/*
* 'timeout' is given in us. Note also that timeout handling is not exact --
* twsi_locked_start() total wait can be more than 2 x timeout
* (twsi_poll_ctrl() is called twice). 'mask' can be either TWSI_STATUS_START
* or TWSI_STATUS_RPTD_START
*/
static int
twsi_locked_start(device_t dev, struct twsi_softc *sc, int32_t mask,
u_char slave, int timeout)
{
int read_access, iflg_set = 0;
uint32_t status;
mtx_assert(&sc->mutex, MA_OWNED);
if (mask == TWSI_STATUS_RPTD_START)
/* read IFLG to know if it should be cleared later; from NBSD */
iflg_set = TWSI_READ(sc, sc->reg_control) & TWSI_CONTROL_IFLG;
twsi_control_set(sc, TWSI_CONTROL_START);
if (mask == TWSI_STATUS_RPTD_START && iflg_set) {
debugf("IFLG set, clearing\n");
twsi_clear_iflg(sc);
}
/*
* Without this delay we timeout checking IFLG if the timeout is 0.
* NBSD driver always waits here too.
*/
DELAY(1000);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout sending %sSTART condition\n",
mask == TWSI_STATUS_START ? "" : "repeated ");
return (IIC_ETIMEOUT);
}
status = TWSI_READ(sc, sc->reg_status);
if (status != mask) {
debugf("wrong status (%02x) after sending %sSTART condition\n",
status, mask == TWSI_STATUS_START ? "" : "repeated ");
return (IIC_ESTATUS);
}
TWSI_WRITE(sc, sc->reg_data, slave);
twsi_clear_iflg(sc);
DELAY(1000);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout sending slave address\n");
return (IIC_ETIMEOUT);
}
read_access = (slave & 0x1) ? 1 : 0;
status = TWSI_READ(sc, sc->reg_status);
if (status != (read_access ?
TWSI_STATUS_ADDR_R_ACK : TWSI_STATUS_ADDR_W_ACK)) {
debugf("no ACK (status: %02x) after sending slave address\n",
status);
return (IIC_ENOACK);
}
return (IIC_NOERR);
}
static int
twsi_write(device_t dev, const char *buf, int len, int *sent, int timeout)
{
struct twsi_softc *sc;
uint32_t status;
int rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
*sent = 0;
while (*sent < len) {
TWSI_WRITE(sc, sc->reg_data, *buf++);
twsi_clear_iflg(sc);
DELAY(1000);
if (twsi_poll_ctrl(sc, timeout, TWSI_CONTROL_IFLG)) {
debugf("timeout writing data\n");
rv = IIC_ETIMEOUT;
goto out;
}
status = TWSI_READ(sc, sc->reg_status);
if (status != TWSI_STATUS_DATA_WR_ACK) {
debugf("wrong status (%02x) while writing\n", status);
rv = IIC_ESTATUS;
goto out;
}
(*sent)++;
}
rv = IIC_NOERR;
out:
mtx_unlock(&sc->mutex);
return (rv);
}
static int
twsi_read(device_t dev, char *buf, int len, int *read, int last, int delay)
{
struct twsi_softc *sc;
uint32_t status;
int last_byte, rv;
sc = device_get_softc(dev);
mtx_lock(&sc->mutex);
*read = 0;
while (*read < len) {
/*
* Check if we are reading last byte of the last buffer,
* do not send ACK then, per I2C specs
*/
last_byte = ((*read == len - 1) && last) ? 1 : 0;
if (last_byte)
twsi_control_clear(sc, TWSI_CONTROL_ACK);
else
twsi_control_set(sc, TWSI_CONTROL_ACK);
twsi_clear_iflg(sc);
DELAY(1000);
if (twsi_poll_ctrl(sc, delay, TWSI_CONTROL_IFLG)) {
debugf("timeout reading data\n");
rv = IIC_ETIMEOUT;
goto out;
}
status = TWSI_READ(sc, sc->reg_status);
if (status != (last_byte ?
TWSI_STATUS_DATA_RD_NOACK : TWSI_STATUS_DATA_RD_ACK)) {
debugf("wrong status (%02x) while reading\n", status);
rv = IIC_ESTATUS;
goto out;
}
*buf++ = TWSI_READ(sc, sc->reg_data);
(*read)++;
}
rv = IIC_NOERR;
out:
mtx_unlock(&sc->mutex);
return (rv);
}
static __inline void
twsi_control_set(struct mv_twsi_softc *sc, uint32_t mask)
{
uint32_t val;
val = TWSI_READ(sc, TWSI_CONTROL);
val |= mask;
TWSI_WRITE(sc, TWSI_CONTROL, val);
}
static __inline void
twsi_control_set(struct twsi_softc *sc, uint32_t mask)
{
uint32_t val;
val = TWSI_READ(sc, sc->reg_control);
val &= ~(TWSI_CONTROL_STOP | TWSI_CONTROL_START);
val |= mask;
TWSI_WRITE(sc, sc->reg_control, val);
}
/*
* timeout given in us
* returns
* 0 on successful mask change
* non-zero on timeout
*/
static int
twsi_poll_ctrl(struct twsi_softc *sc, int timeout, uint32_t mask)
{
timeout /= 10;
while (!(TWSI_READ(sc, sc->reg_control) & mask)) {
DELAY(10);
if (--timeout < 0)
return (timeout);
}
return (0);
}
/*
* timeout given in us
* returns
* 0 on sucessfull mask change
* non-zero on timeout
*/
static int
twsi_poll_ctrl(struct mv_twsi_softc *sc, int timeout, uint32_t mask)
{
timeout /= 10;
while (!(TWSI_READ(sc, TWSI_CONTROL) & mask)) {
DELAY(10);
if (--timeout < 0)
return (timeout);
}
return (0);
}
