// SPDX-License-Identifier: GPL-2.0-or-later
/*-
 * Finger Sensing Pad PS/2 mouse driver.
 *
 * Copyright (C) 2005-2007 Asia Vital Components Co., Ltd.
 * Copyright (C) 2005-2012 Tai-hwa Liang, Sentelic Corporation.
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/ctype.h>
#include <linux/libps2.h>
#include <linux/serio.h>
#include <linux/jiffies.h>
#include <linux/slab.h>

#include "psmouse.h"
#include "sentelic.h"

/*
 * Timeout for FSP PS/2 command only (in milliseconds).
 */
#define FSP_CMD_TIMEOUT         200
#define FSP_CMD_TIMEOUT2        30

#define GET_ABS_X(packet)       ((packet[1] << 2) | ((packet[3] >> 2) & 0x03))
#define GET_ABS_Y(packet)       ((packet[2] << 2) | (packet[3] & 0x03))

/** Driver version. */
static const char fsp_drv_ver[] = "1.1.0-K";

/*
 * Make sure that the value being sent to FSP will not conflict with
 * possible sample rate values.
 */
static unsigned char fsp_test_swap_cmd(unsigned char reg_val)
{
        switch (reg_val) {
        case 10: case 20: case 40: case 60: case 80: case 100: case 200:
                /*
                 * The requested value being sent to FSP matched to possible
                 * sample rates, swap the given value such that the hardware
                 * wouldn't get confused.
                 */
                return (reg_val >> 4) | (reg_val << 4);
        default:
                return reg_val; /* swap isn't necessary */
        }
}

/*
 * Make sure that the value being sent to FSP will not conflict with certain
 * commands.
 */
static unsigned char fsp_test_invert_cmd(unsigned char reg_val)
{
        switch (reg_val) {
        case 0xe9: case 0xee: case 0xf2: case 0xff:
                /*
                 * The requested value being sent to FSP matched to certain
                 * commands, inverse the given value such that the hardware
                 * wouldn't get confused.
                 */
                return ~reg_val;
        default:
                return reg_val; /* inversion isn't necessary */
        }
}

static int fsp_reg_read(struct psmouse *psmouse, int reg_addr, int *reg_val)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char param[3];
        unsigned char addr;
        int rc = -1;

        /*
         * We need to shut off the device and switch it into command
         * mode so we don't confuse our protocol handler. We don't need
         * to do that for writes because sysfs set helper does this for
         * us.
         */
        psmouse_deactivate(psmouse);

        ps2_begin_command(ps2dev);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        /* should return 0xfe(request for resending) */
        ps2_sendbyte(ps2dev, 0x66, FSP_CMD_TIMEOUT2);
        /* should return 0xfc(failed) */
        ps2_sendbyte(ps2dev, 0x88, FSP_CMD_TIMEOUT2);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        if ((addr = fsp_test_invert_cmd(reg_addr)) != reg_addr) {
                ps2_sendbyte(ps2dev, 0x68, FSP_CMD_TIMEOUT2);
        } else if ((addr = fsp_test_swap_cmd(reg_addr)) != reg_addr) {
                /* swapping is required */
                ps2_sendbyte(ps2dev, 0xcc, FSP_CMD_TIMEOUT2);
                /* expect 0xfe */
        } else {
                /* swapping isn't necessary */
                ps2_sendbyte(ps2dev, 0x66, FSP_CMD_TIMEOUT2);
                /* expect 0xfe */
        }
        /* should return 0xfc(failed) */
        ps2_sendbyte(ps2dev, addr, FSP_CMD_TIMEOUT);

        if (__ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO) < 0)
                goto out;

        *reg_val = param[2];
        rc = 0;

 out:
        ps2_end_command(ps2dev);
        psmouse_activate(psmouse);
        psmouse_dbg(psmouse,
                    "READ REG: 0x%02x is 0x%02x (rc = %d)\n",
                    reg_addr, *reg_val, rc);
        return rc;
}

static int fsp_reg_write(struct psmouse *psmouse, int reg_addr, int reg_val)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char v;
        int rc = -1;

        ps2_begin_command(ps2dev);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        if ((v = fsp_test_invert_cmd(reg_addr)) != reg_addr) {
                /* inversion is required */
                ps2_sendbyte(ps2dev, 0x74, FSP_CMD_TIMEOUT2);
        } else {
                if ((v = fsp_test_swap_cmd(reg_addr)) != reg_addr) {
                        /* swapping is required */
                        ps2_sendbyte(ps2dev, 0x77, FSP_CMD_TIMEOUT2);
                } else {
                        /* swapping isn't necessary */
                        ps2_sendbyte(ps2dev, 0x55, FSP_CMD_TIMEOUT2);
                }
        }
        /* write the register address in correct order */
        ps2_sendbyte(ps2dev, v, FSP_CMD_TIMEOUT2);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        if ((v = fsp_test_invert_cmd(reg_val)) != reg_val) {
                /* inversion is required */
                ps2_sendbyte(ps2dev, 0x47, FSP_CMD_TIMEOUT2);
        } else if ((v = fsp_test_swap_cmd(reg_val)) != reg_val) {
                /* swapping is required */
                ps2_sendbyte(ps2dev, 0x44, FSP_CMD_TIMEOUT2);
        } else {
                /* swapping isn't necessary */
                ps2_sendbyte(ps2dev, 0x33, FSP_CMD_TIMEOUT2);
        }

        /* write the register value in correct order */
        ps2_sendbyte(ps2dev, v, FSP_CMD_TIMEOUT2);
        rc = 0;

 out:
        ps2_end_command(ps2dev);
        psmouse_dbg(psmouse,
                    "WRITE REG: 0x%02x to 0x%02x (rc = %d)\n",
                    reg_addr, reg_val, rc);
        return rc;
}

/* Enable register clock gating for writing certain registers */
static int fsp_reg_write_enable(struct psmouse *psmouse, bool enable)
{
        int v, nv;

        if (fsp_reg_read(psmouse, FSP_REG_SYSCTL1, &v) == -1)
                return -1;

        if (enable)
                nv = v | FSP_BIT_EN_REG_CLK;
        else
                nv = v & ~FSP_BIT_EN_REG_CLK;

        /* only write if necessary */
        if (nv != v)
                if (fsp_reg_write(psmouse, FSP_REG_SYSCTL1, nv) == -1)
                        return -1;

        return 0;
}

static int fsp_page_reg_read(struct psmouse *psmouse, int *reg_val)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char param[3];
        int rc = -1;

        psmouse_deactivate(psmouse);

        ps2_begin_command(ps2dev);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        ps2_sendbyte(ps2dev, 0x66, FSP_CMD_TIMEOUT2);
        ps2_sendbyte(ps2dev, 0x88, FSP_CMD_TIMEOUT2);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        ps2_sendbyte(ps2dev, 0x83, FSP_CMD_TIMEOUT2);
        ps2_sendbyte(ps2dev, 0x88, FSP_CMD_TIMEOUT2);

        /* get the returned result */
        if (__ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
                goto out;

        *reg_val = param[2];
        rc = 0;

 out:
        ps2_end_command(ps2dev);
        psmouse_activate(psmouse);
        psmouse_dbg(psmouse,
                    "READ PAGE REG: 0x%02x (rc = %d)\n",
                    *reg_val, rc);
        return rc;
}

static int fsp_page_reg_write(struct psmouse *psmouse, int reg_val)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char v;
        int rc = -1;

        ps2_begin_command(ps2dev);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        ps2_sendbyte(ps2dev, 0x38, FSP_CMD_TIMEOUT2);
        ps2_sendbyte(ps2dev, 0x88, FSP_CMD_TIMEOUT2);

        if (ps2_sendbyte(ps2dev, 0xf3, FSP_CMD_TIMEOUT) < 0)
                goto out;

        if ((v = fsp_test_invert_cmd(reg_val)) != reg_val) {
                ps2_sendbyte(ps2dev, 0x47, FSP_CMD_TIMEOUT2);
        } else if ((v = fsp_test_swap_cmd(reg_val)) != reg_val) {
                /* swapping is required */
                ps2_sendbyte(ps2dev, 0x44, FSP_CMD_TIMEOUT2);
        } else {
                /* swapping isn't necessary */
                ps2_sendbyte(ps2dev, 0x33, FSP_CMD_TIMEOUT2);
        }

        ps2_sendbyte(ps2dev, v, FSP_CMD_TIMEOUT2);
        rc = 0;

 out:
        ps2_end_command(ps2dev);
        psmouse_dbg(psmouse,
                    "WRITE PAGE REG: to 0x%02x (rc = %d)\n",
                    reg_val, rc);
        return rc;
}

static int fsp_get_version(struct psmouse *psmouse, int *version)
{
        if (fsp_reg_read(psmouse, FSP_REG_VERSION, version))
                return -EIO;

        return 0;
}

static int fsp_get_revision(struct psmouse *psmouse, int *rev)
{
        if (fsp_reg_read(psmouse, FSP_REG_REVISION, rev))
                return -EIO;

        return 0;
}

static int fsp_get_sn(struct psmouse *psmouse, int *sn)
{
        int v0, v1, v2;
        int rc = -EIO;

        /* production number since Cx is available at: 0x0b40 ~ 0x0b42 */
        if (fsp_page_reg_write(psmouse, FSP_PAGE_0B))
                goto out;
        if (fsp_reg_read(psmouse, FSP_REG_SN0, &v0))
                goto out;
        if (fsp_reg_read(psmouse, FSP_REG_SN1, &v1))
                goto out;
        if (fsp_reg_read(psmouse, FSP_REG_SN2, &v2))
                goto out;
        *sn = (v0 << 16) | (v1 << 8) | v2;
        rc = 0;
out:
        fsp_page_reg_write(psmouse, FSP_PAGE_DEFAULT);
        return rc;
}

static int fsp_get_buttons(struct psmouse *psmouse, int *btn)
{
        static const int buttons[] = {
                0x16, /* Left/Middle/Right/Forward/Backward & Scroll Up/Down */
                0x06, /* Left/Middle/Right & Scroll Up/Down/Right/Left */
                0x04, /* Left/Middle/Right & Scroll Up/Down */
                0x02, /* Left/Middle/Right */
        };
        int val;

        if (fsp_reg_read(psmouse, FSP_REG_TMOD_STATUS, &val) == -1)
                return -EIO;

        *btn = buttons[(val & 0x30) >> 4];
        return 0;
}

/* Enable on-pad command tag output */
static int fsp_opc_tag_enable(struct psmouse *psmouse, bool enable)
{
        int v, nv;
        int res = 0;

        if (fsp_reg_read(psmouse, FSP_REG_OPC_QDOWN, &v) == -1) {
                psmouse_err(psmouse, "Unable get OPC state.\n");
                return -EIO;
        }

        if (enable)
                nv = v | FSP_BIT_EN_OPC_TAG;
        else
                nv = v & ~FSP_BIT_EN_OPC_TAG;

        /* only write if necessary */
        if (nv != v) {
                fsp_reg_write_enable(psmouse, true);
                res = fsp_reg_write(psmouse, FSP_REG_OPC_QDOWN, nv);
                fsp_reg_write_enable(psmouse, false);
        }

        if (res != 0) {
                psmouse_err(psmouse, "Unable to enable OPC tag.\n");
                res = -EIO;
        }

        return res;
}

static int fsp_onpad_vscr(struct psmouse *psmouse, bool enable)
{
        struct fsp_data *pad = psmouse->private;
        int val;

        if (fsp_reg_read(psmouse, FSP_REG_ONPAD_CTL, &val))
                return -EIO;

        pad->vscroll = enable;

        if (enable)
                val |= (FSP_BIT_FIX_VSCR | FSP_BIT_ONPAD_ENABLE);
        else
                val &= ~FSP_BIT_FIX_VSCR;

        if (fsp_reg_write(psmouse, FSP_REG_ONPAD_CTL, val))
                return -EIO;

        return 0;
}

static int fsp_onpad_hscr(struct psmouse *psmouse, bool enable)
{
        struct fsp_data *pad = psmouse->private;
        int val, v2;

        if (fsp_reg_read(psmouse, FSP_REG_ONPAD_CTL, &val))
                return -EIO;

        if (fsp_reg_read(psmouse, FSP_REG_SYSCTL5, &v2))
                return -EIO;

        pad->hscroll = enable;

        if (enable) {
                val |= (FSP_BIT_FIX_HSCR | FSP_BIT_ONPAD_ENABLE);
                v2 |= FSP_BIT_EN_MSID6;
        } else {
                val &= ~FSP_BIT_FIX_HSCR;
                v2 &= ~(FSP_BIT_EN_MSID6 | FSP_BIT_EN_MSID7 | FSP_BIT_EN_MSID8);
        }

        if (fsp_reg_write(psmouse, FSP_REG_ONPAD_CTL, val))
                return -EIO;

        /* reconfigure horizontal scrolling packet output */
        if (fsp_reg_write(psmouse, FSP_REG_SYSCTL5, v2))
                return -EIO;

        return 0;
}

/*
 * Write device specific initial parameters.
 *
 * ex: 0xab 0xcd - write oxcd into register 0xab
 */
static ssize_t fsp_attr_set_setreg(struct psmouse *psmouse, void *data,
                                   const char *buf, size_t count)
{
        unsigned int reg, val;
        char *rest;
        ssize_t retval;

        reg = simple_strtoul(buf, &rest, 16);
        if (rest == buf || *rest != ' ' || reg > 0xff)
                return -EINVAL;

        retval = kstrtouint(rest + 1, 16, &val);
        if (retval)
                return retval;

        if (val > 0xff)
                return -EINVAL;

        if (fsp_reg_write_enable(psmouse, true))
                return -EIO;

        retval = fsp_reg_write(psmouse, reg, val) < 0 ? -EIO : count;

        fsp_reg_write_enable(psmouse, false);

        return retval;
}

PSMOUSE_DEFINE_WO_ATTR(setreg, S_IWUSR, NULL, fsp_attr_set_setreg);

static ssize_t fsp_attr_show_getreg(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        struct fsp_data *pad = psmouse->private;

        return sprintf(buf, "%02x%02x\n", pad->last_reg, pad->last_val);
}

/*
 * Read a register from device.
 *
 * ex: 0xab -- read content from register 0xab
 */
static ssize_t fsp_attr_set_getreg(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        struct fsp_data *pad = psmouse->private;
        unsigned int reg, val;
        int err;

        err = kstrtouint(buf, 16, &reg);
        if (err)
                return err;

        if (reg > 0xff)
                return -EINVAL;

        if (fsp_reg_read(psmouse, reg, &val))
                return -EIO;

        pad->last_reg = reg;
        pad->last_val = val;

        return count;
}

PSMOUSE_DEFINE_ATTR(getreg, S_IWUSR | S_IRUGO, NULL,
                        fsp_attr_show_getreg, fsp_attr_set_getreg);

static ssize_t fsp_attr_show_pagereg(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        int val = 0;

        if (fsp_page_reg_read(psmouse, &val))
                return -EIO;

        return sprintf(buf, "%02x\n", val);
}

static ssize_t fsp_attr_set_pagereg(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        unsigned int val;
        int err;

        err = kstrtouint(buf, 16, &val);
        if (err)
                return err;

        if (val > 0xff)
                return -EINVAL;

        if (fsp_page_reg_write(psmouse, val))
                return -EIO;

        return count;
}

PSMOUSE_DEFINE_ATTR(page, S_IWUSR | S_IRUGO, NULL,
                        fsp_attr_show_pagereg, fsp_attr_set_pagereg);

static ssize_t fsp_attr_show_vscroll(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        struct fsp_data *pad = psmouse->private;

        return sprintf(buf, "%d\n", pad->vscroll);
}

static ssize_t fsp_attr_set_vscroll(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        unsigned int val;
        int err;

        err = kstrtouint(buf, 10, &val);
        if (err)
                return err;

        if (val > 1)
                return -EINVAL;

        fsp_onpad_vscr(psmouse, val);

        return count;
}

PSMOUSE_DEFINE_ATTR(vscroll, S_IWUSR | S_IRUGO, NULL,
                        fsp_attr_show_vscroll, fsp_attr_set_vscroll);

static ssize_t fsp_attr_show_hscroll(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        struct fsp_data *pad = psmouse->private;

        return sprintf(buf, "%d\n", pad->hscroll);
}

static ssize_t fsp_attr_set_hscroll(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        unsigned int val;
        int err;

        err = kstrtouint(buf, 10, &val);
        if (err)
                return err;

        if (val > 1)
                return -EINVAL;

        fsp_onpad_hscr(psmouse, val);

        return count;
}

PSMOUSE_DEFINE_ATTR(hscroll, S_IWUSR | S_IRUGO, NULL,
                        fsp_attr_show_hscroll, fsp_attr_set_hscroll);

static ssize_t fsp_attr_show_flags(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        struct fsp_data *pad = psmouse->private;

        return sprintf(buf, "%c\n",
                        pad->flags & FSPDRV_FLAG_EN_OPC ? 'C' : 'c');
}

static ssize_t fsp_attr_set_flags(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        struct fsp_data *pad = psmouse->private;
        size_t i;

        for (i = 0; i < count; i++) {
                switch (buf[i]) {
                case 'C':
                        pad->flags |= FSPDRV_FLAG_EN_OPC;
                        break;
                case 'c':
                        pad->flags &= ~FSPDRV_FLAG_EN_OPC;
                        break;
                default:
                        return -EINVAL;
                }
        }
        return count;
}

PSMOUSE_DEFINE_ATTR(flags, S_IWUSR | S_IRUGO, NULL,
                        fsp_attr_show_flags, fsp_attr_set_flags);

static ssize_t fsp_attr_show_ver(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        return sprintf(buf, "Sentelic FSP kernel module %s\n", fsp_drv_ver);
}

PSMOUSE_DEFINE_RO_ATTR(ver, S_IRUGO, NULL, fsp_attr_show_ver);

static struct attribute *fsp_attributes[] = {
        &psmouse_attr_setreg.dattr.attr,
        &psmouse_attr_getreg.dattr.attr,
        &psmouse_attr_page.dattr.attr,
        &psmouse_attr_vscroll.dattr.attr,
        &psmouse_attr_hscroll.dattr.attr,
        &psmouse_attr_flags.dattr.attr,
        &psmouse_attr_ver.dattr.attr,
        NULL
};

static struct attribute_group fsp_attribute_group = {
        .attrs = fsp_attributes,
};

#ifdef  FSP_DEBUG
static void fsp_packet_debug(struct psmouse *psmouse, unsigned char packet[])
{
        static unsigned int ps2_packet_cnt;
        static unsigned int ps2_last_second;
        unsigned int jiffies_msec;
        const char *packet_type = "UNKNOWN";
        unsigned short abs_x = 0, abs_y = 0;

        /* Interpret & dump the packet data. */
        switch (packet[0] >> FSP_PKT_TYPE_SHIFT) {
        case FSP_PKT_TYPE_ABS:
                packet_type = "Absolute";
                abs_x = GET_ABS_X(packet);
                abs_y = GET_ABS_Y(packet);
                break;
        case FSP_PKT_TYPE_NORMAL:
                packet_type = "Normal";
                break;
        case FSP_PKT_TYPE_NOTIFY:
                packet_type = "Notify";
                break;
        case FSP_PKT_TYPE_NORMAL_OPC:
                packet_type = "Normal-OPC";
                break;
        }

        ps2_packet_cnt++;
        jiffies_msec = jiffies_to_msecs(jiffies);
        psmouse_dbg(psmouse,
                    "%08dms %s packets: %02x, %02x, %02x, %02x; "
                    "abs_x: %d, abs_y: %d\n",
                    jiffies_msec, packet_type,
                    packet[0], packet[1], packet[2], packet[3], abs_x, abs_y);

        if (jiffies_msec - ps2_last_second > 1000) {
                psmouse_dbg(psmouse, "PS/2 packets/sec = %d\n", ps2_packet_cnt);
                ps2_packet_cnt = 0;
                ps2_last_second = jiffies_msec;
        }
}
#else
static void fsp_packet_debug(struct psmouse *psmouse, unsigned char packet[])
{
}
#endif

static void fsp_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);
        }
}

static psmouse_ret_t fsp_process_byte(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct fsp_data *ad = psmouse->private;
        unsigned char *packet = psmouse->packet;
        unsigned char button_status = 0, lscroll = 0, rscroll = 0;
        unsigned short abs_x, abs_y, fgrs = 0;

        if (psmouse->pktcnt < 4)
                return PSMOUSE_GOOD_DATA;

        /*
         * Full packet accumulated, process it
         */

        fsp_packet_debug(psmouse, packet);

        switch (psmouse->packet[0] >> FSP_PKT_TYPE_SHIFT) {
        case FSP_PKT_TYPE_ABS:

                if ((packet[0] == 0x48 || packet[0] == 0x49) &&
                    packet[1] == 0 && packet[2] == 0) {
                        /*
                         * Ignore coordinate noise when finger leaving the
                         * surface, otherwise cursor may jump to upper-left
                         * corner.
                         */
                        packet[3] &= 0xf0;
                }

                abs_x = GET_ABS_X(packet);
                abs_y = GET_ABS_Y(packet);

                if (packet[0] & FSP_PB0_MFMC) {
                        /*
                         * MFMC packet: assume that there are two fingers on
                         * pad
                         */
                        fgrs = 2;

                        /* MFMC packet */
                        if (packet[0] & FSP_PB0_MFMC_FGR2) {
                                /* 2nd finger */
                                if (ad->last_mt_fgr == 2) {
                                        /*
                                         * workaround for buggy firmware
                                         * which doesn't clear MFMC bit if
                                         * the 1st finger is up
                                         */
                                        fgrs = 1;
                                        fsp_set_slot(dev, 0, false, 0, 0);
                                }
                                ad->last_mt_fgr = 2;

                                fsp_set_slot(dev, 1, fgrs == 2, abs_x, abs_y);
                        } else {
                                /* 1st finger */
                                if (ad->last_mt_fgr == 1) {
                                        /*
                                         * workaround for buggy firmware
                                         * which doesn't clear MFMC bit if
                                         * the 2nd finger is up
                                         */
                                        fgrs = 1;
                                        fsp_set_slot(dev, 1, false, 0, 0);
                                }
                                ad->last_mt_fgr = 1;
                                fsp_set_slot(dev, 0, fgrs != 0, abs_x, abs_y);
                        }
                } else {
                        /* SFAC packet */
                        if ((packet[0] & (FSP_PB0_LBTN|FSP_PB0_PHY_BTN)) ==
                                FSP_PB0_LBTN) {
                                /* On-pad click in SFAC mode should be handled
                                 * by userspace.  On-pad clicks in MFMC mode
                                 * are real clickpad clicks, and not ignored.
                                 */
                                packet[0] &= ~FSP_PB0_LBTN;
                        }

                        /* no multi-finger information */
                        ad->last_mt_fgr = 0;

                        if (abs_x != 0 && abs_y != 0)
                                fgrs = 1;

                        fsp_set_slot(dev, 0, fgrs > 0, abs_x, abs_y);
                        fsp_set_slot(dev, 1, false, 0, 0);
                }
                if (fgrs == 1 || (fgrs == 2 && !(packet[0] & FSP_PB0_MFMC_FGR2))) {
                        input_report_abs(dev, ABS_X, abs_x);
                        input_report_abs(dev, ABS_Y, abs_y);
                }
                input_report_key(dev, BTN_LEFT, packet[0] & 0x01);
                input_report_key(dev, BTN_RIGHT, packet[0] & 0x02);
                input_report_key(dev, BTN_TOUCH, fgrs);
                input_report_key(dev, BTN_TOOL_FINGER, fgrs == 1);
                input_report_key(dev, BTN_TOOL_DOUBLETAP, fgrs == 2);
                break;

        case FSP_PKT_TYPE_NORMAL_OPC:
                /* on-pad click, filter it if necessary */
                if ((ad->flags & FSPDRV_FLAG_EN_OPC) != FSPDRV_FLAG_EN_OPC)
                        packet[0] &= ~FSP_PB0_LBTN;
                fallthrough;

        case FSP_PKT_TYPE_NORMAL:
                /* normal packet */
                /* special packet data translation from on-pad packets */
                if (packet[3] != 0) {
                        if (packet[3] & BIT(0))
                                button_status |= 0x01;  /* wheel down */
                        if (packet[3] & BIT(1))
                                button_status |= 0x0f;  /* wheel up */
                        if (packet[3] & BIT(2))
                                button_status |= BIT(4);/* horizontal left */
                        if (packet[3] & BIT(3))
                                button_status |= BIT(5);/* horizontal right */
                        /* push back to packet queue */
                        if (button_status != 0)
                                packet[3] = button_status;
                        rscroll = (packet[3] >> 4) & 1;
                        lscroll = (packet[3] >> 5) & 1;
                }
                /*
                 * Processing wheel up/down and extra button events
                 */
                input_report_rel(dev, REL_WHEEL,
                                 (int)(packet[3] & 8) - (int)(packet[3] & 7));
                input_report_rel(dev, REL_HWHEEL, lscroll - rscroll);
                input_report_key(dev, BTN_BACK, lscroll);
                input_report_key(dev, BTN_FORWARD, rscroll);

                /*
                 * Standard PS/2 Mouse
                 */
                psmouse_report_standard_packet(dev, packet);
                break;
        }

        input_sync(dev);

        return PSMOUSE_FULL_PACKET;
}

static int fsp_activate_protocol(struct psmouse *psmouse)
{
        struct fsp_data *pad = psmouse->private;
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        unsigned char param[2];
        int val;

        /*
         * Standard procedure to enter FSP Intellimouse mode
         * (scrolling wheel, 4th and 5th buttons)
         */
        param[0] = 200;
        ps2_command(ps2dev, param, PSMOUSE_CMD_SETRATE);
        param[0] = 200;
        ps2_command(ps2dev, param, PSMOUSE_CMD_SETRATE);
        param[0] =  80;
        ps2_command(ps2dev, param, PSMOUSE_CMD_SETRATE);

        ps2_command(ps2dev, param, PSMOUSE_CMD_GETID);
        if (param[0] != 0x04) {
                psmouse_err(psmouse,
                            "Unable to enable 4 bytes packet format.\n");
                return -EIO;
        }

        if (pad->ver < FSP_VER_STL3888_C0) {
                /* Preparing relative coordinates output for older hardware */
                if (fsp_reg_read(psmouse, FSP_REG_SYSCTL5, &val)) {
                        psmouse_err(psmouse,
                                    "Unable to read SYSCTL5 register.\n");
                        return -EIO;
                }

                if (fsp_get_buttons(psmouse, &pad->buttons)) {
                        psmouse_err(psmouse,
                                    "Unable to retrieve number of buttons.\n");
                        return -EIO;
                }

                val &= ~(FSP_BIT_EN_MSID7 | FSP_BIT_EN_MSID8 | FSP_BIT_EN_AUTO_MSID8);
                /* Ensure we are not in absolute mode */
                val &= ~FSP_BIT_EN_PKT_G0;
                if (pad->buttons == 0x06) {
                        /* Left/Middle/Right & Scroll Up/Down/Right/Left */
                        val |= FSP_BIT_EN_MSID6;
                }

                if (fsp_reg_write(psmouse, FSP_REG_SYSCTL5, val)) {
                        psmouse_err(psmouse,
                                    "Unable to set up required mode bits.\n");
                        return -EIO;
                }

                /*
                 * Enable OPC tags such that driver can tell the difference
                 * between on-pad and real button click
                 */
                if (fsp_opc_tag_enable(psmouse, true))
                        psmouse_warn(psmouse,
                                     "Failed to enable OPC tag mode.\n");
                /* enable on-pad click by default */
                pad->flags |= FSPDRV_FLAG_EN_OPC;

                /* Enable on-pad vertical and horizontal scrolling */
                fsp_onpad_vscr(psmouse, true);
                fsp_onpad_hscr(psmouse, true);
        } else {
                /* Enable absolute coordinates output for Cx/Dx hardware */
                if (fsp_reg_write(psmouse, FSP_REG_SWC1,
                                  FSP_BIT_SWC1_EN_ABS_1F |
                                  FSP_BIT_SWC1_EN_ABS_2F |
                                  FSP_BIT_SWC1_EN_FUP_OUT |
                                  FSP_BIT_SWC1_EN_ABS_CON)) {
                        psmouse_err(psmouse,
                                    "Unable to enable absolute coordinates output.\n");
                        return -EIO;
                }
        }

        return 0;
}

static int fsp_set_input_params(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct fsp_data *pad = psmouse->private;

        if (pad->ver < FSP_VER_STL3888_C0) {
                __set_bit(BTN_MIDDLE, dev->keybit);
                __set_bit(BTN_BACK, dev->keybit);
                __set_bit(BTN_FORWARD, dev->keybit);
                __set_bit(REL_WHEEL, dev->relbit);
                __set_bit(REL_HWHEEL, dev->relbit);
        } else {
                /*
                 * Hardware prior to Cx performs much better in relative mode;
                 * hence, only enable absolute coordinates output as well as
                 * multi-touch output for the newer hardware.
                 *
                 * Maximum coordinates can be computed as:
                 *
                 *      number of scanlines * 64 - 57
                 *
                 * where number of X/Y scanline lines are 16/12.
                 */
                int abs_x = 967, abs_y = 711;

                __set_bit(EV_ABS, dev->evbit);
                __clear_bit(EV_REL, dev->evbit);
                __set_bit(BTN_TOUCH, dev->keybit);
                __set_bit(BTN_TOOL_FINGER, dev->keybit);
                __set_bit(BTN_TOOL_DOUBLETAP, dev->keybit);
                __set_bit(INPUT_PROP_SEMI_MT, dev->propbit);

                input_set_abs_params(dev, ABS_X, 0, abs_x, 0, 0);
                input_set_abs_params(dev, ABS_Y, 0, abs_y, 0, 0);
                input_mt_init_slots(dev, 2, 0);
                input_set_abs_params(dev, ABS_MT_POSITION_X, 0, abs_x, 0, 0);
                input_set_abs_params(dev, ABS_MT_POSITION_Y, 0, abs_y, 0, 0);
        }

        return 0;
}

int fsp_detect(struct psmouse *psmouse, bool set_properties)
{
        int id;

        if (fsp_reg_read(psmouse, FSP_REG_DEVICE_ID, &id))
                return -EIO;

        if (id != 0x01)
                return -ENODEV;

        if (set_properties) {
                psmouse->vendor = "Sentelic";
                psmouse->name = "FingerSensingPad";
        }

        return 0;
}

static void fsp_reset(struct psmouse *psmouse)
{
        fsp_opc_tag_enable(psmouse, false);
        fsp_onpad_vscr(psmouse, false);
        fsp_onpad_hscr(psmouse, false);
}

static void fsp_disconnect(struct psmouse *psmouse)
{
        sysfs_remove_group(&psmouse->ps2dev.serio->dev.kobj,
                           &fsp_attribute_group);

        fsp_reset(psmouse);
        kfree(psmouse->private);
}

static int fsp_reconnect(struct psmouse *psmouse)
{
        int version;

        if (fsp_detect(psmouse, 0))
                return -ENODEV;

        if (fsp_get_version(psmouse, &version))
                return -ENODEV;

        if (fsp_activate_protocol(psmouse))
                return -EIO;

        return 0;
}

int fsp_init(struct psmouse *psmouse)
{
        struct fsp_data *priv;
        int ver, rev, sn = 0;
        int error;

        if (fsp_get_version(psmouse, &ver) ||
            fsp_get_revision(psmouse, &rev)) {
                return -ENODEV;
        }
        if (ver >= FSP_VER_STL3888_C0) {
                /* firmware information is only available since C0 */
                fsp_get_sn(psmouse, &sn);
        }

        psmouse_info(psmouse,
                     "Finger Sensing Pad, hw: %d.%d.%d, sn: %x, sw: %s\n",
                     ver >> 4, ver & 0x0F, rev, sn, fsp_drv_ver);

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

        priv->ver = ver;
        priv->rev = rev;

        psmouse->protocol_handler = fsp_process_byte;
        psmouse->disconnect = fsp_disconnect;
        psmouse->reconnect = fsp_reconnect;
        psmouse->cleanup = fsp_reset;
        psmouse->pktsize = 4;

        error = fsp_activate_protocol(psmouse);
        if (error)
                goto err_out;

        /* Set up various supported input event bits */
        error = fsp_set_input_params(psmouse);
        if (error)
                goto err_out;

        error = sysfs_create_group(&psmouse->ps2dev.serio->dev.kobj,
                                   &fsp_attribute_group);
        if (error) {
                psmouse_err(psmouse,
                            "Failed to create sysfs attributes (%d)", error);
                goto err_out;
        }

        return 0;

 err_out:
        kfree(psmouse->private);
        psmouse->private = NULL;
        return error;
}