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/*
* ------------------------------------------------------------------------------
*
* Emulation of PCF8574 8 Bit IO-Expander
*
* (C) 2005 Lightmaze Solutions AG
* Author: Jochen Karrer
*
* State: Untested, might work
*
*
* This program is free software; you can distribute it and/or modify it
* under the terms of the GNU General Public License (Version 2) as
* published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
* ------------------------------------------------------------------------------
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
#include "i2c.h"
#include "signode.h"
#include "pcf8574.h"
#if 0
#define dprintf(x...) { fprintf(stderr,x); }
#else
#define dprintf(x...)
#endif
#define PCF_STATE_DATA1 (0)
struct PCF8574 {
I2C_Slave i2c_slave;
int state;
uint8_t outval; /* buffer for write */
SigNode *port[8];
};
static void
set_ports(PCF8574 *pcf) {
int i;
for(i=0;i<8;i++) {
if(!pcf->port[i]) {
continue;
}
if(pcf->outval&(1<<i)) {
SigNode_Set(pcf->port[i],SIG_PULLUP);
} else {
SigNode_Set(pcf->port[i],SIG_LOW);
}
}
}
static uint8_t
get_ports(PCF8574 *pcf) {
int i;
uint8_t value = 0;
for(i=0;i<8;i++) {
int sigval;
if(!pcf->port[i]) {
continue;
}
sigval = SigNode_Val(pcf->port[i]);
if((sigval == SIG_LOW) || (sigval == SIG_PULLDOWN)) {
} else {
value = value | (1<<i);
}
}
return value;
}
/*
* ------------------------------------
* PCF8574 Write state machine
* ------------------------------------
*/
static int
pcf8574_write(void *dev,uint8_t data) {
PCF8574 *pcf = dev;
switch(pcf->state) {
case PCF_STATE_DATA1:
dprintf("PCF8574 Write 0x%02x to %04x\n",data,pcf->reg_address);
pcf->outval = data;
pcf->state = PCF_STATE_DATA1;
set_ports(pcf);
break;
}
return I2C_ACK;
};
static int
pcf8574_read(void *dev,uint8_t *data)
{
PCF8574 *pcf = dev;
switch(pcf->state) {
case PCF_STATE_DATA1:
*data = get_ports(pcf);
pcf->state = PCF_STATE_DATA1;
break;
}
return I2C_DONE;
};
static int
pcf8574_start(void *dev,int i2c_addr,int operation) {
PCF8574 *pcf = dev;
dprintf("pcf8574 start\n");
pcf->state = PCF_STATE_DATA1;
return I2C_ACK;
}
static void
pcf8574_stop(void *dev) {
PCF8574 *pcf = dev;
dprintf("pcf8574 stop\n");
pcf->state = PCF_STATE_DATA1;
}
static I2C_SlaveOps pcf8574_ops = {
.start = pcf8574_start,
.stop = pcf8574_stop,
.read = pcf8574_read,
.write = pcf8574_write
};
I2C_Slave *
PCF8574_New(char *name) {
char *nodename = alloca(strlen(name)+20);
PCF8574 *pcf = malloc(sizeof(PCF8574));
I2C_Slave *i2c_slave;
int i;
if(!pcf) {
fprintf(stderr,"Out of memory\n");
exit(8152);
}
memset(pcf,0,sizeof(PCF8574));
i2c_slave = &pcf->i2c_slave;
i2c_slave->devops = &pcf8574_ops;
i2c_slave->dev = pcf;
i2c_slave->speed = I2C_SPEED_FAST;
for(i=0;i<8;i++) {
sprintf(nodename,"%s.P%02d",name,i);
pcf->port[i]=SigNode_New(nodename);
if(!pcf->port[i]) {
fprintf(stderr,"PCF8574: Can not create Signal node %s",nodename);
sleep(1);
}
}
pcf->outval = 0xff;
set_ports(pcf);
fprintf(stderr,"PCF8574 8 Bit IO-Expander \"%s\" created\n",name);
return i2c_slave;
}
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