are in IAP mode or not */
        error = elan_i2c_iap_get_mode(client, &mode);
        if (error)
                return error;

        if (mode == MAIN_MODE) {
                dev_err(dev, "wrong mode: %d\n", mode);
                return -EIO;
        }

        if (ic_type >= 0x0D && iap_version >= 1) {
                error = elan_read_write_iap_type(client, fw_page_size);
                if (error)
                        return error;
        }

        /* Set flash key again */
        error = elan_i2c_set_flash_key(client);
        if (error)
                return error;

        /* Wait for F/W IAP initialization */
        msleep(30);

        /* read back to check we actually enabled successfully. */
        error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CMD, val);
        if (error) {
                dev_err(dev, "cannot read iap password: %d\n",
                        error);
                return error;
        }

        password = le16_to_cpup((__le16 *)val);
        if (password != ETP_I2C_IAP_PASSWORD) {
                dev_err(dev, "wrong iap password: 0x%X\n", password);
                return -EIO;
        }

        return 0;
}

static int elan_i2c_write_fw_block(struct i2c_client *client, u16 fw_page_size,
                                   const u8 *page, u16 checksum, int idx)
{
        struct device *dev = &client->dev;
        u8 val[3];
        u16 result;
        int ret, error;

        u8 *page_store __free(kfree) = kmalloc(fw_page_size + 4, GFP_KERNEL);
        if (!page_store)
                return -ENOMEM;

        page_store[0] = ETP_I2C_IAP_REG_L;
        page_store[1] = ETP_I2C_IAP_REG_H;
        memcpy(&page_store[2], page, fw_page_size);
        /* recode checksum at last two bytes */
        put_unaligned_le16(checksum, &page_store[fw_page_size + 2]);

        ret = i2c_master_send(client, page_store, fw_page_size + 4);
        if (ret != fw_page_size + 4) {
                error = ret < 0 ? ret : -EIO;
                dev_err(dev, "Failed to write page %d: %d\n", idx, error);
                return error;
        }

        /* Wait for F/W to update one page ROM data. */
        msleep(fw_page_size == ETP_FW_PAGE_SIZE_512 ? 50 : 35);

        error = elan_i2c_read_cmd(client, ETP_I2C_IAP_CTRL_CMD, val);
        if (error) {
                dev_err(dev, "Failed to read IAP write result: %d\n", error);
                return error;
        }

        result = le16_to_cpup((__le16 *)val);
        if (result & (ETP_FW_IAP_PAGE_ERR | ETP_FW_IAP_INTF_ERR)) {
                dev_err(dev, "IAP reports failed write: %04hx\n",
                        result);
                return -EIO;
        }

        return 0;
}

static int elan_i2c_finish_fw_update(struct i2c_client *client,
                                     struct completion *completion)
{
        struct device *dev = &client->dev;
        int error = 0;
        int len;
        u8 buffer[ETP_I2C_REPORT_MAX_LEN];

        len = i2c_master_recv(client, buffer, ETP_I2C_REPORT_MAX_LEN);
        if (len <= 0) {
                error = len < 0 ? len : -EIO;
                dev_warn(dev, "failed to read I2C data after FW WDT reset: %d (%d)\n",
                        error, len);
        }

        reinit_completion(completion);
        enable_irq(client->irq);

        error = elan_i2c_write_cmd(client, ETP_I2C_STAND_CMD, ETP_I2C_RESET);
        if (error) {
                dev_err(dev, "device reset failed: %d\n", error);
        } else if (!wait_for_completion_timeout(completion,
                                                msecs_to_jiffies(300))) {
                dev_err(dev, "timeout waiting for device reset\n");
                error = -ETIMEDOUT;
        }

        disable_irq(client->irq);

        if (error)
                return error;

        len = i2c_master_recv(client, buffer, ETP_I2C_INF_LENGTH);
        if (len != ETP_I2C_INF_LENGTH) {
                error = len < 0 ? len : -EIO;
                dev_err(dev, "failed to read INT signal: %d (%d)\n",
                        error, len);
                return error;
        }

        return 0;
}

static int elan_i2c_get_report_features(struct i2c_client *client, u8 pattern,
                                        unsigned int *features,
                                        unsigned int *report_len)
{
        *features = ETP_FEATURE_REPORT_MK;
        *report_len = pattern <= 0x01 ?
                        ETP_I2C_REPORT_LEN : ETP_I2C_REPORT_LEN_ID2;
        return 0;
}

static int elan_i2c_get_report(struct i2c_client *client,
                               u8 *report, unsigned int report_len)
{
        int len;

        len = i2c_master_recv(client, report, report_len);
        if (len < 0) {
                dev_err(&client->dev, "failed to read report data: %d\n", len);
                return len;
        }

        if (len != report_len) {
                dev_err(&client->dev,
                        "wrong report length (%d vs %d expected)\n",
                        len, report_len);
                return -EIO;
        }

        return 0;
}

const struct elan_transport_ops elan_i2c_ops = {
        .initialize             = elan_i2c_initialize,
        .sleep_control          = elan_i2c_sleep_control,
        .power_control          = elan_i2c_power_control,
        .set_mode               = elan_i2c_set_mode,

        .calibrate              = elan_i2c_calibrate,
        .calibrate_result       = elan_i2c_calibrate_result,

        .get_baseline_data      = elan_i2c_get_baseline_data,

        .get_version            = elan_i2c_get_version,
        .get_sm_version         = elan_i2c_get_sm_version,
        .get_product_id         = elan_i2c_get_product_id,
        .get_checksum           = elan_i2c_get_checksum,
        .get_pressure_adjustment = elan_i2c_get_pressure_adjustment,

        .get_max                = elan_i2c_get_max,
        .get_resolution         = elan_i2c_get_resolution,
        .get_num_traces         = elan_i2c_get_num_traces,

        .iap_get_mode           = elan_i2c_iap_get_mode,
        .iap_reset              = elan_i2c_iap_reset,

        .prepare_fw_update      = elan_i2c_prepare_fw_update,
        .write_fw_block         = elan_i2c_write_fw_block,
        .finish_fw_update       = elan_i2c_finish_fw_update,

        .get_pattern            = elan_i2c_get_pattern,

        .get_report_features    = elan_i2c_get_report_features,
        .get_report             = elan_i2c_get_report,
};