mou_ps2.c

一个linux下的根文件系统的源码

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>

#include "device.h"

#define	SCALE		3	/* default scaling factor for acceleration */
#define	THRESH		5	/* default threshhold for acceleration */

#define PS2_SCALE	230	/* Set 1:1 scale factor */
#define PS2_ENABLE	244	/* Enable PS/2 device */
#define PS2_DEFAULT	246	/* Set default settings */


/* Make sure the mouse is enabled and in a sane state */
static unsigned char InitPs2[] = { PS2_DEFAULT, PS2_SCALE, PS2_ENABLE };

#define	SCALE		3	/* default scaling factor for acceleration */
#define	THRESH		5	/* default threshhold for acceleration */

#define PS2_DEV_FILE	"/dev/input/mouse0"
//#define PS2_DEV_FILE	"/dev/psaux"

static int  	PS2_Open(MOUSEDEVICE *pmd);
static void 	PS2_Close(void);
static int  	PS2_GetButtonInfo(void);
static void	MOU_GetDefaultAccel(int *pscale,int *pthresh);
static int  	PS2_Read(MWCOORD *dx, MWCOORD *dy, MWCOORD *dz, int *bp);

MOUSEDEVICE mousedev = {
	PS2_Open,
	PS2_Close,
	PS2_GetButtonInfo,
	MOU_GetDefaultAccel,
	PS2_Read,
	NULL
};

static int mouse_fd;

/*
 * Open up the mouse device.
 * Returns the fd if successful, or negative if unsuccessful.
 */
static int
PS2_Open(MOUSEDEVICE *pmd)
{
	//mouse_fd = open (PS2_DEV_FILE, O_RDONLY | O_NOCTTY | O_NONBLOCK);
	mouse_fd = open (PS2_DEV_FILE, O_RDONLY | O_NOCTTY | O_NONBLOCK);
	if (mouse_fd < 0) 
			return -1;
	//write(mouse_fd, InitPs2, sizeof(InitPs2));
	return mouse_fd;

}

/*
 * Close the mouse device.
 */
static void
PS2_Close(void)
{
	if (mouse_fd > 0)
		close(mouse_fd);
	mouse_fd = -1;
}

/*
 * Get mouse buttons supported
 */
static int
PS2_GetButtonInfo(void)
{
	return MWBUTTON_L | MWBUTTON_M | MWBUTTON_R;
}

/*
 * Get default mouse acceleration settings
 */
static void
MOU_GetDefaultAccel(int *pscale,int *pthresh)
{
	*pscale = SCALE;
	*pthresh = THRESH;
}

static int
PS2_Read(MWCOORD *dx, MWCOORD *dy, MWCOORD *dz, int *bp)
{
	static unsigned char buf[5];
	static int nbytes;
	int n;
	int buttons[5] = { 0, 4, 1, 5, 0};

	while((n = read(mouse_fd, &buf[nbytes], 3 - nbytes))) {
		if(n < 0) {
			if ((errno == EINTR) || (errno == EAGAIN))
				return 0;
			else return -1;
		}

		nbytes += n;

		if(nbytes == 3) {
			/* Check header byte. */
			if ((buf[0] & 0xc0) != 0) {
				buf[0] = buf[1];
				buf[1] = buf[2];
				nbytes = 2;
				return -1;
			}

			*bp = buttons[(buf[0] & 0x07)];
			*dx = (buf[0] & 0x10) ? buf[1] - 256 : buf[1];
			*dy = (buf[0] & 0x20) ? -(buf[2] - 256) : -buf[2];

			//printf("bp = %d\n",*bp);
			*dz = 0;
			nbytes = 0;
			return 1;
		}
	}
	return 0;

}