// SPDX-License-Identifier: GPL-2.0-only
/*
 * BYD TouchPad PS/2 mouse driver
 *
 * Copyright (C) 2015 Chris Diamand <chris@diamand.org>
 * Copyright (C) 2015 Richard Pospesel
 * Copyright (C) 2015 Tai Chi Minh Ralph Eastwood
 * Copyright (C) 2015 Martin Wimpress
 * Copyright (C) 2015 Jay Kuri
 */

#include <linux/delay.h>
#include <linux/input.h>
#include <linux/libps2.h>
#include <linux/serio.h>
#include <linux/slab.h>

#include "psmouse.h"
#include "byd.h"

/* PS2 Bits */
#define PS2_Y_OVERFLOW  BIT_MASK(7)
#define PS2_X_OVERFLOW  BIT_MASK(6)
#define PS2_Y_SIGN      BIT_MASK(5)
#define PS2_X_SIGN      BIT_MASK(4)
#define PS2_ALWAYS_1    BIT_MASK(3)
#define PS2_MIDDLE      BIT_MASK(2)
#define PS2_RIGHT       BIT_MASK(1)
#define PS2_LEFT        BIT_MASK(0)

/*
 * BYD pad constants
 */

/*
 * True device resolution is unknown, however experiments show the
 * resolution is about 111 units/mm.
 * Absolute coordinate packets are in the range 0-255 for both X and Y
 * we pick ABS_X/ABS_Y dimensions which are multiples of 256 and in
 * the right ballpark given the touchpad's physical dimensions and estimate
 * resolution per spec sheet, device active area dimensions are
 * 101.6 x 60.1 mm.
 */
#define BYD_PAD_WIDTH           11264
#define BYD_PAD_HEIGHT          6656
#define BYD_PAD_RESOLUTION      111

/*
 * Given the above dimensions, relative packets velocity is in multiples of
 * 1 unit / 11 milliseconds.  We use this dt to estimate distance traveled
 */
#define BYD_DT                  11
/* Time in jiffies used to timeout various touch events (64 ms) */
#define BYD_TOUCH_TIMEOUT       msecs_to_jiffies(64)

/* BYD commands reverse engineered from windows driver */

/*
 * Swipe gesture from off-pad to on-pad
 *  0 : disable
 *  1 : enable
 */
#define BYD_CMD_SET_OFFSCREEN_SWIPE             0x10cc
/*
 * Tap and drag delay time
 *  0 : disable
 *  1 - 8 : least to most delay
 */
#define BYD_CMD_SET_TAP_DRAG_DELAY_TIME         0x10cf
/*
 * Physical buttons function mapping
 *  0 : enable
 *  4 : normal
 *  5 : left button custom command
 *  6 : right button custom command
 *  8 : disable
 */
#define BYD_CMD_SET_PHYSICAL_BUTTONS            0x10d0
/*
 * Absolute mode (1 byte X/Y resolution)
 *  0 : disable
 *  2 : enable
 */
#define BYD_CMD_SET_ABSOLUTE_MODE               0x10d1
/*
 * Two finger scrolling
 *  1 : vertical
 *  2 : horizontal
 *  3 : vertical + horizontal
 *  4 : disable
 */
#define BYD_CMD_SET_TWO_FINGER_SCROLL           0x10d2
/*
 * Handedness
 *  1 : right handed
 *  2 : left handed
 */
#define BYD_CMD_SET_HANDEDNESS                  0x10d3
/*
 * Tap to click
 *  1 : enable
 *  2 : disable
 */
#define BYD_CMD_SET_TAP                         0x10d4
/*
 * Tap and drag
 *  1 : tap and hold to drag
 *  2 : tap and hold to drag + lock
 *  3 : disable
 */
#define BYD_CMD_SET_TAP_DRAG                    0x10d5
/*
 * Touch sensitivity
 *  1 - 7 : least to most sensitive
 */
#define BYD_CMD_SET_TOUCH_SENSITIVITY           0x10d6
/*
 * One finger scrolling
 *  1 : vertical
 *  2 : horizontal
 *  3 : vertical + horizontal
 *  4 : disable
 */
#define BYD_CMD_SET_ONE_FINGER_SCROLL           0x10d7
/*
 * One finger scrolling function
 *  1 : free scrolling
 *  2 : edge motion
 *  3 : free scrolling + edge motion
 *  4 : disable
 */
#define BYD_CMD_SET_ONE_FINGER_SCROLL_FUNC      0x10d8
/*
 * Sliding speed
 *  1 - 5 : slowest to fastest
 */
#define BYD_CMD_SET_SLIDING_SPEED               0x10da
/*
 * Edge motion
 *  1 : disable
 *  2 : enable when dragging
 *  3 : enable when dragging and pointing
 */
#define BYD_CMD_SET_EDGE_MOTION                 0x10db
/*
 * Left edge region size
 *  0 - 7 : smallest to largest width
 */
#define BYD_CMD_SET_LEFT_EDGE_REGION            0x10dc
/*
 * Top edge region size
 *  0 - 9 : smallest to largest height
 */
#define BYD_CMD_SET_TOP_EDGE_REGION             0x10dd
/*
 * Disregard palm press as clicks
 *  1 - 6 : smallest to largest
 */
#define BYD_CMD_SET_PALM_CHECK                  0x10de
/*
 * Right edge region size
 *  0 - 7 : smallest to largest width
 */
#define BYD_CMD_SET_RIGHT_EDGE_REGION           0x10df
/*
 * Bottom edge region size
 *  0 - 9 : smallest to largest height
 */
#define BYD_CMD_SET_BOTTOM_EDGE_REGION          0x10e1
/*
 * Multitouch gestures
 *  1 : enable
 *  2 : disable
 */
#define BYD_CMD_SET_MULTITOUCH                  0x10e3
/*
 * Edge motion speed
 *  0 : control with finger pressure
 *  1 - 9 : slowest to fastest
 */
#define BYD_CMD_SET_EDGE_MOTION_SPEED           0x10e4
/*
 * Two finger scolling function
 *  0 : free scrolling
 *  1 : free scrolling (with momentum)
 *  2 : edge motion
 *  3 : free scrolling (with momentum) + edge motion
 *  4 : disable
 */
#define BYD_CMD_SET_TWO_FINGER_SCROLL_FUNC      0x10e5

/*
 * The touchpad generates a mixture of absolute and relative packets, indicated
 * by the last byte of each packet being set to one of the following:
 */
#define BYD_PACKET_ABSOLUTE                     0xf8
#define BYD_PACKET_RELATIVE                     0x00
/* Multitouch gesture packets */
#define BYD_PACKET_PINCH_IN                     0xd8
#define BYD_PACKET_PINCH_OUT                    0x28
#define BYD_PACKET_ROTATE_CLOCKWISE             0x29
#define BYD_PACKET_ROTATE_ANTICLOCKWISE         0xd7
#define BYD_PACKET_TWO_FINGER_SCROLL_RIGHT      0x2a
#define BYD_PACKET_TWO_FINGER_SCROLL_DOWN       0x2b
#define BYD_PACKET_TWO_FINGER_SCROLL_UP         0xd5
#define BYD_PACKET_TWO_FINGER_SCROLL_LEFT       0xd6
#define BYD_PACKET_THREE_FINGER_SWIPE_RIGHT     0x2c
#define BYD_PACKET_THREE_FINGER_SWIPE_DOWN      0x2d
#define BYD_PACKET_THREE_FINGER_SWIPE_UP        0xd3
#define BYD_PACKET_THREE_FINGER_SWIPE_LEFT      0xd4
#define BYD_PACKET_FOUR_FINGER_DOWN             0x33
#define BYD_PACKET_FOUR_FINGER_UP               0xcd
#define BYD_PACKET_REGION_SCROLL_RIGHT          0x35
#define BYD_PACKET_REGION_SCROLL_DOWN           0x36
#define BYD_PACKET_REGION_SCROLL_UP             0xca
#define BYD_PACKET_REGION_SCROLL_LEFT           0xcb
#define BYD_PACKET_RIGHT_CORNER_CLICK           0xd2
#define BYD_PACKET_LEFT_CORNER_CLICK            0x2e
#define BYD_PACKET_LEFT_AND_RIGHT_CORNER_CLICK  0x2f
#define BYD_PACKET_ONTO_PAD_SWIPE_RIGHT         0x37
#define BYD_PACKET_ONTO_PAD_SWIPE_DOWN          0x30
#define BYD_PACKET_ONTO_PAD_SWIPE_UP            0xd0
#define BYD_PACKET_ONTO_PAD_SWIPE_LEFT          0xc9

struct byd_data {
        struct timer_list timer;
        struct psmouse *psmouse;
        s32 abs_x;
        s32 abs_y;
        typeof(jiffies) last_touch_time;
        bool btn_left;
        bool btn_right;
        bool touch;
};

static void byd_report_input(struct psmouse *psmouse)
{
        struct byd_data *priv = psmouse->private;
        struct input_dev *dev = psmouse->dev;

        input_report_key(dev, BTN_TOUCH, priv->touch);
        input_report_key(dev, BTN_TOOL_FINGER, priv->touch);

        input_report_abs(dev, ABS_X, priv->abs_x);
        input_report_abs(dev, ABS_Y, priv->abs_y);
        input_report_key(dev, BTN_LEFT, priv->btn_left);
        input_report_key(dev, BTN_RIGHT, priv->btn_right);

        input_sync(dev);
}

static void byd_clear_touch(struct timer_list *t)
{
        struct byd_data *priv = timer_container_of(priv, t, timer);
        struct psmouse *psmouse = priv->psmouse;

        guard(serio_pause_rx)(psmouse->ps2dev.serio);

        priv->touch = false;

        byd_report_input(psmouse);

        /*
         * Move cursor back to center of pad when we lose touch - this
         * specifically improves user experience when moving cursor with one
         * finger, and pressing a button with another.
         */
        priv->abs_x = BYD_PAD_WIDTH / 2;
        priv->abs_y = BYD_PAD_HEIGHT / 2;
}

static psmouse_ret_t byd_process_byte(struct psmouse *psmouse)
{
        struct byd_data *priv = psmouse->private;
        u8 *pkt = psmouse->packet;

        if (psmouse->pktcnt > 0 && !(pkt[0] & PS2_ALWAYS_1)) {
                psmouse_warn(psmouse, "Always_1 bit not 1. pkt[0] = %02x\n",
                             pkt[0]);
                return PSMOUSE_BAD_DATA;
        }

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

        /* Otherwise, a full packet has been received */
        switch (pkt[3]) {
        case BYD_PACKET_ABSOLUTE:
                /* Only use absolute packets for the start of movement. */
                if (!priv->touch) {
                        /* needed to detect tap */
                        typeof(jiffies) tap_time =
                                priv->last_touch_time + BYD_TOUCH_TIMEOUT;
                        priv->touch = time_after(jiffies, tap_time);

                        /* init abs position */
                        priv->abs_x = pkt[1] * (BYD_PAD_WIDTH / 256);
                        priv->abs_y = (255 - pkt[2]) * (BYD_PAD_HEIGHT / 256);
                }
                break;
        case BYD_PACKET_RELATIVE: {
                /* Standard packet */
                /* Sign-extend if a sign bit is set. */
                u32 signx = pkt[0] & PS2_X_SIGN ? ~0xFF : 0;
                u32 signy = pkt[0] & PS2_Y_SIGN ? ~0xFF : 0;
                s32 dx = signx | (int) pkt[1];
                s32 dy = signy | (int) pkt[2];

                /* Update position based on velocity */
                priv->abs_x += dx * BYD_DT;
                priv->abs_y -= dy * BYD_DT;

                priv->touch = true;
                break;
        }
        default:
                psmouse_warn(psmouse, "Unrecognized Z: pkt = %*ph\n",
                             4, psmouse->packet);
                return PSMOUSE_BAD_DATA;
        }

        priv->btn_left = pkt[0] & PS2_LEFT;
        priv->btn_right = pkt[0] & PS2_RIGHT;

        byd_report_input(psmouse);

        /* Reset time since last touch. */
        if (priv->touch) {
                priv->last_touch_time = jiffies;
                mod_timer(&priv->timer, jiffies + BYD_TOUCH_TIMEOUT);
        }

        return PSMOUSE_FULL_PACKET;
}

static int byd_reset_touchpad(struct psmouse *psmouse)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        u8 param[4];
        size_t i;

        static const struct {
                u16 command;
                u8 arg;
        } seq[] = {
                /*
                 * Intellimouse initialization sequence, to get 4-byte instead
                 * of 3-byte packets.
                 */
                { PSMOUSE_CMD_SETRATE, 0xC8 },
                { PSMOUSE_CMD_SETRATE, 0x64 },
                { PSMOUSE_CMD_SETRATE, 0x50 },
                { PSMOUSE_CMD_GETID, 0 },
                { PSMOUSE_CMD_ENABLE, 0 },
                /*
                 * BYD-specific initialization, which enables absolute mode and
                 * (if desired), the touchpad's built-in gesture detection.
                 */
                { 0x10E2, 0x00 },
                { 0x10E0, 0x02 },
                /* The touchpad should reply with 4 seemingly-random bytes */
                { 0x14E0, 0x01 },
                /* Pairs of parameters and values. */
                { BYD_CMD_SET_HANDEDNESS, 0x01 },
                { BYD_CMD_SET_PHYSICAL_BUTTONS, 0x04 },
                { BYD_CMD_SET_TAP, 0x02 },
                { BYD_CMD_SET_ONE_FINGER_SCROLL, 0x04 },
                { BYD_CMD_SET_ONE_FINGER_SCROLL_FUNC, 0x04 },
                { BYD_CMD_SET_EDGE_MOTION, 0x01 },
                { BYD_CMD_SET_PALM_CHECK, 0x00 },
                { BYD_CMD_SET_MULTITOUCH, 0x02 },
                { BYD_CMD_SET_TWO_FINGER_SCROLL, 0x04 },
                { BYD_CMD_SET_TWO_FINGER_SCROLL_FUNC, 0x04 },
                { BYD_CMD_SET_LEFT_EDGE_REGION, 0x00 },
                { BYD_CMD_SET_TOP_EDGE_REGION, 0x00 },
                { BYD_CMD_SET_RIGHT_EDGE_REGION, 0x00 },
                { BYD_CMD_SET_BOTTOM_EDGE_REGION, 0x00 },
                { BYD_CMD_SET_ABSOLUTE_MODE, 0x02 },
                /* Finalize initialization. */
                { 0x10E0, 0x00 },
                { 0x10E2, 0x01 },
        };

        for (i = 0; i < ARRAY_SIZE(seq); ++i) {
                memset(param, 0, sizeof(param));
                param[0] = seq[i].arg;
                if (ps2_command(ps2dev, param, seq[i].command))
                        return -EIO;
        }

        psmouse_set_state(psmouse, PSMOUSE_ACTIVATED);
        return 0;
}

static int byd_reconnect(struct psmouse *psmouse)
{
        int retry = 0, error = 0;

        psmouse_dbg(psmouse, "Reconnect\n");
        do {
                psmouse_reset(psmouse);
                if (retry)
                        ssleep(1);
                error = byd_detect(psmouse, 0);
        } while (error && ++retry < 3);

        if (error)
                return error;

        psmouse_dbg(psmouse, "Reconnected after %d attempts\n", retry);

        error = byd_reset_touchpad(psmouse);
        if (error) {
                psmouse_err(psmouse, "Unable to initialize device\n");
                return error;
        }

        return 0;
}

static void byd_disconnect(struct psmouse *psmouse)
{
        struct byd_data *priv = psmouse->private;

        if (priv) {
                timer_delete(&priv->timer);
                kfree(psmouse->private);
                psmouse->private = NULL;
        }
}

int byd_detect(struct psmouse *psmouse, bool set_properties)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        u8 param[4] = {0x03, 0x00, 0x00, 0x00};

        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
                return -1;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
                return -1;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
                return -1;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_SETRES))
                return -1;
        if (ps2_command(ps2dev, param, PSMOUSE_CMD_GETINFO))
                return -1;

        if (param[1] != 0x03 || param[2] != 0x64)
                return -ENODEV;

        psmouse_dbg(psmouse, "BYD touchpad detected\n");

        if (set_properties) {
                psmouse->vendor = "BYD";
                psmouse->name = "TouchPad";
        }

        return 0;
}

int byd_init(struct psmouse *psmouse)
{
        struct input_dev *dev = psmouse->dev;
        struct byd_data *priv;

        if (psmouse_reset(psmouse))
                return -EIO;

        if (byd_reset_touchpad(psmouse))
                return -EIO;

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

        priv->psmouse = psmouse;
        timer_setup(&priv->timer, byd_clear_touch, 0);

        psmouse->private = priv;
        psmouse->disconnect = byd_disconnect;
        psmouse->reconnect = byd_reconnect;
        psmouse->protocol_handler = byd_process_byte;
        psmouse->pktsize = 4;
        psmouse->resync_time = 0;

        __set_bit(INPUT_PROP_POINTER, dev->propbit);
        /* Touchpad */
        __set_bit(BTN_TOUCH, dev->keybit);
        __set_bit(BTN_TOOL_FINGER, dev->keybit);
        /* Buttons */
        __set_bit(BTN_LEFT, dev->keybit);
        __set_bit(BTN_RIGHT, dev->keybit);
        __clear_bit(BTN_MIDDLE, dev->keybit);

        /* Absolute position */
        __set_bit(EV_ABS, dev->evbit);
        input_set_abs_params(dev, ABS_X, 0, BYD_PAD_WIDTH, 0, 0);
        input_set_abs_params(dev, ABS_Y, 0, BYD_PAD_HEIGHT, 0, 0);
        input_abs_set_res(dev, ABS_X, BYD_PAD_RESOLUTION);
        input_abs_set_res(dev, ABS_Y, BYD_PAD_RESOLUTION);
        /* No relative support */
        __clear_bit(EV_REL, dev->evbit);
        __clear_bit(REL_X, dev->relbit);
        __clear_bit(REL_Y, dev->relbit);

        return 0;
}