static int
at91_twi_rst_card(device_t dev, u_char speed, u_char addr, u_char *oldaddr)
{
struct at91_twi_softc *sc;
int clk;
sc = device_get_softc(dev);
AT91_TWI_LOCK(sc);
if (oldaddr)
*oldaddr = sc->twi_addr;
sc->twi_addr = addr;
/*
* speeds are for 1.5kb/s, 45kb/s and 90kb/s.
*/
switch (speed) {
case IIC_SLOW:
clk = TWI_SLOW_CLOCK;
break;
case IIC_FAST:
clk = TWI_FAST_CLOCK;
break;
case IIC_UNKNOWN:
case IIC_FASTEST:
default:
clk = TWI_FASTEST_CLOCK;
break;
}
sc->cwgr = TWI_CWGR_CKDIV(1) | TWI_CWGR_CHDIV(TWI_CWGR_DIV(clk)) |
TWI_CWGR_CLDIV(TWI_CWGR_DIV(clk));
WR4(sc, TWI_CR, TWI_CR_SWRST);
WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
WR4(sc, TWI_CWGR, sc->cwgr);
printf("setting cwgr to %#x\n", sc->cwgr);
AT91_TWI_UNLOCK(sc);
return 0;
}
static void
at91_twi_intr(void *xsc)
{
struct at91_twi_softc *sc = xsc;
uint32_t status;
status = RD4(sc, TWI_SR);
if (status == 0)
return;
AT91_TWI_LOCK(sc);
sc->flags |= status & (TWI_SR_OVRE | TWI_SR_UNRE | TWI_SR_NACK);
if (status & TWI_SR_RXRDY)
sc->flags |= TWI_SR_RXRDY;
if (status & TWI_SR_TXRDY)
sc->flags |= TWI_SR_TXRDY;
if (status & TWI_SR_TXCOMP)
sc->flags |= TWI_SR_TXCOMP;
WR4(sc, TWI_IDR, status);
wakeup(sc);
AT91_TWI_UNLOCK(sc);
return;
}
static int
at91_twi_transfer(device_t dev, struct iic_msg *msgs, uint32_t nmsgs)
{
struct at91_twi_softc *sc;
int i, len, err;
uint32_t rdwr;
uint8_t *buf;
uint32_t sr;
sc = device_get_softc(dev);
err = 0;
AT91_TWI_LOCK(sc);
for (i = 0; i < nmsgs; i++) {
/*
* The linux atmel driver doesn't use the internal device
* address feature of twi. A separate i2c message needs to
* be written to use this.
* See http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2004-September/024411.html
* for details. Upon reflection, we could use this as an
* optimization, but it is unclear the code bloat will
* result in faster/better operations.
*/
rdwr = (msgs[i].flags & IIC_M_RD) ? TWI_MMR_MREAD : 0;
WR4(sc, TWI_MMR, TWI_MMR_DADR(msgs[i].slave) | rdwr);
len = msgs[i].len;
buf = msgs[i].buf;
/* zero byte transfers aren't allowed */
if (len == 0 || buf == NULL) {
err = EINVAL;
goto out;
}
if (len == 1 && msgs[i].flags & IIC_M_RD)
WR4(sc, TWI_CR, TWI_CR_START | TWI_CR_STOP);
else
WR4(sc, TWI_CR, TWI_CR_START);
if (msgs[i].flags & IIC_M_RD) {
sr = RD4(sc, TWI_SR);
while (!(sr & TWI_SR_TXCOMP)) {
if ((sr = RD4(sc, TWI_SR)) & TWI_SR_RXRDY) {
len--;
*buf++ = RD4(sc, TWI_RHR) & 0xff;
if (len == 1)
WR4(sc, TWI_CR, TWI_CR_STOP);
}
}
if (len > 0 || (sr & TWI_SR_NACK)) {
err = ENXIO; // iic nack convention
goto out;
}
} else {
while (len--) {
if ((err = at91_twi_wait(sc, TWI_SR_TXRDY)))
goto out;
WR4(sc, TWI_THR, *buf++);
}
WR4(sc, TWI_CR, TWI_CR_STOP);
}
if ((err = at91_twi_wait(sc, TWI_SR_TXCOMP)))
break;
}
out:
if (err) {
WR4(sc, TWI_CR, TWI_CR_SWRST);
WR4(sc, TWI_CR, TWI_CR_MSEN | TWI_CR_SVDIS);
WR4(sc, TWI_CWGR, sc->cwgr);
}
AT91_TWI_UNLOCK(sc);
return (err);
}
