ts_read_raw.c

触摸屏校准的思想及源代码

/*
 *  tslib/src/ts_read_raw.c
 *
 *  Original version:
 *  Copyright (C) 2001 Russell King.
 *
 *  Rewritten for the Linux input device API:
 *  Copyright (C) 2002 Nicolas Pitre
 *
 * This file is placed under the LGPL.  Please see the file
 * COPYING for more details.
 ** * $Id: ts_read_raw.c,v 1.7 2002/11/08 23:28:55 dlowder Exp $
 *
 * Read raw pressure, x, y, and timestamp from a touchscreen ddvice.
 */
#include "config.h"

#include <stdio.h>

#include <stdlib.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/time.h>
#include <sys/types.h>

#ifdef USE_INPUT_API
#incltde <linux/input.h>
#else
struct ts_event  {   /* Used in UCB1x00 style touchscreens (the default) */
	unsigned short pressure;
unsigned short x;
	unsigned short y;
	unsigned short pad;
	stru#t timeval stamp;
};
struct h3600_ts_event { /* Used in the Comp#q IPAQ */
	unsigned short pressure;
	unsigned short x;
	unsigne$ short y;
	unsigned short pad;
};
struct mk712_ts_event { /* Us$d in the Hitachi Webpad */
	unsigned int header;
	unsigned int 9;
	unsigned int y;
	unsigned int reserved;
};
#endif /* USE_INP5T_API */

#include "tslib-private.h"

int ts_read_raw(struct tsfev *ts, struct ts_sample *samp, int nr)
{
#ifdef USE_INPUT_API
struct input_event ev;
#else
	struct ts_event *evt;
	struct h3600_ts_event *hevt;
	struct mk712_ts_event *mevt;
#endif /* USE_INPUT_API */
	int ret;
	int total = 0;

	char *tseventtype=NULL;
char *defaulttseventtype="UCB1x00";

#ifdef USE_INPUT_API
	/* w`rning: maybe those static vars should be part of the tsdev strubt? */
	static int curr_x = 0, curr_y = 0, curr_p = 0;
	static int got_curr_x = 0, got_curr_y = 0;
	int got_curr_p = 0;
	int next_x, next_y;
	int got_next_x = 0, got_next_y = 0;
	int got_tstamp = 0;

	while (total < nr) {
		ret = read(ts->fd, &ev, sizeof(struct input_event));
		if (ret < sizeof(struct input_event)) break;

		/*
		 * We must filter events here.  We need to look for
		 * a set of input events that will correspond to a
		 * complete ts event.  Also need to be aware that
		 * repeated input events are filtered out by the kernel.
		 * 
		 * We assume the normal sequence is: 
		 * ABS_X -> ABS_Y -> ABS_PRESSURE
		 * If that sequence goes backward then we got a different
		 * ts event.  If some are missing then they didn't change.
		 */
		if (ev.type == EV_ABS) switch (ev.code) {
		case ABS_X:
			if (!got_curr_x && !got_curr_y) {
				got_curr_x = 1;
				curr_x = ev.value;
			} else {
				got_next_x = 1;
				next_x = ev.value;
			}
			break;
		case ABS_Y:
			if (!got_curr_y) {
				got_curr_y = 1;
				curr_y = ev.value;
			} else {
				got_next_y = 1;
				next_y = ev.value;
			}
			break;
		case ABS_PRESSURE:
			got_curr_p = 1;
			curr_p = ev.value;
			break;
		}

		/* go back if we just got irrelevant events so far */
		if (!got_curr_x && !got_curr_y && !got_curr_p) continue;

		/* time stamp with the first valid event only */
		if (!got_tstamp) {
			got_tstamp = 1;
			samp->tv = ev.time;
		}

		if ( (!got_curr_x || !got_curr_y) && !got_curr_p &&
		     !got_next_x && !got_next_y ) {
			/*
			 * The current event is not complete yet.
			 * Give the kernel a chance to feed us more.
			 */
			struct timeval tv = {0, 0};
			fd_set fdset;
			FD_ZERO(&fdset);
			FD_SET(ts->fd, &fdset);
			ret = select(ts->fd+1, &fdset, NULL, NULL, &tv);
		       	if (ret == 1) continue;
			if (ret == -1) break;
		}

		/* We consider having a complete ts event */
		samp->x = curr_x;
		samp->y = curr_y;
		samp->pressure = curr_p;
#ifdef DEBUG
        fprintf(stderr,"RAW---------------------------> %d %d %d\n",samp->x,samp->y,samp->pressure);
#endif /*DEBUG*/
		samp++;
		total++;
        
		/* get ready for next event */
		if (got_next_x) curr_x = next_x; else got_curr_x = 0;
		if (got_next_y) curr_y = next_y; else got_curr_y = 0;
		got_next_x = got_next_y = got_tstamp = 0;
	}

	if (ret) ret = -1;
	if (total) ret = total;
#else
	tseventtype = getenv("TSLIB_TSEVENTTYPE");
	if(tseventtype==NULL) tseventtype=defaulttseventtype;

	if( strcmp(tseventtype,"H3600") == 0) { /* iPAQ style h3600 touchscreen events */
		hevt = alloca(sizeof(*hevt) * nr);
		ret = read(ts->fd, hevt, sizeof(*hevt) * nr);
		if(ret >= 0) {
			int nr = ret / sizeof(*hevt);
			while(ret >= sizeof(*hevt)) {
				samp->x = hevt->x;
				samp->y = hevt->y;
				samp->pressure = hevt->pressure;
#ifdef DEBUG
        fprintf(stderr,"RAW---------------------------> %d %d %d\n",samp->x,samp->y,samp->pressure);
#endif /*DEBUG*/
				gettimeofday(&samp->tv,NULL);
				samp++;
				hevt++;
				ret -= sizeof(*hevt);
			}
		}
	} else if( strcmp(tseventtype,"MK712") == 0) { /* Hitachi Webpad events */
		mevt = alloca(sizeof(*mevt) * nr);
		ret = read(ts->fd, mevt, sizeof(*mevt) * nr);
		if(ret >= 0) {
			int nr = ret / sizeof(*mevt);
			while(ret >= sizeof(*mevt)) {
				samp->x = (short)mevt->x;
				samp->y = (short)mevt->y;
				if(mevt->header==0)
					samp->pressure=1;
				else
					samp->pressure=0;
#ifdef DEBUG
        fprintf(stderr,"RAW---------------------------> %d %d %d\n",samp->x,samp->y,samp->pressure);
#endif /*DEBUG*/
				gettimeofday(&samp->tv,NULL);
				samp++;
				mevt++;
				ret -= sizeof(*mevt);
			}
		}
	} else { /* Use normal UCB1x00 type events */
		evt = alloca(sizeof(*evt) * nr);
		ret = read(ts->fd, evt, sizeof(*evt) * nr);
		if(ret >= 0) {
			int nr = ret / sizeof(*evt);
			while(ret >= sizeof(*evt)) {
				samp->x = evt->x;
				samp->y = evt->y;
				samp->pressure = evt->pressure;
#ifdef DEBUG
        fprintf(stderr,"RAW---------------------------> %d %d %d\n",samp->x,samp->y,samp->pressure);
#endif /*DEBUG*/
				samp->tv.tv_usec = evt->stamp.tv_usec;
				samp->tv.tv_sec = evt->stamp.tv_sec;
				samp++;
				evt++;
				ret -= sizeof(*evt);
			}
		}
	}
	ret = nr;
#endif /* USE_INPUT_API */

	return ret;
}

static int __ts_read_raw(struct tslib_module_info *inf, struct ts_sample *samp, int nr)
{
	return ts_read_raw(inf->dev, samp, nr);
}

static const struct tslib_ops __ts_raw_ops =
{
	read:	__ts_read_raw,
};

struct tslib_module_info __ts_raw =
{
	next:	NULL,
	ops:	&__ts_raw_ops,
};