source: mainline/uspace/srv/hid/isdv4_tablet/isdv4.c@ 95f1b8f

/*
 * Copyright (c) 2012 Martin Sucha
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <async.h>
#include <errno.h>
#include <io/chardev.h>
#include <mem.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

#include "isdv4.h"

#define BUF_SIZE 64

#define START_OF_PACKET 128
#define CONTROL_PACKET 64
#define TOUCH_EVENT 16
#define FINGER1 1
#define FINGER2 2
#define TIP 1
#define BUTTON1 2
#define BUTTON2 4
#define PROXIMITY 32

#define CMD_START '1'
#define CMD_STOP '0'
#define CMD_QUERY_STYLUS '*'
#define CMD_QUERY_TOUCH '%'

/* packet_consumer_fn(uint8_t *packet, size_t size, isdv4_state_t *state,
   void *data)
   return true if reading of packets should continue */
typedef bool (*packet_consumer_fn)(uint8_t *, size_t, isdv4_state_t *);

static void isdv4_event_init(isdv4_event_t *event)
{
        memset(event, 0, sizeof(isdv4_event_t));
}

/**
 * Parse event packet and emit events
 * @return true if reading of packets should continue
 */
static bool parse_event(uint8_t *packet, size_t size, isdv4_state_t *state)
{
        if (size < 1)
                return false;

        bool control_packet = ((packet[0] & CONTROL_PACKET) > 0);
        if (control_packet)
                return true;

        /* This is an event initiated by the device */
        isdv4_event_t event;
        isdv4_event_init(&event);

        if (packet[0] & TOUCH_EVENT) {
                if (size != 5)
                        return true;

                /* This is a touch event */
                bool finger1 = (packet[0] & FINGER1) > 0;
                event.x = ((packet[1] & 127) << 7) | (packet[2] & 127);
                event.y = ((packet[3] & 127) << 7) | (packet[4] & 127);
                event.source = TOUCH;

                if (!state->stylus_in_proximity) {
                        if (!finger1 && state->finger1_pressed) {
                                state->finger1_pressed = false;

                                event.type = RELEASE;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        else if (finger1 && !state->finger1_pressed) {
                                state->finger1_pressed = true;

                                event.type = PRESS;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        else {
                                event.type = MOVE;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                }
        }
        else {
                if (size != 9)
                        return true;

                /* This is a stylus event */
                bool tip = packet[0] & TIP;
                bool button1 = packet[0] & BUTTON1;
                bool button2 = packet[0] & BUTTON2;
                bool proximity = packet[0] & PROXIMITY;
                event.x = ((packet[1] & 127) << 7) | (packet[2] & 124) | ((packet[6] >> 5) & 3);
                event.y = ((packet[3] & 127) << 7) | (packet[4] & 124) | ((packet[6] >> 3) & 3);
                event.pressure = (packet[5] & 127) | ((packet[6] & 7) << 7);

                if (proximity && !state->stylus_in_proximity) {
                        /* Stylus came into proximity */
                        state->stylus_in_proximity = true;
                        state->stylus_is_eraser = !tip && button2;
                        event.source = (state->stylus_is_eraser ? STYLUS_ERASER : STYLUS_TIP);
                        event.type = PROXIMITY_IN;
                        state->emit_event_fn(&event);
                }
                else if (!proximity && state->stylus_in_proximity) {
                        /* Stylus came out of proximity */
                        state->stylus_in_proximity = false;
                        event.source = (state->stylus_is_eraser ? STYLUS_ERASER : STYLUS_TIP);
                        event.type = PROXIMITY_OUT;
                        state->emit_event_fn(&event);
                }
                else {
                        /* Proximity state didn't change, but we need to check if it is still eraser */
                        if (state->stylus_is_eraser && !button2) {
                                event.type = PROXIMITY_OUT;
                                event.source = STYLUS_ERASER;
                                state->emit_event_fn(&event);
                                event.type = PROXIMITY_IN;
                                event.source = STYLUS_TIP;
                                state->emit_event_fn(&event);
                                state->stylus_is_eraser = false;
                        }
                        else if (!state->stylus_is_eraser && !tip && button2) {
                                event.type = PROXIMITY_OUT;
                                event.source = STYLUS_TIP;
                                state->emit_event_fn(&event);
                                event.type = PROXIMITY_IN;
                                event.source = STYLUS_ERASER;
                                state->emit_event_fn(&event);
                                state->stylus_is_eraser = true;
                        }
                }

                if (!state->stylus_is_eraser) {
                        if (tip && !state->tip_pressed) {
                                state->tip_pressed = true;
                                event.type = PRESS;
                                event.source = STYLUS_TIP;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        else if (!tip && state->tip_pressed) {
                                state->tip_pressed = false;
                                event.type = RELEASE;
                                event.source = STYLUS_TIP;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        if (button1 && !state->button1_pressed) {
                                state->button1_pressed = true;
                                event.type = PRESS;
                                event.source = STYLUS_TIP;
                                event.button = 2;
                                state->emit_event_fn(&event);
                        }
                        else if (!button1 && state->button1_pressed) {
                                state->button1_pressed = false;
                                event.type = RELEASE;
                                event.source = STYLUS_TIP;
                                event.button = 2;
                                state->emit_event_fn(&event);
                        }
                        if (button2 && !state->button2_pressed) {
                                state->button2_pressed = true;
                                event.type = PRESS;
                                event.source = STYLUS_TIP;
                                event.button = 3;
                                state->emit_event_fn(&event);
                        }
                        else if (!button2 && state->button2_pressed) {
                                state->button2_pressed = false;
                                event.type = RELEASE;
                                event.source = STYLUS_TIP;
                                event.button = 3;
                                state->emit_event_fn(&event);
                        }
                        event.type = MOVE;
                        event.source = STYLUS_TIP;
                        event.button = 0;
                        state->emit_event_fn(&event);
                }
                else {
                        if (tip && !state->tip_pressed) {
                                state->tip_pressed = true;
                                event.type = PRESS;
                                event.source = STYLUS_ERASER;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        else if (!tip && state->tip_pressed) {
                                state->tip_pressed = false;
                                event.type = RELEASE;
                                event.source = STYLUS_ERASER;
                                event.button = 1;
                                state->emit_event_fn(&event);
                        }
                        event.type = MOVE;
                        event.source = STYLUS_ERASER;
                        event.button = 0;
                        state->emit_event_fn(&event);
                }
        }

        return true;
}

static bool parse_response_stylus(uint8_t *packet, size_t size,
    isdv4_state_t *state)
{
        if (size < 1)
                return false;

        bool control_packet = ((packet[0] & CONTROL_PACKET) > 0);
        if (!control_packet)
                return true;

        if (size != 11)
                return false;

        state->stylus_max_x = ((packet[1] & 127) << 7) | (packet[2] & 124) |
            ((packet[6] >> 5) & 3);
        state->stylus_max_y = ((packet[3] & 127) << 7) | (packet[4] & 124) |
            ((packet[6] >> 3) & 3);
        state->stylus_max_pressure = (packet[5] & 63) | ((packet[6] & 7) << 7);
        state->stylus_max_xtilt = packet[8] & 127;
        state->stylus_max_ytilt = packet[7] & 127;
        state->stylus_tilt_supported = (state->stylus_max_xtilt &&
            state->stylus_max_ytilt);

        return false;
}

static bool parse_response_touch(uint8_t *packet, size_t size,
    isdv4_state_t *state)
{
        if (size < 1)
                return false;

        bool control_packet = ((packet[0] & CONTROL_PACKET) > 0);
        if (!control_packet)
                return true;

        if (size != 11)
                return false;

        state->touch_type = (packet[0] & 63);

        unsigned int touch_resolution = packet[1] & 127;
        state->touch_max_x = ((packet[2] >> 5) & 3) | ((packet[3] & 127) << 7) |
            (packet[4] & 124);
        state->touch_max_y = ((packet[2] >> 3) & 3) | ((packet[5] & 127) << 7) |
            (packet[6] & 124);
        
        if (touch_resolution == 0)
                touch_resolution = 10;

        if (state->touch_max_x == 0 || state->touch_max_y == 0) {
                state->touch_max_x = (1 << touch_resolution);
                state->touch_max_y = (1 << touch_resolution);
        }

        return false;
}

static errno_t read_packets(isdv4_state_t *state, packet_consumer_fn consumer)
{
        bool reading = true;
        while (reading) {
                size_t nread;
                errno_t rc;

                rc = chardev_read(state->chardev, state->buf + state->buf_end,
                    state->buf_size - state->buf_end, &nread);
                if (rc != EOK && nread == 0)
                        return EIO;
                state->buf_end += nread;

                size_t i = 0;

                /* Skip data until a start of packet is found */
                while (i < state->buf_end && (state->buf[i] & START_OF_PACKET) == 0) i++;

                size_t start = i;
                size_t end = i;
                size_t processed_end = i;

                /* Process packets one by one */
                while (reading && i < state->buf_end) {
                        /* Determine the packet length */
                        size_t packet_remaining;
                        if (state->buf[i] & CONTROL_PACKET) {
                                packet_remaining = 11;
                        }
                        else if (state->buf[i] & TOUCH_EVENT) {
                                packet_remaining = 5;
                        }
                        else {
                                packet_remaining = 9;
                        }

                        /* Find the end of the packet */
                        i++; /* We need to skip the first byte with START_OF_PACKET set */
                        packet_remaining--; 
                        while (packet_remaining > 0 && i < state->buf_end &&
                            (state->buf[i] & START_OF_PACKET) == 0) {
                                i++;
                                packet_remaining--;
                        }
                        end = i;

                        /* If we have whole packet, process it */
                        if (end > start && packet_remaining == 0) {
                                reading = consumer(state->buf + start, end - start, state);
                                start = end;
                                processed_end = end;
                        }
                }

                if (processed_end == 0 && state->buf_end == state->buf_size) {
                        /* Packet too large, throw it away */
                        state->buf_end = 0;
                }

                /* Shift the buffer contents to the left */
                size_t unprocessed_len = state->buf_end - processed_end;
                memcpy(state->buf, state->buf + processed_end, unprocessed_len);
                state->buf_end = unprocessed_len;
        }
        return EOK;
}

static bool write_command(chardev_t *chardev, uint8_t command)
{
        errno_t rc;
        size_t nwr;

        rc = chardev_write(chardev, &command, 1, &nwr);
        return rc == EOK;
}

errno_t isdv4_init(isdv4_state_t *state, async_sess_t *sess,
    isdv4_event_fn event_fn)
{
        chardev_t *chardev;
        errno_t rc;

        rc = chardev_open(sess, &chardev);
        if (rc != EOK)
                return rc;

        memset(state, 0, sizeof(isdv4_state_t));

        state->sess = sess;
        state->chardev = chardev;

        state->buf = malloc(BUF_SIZE);
        if (state->buf == NULL) {
                chardev_close(chardev);
                return ENOMEM;
        }

        state->buf_size = BUF_SIZE;
        state->emit_event_fn = event_fn;
        return EOK;
}

errno_t isdv4_init_tablet(isdv4_state_t *state)
{
        if (!write_command(state->chardev, CMD_STOP))
                return EIO;

        async_usleep(250000); /* 250 ms */

        // FIXME: Read all possible garbage before sending commands
        if (!write_command(state->chardev, CMD_QUERY_STYLUS))
                return EIO;

        errno_t rc = read_packets(state, parse_response_stylus);
        if (rc != EOK)
                return rc;

        if (!write_command(state->chardev, CMD_QUERY_TOUCH))
                return EIO;

        rc = read_packets(state, parse_response_touch);
        if (rc != EOK)
                return rc;

        if (!write_command(state->chardev, CMD_START))
                return EIO;

        return EOK;
}

errno_t isdv4_read_events(isdv4_state_t *state)
{
        return read_packets(state, parse_event);
}

void isdv4_fini(isdv4_state_t *state)
{
        free(state->buf);
}