int
pcf_start(device_t dev, u_char slave, int timeout)
{
struct pcf_softc *sc = DEVTOSOFTC(dev);
int error = 0;
PCF_LOCK(sc);
#ifdef PCFDEBUG
device_printf(dev, " >> start for slave %#x\n", (unsigned)slave);
#endif
if ((pcf_get_S1(sc) & nBB) == 0) {
#ifdef PCFDEBUG
printf("pcf: busy!\n");
#endif
PCF_UNLOCK(sc);
return (IIC_EBUSBSY);
}
/* set slave address to PCF. Last bit (LSB) must be set correctly
* according to transfer direction */
pcf_set_S0(sc, slave);
/* START only */
pcf_set_S1(sc, PIN|ESO|STA|ACK);
sc->pcf_started = 1;
/* wait for address sent, polling */
if ((error = pcf_wait_byte(sc)))
goto error;
/* check for ACK */
if (pcf_noack(sc, timeout)) {
error = IIC_ENOACK;
#ifdef PCFDEBUG
printf("pcf: no ack on start!\n");
#endif
goto error;
}
PCF_UNLOCK(sc);
return (0);
error:
pcf_stop_locked(sc);
PCF_UNLOCK(sc);
return (error);
}
static int
pcf_noack(struct pcf_softc *sc, int timeout)
{
int noack;
int k = timeout/10;
PCF_ASSERT_LOCKED(sc);
do {
noack = pcf_get_S1(sc) & LRB;
if (!noack)
break;
DELAY(10); /* XXX wait 10 us */
} while (k--);
return (noack);
}
/*
* Polling mode for master operations wait for a new
* byte incomming or outgoing
*/
int
pcf_wait_byte(struct pcf_softc *sc)
{
int counter = TIMEOUT;
while (counter--) {
if ((pcf_get_S1(sc) & PIN) == 0)
return (0);
}
#ifdef PCFDEBUG
printf("pcf: timeout!\n");
#endif
return (IIC_ETIMEOUT);
}
void
pcf_intr(void *arg)
{
struct pcf_softc *sc = arg;
char data, status, addr;
char error = 0;
PCF_LOCK(sc);
status = pcf_get_S1(sc);
if (status & PIN) {
printf("pcf: spurious interrupt, status=0x%x\n",
status & 0xff);
goto error;
}
if (status & LAB)
printf("pcf: bus arbitration lost!\n");
if (status & BER) {
error = IIC_EBUSERR;
iicbus_intr(sc->iicbus, INTR_ERROR, &error);
goto error;
}
do {
status = pcf_get_S1(sc);
switch(sc->pcf_slave_mode) {
case SLAVE_TRANSMITTER:
if (status & LRB) {
/* ack interrupt line */
dummy_write(sc);
/* no ack, don't send anymore */
sc->pcf_slave_mode = SLAVE_RECEIVER;
iicbus_intr(sc->iicbus, INTR_NOACK, NULL);
break;
}
/* get data from upper code */
iicbus_intr(sc->iicbus, INTR_TRANSMIT, &data);
pcf_set_S0(sc, data);
break;
case SLAVE_RECEIVER:
if (status & AAS) {
addr = pcf_get_S0(sc);
if (status & AD0)
iicbus_intr(sc->iicbus, INTR_GENERAL, &addr);
else
iicbus_intr(sc->iicbus, INTR_START, &addr);
if (addr & LSB) {
sc->pcf_slave_mode = SLAVE_TRANSMITTER;
/* get the first char from upper code */
iicbus_intr(sc->iicbus, INTR_TRANSMIT, &data);
/* send first data byte */
pcf_set_S0(sc, data);
}
break;
}
/* stop condition received? */
if (status & STS) {
/* ack interrupt line */
dummy_read(sc);
/* emulate intr stop condition */
iicbus_intr(sc->iicbus, INTR_STOP, NULL);
} else {
/* get data, ack interrupt line */
data = pcf_get_S0(sc);
/* deliver the character */
iicbus_intr(sc->iicbus, INTR_RECEIVE, &data);
}
break;
default:
panic("%s: unknown slave mode (%d)!", __func__,
sc->pcf_slave_mode);
}
} while ((pcf_get_S1(sc) & PIN) == 0);
PCF_UNLOCK(sc);
return;
error:
/* unknown event on bus...reset PCF */
pcf_set_S1(sc, PIN|ESO|ENI|ACK);
sc->pcf_slave_mode = SLAVE_RECEIVER;
PCF_UNLOCK(sc);
return;
}
