// SPDX-License-Identifier: GPL-2.0-only
/*
 * Cypress Trackpad PS/2 mouse driver
 *
 * Copyright (c) 2012 Cypress Semiconductor Corporation.
 *
 * Author:
 *   Dudley Du <dudl@cypress.com>
 *
 * Additional contributors include:
 *   Kamal Mostafa <kamal@canonical.com>
 *   Kyle Fazzari <git@status.e4ward.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/serio.h>
#include <linux/libps2.h>
#include <linux/input.h>
#include <linux/input/mt.h>
#include <linux/sched.h>
#include <linux/wait.h>

#include "cypress_ps2.h"

#undef CYTP_DEBUG_VERBOSE  /* define this and DEBUG for more verbose dump */

static void cypress_set_packet_size(struct psmouse *psmouse, unsigned int n)
{
        struct cytp_data *cytp = psmouse->private;
        cytp->pkt_size = n;
}

static const u8 cytp_rate[] = {10, 20, 40, 60, 100, 200};
static const u8 cytp_resolution[] = {0x00, 0x01, 0x02, 0x03};

static int cypress_ps2_sendbyte(struct psmouse *psmouse, u8 cmd)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        int error;

        error = ps2_sendbyte(ps2dev, cmd, CYTP_CMD_TIMEOUT);
        if (error) {
                psmouse_dbg(psmouse,
                            "sending command 0x%02x failed, resp 0x%02x, error %d\n",
                            cmd, ps2dev->nak, error);
                return error;
        }

#ifdef CYTP_DEBUG_VERBOSE
        psmouse_dbg(psmouse, "sending command 0x%02x succeeded\n", cmd);
#endif

        return 0;
}

static int cypress_ps2_ext_cmd(struct psmouse *psmouse, u8 prefix, u8 nibble)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        int tries = CYTP_PS2_CMD_TRIES;
        int rc;

        ps2_begin_command(ps2dev);

        do {
                /*
                 * Send extension command byte (0xE8 or 0xF3).
                 * If sending the command fails, send recovery command
                 * to make the device return to the ready state.
                 */
                rc = cypress_ps2_sendbyte(psmouse, prefix);
                if (rc == -EAGAIN) {
                        rc = cypress_ps2_sendbyte(psmouse, 0x00);
                        if (rc == -EAGAIN)
                                rc = cypress_ps2_sendbyte(psmouse, 0x0a);
                }

                if (!rc) {
                        rc = cypress_ps2_sendbyte(psmouse, nibble);
                        if (rc == -EAGAIN)
                                rc = cypress_ps2_sendbyte(psmouse, nibble);

                        if (!rc)
                                break;
                }
        } while (--tries > 0);

        ps2_end_command(ps2dev);

        return rc;
}

static bool cypress_verify_cmd_state(struct psmouse *psmouse, u8 cmd, u8* param)
{
        bool rate_match = false;
        bool resolution_match = false;
        int i;

        /* callers will do further checking. */
        if (cmd == CYTP_CMD_READ_CYPRESS_ID ||
            cmd == CYTP_CMD_STANDARD_MODE ||
            cmd == CYTP_CMD_READ_TP_METRICS)
                return true;

        if ((~param[0] & DFLT_RESP_BITS_VALID) == DFLT_RESP_BITS_VALID &&
            (param[0] & DFLT_RESP_BIT_MODE) == DFLT_RESP_STREAM_MODE) {
                for (i = 0; i < sizeof(cytp_resolution); i++)
                        if (cytp_resolution[i] == param[1])
                                resolution_match = true;

                for (i = 0; i < sizeof(cytp_rate); i++)
                        if (cytp_rate[i] == param[2])
                                rate_match = true;

                if (resolution_match && rate_match)
                        return true;
        }

        psmouse_dbg(psmouse, "verify cmd state failed.\n");
        return false;
}

static int cypress_send_ext_cmd(struct psmouse *psmouse, u8 cmd, u8 *param)
{
        u8 cmd_prefix = PSMOUSE_CMD_SETRES & 0xff;
        unsigned int resp_size = cmd == CYTP_CMD_READ_TP_METRICS ? 8 : 3;
        unsigned int ps2_cmd = (PSMOUSE_CMD_GETINFO & 0xff) | (resp_size << 8);
        int tries = CYTP_PS2_CMD_TRIES;
        int error;

        psmouse_dbg(psmouse, "send extension cmd 0x%02x, [%d %d %d %d]\n",
                 cmd, DECODE_CMD_AA(cmd), DECODE_CMD_BB(cmd),
                 DECODE_CMD_CC(cmd), DECODE_CMD_DD(cmd));

        do {
                cypress_ps2_ext_cmd(psmouse, cmd_prefix, DECODE_CMD_DD(cmd));
                cypress_ps2_ext_cmd(psmouse, cmd_prefix, DECODE_CMD_CC(cmd));
                cypress_ps2_ext_cmd(psmouse, cmd_prefix, DECODE_CMD_BB(cmd));
                cypress_ps2_ext_cmd(psmouse, cmd_prefix, DECODE_CMD_AA(cmd));

                error = ps2_command(&psmouse->ps2dev, param, ps2_cmd);
                if (error) {
                        psmouse_dbg(psmouse, "Command 0x%02x failed: %d\n",
                                    cmd, error);
                } else {
                        psmouse_dbg(psmouse,
                                    "Command 0x%02x response data (0x): %*ph\n",
                                    cmd, resp_size, param);

                        if (cypress_verify_cmd_state(psmouse, cmd, param))
                                return 0;
                }
        } while (--tries > 0);

        return -EIO;
}

int cypress_detect(struct psmouse *psmouse, bool set_properties)
{
        u8 param[3];

        if (cypress_send_ext_cmd(psmouse, CYTP_CMD_READ_CYPRESS_ID, param))
                return -ENODEV;

        /* Check for Cypress Trackpad signature bytes: 0x33 0xCC */
        if (param[0] != 0x33 || param[1] != 0xCC)
                return -ENODEV;

        if (set_properties) {
                psmouse->vendor = "Cypress";
                psmouse->name = "Trackpad";
        }

        return 0;
}

static int cypress_read_fw_version(struct psmouse *psmouse)
{
        struct cytp_data *cytp = psmouse->private;
        u8 param[3];

        if (cypress_send_ext_cmd(psmouse, CYTP_CMD_READ_CYPRESS_ID, param))
                return -ENODEV;

        /* Check for Cypress Trackpad signature bytes: 0x33 0xCC */
        if (param[0] != 0x33 || param[1] != 0xCC)
                return -ENODEV;

        cytp->fw_version = param[2] & FW_VERSION_MASX;
        cytp->tp_metrics_supported = (param[2] & TP_METRICS_MASK) ? 1 : 0;

        /*
         * Trackpad fw_version 11 (in Dell XPS12) yields a bogus response to
         * CYTP_CMD_READ_TP_METRICS so do not try to use it. LP: #1103594.
         */
        if (cytp->fw_version >= 11)
                cytp->tp_metrics_supported = 0;

        psmouse_dbg(psmouse, "cytp->fw_version = %d\n", cytp->fw_version);
        psmouse_dbg(psmouse, "cytp->tp_metrics_supported = %d\n",
                 cytp->tp_metrics_supported);

        return 0;
}

static int cypress_read_tp_metrics(struct psmouse *psmouse)
{
        struct cytp_data *cytp = psmouse->private;
        u8 param[8];

        /* set default values for tp metrics. */
        cytp->tp_width = CYTP_DEFAULT_WIDTH;
        cytp->tp_high = CYTP_DEFAULT_HIGH;
        cytp->tp_max_abs_x = CYTP_ABS_MAX_X;
        cytp->tp_max_abs_y = CYTP_ABS_MAX_Y;
        cytp->tp_min_pressure = CYTP_MIN_PRESSURE;
        cytp->tp_max_pressure = CYTP_MAX_PRESSURE;
        cytp->tp_res_x = cytp->tp_max_abs_x / cytp->tp_width;
        cytp->tp_res_y = cytp->tp_max_abs_y / cytp->tp_high;

        if (!cytp->tp_metrics_supported)
                return 0;

        memset(param, 0, sizeof(param));
        if (cypress_send_ext_cmd(psmouse, CYTP_CMD_READ_TP_METRICS, param) == 0) {
                /* Update trackpad parameters. */
                cytp->tp_max_abs_x = (param[1] << 8) | param[0];
                cytp->tp_max_abs_y = (param[3] << 8) | param[2];
                cytp->tp_min_pressure = param[4];
                cytp->tp_max_pressure = param[5];
        }

        if (!cytp->tp_max_pressure ||
            cytp->tp_max_pressure < cytp->tp_min_pressure ||
            !cytp->tp_width || !cytp->tp_high ||
            !cytp->tp_max_abs_x ||
            cytp->tp_max_abs_x < cytp->tp_width ||
            !cytp->tp_max_abs_y ||
            cytp->tp_max_abs_y < cytp->tp_high)
                return -EINVAL;

        cytp->tp_res_x = cytp->tp_max_abs_x / cytp->tp_width;
        cytp->tp_res_y = cytp->tp_max_abs_y / cytp->tp_high;

#ifdef CYTP_DEBUG_VERBOSE
        psmouse_dbg(psmouse, "Dump trackpad hardware configuration as below:\n");
        psmouse_dbg(psmouse, "cytp->tp_width = %d\n", cytp->tp_width);
        psmouse_dbg(psmouse, "cytp->tp_high = %d\n", cytp->tp_high);
        psmouse_dbg(psmouse, "cytp->tp_max_abs_x = %d\n", cytp->tp_max_abs_x);
        psmouse_dbg(psmouse, "cytp->tp_max_abs_y = %d\n", cytp->tp_max_abs_y);
        psmouse_dbg(psmouse, "cytp->tp_min_pressure = %d\n", cytp->tp_min_pressure);
        psmouse_dbg(psmouse, "cytp->tp_max_pressure = %d\n", cytp->tp_max_pressure);
        psmouse_dbg(psmouse, "cytp->tp_res_x = %d\n", cytp->tp_res_x);
        psmouse_dbg(psmouse, "cytp->tp_res_y = %d\n", cytp->tp_res_y);

        psmouse_dbg(psmouse, "tp_type_APA = %d\n",
                        (param[6] & TP_METRICS_BIT_APA) ? 1 : 0);
        psmouse_dbg(psmouse, "tp_type_MTG = %d\n",
                        (param[6] & TP_METRICS_BIT_MTG) ? 1 : 0);
        psmouse_dbg(psmouse, "tp_palm = %d\n",
                        (param[6] & TP_METRICS_BIT_PALM) ? 1 : 0);
        psmouse_dbg(psmouse, "tp_stubborn = %d\n",
                        (param[6] & TP_METRICS_BIT_STUBBORN) ? 1 : 0);
        psmouse_dbg(psmouse, "tp_1f_jitter = %d\n",
                        (param[6] & TP_METRICS_BIT_1F_JITTER) >> 2);
        psmouse_dbg(psmouse, "tp_2f_jitter = %d\n",
                        (param[6] & TP_METRICS_BIT_2F_JITTER) >> 4);
        psmouse_dbg(psmouse, "tp_1f_spike = %d\n",
                        param[7] & TP_METRICS_BIT_1F_SPIKE);
        psmouse_dbg(psmouse, "tp_2f_spike = %d\n",
                        (param[7] & TP_METRICS_BIT_2F_SPIKE) >> 2);
        psmouse_dbg(psmouse, "tp_abs_packet_format_set = %d\n",
                        (param[7] & TP_METRICS_BIT_ABS_PKT_FORMAT_SET) >> 4);
#endif

        return 0;
}

static int cypress_query_hardware(struct psmouse *psmouse)
{
        int error;

        error = cypress_read_fw_version(psmouse);
        if (error)
                return error;

        error = cypress_read_tp_metrics(psmouse);
        if (error)
                return error;

        return 0;
}

static int cypress_set_absolute_mode(struct psmouse *psmouse)
{
        struct cytp_data *cytp = psmouse->private;
        u8 param[3];
        int error;

        error = cypress_send_ext_cmd(psmouse, CYTP_CMD_ABS_WITH_PRESSURE_MODE,
                                     param);
        if (error)
                return error;

        cytp->mode = (cytp->mode & ~CYTP_BIT_ABS_REL_MASK)
                        | CYTP_BIT_ABS_PRESSURE;
        cypress_set_packet_size(psmouse, 5);

        return 0;
}

/*
 * Reset trackpad device.
 * This is also the default mode when trackpad powered on.
 */
static void cypress_reset(struct psmouse *psmouse)
{
        struct cytp_data *cytp = psmouse->private;

        cytp->mode = 0;

        psmouse_reset(psmouse);
}

static int cypress_set_input_params(struct input_dev *input,
                                    struct cytp_data *cytp)
{
        int error;

        if (!cytp->tp_res_x || !cytp->tp_res_y)
                return -EINVAL;

        __set_bit(EV_ABS, input->evbit);
        input_set_abs_params(input, ABS_X, 0, cytp->tp_max_abs_x, 0, 0);
        input_set_abs_params(input, ABS_Y, 0, cytp->tp_max_abs_y, 0, 0);
        input_set_abs_params(input, ABS_PRESSURE,
                             cytp->tp_min_pressure, cytp->tp_max_pressure, 0, 0);
        input_set_abs_params(input, ABS_TOOL_WIDTH, 0, 255, 0, 0);

        /* finger position */
        input_set_abs_params(input, ABS_MT_POSITION_X, 0, cytp->tp_max_abs_x, 0, 0);
        input_set_abs_params(input, ABS_MT_POSITION_Y, 0, cytp->tp_max_abs_y, 0, 0);
        input_set_abs_params(input, ABS_MT_PRESSURE, 0, 255, 0, 0);

        error = input_mt_init_slots(input, CYTP_MAX_MT_SLOTS,
                                    INPUT_MT_DROP_UNUSED | INPUT_MT_TRACK);
        if (error)
                return error;

        __set_bit(INPUT_PROP_SEMI_MT, input->propbit);

        input_abs_set_res(input, ABS_X, cytp->tp_res_x);
        input_abs_set_res(input, ABS_Y, cytp->tp_res_y);

        input_abs_set_res(input, ABS_MT_POSITION_X, cytp->tp_res_x);
        input_abs_set_res(input, ABS_MT_POSITION_Y, cytp->tp_res_y);

        __set_bit(BTN_TOUCH, input->keybit);
        __set_bit(BTN_TOOL_FINGER, input->keybit);
        __set_bit(BTN_TOOL_DOUBLETAP, input->keybit);
        __set_bit(BTN_TOOL_TRIPLETAP, input->keybit);
        __set_bit(BTN_TOOL_QUADTAP, input->keybit);
        __set_bit(BTN_TOOL_QUINTTAP, input->keybit);

        __clear_bit(EV_REL, input->evbit);
        __clear_bit(REL_X, input->relbit);
        __clear_bit(REL_Y, input->relbit);

        __set_bit(EV_KEY, input->evbit);
        __set_bit(BTN_LEFT, input->keybit);
        __set_bit(BTN_RIGHT, input->keybit);
        __set_bit(BTN_MIDDLE, input->keybit);

        return 0;
}

static int cypress_get_finger_count(u8 header_byte)
{
        u8 bits6_7;
        int finger_count;

        bits6_7 = header_byte >> 6;
        finger_count = bits6_7 & 0x03;

        if (finger_count == 1)
                return 1;

        if (header_byte & ABS_HSCROLL_BIT) {
                /* HSCROLL gets added on to 0 finger count. */
                switch (finger_count) {
                        case 0: return 4;
                        case 2: return 5;
                        default:
                                /* Invalid contact (e.g. palm). Ignore it. */
                                return 0;
                }
        }

        return finger_count;
}


static int cypress_parse_packet(struct psmouse *psmouse,
                                struct cytp_data *cytp,
                                struct cytp_report_data *report_data)
{
        u8 *packet = psmouse->packet;
        u8 header_byte = packet[0];

        memset(report_data, 0, sizeof(struct cytp_report_data));

        report_data->contact_cnt = cypress_get_finger_count(header_byte);
        report_data->tap = (header_byte & ABS_MULTIFINGER_TAP) ? 1 : 0;

        if (report_data->contact_cnt == 1) {
                report_data->contacts[0].x =
                        ((packet[1] & 0x70) << 4) | packet[2];
                report_data->contacts[0].y =
                        ((packet[1] & 0x07) << 8) | packet[3];
                if (cytp->mode & CYTP_BIT_ABS_PRESSURE)
                        report_data->contacts[0].z = packet[4];

        } else if (report_data->contact_cnt >= 2) {
                report_data->contacts[0].x =
                        ((packet[1] & 0x70) << 4) | packet[2];
                report_data->contacts[0].y =
                        ((packet[1] & 0x07) << 8) | packet[3];
                if (cytp->mode & CYTP_BIT_ABS_PRESSURE)
                        report_data->contacts[0].z = packet[4];

                report_data->contacts[1].x =
                        ((packet[5] & 0xf0) << 4) | packet[6];
                report_data->contacts[1].y =
                        ((packet[5] & 0x0f) << 8) | packet[7];
                if (cytp->mode & CYTP_BIT_ABS_PRESSURE)
                        report_data->contacts[1].z = report_data->contacts[0].z;
        }

        report_data->left = (header_byte & BTN_LEFT_BIT) ? 1 : 0;
        report_data->right = (header_byte & BTN_RIGHT_BIT) ? 1 : 0;

        /*
         * This is only true if one of the mouse buttons were tapped.  Make
         * sure it doesn't turn into a click. The regular tap-to-click
         * functionality will handle that on its own. If we don't do this,
         * disabling tap-to-click won't affect the mouse button zones.
         */
        if (report_data->tap)
                report_data->left = 0;

#ifdef CYTP_DEBUG_VERBOSE
        {
                int i;
                int n = report_data->contact_cnt;
                psmouse_dbg(psmouse, "Dump parsed report data as below:\n");
                psmouse_dbg(psmouse, "contact_cnt = %d\n",
                        report_data->contact_cnt);
                if (n > CYTP_MAX_MT_SLOTS)
                    n = CYTP_MAX_MT_SLOTS;
                for (i = 0; i < n; i++)
                        psmouse_dbg(psmouse, "contacts[%d] = {%d, %d, %d}\n", i,
                                        report_data->contacts[i].x,
                                        report_data->contacts[i].y,
                                        report_data->contacts[i].z);
                psmouse_dbg(psmouse, "left = %d\n", report_data->left);
                psmouse_dbg(psmouse, "right = %d\n", report_data->right);
                psmouse_dbg(psmouse, "middle = %d\n", report_data->middle);
        }
#endif

        return 0;
}

static void cypress_process_packet(struct psmouse *psmouse, bool zero_pkt)
{
        int i;
        struct input_dev *input = psmouse->dev;
        struct cytp_data *cytp = psmouse->private;
        struct cytp_report_data report_data;
        struct cytp_contact *contact;
        struct input_mt_pos pos[CYTP_MAX_MT_SLOTS];
        int slots[CYTP_MAX_MT_SLOTS];
        int n;

        cypress_parse_packet(psmouse, cytp, &report_data);

        n = report_data.contact_cnt;
        if (n > CYTP_MAX_MT_SLOTS)
                n = CYTP_MAX_MT_SLOTS;

        for (i = 0; i < n; i++) {
                contact = &report_data.contacts[i];
                pos[i].x = contact->x;
                pos[i].y = contact->y;
        }

        input_mt_assign_slots(input, slots, pos, n, 0);

        for (i = 0; i < n; i++) {
                contact = &report_data.contacts[i];
                input_mt_slot(input, slots[i]);
                input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
                input_report_abs(input, ABS_MT_POSITION_X, contact->x);
                input_report_abs(input, ABS_MT_POSITION_Y, contact->y);
                input_report_abs(input, ABS_MT_PRESSURE, contact->z);
        }

        input_mt_sync_frame(input);

        input_mt_report_finger_count(input, report_data.contact_cnt);

        input_report_key(input, BTN_LEFT, report_data.left);
        input_report_key(input, BTN_RIGHT, report_data.right);
        input_report_key(input, BTN_MIDDLE, report_data.middle);

        input_sync(input);
}

static psmouse_ret_t cypress_validate_byte(struct psmouse *psmouse)
{
        int contact_cnt;
        int index = psmouse->pktcnt - 1;
        u8 *packet = psmouse->packet;
        struct cytp_data *cytp = psmouse->private;

        if (index < 0 || index > cytp->pkt_size)
                return PSMOUSE_BAD_DATA;

        if (index == 0 && (packet[0] & 0xfc) == 0) {
                /* call packet process for reporting finger leave. */
                cypress_process_packet(psmouse, 1);
                return PSMOUSE_FULL_PACKET;
        }

        /*
         * Perform validation (and adjust packet size) based only on the
         * first byte; allow all further bytes through.
         */
        if (index != 0)
                return PSMOUSE_GOOD_DATA;

        /*
         * If absolute/relative mode bit has not been set yet, just pass
         * the byte through.
         */
        if ((cytp->mode & CYTP_BIT_ABS_REL_MASK) == 0)
                return PSMOUSE_GOOD_DATA;

        if ((packet[0] & 0x08) == 0x08)
                return PSMOUSE_BAD_DATA;

        contact_cnt = cypress_get_finger_count(packet[0]);
        if (cytp->mode & CYTP_BIT_ABS_NO_PRESSURE)
                cypress_set_packet_size(psmouse, contact_cnt == 2 ? 7 : 4);
        else
                cypress_set_packet_size(psmouse, contact_cnt == 2 ? 8 : 5);

        return PSMOUSE_GOOD_DATA;
}

static psmouse_ret_t cypress_protocol_handler(struct psmouse *psmouse)
{
        struct cytp_data *cytp = psmouse->private;

        if (psmouse->pktcnt >= cytp->pkt_size) {
                cypress_process_packet(psmouse, 0);
                return PSMOUSE_FULL_PACKET;
        }

        return cypress_validate_byte(psmouse);
}

static void cypress_set_rate(struct psmouse *psmouse, unsigned int rate)
{
        struct cytp_data *cytp = psmouse->private;
        u8 rate_param;

        if (rate >= 80) {
                psmouse->rate = 80;
                cytp->mode |= CYTP_BIT_HIGH_RATE;
        } else {
                psmouse->rate = 40;
                cytp->mode &= ~CYTP_BIT_HIGH_RATE;
        }

        rate_param = (u8)rate;
        ps2_command(&psmouse->ps2dev, &rate_param, PSMOUSE_CMD_SETRATE);
}

static void cypress_disconnect(struct psmouse *psmouse)
{
        cypress_reset(psmouse);
        kfree(psmouse->private);
        psmouse->private = NULL;
}

static int cypress_reconnect(struct psmouse *psmouse)
{
        int tries = CYTP_PS2_CMD_TRIES;
        int error;

        do {
                cypress_reset(psmouse);
                error = cypress_detect(psmouse, false);
        } while (error && (--tries > 0));

        if (error) {
                psmouse_err(psmouse, "Reconnect: unable to detect trackpad.\n");
                return error;
        }

        error = cypress_set_absolute_mode(psmouse);
        if (error) {
                psmouse_err(psmouse, "Reconnect: Unable to initialize Cypress absolute mode.\n");
                return error;
        }

        return 0;
}

int cypress_init(struct psmouse *psmouse)
{
        struct cytp_data *cytp;
        int error;

        cytp = kzalloc_obj(*cytp);
        if (!cytp)
                return -ENOMEM;

        psmouse->private = cytp;
        psmouse->pktsize = 8;

        cypress_reset(psmouse);

        error = cypress_query_hardware(psmouse);
        if (error) {
                psmouse_err(psmouse, "Unable to query Trackpad hardware.\n");
                goto err_exit;
        }

        error = cypress_set_absolute_mode(psmouse);
        if (error) {
                psmouse_err(psmouse, "init: Unable to initialize Cypress absolute mode.\n");
                goto err_exit;
        }

        error = cypress_set_input_params(psmouse->dev, cytp);
        if (error) {
                psmouse_err(psmouse, "init: Unable to set input params.\n");
                goto err_exit;
        }

        psmouse->model = 1;
        psmouse->protocol_handler = cypress_protocol_handler;
        psmouse->set_rate = cypress_set_rate;
        psmouse->disconnect = cypress_disconnect;
        psmouse->reconnect = cypress_reconnect;
        psmouse->cleanup = cypress_reset;
        psmouse->resync_time = 0;

        return 0;

err_exit:
        /*
         * Reset Cypress Trackpad as a standard mouse. Then
         * let psmouse driver communicating with it as default PS2 mouse.
         */
        cypress_reset(psmouse);

        psmouse->private = NULL;
        kfree(cytp);

        return error;
}