// SPDX-License-Identifier: GPL-2.0-only
/*
 * Elantech Touchpad driver (v6)
 *
 * Copyright (C) 2007-2009 Arjan Opmeer <arjan@opmeer.net>
 *
 * Trademarks are the property of their respective owners.
 */

#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/platform_device.h>
#include <linux/serio.h>
#include <linux/libps2.h>
#include <linux/unaligned.h>
#include "psmouse.h"
#include "elantech.h"
#include "elan_i2c.h"

#define elantech_debug(fmt, ...)                                        \
        do {                                                            \
                if (etd->info.debug)                                    \
                        psmouse_printk(KERN_DEBUG, psmouse,             \
                                        fmt, ##__VA_ARGS__);            \
        } while (0)

/*
 * Send a Synaptics style sliced query command
 */
static int synaptics_send_cmd(struct psmouse *psmouse, unsigned char c,
                                unsigned char *param)
{
        if (ps2_sliced_command(&psmouse->ps2dev, c) ||
            ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
                psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
                return -1;
        }

        return 0;
}

/*
 * V3 and later support this fast command
 */
static int elantech_send_cmd(struct psmouse *psmouse, unsigned char c,
                                unsigned char *param)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;

        if (ps2_command(ps2dev, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            ps2_command(ps2dev, NULL, c) ||
            ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
                psmouse_err(psmouse, "%s query 0x%02x failed.\n", __func__, c);
                return -1;
        }

        return 0;
}

/*
 * A retrying version of ps2_command
 */
static int elantech_ps2_command(struct psmouse *psmouse,
                                unsigned char *param, int command)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        struct elantech_data *etd = psmouse->private;
        int rc;
        int tries = ETP_PS2_COMMAND_TRIES;

        do {
                rc = ps2_command(ps2dev, param, command);
                if (rc == 0)
                        break;
                tries--;
                elantech_debug("retrying ps2 command 0x%02x (%d).\n",
                                command, tries);
                msleep(ETP_PS2_COMMAND_DELAY);
        } while (tries > 0);

        if (rc)
                psmouse_err(psmouse, "ps2 command 0x%02x failed.\n", command);

        return rc;
}

/*
 * Send an Elantech style special command to read 3 bytes from a register
 */
static int elantech_read_reg_params(struct psmouse *psmouse, u8 reg, u8 *param)
{
        if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
            elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, reg) ||
            elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
                psmouse_err(psmouse,
                            "failed to read register %#02x\n", reg);
                return -EIO;
        }

        return 0;
}

/*
 * Send an Elantech style special command to write a register with a parameter
 */
static int elantech_write_reg_params(struct psmouse *psmouse, u8 reg, u8 *param)
{
        if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
            elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, reg) ||
            elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, param[0]) ||
            elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
            elantech_ps2_command(psmouse, NULL, param[1]) ||
            elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
                psmouse_err(psmouse,
                            "failed to write register %#02x with value %#02x%#02x\n",
                            reg, param[0], param[1]);
                return -EIO;
        }

        return 0;
}

/*
 * Send an Elantech style special command to read a value from a register
 */
static int elantech_read_reg(struct psmouse *psmouse, unsigned char reg,
                                unsigned char *val)
{
        struct elantech_data *etd = psmouse->private;
        unsigned char param[3];
        int rc = 0;

        if (reg < 0x07 || reg > 0x26)
                return -1;

        if (reg > 0x11 && reg < 0x20)
                return -1;

        switch (etd->info.hw_version) {
        case 1:
                if (ps2_sliced_command(&psmouse->ps2dev, ETP_REGISTER_READ) ||
                    ps2_sliced_command(&psmouse->ps2dev, reg) ||
                    ps2_command(&psmouse->ps2dev, param, PSMOUSE_CMD_GETINFO)) {
                        rc = -1;
                }
                break;

        case 2:
                if (elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse,  NULL, ETP_REGISTER_READ) ||
                    elantech_ps2_command(psmouse,  NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse,  NULL, reg) ||
                    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
                        rc = -1;
                }
                break;

        case 3 ... 4:
                if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, reg) ||
                    elantech_ps2_command(psmouse, param, PSMOUSE_CMD_GETINFO)) {
                        rc = -1;
                }
                break;
        }

        if (rc)
                psmouse_err(psmouse, "failed to read register 0x%02x.\n", reg);
        else if (etd->info.hw_version != 4)
                *val = param[0];
        else
                *val = param[1];

        return rc;
}

/*
 * Send an Elantech style special command to write a register with a value
 */
static int elantech_write_reg(struct psmouse *psmouse, unsigned char reg,
                                unsigned char val)
{
        struct elantech_data *etd = psmouse->private;
        int rc = 0;

        if (reg < 0x07 || reg > 0x26)
                return -1;

        if (reg > 0x11 && reg < 0x20)
                return -1;

        switch (etd->info.hw_version) {
        case 1:
                if (ps2_sliced_command(&psmouse->ps2dev, ETP_REGISTER_WRITE) ||
                    ps2_sliced_command(&psmouse->ps2dev, reg) ||
                    ps2_sliced_command(&psmouse->ps2dev, val) ||
                    ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_SETSCALE11)) {
                        rc = -1;
                }
                break;

        case 2:
                if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_WRITE) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, reg) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, val) ||
                    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
                        rc = -1;
                }
                break;

        case 3:
                if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, reg) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, val) ||
                    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
                        rc = -1;
                }
                break;

        case 4:
                if (elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, reg) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, ETP_REGISTER_READWRITE) ||
                    elantech_ps2_command(psmouse, NULL, ETP_PS2_CUSTOM_COMMAND) ||
                    elantech_ps2_command(psmouse, NULL, val) ||
                    elantech_ps2_command(psmouse, NULL, PSMOUSE_CMD_SETSCALE11)) {
                        rc = -1;
                }
                break;
        }

        if (rc)
                psmouse_err(psmouse,
                            "failed to write register 0x%02x with value 0x%02x.\n",
                            reg, val);

        return rc;
}

/*
 * Dump a complete mouse movement packet to the syslog
 */
static void elantech_packet_dump(struct psmouse *psmouse)
{
        psmouse_printk(KERN_DEBUG, psmouse, "PS/2 packet [%*ph]\n",
                       psmouse->pktsize, psmouse->packet);
}

/*
 * Advertise INPUT_PROP_BUTTONPAD for clickpads. The testing of bit 12 in
 * fw_version for this is based on the following fw_version & caps table:
 *
 * Laptop-model:           fw_version:     caps:           buttons:
 * Acer S3                 0x461f00        10, 13, 0e      clickpad
 * Acer S7-392             0x581f01        50, 17, 0d      clickpad
 * Acer V5-131             0x461f02        01, 16, 0c      clickpad
 * Acer V5-551             0x461f00        ?               clickpad
 * Asus K53SV              0x450f01        78, 15, 0c      2 hw buttons
 * Asus G46VW              0x460f02        00, 18, 0c      2 hw buttons
 * Asus G750JX             0x360f00        00, 16, 0c      2 hw buttons
 * Asus TP500LN            0x381f17        10, 14, 0e      clickpad
 * Asus X750JN             0x381f17        10, 14, 0e      clickpad
 * Asus UX31               0x361f00        20, 15, 0e      clickpad
 * Asus UX32VD             0x361f02        00, 15, 0e      clickpad
 * Avatar AVIU-145A2       0x361f00        ?               clickpad
 * Fujitsu CELSIUS H760    0x570f02        40, 14, 0c      3 hw buttons (**)
 * Fujitsu CELSIUS H780    0x5d0f02        41, 16, 0d      3 hw buttons (**)
 * Fujitsu LIFEBOOK E544   0x470f00        d0, 12, 09      2 hw buttons
 * Fujitsu LIFEBOOK E546   0x470f00        50, 12, 09      2 hw buttons
 * Fujitsu LIFEBOOK E547   0x470f00        50, 12, 09      2 hw buttons
 * Fujitsu LIFEBOOK E554   0x570f01        40, 14, 0c      2 hw buttons
 * Fujitsu LIFEBOOK E557   0x570f01        40, 14, 0c      2 hw buttons
 * Fujitsu T725            0x470f01        05, 12, 09      2 hw buttons
 * Fujitsu H730            0x570f00        c0, 14, 0c      3 hw buttons (**)
 * Gigabyte U2442          0x450f01        58, 17, 0c      2 hw buttons
 * Lenovo L430             0x350f02        b9, 15, 0c      2 hw buttons (*)
 * Lenovo L530             0x350f02        b9, 15, 0c      2 hw buttons (*)
 * Samsung NF210           0x150b00        78, 14, 0a      2 hw buttons
 * Samsung NP770Z5E        0x575f01        10, 15, 0f      clickpad
 * Samsung NP700Z5B        0x361f06        21, 15, 0f      clickpad
 * Samsung NP900X3E-A02    0x575f03        ?               clickpad
 * Samsung NP-QX410        0x851b00        19, 14, 0c      clickpad
 * Samsung RC512           0x450f00        08, 15, 0c      2 hw buttons
 * Samsung RF710           0x450f00        ?               2 hw buttons
 * System76 Pangolin       0x250f01        ?               2 hw buttons
 * (*) + 3 trackpoint buttons
 * (**) + 0 trackpoint buttons
 * Note: Lenovo L430 and Lenovo L530 have the same fw_version/caps
 */
static inline int elantech_is_buttonpad(struct elantech_device_info *info)
{
        return info->fw_version & 0x001000;
}

/*
 * Interpret complete data packets and report absolute mode input events for
 * hardware version 1. (4 byte packets)
 */
static void elantech_report_absolute_v1(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        int fingers;

        if (etd->info.fw_version < 0x020000) {
                /*
                 * byte 0:  D   U  p1  p2   1  p3   R   L
                 * byte 1:  f   0  th  tw  x9  x8  y9  y8
                 */
                fingers = ((packet[1] & 0x80) >> 7) +
                                ((packet[1] & 0x30) >> 4);
        } else {
                /*
                 * byte 0: n1  n0  p2  p1   1  p3   R   L
                 * byte 1:  0   0   0   0  x9  x8  y9  y8
                 */
                fingers = (packet[0] & 0xc0) >> 6;
        }

        if (etd->info.jumpy_cursor) {
                if (fingers != 1) {
                        etd->single_finger_reports = 0;
                } else if (etd->single_finger_reports < 2) {
                        /* Discard first 2 reports of one finger, bogus */
                        etd->single_finger_reports++;
                        elantech_debug("discarding packet\n");
                        return;
                }
        }

        input_report_key(dev, BTN_TOUCH, fingers != 0);

        /*
         * byte 2: x7  x6  x5  x4  x3  x2  x1  x0
         * byte 3: y7  y6  y5  y4  y3  y2  y1  y0
         */
        if (fingers) {
                input_report_abs(dev, ABS_X,
                        ((packet[1] & 0x0c) << 6) | packet[2]);
                input_report_abs(dev, ABS_Y,
                        etd->y_max - (((packet[1] & 0x03) << 8) | packet[3]));
        }

        input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
        input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
        input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);

        psmouse_report_standard_buttons(dev, packet[0]);

        if (etd->info.fw_version < 0x020000 &&
            (etd->info.capabilities[0] & ETP_CAP_HAS_ROCKER)) {
                /* rocker up */
                input_report_key(dev, BTN_FORWARD, packet[0] & 0x40);
                /* rocker down */
                input_report_key(dev, BTN_BACK, packet[0] & 0x80);
        }

        input_sync(dev);
}

static void elantech_set_slot(struct input_dev *dev, int slot, bool active,
                              unsigned int x, unsigned int y)
{
        input_mt_slot(dev, slot);
        input_mt_report_slot_state(dev, MT_TOOL_FINGER, active);
        if (active) {
                input_report_abs(dev, ABS_MT_POSITION_X, x);
                input_report_abs(dev, ABS_MT_POSITION_Y, y);
        }
}

/* x1 < x2 and y1 < y2 when two fingers, x = y = 0 when not pressed */
static void elantech_report_semi_mt_data(struct input_dev *dev,
                                         unsigned int num_fingers,
                                         unsigned int x1, unsigned int y1,
                                         unsigned int x2, unsigned int y2)
{
        elantech_set_slot(dev, 0, num_fingers != 0, x1, y1);
        elantech_set_slot(dev, 1, num_fingers >= 2, x2, y2);
}

/*
 * Interpret complete data packets and report absolute mode input events for
 * hardware version 2. (6 byte packets)
 */
static void elantech_report_absolute_v2(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        struct input_dev *dev = psmouse->dev;
        unsigned char *packet = psmouse->packet;
        unsigned int fingers, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
        unsigned int width = 0, pres = 0;

        /* byte 0: n1  n0   .   .   .   .   R   L */
        fingers = (packet[0] & 0xc0) >> 6;

        switch (fingers) {
        case 3:
                /*
                 * Same as one finger, except report of more than 3 fingers:
                 * byte 3:  n4  .   w1  w0   .   .   .   .
                 */
                if (packet[3] & 0x80)
                        fingers = 4;
                fallthrough;
        case 1:
                /*
                 * byte 1:  .   .   .   .  x11 x10 x9  x8
                 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
                 */
                x1 = ((packet[1] & 0x0f) << 8) | packet[2];
                /*
                 * byte 4:  .   .   .   .  y11 y10 y9  y8
                 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
                 */
                y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);

                pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
                width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);
                break;

        case 2:
                /*
                 * The coordinate of each finger is reported separately
                 * with a lower resolution for two finger touches:
                 * byte 0:  .   .  ay8 ax8  .   .   .   .
                 * byte 1: ax7 ax6 ax5 ax4 ax3 ax2 ax1 ax0
                 */
                x1 = (((packet[0] & 0x10) << 4) | packet[1]) << 2;
                /* byte 2: ay7 ay6 ay5 ay4 ay3 ay2 ay1 ay0 */
                y1 = etd->y_max -
                        ((((packet[0] & 0x20) << 3) | packet[2]) << 2);
                /*
                 * byte 3:  .   .  by8 bx8  .   .   .   .
                 * byte 4: bx7 bx6 bx5 bx4 bx3 bx2 bx1 bx0
                 */
                x2 = (((packet[3] & 0x10) << 4) | packet[4]) << 2;
                /* byte 5: by7 by8 by5 by4 by3 by2 by1 by0 */
                y2 = etd->y_max -
                        ((((packet[3] & 0x20) << 3) | packet[5]) << 2);

                /* Unknown so just report sensible values */
                pres = 127;
                width = 7;
                break;
        }

        input_report_key(dev, BTN_TOUCH, fingers != 0);
        if (fingers != 0) {
                input_report_abs(dev, ABS_X, x1);
                input_report_abs(dev, ABS_Y, y1);
        }
        elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
        input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
        input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
        input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);
        input_report_key(dev, BTN_TOOL_QUADTAP, fingers == 4);
        psmouse_report_standard_buttons(dev, packet[0]);
        if (etd->info.reports_pressure) {
                input_report_abs(dev, ABS_PRESSURE, pres);
                input_report_abs(dev, ABS_TOOL_WIDTH, width);
        }

        input_sync(dev);
}

static void elantech_report_trackpoint(struct psmouse *psmouse,
                                       int packet_type)
{
        /*
         * byte 0:  0   0  sx  sy   0   M   R   L
         * byte 1:~sx   0   0   0   0   0   0   0
         * byte 2:~sy   0   0   0   0   0   0   0
         * byte 3:  0   0 ~sy ~sx   0   1   1   0
         * byte 4: x7  x6  x5  x4  x3  x2  x1  x0
         * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
         *
         * x and y are written in two's complement spread
         * over 9 bits with sx/sy the relative top bit and
         * x7..x0 and y7..y0 the lower bits.
         * The sign of y is opposite to what the input driver
         * expects for a relative movement
         */

        struct elantech_data *etd = psmouse->private;
        struct input_dev *tp_dev = etd->tp_dev;
        unsigned char *packet = psmouse->packet;
        int x, y;
        u32 t;

        t = get_unaligned_le32(&packet[0]);

        switch (t & ~7U) {
        case 0x06000030U:
        case 0x16008020U:
        case 0x26800010U:
        case 0x36808000U:

                /*
                 * This firmware misreport coordinates for trackpoint
                 * occasionally. Discard packets outside of [-127, 127] range
                 * to prevent cursor jumps.
                 */
                if (packet[4] == 0x80 || packet[5] == 0x80 ||
                    packet[1] >> 7 == packet[4] >> 7 ||
                    packet[2] >> 7 == packet[5] >> 7) {
                        elantech_debug("discarding packet [%6ph]\n", packet);
                        break;

                }
                x = packet[4] - (int)((packet[1]^0x80) << 1);
                y = (int)((packet[2]^0x80) << 1) - packet[5];

                psmouse_report_standard_buttons(tp_dev, packet[0]);

                input_report_rel(tp_dev, REL_X, x);
                input_report_rel(tp_dev, REL_Y, y);

                input_sync(tp_dev);

                break;

        default:
                /* Dump unexpected packet sequences if debug=1 (default) */
                if (etd->info.debug == 1)
                        elantech_packet_dump(psmouse);

                break;
        }
}

/*
 * Interpret complete data packets and report absolute mode input events for
 * hardware version 3. (12 byte packets for two fingers)
 */
static void elantech_report_absolute_v3(struct psmouse *psmouse,
                                        int packet_type)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        unsigned int fingers = 0, x1 = 0, y1 = 0, x2 = 0, y2 = 0;
        unsigned int width = 0, pres = 0;

        /* byte 0: n1  n0   .   .   .   .   R   L */
        fingers = (packet[0] & 0xc0) >> 6;

        switch (fingers) {
        case 3:
        case 1:
                /*
                 * byte 1:  .   .   .   .  x11 x10 x9  x8
                 * byte 2: x7  x6  x5  x4  x4  x2  x1  x0
                 */
                x1 = ((packet[1] & 0x0f) << 8) | packet[2];
                /*
                 * byte 4:  .   .   .   .  y11 y10 y9  y8
                 * byte 5: y7  y6  y5  y4  y3  y2  y1  y0
                 */
                y1 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
                break;

        case 2:
                if (packet_type == PACKET_V3_HEAD) {
                        /*
                         * byte 1:   .    .    .    .  ax11 ax10 ax9  ax8
                         * byte 2: ax7  ax6  ax5  ax4  ax3  ax2  ax1  ax0
                         */
                        etd->mt[0].x = ((packet[1] & 0x0f) << 8) | packet[2];
                        /*
                         * byte 4:   .    .    .    .  ay11 ay10 ay9  ay8
                         * byte 5: ay7  ay6  ay5  ay4  ay3  ay2  ay1  ay0
                         */
                        etd->mt[0].y = etd->y_max -
                                (((packet[4] & 0x0f) << 8) | packet[5]);
                        /*
                         * wait for next packet
                         */
                        return;
                }

                /* packet_type == PACKET_V3_TAIL */
                x1 = etd->mt[0].x;
                y1 = etd->mt[0].y;
                x2 = ((packet[1] & 0x0f) << 8) | packet[2];
                y2 = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
                break;
        }

        pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
        width = ((packet[0] & 0x30) >> 2) | ((packet[3] & 0x30) >> 4);

        input_report_key(dev, BTN_TOUCH, fingers != 0);
        if (fingers != 0) {
                input_report_abs(dev, ABS_X, x1);
                input_report_abs(dev, ABS_Y, y1);
        }
        elantech_report_semi_mt_data(dev, fingers, x1, y1, x2, y2);
        input_report_key(dev, BTN_TOOL_FINGER, fingers == 1);
        input_report_key(dev, BTN_TOOL_DOUBLETAP, fingers == 2);
        input_report_key(dev, BTN_TOOL_TRIPLETAP, fingers == 3);

        /* For clickpads map both buttons to BTN_LEFT */
        if (elantech_is_buttonpad(&etd->info))
                input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
        else
                psmouse_report_standard_buttons(dev, packet[0]);

        input_report_abs(dev, ABS_PRESSURE, pres);
        input_report_abs(dev, ABS_TOOL_WIDTH, width);

        input_sync(dev);
}

static void elantech_input_sync_v4(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;

        /* For clickpads map both buttons to BTN_LEFT */
        if (elantech_is_buttonpad(&etd->info))
                input_report_key(dev, BTN_LEFT, packet[0] & 0x03);
        else
                psmouse_report_standard_buttons(dev, packet[0]);

        input_mt_report_pointer_emulation(dev, true);
        input_sync(dev);
}

static void process_packet_status_v4(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        unsigned char *packet = psmouse->packet;
        unsigned fingers;
        int i;

        /* notify finger state change */
        fingers = packet[1] & 0x1f;
        for (i = 0; i < ETP_MAX_FINGERS; i++) {
                if ((fingers & (1 << i)) == 0) {
                        input_mt_slot(dev, i);
                        input_mt_report_slot_state(dev, MT_TOOL_FINGER, false);
                }
        }

        elantech_input_sync_v4(psmouse);
}

static void process_packet_head_v4(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        int id;
        int pres, traces;

        id = ((packet[3] & 0xe0) >> 5) - 1;
        if (id < 0 || id >= ETP_MAX_FINGERS)
                return;

        etd->mt[id].x = ((packet[1] & 0x0f) << 8) | packet[2];
        etd->mt[id].y = etd->y_max - (((packet[4] & 0x0f) << 8) | packet[5]);
        pres = (packet[1] & 0xf0) | ((packet[4] & 0xf0) >> 4);
        traces = (packet[0] & 0xf0) >> 4;

        input_mt_slot(dev, id);
        input_mt_report_slot_state(dev, MT_TOOL_FINGER, true);

        input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
        input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);
        input_report_abs(dev, ABS_MT_PRESSURE, pres);
        input_report_abs(dev, ABS_MT_TOUCH_MAJOR, traces * etd->width);
        /* report this for backwards compatibility */
        input_report_abs(dev, ABS_TOOL_WIDTH, traces);

        elantech_input_sync_v4(psmouse);
}

static void process_packet_motion_v4(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        int weight, delta_x1 = 0, delta_y1 = 0, delta_x2 = 0, delta_y2 = 0;
        int id, sid;

        id = ((packet[0] & 0xe0) >> 5) - 1;
        if (id < 0 || id >= ETP_MAX_FINGERS)
                return;

        sid = ((packet[3] & 0xe0) >> 5) - 1;
        weight = (packet[0] & 0x10) ? ETP_WEIGHT_VALUE : 1;
        /*
         * Motion packets give us the delta of x, y values of specific fingers,
         * but in two's complement. Let the compiler do the conversion for us.
         * Also _enlarge_ the numbers to int, in case of overflow.
         */
        delta_x1 = (signed char)packet[1];
        delta_y1 = (signed char)packet[2];
        delta_x2 = (signed char)packet[4];
        delta_y2 = (signed char)packet[5];

        etd->mt[id].x += delta_x1 * weight;
        etd->mt[id].y -= delta_y1 * weight;
        input_mt_slot(dev, id);
        input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[id].x);
        input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[id].y);

        if (sid >= 0 && sid < ETP_MAX_FINGERS) {
                etd->mt[sid].x += delta_x2 * weight;
                etd->mt[sid].y -= delta_y2 * weight;
                input_mt_slot(dev, sid);
                input_report_abs(dev, ABS_MT_POSITION_X, etd->mt[sid].x);
                input_report_abs(dev, ABS_MT_POSITION_Y, etd->mt[sid].y);
        }

        elantech_input_sync_v4(psmouse);
}

static void elantech_report_absolute_v4(struct psmouse *psmouse,
                                        int packet_type)
{
        switch (packet_type) {
        case PACKET_V4_STATUS:
                process_packet_status_v4(psmouse);
                break;

        case PACKET_V4_HEAD:
                process_packet_head_v4(psmouse);
                break;

        case PACKET_V4_MOTION:
                process_packet_motion_v4(psmouse);
                break;

        case PACKET_UNKNOWN:
        default:
                /* impossible to get here */
                break;
        }
}

static int elantech_packet_check_v1(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        unsigned char p1, p2, p3;

        /* Parity bits are placed differently */
        if (etd->info.fw_version < 0x020000) {
                /* byte 0:  D   U  p1  p2   1  p3   R   L */
                p1 = (packet[0] & 0x20) >> 5;
                p2 = (packet[0] & 0x10) >> 4;
        } else {
                /* byte 0: n1  n0  p2  p1   1  p3   R   L */
                p1 = (packet[0] & 0x10) >> 4;
                p2 = (packet[0] & 0x20) >> 5;
        }

        p3 = (packet[0] & 0x04) >> 2;

        return etd->parity[packet[1]] == p1 &&
               etd->parity[packet[2]] == p2 &&
               etd->parity[packet[3]] == p3;
}

static int elantech_debounce_check_v2(struct psmouse *psmouse)
{
        /*
         * When we encounter packet that matches this exactly, it means the
         * hardware is in debounce status. Just ignore the whole packet.
         */
        static const u8 debounce_packet[] = {
                0x84, 0xff, 0xff, 0x02, 0xff, 0xff
        };
        unsigned char *packet = psmouse->packet;

        return !memcmp(packet, debounce_packet, sizeof(debounce_packet));
}

static int elantech_packet_check_v2(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;

        /*
         * V2 hardware has two flavors. Older ones that do not report pressure,
         * and newer ones that reports pressure and width. With newer ones, all
         * packets (1, 2, 3 finger touch) have the same constant bits. With
         * older ones, 1/3 finger touch packets and 2 finger touch packets
         * have different constant bits.
         * With all three cases, if the constant bits are not exactly what I
         * expected, I consider them invalid.
         */
        if (etd->info.reports_pressure)
                return (packet[0] & 0x0c) == 0x04 &&
                       (packet[3] & 0x0f) == 0x02;

        if ((packet[0] & 0xc0) == 0x80)
                return (packet[0] & 0x0c) == 0x0c &&
                       (packet[3] & 0x0e) == 0x08;

        return (packet[0] & 0x3c) == 0x3c &&
               (packet[1] & 0xf0) == 0x00 &&
               (packet[3] & 0x3e) == 0x38 &&
               (packet[4] & 0xf0) == 0x00;
}

/*
 * We check the constant bits to determine what packet type we get,
 * so packet checking is mandatory for v3 and later hardware.
 */
static int elantech_packet_check_v3(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        static const u8 debounce_packet[] = {
                0xc4, 0xff, 0xff, 0x02, 0xff, 0xff
        };
        unsigned char *packet = psmouse->packet;

        /*
         * check debounce first, it has the same signature in byte 0
         * and byte 3 as PACKET_V3_HEAD.
         */
        if (!memcmp(packet, debounce_packet, sizeof(debounce_packet)))
                return PACKET_DEBOUNCE;

        /*
         * If the hardware flag 'crc_enabled' is set the packets have
         * different signatures.
         */
        if (etd->info.crc_enabled) {
                if ((packet[3] & 0x09) == 0x08)
                        return PACKET_V3_HEAD;

                if ((packet[3] & 0x09) == 0x09)
                        return PACKET_V3_TAIL;
        } else {
                if ((packet[0] & 0x0c) == 0x04 && (packet[3] & 0xcf) == 0x02)
                        return PACKET_V3_HEAD;

                if ((packet[0] & 0x0c) == 0x0c && (packet[3] & 0xce) == 0x0c)
                        return PACKET_V3_TAIL;
                if ((packet[3] & 0x0f) == 0x06)
                        return PACKET_TRACKPOINT;
        }

        return PACKET_UNKNOWN;
}

static int elantech_packet_check_v4(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        unsigned char *packet = psmouse->packet;
        unsigned char packet_type = packet[3] & 0x03;
        unsigned int ic_version;
        bool sanity_check;

        if (etd->tp_dev && (packet[3] & 0x0f) == 0x06)
                return PACKET_TRACKPOINT;

        /* This represents the version of IC body. */
        ic_version = (etd->info.fw_version & 0x0f0000) >> 16;

        /*
         * Sanity check based on the constant bits of a packet.
         * The constant bits change depending on the value of
         * the hardware flag 'crc_enabled' and the version of
         * the IC body, but are the same for every packet,
         * regardless of the type.
         */
        if (etd->info.crc_enabled)
                sanity_check = ((packet[3] & 0x08) == 0x00);
        else if (ic_version == 7 && etd->info.samples[1] == 0x2A)
                sanity_check = ((packet[3] & 0x1c) == 0x10);
        else
                sanity_check = ((packet[0] & 0x08) == 0x00 &&
                                (packet[3] & 0x1c) == 0x10);

        if (!sanity_check)
                return PACKET_UNKNOWN;

        switch (packet_type) {
        case 0:
                return PACKET_V4_STATUS;

        case 1:
                return PACKET_V4_HEAD;

        case 2:
                return PACKET_V4_MOTION;
        }

        return PACKET_UNKNOWN;
}

/*
 * Process byte stream from mouse and handle complete packets
 */
static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        int packet_type;

        if (psmouse->pktcnt < psmouse->pktsize)
                return PSMOUSE_GOOD_DATA;

        if (etd->info.debug > 1)
                elantech_packet_dump(psmouse);

        switch (etd->info.hw_version) {
        case 1:
                if (etd->info.paritycheck && !elantech_packet_check_v1(psmouse))
                        return PSMOUSE_BAD_DATA;

                elantech_report_absolute_v1(psmouse);
                break;

        case 2:
                /* ignore debounce */
                if (elantech_debounce_check_v2(psmouse))
                        return PSMOUSE_FULL_PACKET;

                if (etd->info.paritycheck && !elantech_packet_check_v2(psmouse))
                        return PSMOUSE_BAD_DATA;

                elantech_report_absolute_v2(psmouse);
                break;

        case 3:
                packet_type = elantech_packet_check_v3(psmouse);
                switch (packet_type) {
                case PACKET_UNKNOWN:
                        return PSMOUSE_BAD_DATA;

                case PACKET_DEBOUNCE:
                        /* ignore debounce */
                        break;

                case PACKET_TRACKPOINT:
                        elantech_report_trackpoint(psmouse, packet_type);
                        break;

                default:
                        elantech_report_absolute_v3(psmouse, packet_type);
                        break;
                }

                break;

        case 4:
                packet_type = elantech_packet_check_v4(psmouse);
                switch (packet_type) {
                case PACKET_UNKNOWN:
                        return PSMOUSE_BAD_DATA;

                case PACKET_TRACKPOINT:
                        elantech_report_trackpoint(psmouse, packet_type);
                        break;

                default:
                        elantech_report_absolute_v4(psmouse, packet_type);
                        break;
                }

                break;
        }

        return PSMOUSE_FULL_PACKET;
}

/*
 * This writes the reg_07 value again to the hardware at the end of every
 * set_rate call because the register loses its value. reg_07 allows setting
 * absolute mode on v4 hardware
 */
static void elantech_set_rate_restore_reg_07(struct psmouse *psmouse,
                unsigned int rate)
{
        struct elantech_data *etd = psmouse->private;

        etd->original_set_rate(psmouse, rate);
        if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
                psmouse_err(psmouse, "restoring reg_07 failed\n");
}

/*
 * Put the touchpad into absolute mode
 */
static int elantech_set_absolute_mode(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;
        unsigned char val;
        int tries = ETP_READ_BACK_TRIES;
        int rc = 0;

        switch (etd->info.hw_version) {
        case 1:
                etd->reg_10 = 0x16;
                etd->reg_11 = 0x8f;
                if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
                    elantech_write_reg(psmouse, 0x11, etd->reg_11)) {
                        rc = -1;
                }
                break;

        case 2:
                                        /* Windows driver values */
                etd->reg_10 = 0x54;
                etd->reg_11 = 0x88;     /* 0x8a */
                etd->reg_21 = 0x60;     /* 0x00 */
                if (elantech_write_reg(psmouse, 0x10, etd->reg_10) ||
                    elantech_write_reg(psmouse, 0x11, etd->reg_11) ||
                    elantech_write_reg(psmouse, 0x21, etd->reg_21)) {
                        rc = -1;
                }
                break;

        case 3:
                if (etd->info.set_hw_resolution)
                        etd->reg_10 = 0x0b;
                else
                        etd->reg_10 = 0x01;

                if (elantech_write_reg(psmouse, 0x10, etd->reg_10))
                        rc = -1;

                break;

        case 4:
                etd->reg_07 = 0x01;
                if (elantech_write_reg(psmouse, 0x07, etd->reg_07))
                        rc = -1;

                goto skip_readback_reg_10; /* v4 has no reg 0x10 to read */
        }

        if (rc == 0) {
                /*
                 * Read back reg 0x10. For hardware version 1 we must make
                 * sure the absolute mode bit is set. For hardware version 2
                 * the touchpad is probably initializing and not ready until
                 * we read back the value we just wrote.
                 */
                do {
                        rc = elantech_read_reg(psmouse, 0x10, &val);
                        if (rc == 0)
                                break;
                        tries--;
                        elantech_debug("retrying read (%d).\n", tries);
                        msleep(ETP_READ_BACK_DELAY);
                } while (tries > 0);

                if (rc) {
                        psmouse_err(psmouse,
                                    "failed to read back register 0x10.\n");
                } else if (etd->info.hw_version == 1 &&
                           !(val & ETP_R10_ABSOLUTE_MODE)) {
                        psmouse_err(psmouse,
                                    "touchpad refuses to switch to absolute mode.\n");
                        rc = -1;
                }
        }

 skip_readback_reg_10:
        if (rc)
                psmouse_err(psmouse, "failed to initialise registers.\n");

        return rc;
}

/*
 * (value from firmware) * 10 + 790 = dpi
 * we also have to convert dpi to dots/mm (*10/254 to avoid floating point)
 */
static unsigned int elantech_convert_res(unsigned int val)
{
        return (val * 10 + 790) * 10 / 254;
}

static int elantech_get_resolution_v4(struct psmouse *psmouse,
                                      unsigned int *x_res,
                                      unsigned int *y_res,
                                      unsigned int *bus)
{
        unsigned char param[3];

        if (elantech_send_cmd(psmouse, ETP_RESOLUTION_QUERY, param))
                return -1;

        *x_res = elantech_convert_res(param[1] & 0x0f);
        *y_res = elantech_convert_res((param[1] & 0xf0) >> 4);
        *bus = param[2];

        return 0;
}

static void elantech_set_buttonpad_prop(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;

        if (elantech_is_buttonpad(&etd->info)) {
                __set_bit(INPUT_PROP_BUTTONPAD, dev->propbit);
                __clear_bit(BTN_RIGHT, dev->keybit);
        }
}

/*
 * Some hw_version 4 models do have a middle button
 */
static const struct dmi_system_id elantech_dmi_has_middle_button[] = {
#if defined(CONFIG_DMI) && defined(CONFIG_X86)
        {
                /* Fujitsu H730 has a middle button */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
                },
        },
        {
                /* Fujitsu H760 also has a middle button */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H760"),
                },
        },
        {
                /* Fujitsu H780 also has a middle button */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H780"),
                },
        },
#endif
        { }
};

/*
 * Set the appropriate event bits for the input subsystem
 */
static int elantech_set_input_params(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct elantech_data *etd = psmouse->private;
        struct elantech_device_info *info = &etd->info;
        unsigned int x_min = info->x_min, y_min = info->y_min,
                     x_max = info->x_max, y_max = info->y_max,
                     width = info->width;

        __set_bit(INPUT_PROP_POINTER, dev->propbit);
        __set_bit(EV_KEY, dev->evbit);
        __set_bit(EV_ABS, dev->evbit);
        __clear_bit(EV_REL, dev->evbit);

        __set_bit(BTN_LEFT, dev->keybit);
        if (info->has_middle_button)
                __set_bit(BTN_MIDDLE, dev->keybit);
        __set_bit(BTN_RIGHT, dev->keybit);

        __set_bit(BTN_TOUCH, dev->keybit);
        __set_bit(BTN_TOOL_FINGER, dev->keybit);
        __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
        __set_bit(BTN_TOOL_TRIPLETAP, dev->keybit);

        switch (info->hw_version) {
        case 1:
                /* Rocker button */
                if (info->fw_version < 0x020000 &&
                    (info->capabilities[0] & ETP_CAP_HAS_ROCKER)) {
                        __set_bit(BTN_FORWARD, dev->keybit);
                        __set_bit(BTN_BACK, dev->keybit);
                }
                input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
                input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
                break;

        case 2:
                __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
                __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);
                fallthrough;
        case 3:
                if (info->hw_version == 3)
                        elantech_set_buttonpad_prop(psmouse);
                input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
                input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
                if (info->reports_pressure) {
                        input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
                                             ETP_PMAX_V2, 0, 0);
                        input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
                                             ETP_WMAX_V2, 0, 0);
                }
                input_mt_init_slots(dev, 2, INPUT_MT_SEMI_MT);
                input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
                input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
                break;

        case 4:
                elantech_set_buttonpad_prop(psmouse);
                __set_bit(BTN_TOOL_QUADTAP, dev->keybit);
                /* For X to recognize me as touchpad. */
                input_set_abs_params(dev, ABS_X, x_min, x_max, 0, 0);
                input_set_abs_params(dev, ABS_Y, y_min, y_max, 0, 0);
                /*
                 * range of pressure and width is the same as v2,
                 * report ABS_PRESSURE, ABS_TOOL_WIDTH for compatibility.
                 */
                input_set_abs_params(dev, ABS_PRESSURE, ETP_PMIN_V2,
                                     ETP_PMAX_V2, 0, 0);
                input_set_abs_params(dev, ABS_TOOL_WIDTH, ETP_WMIN_V2,
                                     ETP_WMAX_V2, 0, 0);
                /* Multitouch capable pad, up to 5 fingers. */
                input_mt_init_slots(dev, ETP_MAX_FINGERS, 0);
                input_set_abs_params(dev, ABS_MT_POSITION_X, x_min, x_max, 0, 0);
                input_set_abs_params(dev, ABS_MT_POSITION_Y, y_min, y_max, 0, 0);
                input_set_abs_params(dev, ABS_MT_PRESSURE, ETP_PMIN_V2,
                                     ETP_PMAX_V2, 0, 0);
                /*
                 * The firmware reports how many trace lines the finger spans,
                 * convert to surface unit as Protocol-B requires.
                 */
                input_set_abs_params(dev, ABS_MT_TOUCH_MAJOR, 0,
                                     ETP_WMAX_V2 * width, 0, 0);
                break;
        }

        input_abs_set_res(dev, ABS_X, info->x_res);
        input_abs_set_res(dev, ABS_Y, info->y_res);
        if (info->hw_version > 1) {
                input_abs_set_res(dev, ABS_MT_POSITION_X, info->x_res);
                input_abs_set_res(dev, ABS_MT_POSITION_Y, info->y_res);
        }

        etd->y_max = y_max;
        etd->width = width;

        return 0;
}

struct elantech_attr_data {
        size_t          field_offset;
        unsigned char   reg;
};

/*
 * Display a register value by reading a sysfs entry
 */
static ssize_t elantech_show_int_attr(struct psmouse *psmouse, void *data,
                                        char *buf)
{
        struct elantech_data *etd = psmouse->private;
        struct elantech_attr_data *attr = data;
        unsigned char *reg = (unsigned char *) etd + attr->field_offset;
        int rc = 0;

        if (attr->reg)
                rc = elantech_read_reg(psmouse, attr->reg, reg);

        return sprintf(buf, "0x%02x\n", (attr->reg && rc) ? -1 : *reg);
}

/*
 * Write a register value by writing a sysfs entry
 */
static ssize_t elantech_set_int_attr(struct psmouse *psmouse,
                                     void *data, const char *buf, size_t count)
{
        struct elantech_data *etd = psmouse->private;
        struct elantech_attr_data *attr = data;
        unsigned char *reg = (unsigned char *) etd + attr->field_offset;
        unsigned char value;
        int err;

        err = kstrtou8(buf, 16, &value);
        if (err)
                return err;

        /* Do we need to preserve some bits for version 2 hardware too? */
        if (etd->info.hw_version == 1) {
                if (attr->reg == 0x10)
                        /* Force absolute mode always on */
                        value |= ETP_R10_ABSOLUTE_MODE;
                else if (attr->reg == 0x11)
                        /* Force 4 byte mode always on */
                        value |= ETP_R11_4_BYTE_MODE;
        }

        if (!attr->reg || elantech_write_reg(psmouse, attr->reg, value) == 0)
                *reg = value;

        return count;
}

#define ELANTECH_INT_ATTR(_name, _register)                             \
        static struct elantech_attr_data elantech_attr_##_name = {      \
                .field_offset = offsetof(struct elantech_data, _name),  \
                .reg = _register,                                       \
        };                                                              \
        PSMOUSE_DEFINE_ATTR(_name, 0644,                                \
                            &elantech_attr_##_name,                     \
                            elantech_show_int_attr,                     \
                            elantech_set_int_attr)

#define ELANTECH_INFO_ATTR(_name)                                              \
        static struct elantech_attr_data elantech_attr_##_name = {             \
                .field_offset = offsetof(struct elantech_data, info) +         \
                                offsetof(struct elantech_device_info, _name),  \
                .reg = 0,                                                      \
        };                                                                     \
        PSMOUSE_DEFINE_ATTR(_name, 0644,                                       \
                            &elantech_attr_##_name,                            \
                            elantech_show_int_attr,                            \
                            elantech_set_int_attr)

ELANTECH_INT_ATTR(reg_07, 0x07);
ELANTECH_INT_ATTR(reg_10, 0x10);
ELANTECH_INT_ATTR(reg_11, 0x11);
ELANTECH_INT_ATTR(reg_20, 0x20);
ELANTECH_INT_ATTR(reg_21, 0x21);
ELANTECH_INT_ATTR(reg_22, 0x22);
ELANTECH_INT_ATTR(reg_23, 0x23);
ELANTECH_INT_ATTR(reg_24, 0x24);
ELANTECH_INT_ATTR(reg_25, 0x25);
ELANTECH_INT_ATTR(reg_26, 0x26);
ELANTECH_INFO_ATTR(debug);
ELANTECH_INFO_ATTR(paritycheck);
ELANTECH_INFO_ATTR(crc_enabled);

static struct attribute *elantech_attrs[] = {
        &psmouse_attr_reg_07.dattr.attr,
        &psmouse_attr_reg_10.dattr.attr,
        &psmouse_attr_reg_11.dattr.attr,
        &psmouse_attr_reg_20.dattr.attr,
        &psmouse_attr_reg_21.dattr.attr,
        &psmouse_attr_reg_22.dattr.attr,
        &psmouse_attr_reg_23.dattr.attr,
        &psmouse_attr_reg_24.dattr.attr,
        &psmouse_attr_reg_25.dattr.attr,
        &psmouse_attr_reg_26.dattr.attr,
        &psmouse_attr_debug.dattr.attr,
        &psmouse_attr_paritycheck.dattr.attr,
        &psmouse_attr_crc_enabled.dattr.attr,
        NULL
};

static const struct attribute_group elantech_attr_group = {
        .attrs = elantech_attrs,
};

static bool elantech_is_signature_valid(const unsigned char *param)
{
        static const unsigned char rates[] = { 200, 100, 80, 60, 40, 20, 10 };
        int i;

        if (param[0] == 0)
                return false;

        if (param[1] == 0)
                return true;

        /*
         * Some hw_version >= 4 models have a revision higher then 20. Meaning
         * that param[2] may be 10 or 20, skip the rates check for these.
         */
        if ((param[0] & 0x0f) >= 0x06 && (param[1] & 0xaf) == 0x0f &&
            param[2] < 40)
                return true;

        for (i = 0; i < ARRAY_SIZE(rates); i++)
                if (param[2] == rates[i])
                        return false;

        return true;
}

/*
 * Use magic knock to detect Elantech touchpad
 */
int elantech_detect(struct psmouse *psmouse, bool set_properties)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char param[3];

        ps2_command(ps2dev, NULL, PSMOUSE_CMD_RESET_DIS);

        if (ps2_command(ps2dev,  NULL, PSMOUSE_CMD_DISABLE) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
            ps2_command(ps2dev,  NULL, PSMOUSE_CMD_SETSCALE11) ||
            ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO)) {
                psmouse_dbg(psmouse, "sending Elantech magic knock failed.\n");
                return -1;
        }

        /*
         * Report this in case there are Elantech models that use a different
         * set of magic numbers
         */
        if (param[0] != 0x3c || param[1] != 0x03 ||
            (param[2] != 0xc8 && param[2] != 0x00)) {
                psmouse_dbg(psmouse,
                            "unexpected magic knock result 0x%02x, 0x%02x, 0x%02x.\n",
                            param[0], param[1], param[2]);
                return -1;
        }

        /*
         * Query touchpad's firmware version and see if it reports known
         * value to avoid mis-detection. Logitech mice are known to respond
         * to Elantech magic knock and there might be more.
         */
        if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
                psmouse_dbg(psmouse, "failed to query firmware version.\n");
                return -1;
        }

        psmouse_dbg(psmouse,
                    "Elantech version query result 0x%02x, 0x%02x, 0x%02x.\n",
                    param[0], param[1], param[2]);

        if (!elantech_is_signature_valid(param)) {
                psmouse_dbg(psmouse,
                            "Probably not a real Elantech touchpad. Aborting.\n");
                return -1;
        }

        if (set_properties) {
                psmouse->vendor = "Elantech";
                psmouse->name = "Touchpad";
        }

        return 0;
}

/*
 * Clean up sysfs entries when disconnecting
 */
static void elantech_disconnect(struct psmouse *psmouse)
{
        struct elantech_data *etd = psmouse->private;

        /*
         * We might have left a breadcrumb when trying to
         * set up SMbus companion.
         */
        psmouse_smbus_cleanup(psmouse);

        if (etd->tp_dev)
                input_unregister_device(etd->tp_dev);
        sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
                           &elantech_attr_group);
        kfree(psmouse->private);
        psmouse->private = NULL;
}

/*
 * Some hw_version 4 models fail to properly activate absolute mode on
 * resume without going through disable/enable cycle.
 */
static const struct dmi_system_id elantech_needs_reenable[] = {
#if defined(CONFIG_DMI) && defined(CONFIG_X86)
        {
                /* Lenovo N24 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "81AF"),
                },
        },
#endif
        { }
};

/*
 * Put the touchpad back into absolute mode when reconnecting
 */
static int elantech_reconnect(struct psmouse *psmouse)
{
        int err;

        psmouse_reset(psmouse);

        if (elantech_detect(psmouse, 0))
                return -1;

        if (dmi_check_system(elantech_needs_reenable)) {
                err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_DISABLE);
                if (err)
                        psmouse_warn(psmouse, "failed to deactivate mouse on %s: %d\n",
                                     psmouse->ps2dev.serio->phys, err);

                err = ps2_command(&psmouse->ps2dev, NULL, PSMOUSE_CMD_ENABLE);
                if (err)
                        psmouse_warn(psmouse, "failed to reactivate mouse on %s: %d\n",
                                     psmouse->ps2dev.serio->phys, err);
        }

        if (elantech_set_absolute_mode(psmouse)) {
                psmouse_err(psmouse,
                            "failed to put touchpad back into absolute mode.\n");
                return -1;
        }

        return 0;
}

/*
 * Some hw_version 4 models do not work with crc_disabled
 */
static const struct dmi_system_id elantech_dmi_force_crc_enabled[] = {
#if defined(CONFIG_DMI) && defined(CONFIG_X86)
        {
                /* Fujitsu H730 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H730"),
                },
        },
        {
                /* Fujitsu H760 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "CELSIUS H760"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E544  does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E544"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E546  does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E546"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E547 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E547"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E554  does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E554"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E556 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E556"),
                },
        },
        {
                /* Fujitsu LIFEBOOK E557 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK E557"),
                },
        },
        {
                /* Fujitsu LIFEBOOK U745 does not work with crc_enabled == 0 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "FUJITSU"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "LIFEBOOK U745"),
                },
        },
#endif
        { }
};

/*
 * Some hw_version 3 models go into error state when we try to set
 * bit 3 and/or bit 1 of r10.
 */
static const struct dmi_system_id no_hw_res_dmi_table[] = {
#if defined(CONFIG_DMI) && defined(CONFIG_X86)
        {
                /* Gigabyte U2442 */
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "GIGABYTE"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "U2442"),
                },
        },
#endif
        { }
};

/*
 * Change Report id 0x5E to 0x5F.
 */
static int elantech_change_report_id(struct psmouse *psmouse)
{
        /*
         * NOTE: the code is expecting to receive param[] as an array of 3
         * items (see __ps2_command()), even if in this case only 2 are
         * actually needed. Make sure the array size is 3 to avoid potential
         * stack out-of-bound accesses.
         */
        unsigned char param[3] = { 0x10, 0x03 };

        if (elantech_write_reg_params(psmouse, 0x7, param) ||
            elantech_read_reg_params(psmouse, 0x7, param) ||
            param[0] != 0x10 || param[1] != 0x03) {
                psmouse_err(psmouse, "Unable to change report ID to 0x5f.\n");
                return -EIO;
        }

        return 0;
}
/*
 * determine hardware version and set some properties according to it.
 */
static int elantech_set_properties(struct elantech_device_info *info)
{
        /* This represents the version of IC body. */
        info->ic_version = (info->fw_version & 0x0f0000) >> 16;

        /* Early version of Elan touchpads doesn't obey the rule. */
        if (info->fw_version < 0x020030 || info->fw_version == 0x020600)
                info->hw_version = 1;
        else {
                switch (info->ic_version) {
                case 2:
                case 4:
                        info->hw_version = 2;
                        break;
                case 5:
                        info->hw_version = 3;
                        break;
                case 6 ... 15:
                        info->hw_version = 4;
                        break;
                default:
                        return -1;
                }
        }

        /* Get information pattern for hw_version 4 */
        info->pattern = 0x00;
        if (info->ic_version == 0x0f && (info->fw_version & 0xff) <= 0x02)
                info->pattern = info->fw_version & 0xff;

        /* decide which send_cmd we're gonna use early */
        info->send_cmd = info->hw_version >= 3 ? elantech_send_cmd :
                                                 synaptics_send_cmd;

        /* Turn on packet checking by default */
        info->paritycheck = 1;

        /*
         * This firmware suffers from misreporting coordinates when
         * a touch action starts causing the mouse cursor or scrolled page
         * to jump. Enable a workaround.
         */
        info->jumpy_cursor =
                (info->fw_version == 0x020022 || info->fw_version == 0x020600);

        if (info->hw_version > 1) {
                /* For now show extra debug information */
                info->debug = 1;

                if (info->fw_version >= 0x020800)
                        info->reports_pressure = true;
        }

        /*
         * The signatures of v3 and v4 packets change depending on the
         * value of this hardware flag.
         */
        info->crc_enabled = (info->fw_version & 0x4000) == 0x4000 ||
                             dmi_check_system(elantech_dmi_force_crc_enabled);

        /* Enable real hardware resolution on hw_version 3 ? */
        info->set_hw_resolution = !dmi_check_system(no_hw_res_dmi_table);

        return 0;
}

static int elantech_query_info(struct psmouse *psmouse,
                               struct elantech_device_info *info)
{
        unsigned char param[3];
        unsigned char traces;
        unsigned char ic_body[3];

        memset(info, 0, sizeof(*info));

        /*
         * Do the version query again so we can store the result
         */
        if (synaptics_send_cmd(psmouse, ETP_FW_VERSION_QUERY, param)) {
                psmouse_err(psmouse, "failed to query firmware version.\n");
                return -EINVAL;
        }
        info->fw_version = (param[0] << 16) | (param[1] << 8) | param[2];

        if (elantech_set_properties(info)) {
                psmouse_err(psmouse, "unknown hardware version, aborting...\n");
                return -EINVAL;
        }
        psmouse_info(psmouse,
                     "assuming hardware version %d (with firmware version 0x%02x%02x%02x)\n",
                     info->hw_version, param[0], param[1], param[2]);

        if (info->send_cmd(psmouse, ETP_CAPABILITIES_QUERY,
            info->capabilities)) {
                psmouse_err(psmouse, "failed to query capabilities.\n");
                return -EINVAL;
        }
        psmouse_info(psmouse,
                     "Synaptics capabilities query result 0x%02x, 0x%02x, 0x%02x.\n",
                     info->capabilities[0], info->capabilities[1],
                     info->capabilities[2]);

        if (info->hw_version != 1) {
                if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, info->samples)) {
                        psmouse_err(psmouse, "failed to query sample data\n");
                        return -EINVAL;
                }
                psmouse_info(psmouse,
                             "Elan sample query result %02x, %02x, %02x\n",
                             info->samples[0],
                             info->samples[1],
                             info->samples[2]);
        }

        if (info->pattern > 0x00 && info->ic_version == 0xf) {
                if (info->send_cmd(psmouse, ETP_ICBODY_QUERY, ic_body)) {
                        psmouse_err(psmouse, "failed to query ic body\n");
                        return -EINVAL;
                }
                info->ic_version = be16_to_cpup((__be16 *)ic_body);
                psmouse_info(psmouse,
                             "Elan ic body: %#04x, current fw version: %#02x\n",
                             info->ic_version, ic_body[2]);
        }

        info->product_id = be16_to_cpup((__be16 *)info->samples);
        if (info->pattern == 0x00)
                info->product_id &= 0xff;

        if (info->samples[1] == 0x74 && info->hw_version == 0x03) {
                /*
                 * This module has a bug which makes absolute mode
                 * unusable, so let's abort so we'll be using standard
                 * PS/2 protocol.
                 */
                psmouse_info(psmouse,
                             "absolute mode broken, forcing standard PS/2 protocol\n");
                return -ENODEV;
        }

        /* The MSB indicates the presence of the trackpoint */
        info->has_trackpoint = (info->capabilities[0] & 0x80) == 0x80;

        if (info->has_trackpoint && info->ic_version == 0x0011 &&
            (info->product_id == 0x08 || info->product_id == 0x09 ||
             info->product_id == 0x0d || info->product_id == 0x0e)) {
                /*
                 * This module has a bug which makes trackpoint in SMBus
                 * mode return invalid data unless trackpoint is switched
                 * from using 0x5e reports to 0x5f. If we are not able to
                 * make the switch, let's abort initialization so we'll be
                 * using standard PS/2 protocol.
                 */
                if (elantech_change_report_id(psmouse)) {
                        psmouse_info(psmouse,
                                     "Trackpoint report is broken, forcing standard PS/2 protocol\n");
                        return -ENODEV;
                }
        }

        info->x_res = 31;
        info->y_res = 31;
        if (info->hw_version == 4) {
                if (elantech_get_resolution_v4(psmouse,
                                               &info->x_res,
                                               &info->y_res,
                                               &info->bus)) {
                        psmouse_warn(psmouse,
                                     "failed to query resolution data.\n");
                }
        }

        /* query range information */
        switch (info->hw_version) {
        case 1:
                info->x_min = ETP_XMIN_V1;
                info->y_min = ETP_YMIN_V1;
                info->x_max = ETP_XMAX_V1;
                info->y_max = ETP_YMAX_V1;
                break;

        case 2:
                if (info->fw_version == 0x020800 ||
                    info->fw_version == 0x020b00 ||
                    info->fw_version == 0x020030) {
                        info->x_min = ETP_XMIN_V2;
                        info->y_min = ETP_YMIN_V2;
                        info->x_max = ETP_XMAX_V2;
                        info->y_max = ETP_YMAX_V2;
                } else {
                        int i;
                        int fixed_dpi;

                        i = (info->fw_version > 0x020800 &&
                             info->fw_version < 0x020900) ? 1 : 2;

                        if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
                                return -EINVAL;

                        fixed_dpi = param[1] & 0x10;

                        if (((info->fw_version >> 16) == 0x14) && fixed_dpi) {
                                if (info->send_cmd(psmouse, ETP_SAMPLE_QUERY, param))
                                        return -EINVAL;

                                info->x_max = (info->capabilities[1] - i) * param[1] / 2;
                                info->y_max = (info->capabilities[2] - i) * param[2] / 2;
                        } else if (info->fw_version == 0x040216) {
                                info->x_max = 819;
                                info->y_max = 405;
                        } else if (info->fw_version == 0x040219 || info->fw_version == 0x040215) {
                                info->x_max = 900;
                                info->y_max = 500;
                        } else {
                                info->x_max = (info->capabilities[1] - i) * 64;
                                info->y_max = (info->capabilities[2] - i) * 64;
                        }
                }
                break;

        case 3:
                if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
                        return -EINVAL;

                info->x_max = (0x0f & param[0]) << 8 | param[1];
                info->y_max = (0xf0 & param[0]) << 4 | param[2];
                break;

        case 4:
                if (info->send_cmd(psmouse, ETP_FW_ID_QUERY, param))
                        return -EINVAL;

                info->x_max = (0x0f & param[0]) << 8 | param[1];
                info->y_max = (0xf0 & param[0]) << 4 | param[2];
                traces = info->capabilities[1];
                if ((traces < 2) || (traces > info->x_max))
                        return -EINVAL;

                info->width = info->x_max / (traces - 1);

                /* column number of traces */
                info->x_traces = traces;

                /* row number of traces */
                traces = info->capabilities[2];
                if ((traces >= 2) && (traces <= info->y_max))
                        info->y_traces = traces;

                break;
        }

        /* check for the middle button: DMI matching or new v4 firmwares */
        info->has_middle_button = dmi_check_system(elantech_dmi_has_middle_button) ||
                                  (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) &&
                                   !elantech_is_buttonpad(info));

        return 0;
}

#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)

/*
 * The newest Elantech device can use a secondary bus (over SMBus) which
 * provides a better bandwidth and allow a better control of the touchpads.
 * This is used to decide if we need to use this bus or not.
 */
enum {
        ELANTECH_SMBUS_NOT_SET = -1,
        ELANTECH_SMBUS_OFF,
        ELANTECH_SMBUS_ON,
};

static int elantech_smbus = IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ?
                ELANTECH_SMBUS_NOT_SET : ELANTECH_SMBUS_OFF;
module_param_named(elantech_smbus, elantech_smbus, int, 0644);
MODULE_PARM_DESC(elantech_smbus, "Use a secondary bus for the Elantech device.");

static const char * const i2c_blacklist_pnp_ids[] = {
        /*
         * These are known to not be working properly as bits are missing
         * in elan_i2c.
         */
        NULL
};

static int elantech_create_smbus(struct psmouse *psmouse,
                                 struct elantech_device_info *info,
                                 bool leave_breadcrumbs)
{
        struct property_entry i2c_props[11] = {};
        struct i2c_board_info smbus_board = {
                I2C_BOARD_INFO("elan_i2c", 0x15),
                .flags = I2C_CLIENT_HOST_NOTIFY,
        };
        unsigned int idx = 0;

        i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-size-x",
                                                   info->x_max + 1);
        i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-size-y",
                                                   info->y_max + 1);
        i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-min-x",
                                                   info->x_min);
        i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-min-y",
                                                   info->y_min);
        if (info->x_res)
                i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-x-mm",
                                                      (info->x_max + 1) / info->x_res);
        if (info->y_res)
                i2c_props[idx++] = PROPERTY_ENTRY_U32("touchscreen-y-mm",
                                                      (info->y_max + 1) / info->y_res);

        if (info->has_trackpoint)
                i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,trackpoint");

        if (info->has_middle_button)
                i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,middle-button");

        if (info->x_traces)
                i2c_props[idx++] = PROPERTY_ENTRY_U32("elan,x_traces",
                                                      info->x_traces);
        if (info->y_traces)
                i2c_props[idx++] = PROPERTY_ENTRY_U32("elan,y_traces",
                                                      info->y_traces);

        if (elantech_is_buttonpad(info))
                i2c_props[idx++] = PROPERTY_ENTRY_BOOL("elan,clickpad");

        smbus_board.fwnode = fwnode_create_software_node(i2c_props, NULL);
        if (IS_ERR(smbus_board.fwnode))
                return PTR_ERR(smbus_board.fwnode);

        return psmouse_smbus_init(psmouse, &smbus_board, NULL, 0, false,
                                  leave_breadcrumbs);
}

/*
 * elantech_setup_smbus - called once the PS/2 devices are enumerated
 * and decides to instantiate a SMBus InterTouch device.
 */
static int elantech_setup_smbus(struct psmouse *psmouse,
                                struct elantech_device_info *info,
                                bool leave_breadcrumbs)
{
        int error;

        if (elantech_smbus == ELANTECH_SMBUS_OFF)
                return -ENXIO;

        if (elantech_smbus == ELANTECH_SMBUS_NOT_SET) {
                /*
                 * New ICs are enabled by default, unless mentioned in
                 * i2c_blacklist_pnp_ids.
                 * Old ICs are up to the user to decide.
                 */
                if (!ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version) ||
                    psmouse_matches_pnp_id(psmouse, i2c_blacklist_pnp_ids))
                        return -ENXIO;
        }

        psmouse_info(psmouse, "Trying to set up SMBus access\n");

        error = elantech_create_smbus(psmouse, info, leave_breadcrumbs);
        if (error) {
                if (error == -EAGAIN)
                        psmouse_info(psmouse, "SMbus companion is not ready yet\n");
                else
                        psmouse_err(psmouse, "unable to create intertouch device\n");

                return error;
        }

        return 0;
}

static bool elantech_use_host_notify(struct psmouse *psmouse,
                                     struct elantech_device_info *info)
{
        if (ETP_NEW_IC_SMBUS_HOST_NOTIFY(info->fw_version))
                return true;

        switch (info->bus) {
        case ETP_BUS_PS2_ONLY:
                /* expected case */
                break;
        case ETP_BUS_SMB_ALERT_ONLY:
        case ETP_BUS_PS2_SMB_ALERT:
                psmouse_dbg(psmouse, "Ignoring SMBus provider through alert protocol.\n");
                break;
        case ETP_BUS_SMB_HST_NTFY_ONLY:
        case ETP_BUS_PS2_SMB_HST_NTFY:
                return true;
        default:
                psmouse_dbg(psmouse,
                            "Ignoring SMBus bus provider %d.\n",
                            info->bus);
        }

        return false;
}

int elantech_init_smbus(struct psmouse *psmouse)
{
        struct elantech_device_info info;
        int error;

        psmouse_reset(psmouse);

        error = elantech_query_info(psmouse, &info);
        if (error)
                goto init_fail;

        if (info.hw_version < 4) {
                error = -ENXIO;
                goto init_fail;
        }

        return elantech_create_smbus(psmouse, &info, false);
 init_fail:
        psmouse_reset(psmouse);
        return error;
}
#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */

/*
 * Initialize the touchpad and create sysfs entries
 */
static int elantech_setup_ps2(struct psmouse *psmouse,
                              struct elantech_device_info *info)
{
        struct elantech_data *etd;
        int i;
        int error = -EINVAL;
        struct input_dev *tp_dev;

        psmouse->private = etd = kzalloc_obj(*etd);
        if (!etd)
                return -ENOMEM;

        etd->info = *info;

        etd->parity[0] = 1;
        for (i = 1; i < 256; i++)
                etd->parity[i] = etd->parity[i & (i - 1)] ^ 1;

        if (elantech_set_absolute_mode(psmouse)) {
                psmouse_err(psmouse,
                            "failed to put touchpad into absolute mode.\n");
                goto init_fail;
        }

        if (info->fw_version == 0x381f17) {
                etd->original_set_rate = psmouse->set_rate;
                psmouse->set_rate = elantech_set_rate_restore_reg_07;
        }

        if (elantech_set_input_params(psmouse)) {
                psmouse_err(psmouse, "failed to query touchpad range.\n");
                goto init_fail;
        }

        error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
                                   &elantech_attr_group);
        if (error) {
                psmouse_err(psmouse,
                            "failed to create sysfs attributes, error: %d.\n",
                            error);
                goto init_fail;
        }

        if (info->has_trackpoint) {
                tp_dev = input_allocate_device();

                if (!tp_dev) {
                        error = -ENOMEM;
                        goto init_fail_tp_alloc;
                }

                etd->tp_dev = tp_dev;
                snprintf(etd->tp_phys, sizeof(etd->tp_phys), "%s/input1",
                        psmouse->ps2dev.serio->phys);
                tp_dev->phys = etd->tp_phys;
                tp_dev->name = "ETPS/2 Elantech TrackPoint";
                tp_dev->id.bustype = BUS_I8042;
                tp_dev->id.vendor  = 0x0002;
                tp_dev->id.product = PSMOUSE_ELANTECH;
                tp_dev->id.version = 0x0000;
                tp_dev->dev.parent = &psmouse->ps2dev.serio->dev;
                tp_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL);
                tp_dev->relbit[BIT_WORD(REL_X)] =
                        BIT_MASK(REL_X) | BIT_MASK(REL_Y);
                tp_dev->keybit[BIT_WORD(BTN_LEFT)] =
                        BIT_MASK(BTN_LEFT) | BIT_MASK(BTN_MIDDLE) |
                        BIT_MASK(BTN_RIGHT);

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

                error = input_register_device(etd->tp_dev);
                if (error < 0)
                        goto init_fail_tp_reg;
        }

        psmouse->protocol_handler = elantech_process_byte;
        psmouse->disconnect = elantech_disconnect;
        psmouse->reconnect = elantech_reconnect;
        psmouse->fast_reconnect = NULL;
        psmouse->pktsize = info->hw_version > 1 ? 6 : 4;

        return 0;
 init_fail_tp_reg:
        input_free_device(tp_dev);
 init_fail_tp_alloc:
        sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
                           &elantech_attr_group);
 init_fail:
        kfree(etd);
        return error;
}

int elantech_init_ps2(struct psmouse *psmouse)
{
        struct elantech_device_info info;
        int error;

        psmouse_reset(psmouse);

        error = elantech_query_info(psmouse, &info);
        if (error)
                goto init_fail;

        error = elantech_setup_ps2(psmouse, &info);
        if (error)
                goto init_fail;

        return 0;
 init_fail:
        psmouse_reset(psmouse);
        return error;
}

int elantech_init(struct psmouse *psmouse)
{
        struct elantech_device_info info;
        int error;

        psmouse_reset(psmouse);

        error = elantech_query_info(psmouse, &info);
        if (error)
                goto init_fail;

#if defined(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)

        if (elantech_use_host_notify(psmouse, &info)) {
                if (!IS_ENABLED(CONFIG_MOUSE_ELAN_I2C_SMBUS) ||
                    !IS_ENABLED(CONFIG_MOUSE_PS2_ELANTECH_SMBUS)) {
                        psmouse_warn(psmouse,
                                     "The touchpad can support a better bus than the too old PS/2 protocol. "
                                     "Make sure MOUSE_PS2_ELANTECH_SMBUS and MOUSE_ELAN_I2C_SMBUS are enabled to get a better touchpad experience.\n");
                }
                error = elantech_setup_smbus(psmouse, &info, true);
                if (!error)
                        return PSMOUSE_ELANTECH_SMBUS;
        }

#endif /* CONFIG_MOUSE_PS2_ELANTECH_SMBUS */

        error = elantech_setup_ps2(psmouse, &info);
        if (error < 0) {
                /*
                 * Not using any flavor of Elantech support, so clean up
                 * SMbus breadcrumbs, if any.
                 */
                psmouse_smbus_cleanup(psmouse);
                goto init_fail;
        }

        return PSMOUSE_ELANTECH;
 init_fail:
        psmouse_reset(psmouse);
        return error;
}