// SPDX-License-Identifier: GPL-2.0-only
/*
 * Stephen Evanchik <evanchsa@gmail.com>
 *
 * Trademarks are the property of their respective owners.
 */

#include <linux/array_size.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/serio.h>
#include <linux/module.h>
#include <linux/input.h>
#include <linux/libps2.h>
#include <linux/proc_fs.h>
#include <linux/string.h>
#include <linux/uaccess.h>
#include "psmouse.h"
#include "trackpoint.h"

static const char * const trackpoint_variants[] = {
        [TP_VARIANT_IBM]                = "IBM",
        [TP_VARIANT_ALPS]               = "ALPS",
        [TP_VARIANT_ELAN]               = "Elan",
        [TP_VARIANT_NXP]                = "NXP",
        [TP_VARIANT_JYT_SYNAPTICS]      = "JYT_Synaptics",
        [TP_VARIANT_SYNAPTICS]          = "Synaptics",
};

/*
 * Power-on Reset: Resets all trackpoint parameters, including RAM values,
 * to defaults.
 * Returns zero on success, non-zero on failure.
 */
static int trackpoint_power_on_reset(struct ps2dev *ps2dev)
{
        u8 param[2] = { TP_POR };
        int err;

        err = ps2_command(ps2dev, param, MAKE_PS2_CMD(1, 2, TP_COMMAND));
        if (err)
                return err;

        /* Check for success response -- 0xAA00 */
        if (param[0] != 0xAA || param[1] != 0x00)
                return -ENODEV;

        return 0;
}

/*
 * Device IO: read, write and toggle bit
 */
static int trackpoint_read(struct ps2dev *ps2dev, u8 loc, u8 *results)
{
        results[0] = loc;

        return ps2_command(ps2dev, results, MAKE_PS2_CMD(1, 1, TP_COMMAND));
}

static int trackpoint_write(struct ps2dev *ps2dev, u8 loc, u8 val)
{
        u8 param[3] = { TP_WRITE_MEM, loc, val };

        return ps2_command(ps2dev, param, MAKE_PS2_CMD(3, 0, TP_COMMAND));
}

static int trackpoint_toggle_bit(struct ps2dev *ps2dev, u8 loc, u8 mask)
{
        u8 param[3] = { TP_TOGGLE, loc, mask };

        /* Bad things will happen if the loc param isn't in this range */
        if (loc < 0x20 || loc >= 0x2F)
                return -EINVAL;

        return ps2_command(ps2dev, param, MAKE_PS2_CMD(3, 0, TP_COMMAND));
}

static int trackpoint_update_bit(struct ps2dev *ps2dev,
                                 u8 loc, u8 mask, u8 value)
{
        int retval;
        u8 data;

        retval = trackpoint_read(ps2dev, loc, &data);
        if (retval)
                return retval;

        if (((data & mask) == mask) != !!value)
                retval = trackpoint_toggle_bit(ps2dev, loc, mask);

        return retval;
}

/*
 * Trackpoint-specific attributes
 */
struct trackpoint_attr_data {
        size_t field_offset;
        u8 command;
        u8 mask;
        bool inverted;
        u8 power_on_default;
};

static ssize_t trackpoint_show_int_attr(struct psmouse *psmouse,
                                        void *data, char *buf)
{
        struct trackpoint_data *tp = psmouse->private;
        struct trackpoint_attr_data *attr = data;
        u8 value = *(u8 *)((void *)tp + attr->field_offset);

        if (attr->inverted)
                value = !value;

        return sprintf(buf, "%u\n", value);
}

static ssize_t trackpoint_set_int_attr(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        struct trackpoint_data *tp = psmouse->private;
        struct trackpoint_attr_data *attr = data;
        u8 *field = (void *)tp + attr->field_offset;
        u8 value;
        int err;

        err = kstrtou8(buf, 10, &value);
        if (err)
                return err;

        *field = value;
        err = trackpoint_write(&psmouse->ps2dev, attr->command, value);

        return err ?: count;
}

#define TRACKPOINT_INT_ATTR(_name, _command, _default)                          \
        static struct trackpoint_attr_data trackpoint_attr_##_name = {          \
                .field_offset = offsetof(struct trackpoint_data, _name),        \
                .command = _command,                                            \
                .power_on_default = _default,                                   \
        };                                                                      \
        PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,                           \
                            &trackpoint_attr_##_name,                           \
                            trackpoint_show_int_attr, trackpoint_set_int_attr)

static ssize_t trackpoint_set_bit_attr(struct psmouse *psmouse, void *data,
                                        const char *buf, size_t count)
{
        struct trackpoint_data *tp = psmouse->private;
        struct trackpoint_attr_data *attr = data;
        bool *field = (void *)tp + attr->field_offset;
        bool value;
        int err;

        err = kstrtobool(buf, &value);
        if (err)
                return err;

        if (attr->inverted)
                value = !value;

        if (*field != value) {
                *field = value;
                err = trackpoint_toggle_bit(&psmouse->ps2dev,
                                            attr->command, attr->mask);
        }

        return err ?: count;
}


#define TRACKPOINT_BIT_ATTR(_name, _command, _mask, _inv, _default)     \
static struct trackpoint_attr_data trackpoint_attr_##_name = {          \
        .field_offset           = offsetof(struct trackpoint_data,      \
                                           _name),                      \
        .command                = _command,                             \
        .mask                   = _mask,                                \
        .inverted               = _inv,                                 \
        .power_on_default       = _default,                             \
        };                                                              \
PSMOUSE_DEFINE_ATTR(_name, S_IWUSR | S_IRUGO,                           \
                    &trackpoint_attr_##_name,                           \
                    trackpoint_show_int_attr, trackpoint_set_bit_attr)

TRACKPOINT_INT_ATTR(sensitivity, TP_SENS, TP_DEF_SENS);
TRACKPOINT_INT_ATTR(speed, TP_SPEED, TP_DEF_SPEED);
TRACKPOINT_INT_ATTR(inertia, TP_INERTIA, TP_DEF_INERTIA);
TRACKPOINT_INT_ATTR(reach, TP_REACH, TP_DEF_REACH);
TRACKPOINT_INT_ATTR(draghys, TP_DRAGHYS, TP_DEF_DRAGHYS);
TRACKPOINT_INT_ATTR(mindrag, TP_MINDRAG, TP_DEF_MINDRAG);
TRACKPOINT_INT_ATTR(thresh, TP_THRESH, TP_DEF_THRESH);
TRACKPOINT_INT_ATTR(upthresh, TP_UP_THRESH, TP_DEF_UP_THRESH);
TRACKPOINT_INT_ATTR(ztime, TP_Z_TIME, TP_DEF_Z_TIME);
TRACKPOINT_INT_ATTR(jenks, TP_JENKS_CURV, TP_DEF_JENKS_CURV);
TRACKPOINT_INT_ATTR(drift_time, TP_DRIFT_TIME, TP_DEF_DRIFT_TIME);

TRACKPOINT_BIT_ATTR(press_to_select, TP_TOGGLE_PTSON, TP_MASK_PTSON, false,
                    TP_DEF_PTSON);
TRACKPOINT_BIT_ATTR(skipback, TP_TOGGLE_SKIPBACK, TP_MASK_SKIPBACK, false,
                    TP_DEF_SKIPBACK);
TRACKPOINT_BIT_ATTR(ext_dev, TP_TOGGLE_EXT_DEV, TP_MASK_EXT_DEV, true,
                    TP_DEF_EXT_DEV);

static bool trackpoint_is_attr_available(struct psmouse *psmouse,
                                         struct attribute *attr)
{
        struct trackpoint_data *tp = psmouse->private;

        return tp->variant_id == TP_VARIANT_IBM ||
                attr == &psmouse_attr_sensitivity.dattr.attr ||
                attr == &psmouse_attr_press_to_select.dattr.attr;
}

static umode_t trackpoint_is_attr_visible(struct kobject *kobj,
                                          struct attribute *attr, int n)
{
        struct device *dev = kobj_to_dev(kobj);
        struct serio *serio = to_serio_port(dev);
        struct psmouse *psmouse = psmouse_from_serio(serio);

        return trackpoint_is_attr_available(psmouse, attr) ? attr->mode : 0;
}

static struct attribute *trackpoint_attrs[] = {
        &psmouse_attr_sensitivity.dattr.attr,
        &psmouse_attr_speed.dattr.attr,
        &psmouse_attr_inertia.dattr.attr,
        &psmouse_attr_reach.dattr.attr,
        &psmouse_attr_draghys.dattr.attr,
        &psmouse_attr_mindrag.dattr.attr,
        &psmouse_attr_thresh.dattr.attr,
        &psmouse_attr_upthresh.dattr.attr,
        &psmouse_attr_ztime.dattr.attr,
        &psmouse_attr_jenks.dattr.attr,
        &psmouse_attr_drift_time.dattr.attr,
        &psmouse_attr_press_to_select.dattr.attr,
        &psmouse_attr_skipback.dattr.attr,
        &psmouse_attr_ext_dev.dattr.attr,
        NULL
};

static struct attribute_group trackpoint_attr_group = {
        .is_visible     = trackpoint_is_attr_visible,
        .attrs          = trackpoint_attrs,
};

#define TRACKPOINT_UPDATE(_power_on, _psmouse, _tp, _name)              \
do {                                                                    \
        struct trackpoint_attr_data *_attr = &trackpoint_attr_##_name;  \
                                                                        \
        if ((!_power_on || _tp->_name != _attr->power_on_default) &&    \
            trackpoint_is_attr_available(_psmouse,                      \
                                &psmouse_attr_##_name.dattr.attr)) {    \
                if (!_attr->mask)                                       \
                        trackpoint_write(&_psmouse->ps2dev,             \
                                         _attr->command, _tp->_name);   \
                else                                                    \
                        trackpoint_update_bit(&_psmouse->ps2dev,        \
                                        _attr->command, _attr->mask,    \
                                        _tp->_name);                    \
        }                                                               \
} while (0)

#define TRACKPOINT_SET_POWER_ON_DEFAULT(_tp, _name)                     \
do {                                                                    \
        _tp->_name = trackpoint_attr_##_name.power_on_default;          \
} while (0)

static int trackpoint_start_protocol(struct psmouse *psmouse,
                                     u8 *variant_id, u8 *firmware_id)
{
        u8 param[2] = { 0 };
        int error;

        error = ps2_command(&psmouse->ps2dev,
                            param, MAKE_PS2_CMD(0, 2, TP_READ_ID));
        if (error)
                return error;

        switch (param[0]) {
        case TP_VARIANT_IBM:
        case TP_VARIANT_ALPS:
        case TP_VARIANT_ELAN:
        case TP_VARIANT_NXP:
        case TP_VARIANT_JYT_SYNAPTICS:
        case TP_VARIANT_SYNAPTICS:
                if (variant_id)
                        *variant_id = param[0];
                if (firmware_id)
                        *firmware_id = param[1];
                return 0;
        }

        return -ENODEV;
}

/*
 * Write parameters to trackpad.
 * in_power_on_state: Set to true if TP is in default / power-on state (ex. if
 *                    power-on reset was run). If so, values will only be
 *                    written to TP if they differ from power-on default.
 */
static int trackpoint_sync(struct psmouse *psmouse, bool in_power_on_state)
{
        struct trackpoint_data *tp = psmouse->private;

        if (!in_power_on_state && tp->variant_id == TP_VARIANT_IBM) {
                /*
                 * Disable features that may make device unusable
                 * with this driver.
                 */
                trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_TWOHAND,
                                      TP_MASK_TWOHAND, TP_DEF_TWOHAND);

                trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_SOURCE_TAG,
                                      TP_MASK_SOURCE_TAG, TP_DEF_SOURCE_TAG);

                trackpoint_update_bit(&psmouse->ps2dev, TP_TOGGLE_MB,
                                      TP_MASK_MB, TP_DEF_MB);
        }

        /*
         * These properties can be changed in this driver. Only
         * configure them if the values are non-default or if the TP is in
         * an unknown state.
         */
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, sensitivity);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, inertia);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, speed);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, reach);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, draghys);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, mindrag);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, thresh);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, upthresh);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ztime);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, jenks);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, drift_time);

        /* toggles */
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, press_to_select);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, skipback);
        TRACKPOINT_UPDATE(in_power_on_state, psmouse, tp, ext_dev);

        return 0;
}

static void trackpoint_defaults(struct trackpoint_data *tp)
{
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, sensitivity);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, speed);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, reach);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, draghys);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, mindrag);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, thresh);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, upthresh);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ztime);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, jenks);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, drift_time);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, inertia);

        /* toggles */
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, press_to_select);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, skipback);
        TRACKPOINT_SET_POWER_ON_DEFAULT(tp, ext_dev);
}

static void trackpoint_disconnect(struct psmouse *psmouse)
{
        device_remove_group(&psmouse->ps2dev.serio->dev,
                            &trackpoint_attr_group);

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

static int trackpoint_reconnect(struct psmouse *psmouse)
{
        struct trackpoint_data *tp = psmouse->private;
        int error;
        bool was_reset;

        error = trackpoint_start_protocol(psmouse, NULL, NULL);
        if (error)
                return error;

        was_reset = tp->variant_id == TP_VARIANT_IBM &&
                    trackpoint_power_on_reset(&psmouse->ps2dev) == 0;

        error = trackpoint_sync(psmouse, was_reset);
        if (error)
                return error;

        return 0;
}

/* List of known incapable device PNP IDs */
static const char * const dt_incompatible_devices[] = {
        "LEN0304",
        "LEN0306",
        "LEN0317",
        "LEN031A",
        "LEN031B",
        "LEN031C",
        "LEN031D",
};

/*
 * Checks if it's a doubletap capable device.
 * The PNP ID format is "PNP: LEN030d PNP0f13".
 */
static bool trackpoint_is_dt_capable(const char *pnp_id)
{
        size_t i;

        if (!pnp_id)
                return false;

        /* Must start with "PNP: LEN03" */
        if (!strstarts(pnp_id, "PNP: LEN03"))
                return false;

        /* Ensure enough length before comparing */
        if (strlen(pnp_id) < 12)
                return false;

        /* Check deny-list */
        for (i = 0; i < ARRAY_SIZE(dt_incompatible_devices); i++) {
                if (!strncmp(pnp_id + 5, dt_incompatible_devices[i], 7))
                        return false;
        }
        return true;
}

int trackpoint_detect(struct psmouse *psmouse, bool set_properties)
{
        struct ps2dev *ps2dev = &psmouse->ps2dev;
        struct trackpoint_data *tp;
        u8 variant_id;
        u8 firmware_id;
        u8 button_info;
        int error;

        error = trackpoint_start_protocol(psmouse, &variant_id, &firmware_id);
        if (error)
                return error;

        if (!set_properties)
                return 0;

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

        trackpoint_defaults(tp);
        tp->variant_id = variant_id;
        tp->firmware_id = firmware_id;

        psmouse->private = tp;

        psmouse->vendor = trackpoint_variants[variant_id];
        psmouse->name = "TrackPoint";

        psmouse->reconnect = trackpoint_reconnect;
        psmouse->disconnect = trackpoint_disconnect;

        if (variant_id != TP_VARIANT_IBM) {
                /* Newer variants do not support extended button query. */
                button_info = 0x33;
        } else {
                error = trackpoint_read(ps2dev, TP_EXT_BTN, &button_info);
                if (error) {
                        psmouse_warn(psmouse,
                                     "failed to get extended button data, assuming 3 buttons\n");
                        button_info = 0x33;
                } else if (!button_info) {
                        psmouse_warn(psmouse,
                                     "got 0 in extended button data, assuming 3 buttons\n");
                        button_info = 0x33;
                }
        }

        if ((button_info & 0x0f) >= 3)
                input_set_capability(psmouse->dev, EV_KEY, BTN_MIDDLE);

        __set_bit(INPUT_PROP_POINTER, psmouse->dev->propbit);
        __set_bit(INPUT_PROP_POINTING_STICK, psmouse->dev->propbit);

        if (variant_id != TP_VARIANT_IBM ||
            trackpoint_power_on_reset(ps2dev) != 0) {
                /*
                 * Write defaults to TP if we did not reset the trackpoint.
                 */
                trackpoint_sync(psmouse, false);
        }

        error = device_add_group(&ps2dev->serio->dev, &trackpoint_attr_group);
        if (error) {
                psmouse_err(psmouse,
                            "failed to create sysfs attributes, error: %d\n",
                            error);
                kfree(psmouse->private);
                psmouse->private = NULL;
                return -1;
        }

        psmouse_info(psmouse,
                     "%s TrackPoint firmware: 0x%02x, buttons: %d/%d\n",
                     psmouse->vendor, firmware_id,
                     (button_info & 0xf0) >> 4, button_info & 0x0f);

        if (trackpoint_is_dt_capable(ps2dev->serio->firmware_id)) {
                error = trackpoint_write(ps2dev, TP_DOUBLETAP, TP_DOUBLETAP_ENABLE);
                if (error)
                        psmouse_warn(psmouse, "Failed to enable doubletap: %d\n", error);
        }

        return 0;
}