int i2c_stop(i2c_t *obj)
{
obj->start_pending = 0;
write_tx_fifo(obj, MXC_S_I2CM_TRANS_TAG_STOP);
return wait_tx_in_progress(obj);
}
int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop)
{
int err, retval = 0;
int i;
if (!(obj->stop_pending) && (obj->i2c->trans & MXC_F_I2CM_TRANS_TX_IN_PROGRESS)) {
return 0;
}
// clear all interrupts
obj->i2c->intfl = 0x3FF;
// write the address to the fifo
if ((err = write_tx_fifo(obj, (MXC_S_I2CM_TRANS_TAG_START | address))) != 0) { // start + addr (write)
i2c_reset(obj);
return err;
}
obj->start_pending = 0;
// start the transaction
obj->i2c->trans |= MXC_F_I2CM_TRANS_TX_START;
// load as much of the cmd into the FIFO as possible
for (i = 0; i < length; i++) {
if ((err = write_tx_fifo(obj, (MXC_S_I2CM_TRANS_TAG_TXDATA_ACK | data[i]))) != 0) { // cmd (expect ACK)
retval = (retval ? retval : err);
break;
}
}
if (stop) {
obj->stop_pending = 0;
if ((err = write_tx_fifo(obj, MXC_S_I2CM_TRANS_TAG_STOP)) != 0) { // stop condition
retval = (retval ? retval : err);
}
if ((err = wait_tx_in_progress(obj)) != 0) {
retval = (retval ? retval : err);
}
} else {
obj->stop_pending = 1;
int timeout = MXC_I2CM_TX_TIMEOUT;
// Wait for TX fifo to be empty
while (!(obj->i2c->intfl & MXC_F_I2CM_INTFL_TX_FIFO_EMPTY) && timeout--);
}
if (retval == 0) {
return length;
}
i2c_reset(obj);
return retval;
}
int i2c_read(i2c_t *obj, int address, char *data, int length, int stop)
{
int err, retval = 0;
int i = length;
int timeout;
if (!(obj->stop_pending) && (obj->i2c->trans & MXC_F_I2CM_TRANS_TX_IN_PROGRESS)) {
return 0;
}
// clear all interrupts
obj->i2c->intfl = 0x3FF;
// start + addr (read)
if ((retval = write_tx_fifo(obj, (MXC_S_I2CM_TRANS_TAG_START | address | I2C_SLAVE_ADDR_READ_BIT))) != 0) {
goto read_done;
}
obj->start_pending = 0;
while (i > 256) {
if ((retval = write_tx_fifo(obj, (MXC_S_I2CM_TRANS_TAG_RXDATA_COUNT | 255))) != 0) {
goto read_done;
}
i -= 256;
}
if (i > 1) {
if ((retval = write_tx_fifo(obj, (MXC_S_I2CM_TRANS_TAG_RXDATA_COUNT | (i - 2)))) != 0) {
goto read_done;
}
}
// start the transaction
obj->i2c->trans |= MXC_F_I2CM_TRANS_TX_START;
if ((retval = write_tx_fifo(obj, MXC_S_I2CM_TRANS_TAG_RXDATA_NACK)) != 0) { // NACK last data byte
goto read_done;
}
if (stop) {
if ((retval = write_tx_fifo(obj, MXC_S_I2CM_TRANS_TAG_STOP)) != 0) { // stop condition
goto read_done;
}
}
timeout = MXC_I2CM_RX_TIMEOUT;
i = 0;
while (i < length) {
while (!(obj->i2c->intfl & MXC_F_I2CM_INTFL_RX_FIFO_NOT_EMPTY) &&
(!(obj->i2c->bb & MXC_F_I2CM_BB_RX_FIFO_CNT))) {
if ((--timeout < 0) || !(obj->i2c->trans & MXC_F_I2CM_TRANS_TX_IN_PROGRESS)) {
retval = -3;
goto read_done;
}
}
timeout = MXC_I2CM_RX_TIMEOUT;
obj->i2c->intfl = MXC_F_I2CM_INTFL_RX_FIFO_NOT_EMPTY;
uint16_t temp = *obj->rxfifo;
if (temp & MXC_S_I2CM_RSTLS_TAG_EMPTY) {
continue;
}
data[i++] = (uint8_t) temp;
}
read_done:
if (stop) {
obj->stop_pending = 0;
if ((err = wait_tx_in_progress(obj)) != 0) {
retval = (retval ? retval : err);
}
} else {
obj->stop_pending = 1;
}
if (retval == 0) {
return length;
}
return retval;
}