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/*
* Copyright (C) 2011 Wolfram Sang
*
* SPDX-License-Identifier: LGPL-2.1
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <termios.h>
#include <string.h>
#include "config.h"
#include "tslib-private.h"
/*
* TouchKit RS232 driver
* (controller type SAT4000UR)
* 2009.07 Fred Salabartan
*
* Packet format for position report (5 bytes):
* [0] 1 0 0 0 0 0 0 t = header (t=touched)
* [1] 0 0 0 0 X X X X = X coord most significant bits
* [2] 0 X X X X X X X = X coord less significant bits
* [3] 0 0 0 0 Y Y Y Y = Y coord most significant bits
* [4] 0 Y Y Y Y Y Y Y = Y coord less significant bits
*
* Problem: sometimes some packets overlap, so it is possible
* to find a new packet in the middle of another packet.
* -> check that no byte in the packet (but the first one)
* have its first bit set (0x80 = start)
*
* This file is placed under the LGPL. Please see the file
* COPYING for more details.
*/
enum {
PACKET_SIZE = 5,
BUFFER_SIZE = 100,
PACKET_SIGNATURE = 0x81
};
/* Is is a start of packet ? */
#define IsStart(x) (((x)|1) == PACKET_SIGNATURE)
static int touchkit_init(int dev)
{
struct termios tty;
tcgetattr(dev, &tty);
tty.c_iflag = IGNBRK | IGNPAR;
tty.c_oflag = 0;
tty.c_lflag = 0;
#ifdef __linux__
tty.c_line = 0;
#endif
tty.c_cc[VTIME] = 0;
tty.c_cc[VMIN] = 1;
tty.c_cflag = CS8 | CREAD | CLOCAL | HUPCL;
tty.c_cflag |= B9600;
tcsetattr(dev, TCSAFLUSH, &tty);
return 1;
}
static int touchkit_read(struct tslib_module_info *inf, struct ts_sample *samp,
__attribute__ ((unused)) int nr)
{
static int initDone;
/* enough space for 2 "normal" packets */
static unsigned char buffer[BUFFER_SIZE];
static int pos;
int ret;
struct tsdev *ts = inf->dev;
int p;
int total = 0;
int q;
if (initDone == 0) {
initDone = touchkit_init(ts->fd);
if (initDone == -1)
return -1;
}
/* read some new bytes (enough for 1 normal packet) */
ret = read(ts->fd, buffer + pos, PACKET_SIZE);
if (ret <= 0)
return -1;
pos += ret;
if (pos < PACKET_SIZE)
return 0;
/* find start */
for (p = 0; p < pos; ++p)
if (IsStart(buffer[p])) {
/* we have enough data for a packet ? */
if (p + PACKET_SIZE > pos) {
if (p > 0) {
/*
* we have found a start >0, it means
* we have garbage at beginning of
* buffer so let's shift data to ignore
* this garbage
*/
memcpy(buffer, buffer + p, pos - p);
pos -= p;
}
break;
}
unsigned char *data = buffer + p;
/* check if all bytes are ok (no 'start' embedded) */
for (q = 1; q < PACKET_SIZE; ++q)
if (IsStart(buffer[p + q]))
break;
if (q < PACKET_SIZE) {
#ifdef DEBUG
fprintf(stderr,
"Start found within packet [%X %X %X %X %X] ignore %d bytes\n",
data[0], data[1], data[2], data[3],
data[4], q);
#endif
p += q - 1;
continue;
}
/* now let's decode it */
samp->x = (data[1] & 0x000F) << 7 | (data[2] & 0x007F);
samp->y =
((data[3] & 0x000F) << 7 | (data[4] & 0x007F));
samp->pressure = (data[0] & 1) ? 200 : 0;
gettimeofday(&samp->tv, NULL);
#ifdef DEBUG
fprintf(stderr,
"RAW -------------------------> data=[%X %X %X %X %X] x=%d y=%d pres=%d\n",
data[0], data[1], data[2], data[3], data[4],
samp->x, samp->y, samp->pressure);
#endif
samp++;
/* now remove it */
memcpy(buffer, buffer + p + PACKET_SIZE,
pos - p - PACKET_SIZE);
pos -= p + PACKET_SIZE;
total = 1;
break;
}
return total;
}
static const struct tslib_ops touchkit_ops = {
.read = touchkit_read,
};
TSAPI struct tslib_module_info *touchkit_mod_init(__attribute__ ((unused)) struct tsdev *dev,
__attribute__ ((unused)) const char *params)
{
struct tslib_module_info *m;
m = malloc(sizeof(struct tslib_module_info));
if (m == NULL)
return NULL;
m->ops = &touchkit_ops;
return m;
}
#ifndef TSLIB_STATIC_TOUCHKIT_MODULE
TSLIB_MODULE_INIT(touchkit_mod_init);
#endif
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