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i2c: improve communication with i2c devices in i2c_write_blocking

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fivdi 2021-04-11 16:11:47 +02:00 committed by Luke Wren
parent 18c39856bd
commit 8f3c3ff12a
1 changed files with 41 additions and 7 deletions
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48
src/rp2_common/hardware_i2c/i2c.c
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@ -43,7 +43,8 @@ uint i2c_init(i2c_inst_t *i2c, uint baudrate) {
I2C_IC_CON_SPEED_VALUE_FAST << I2C_IC_CON_SPEED_LSB |
I2C_IC_CON_MASTER_MODE_BITS |
I2C_IC_CON_IC_SLAVE_DISABLE_BITS |
I2C_IC_CON_IC_RESTART_EN_BITS;
I2C_IC_CON_IC_RESTART_EN_BITS |
I2C_IC_CON_TX_EMPTY_CTRL_BITS;
// Set FIFO watermarks to 1 to make things simpler. This is encoded by a register value of 0.
i2c->hw->tx_tl = 0;
@ -145,7 +146,7 @@ static int i2c_write_blocking_internal(i2c_inst_t *i2c, uint8_t addr, const uint
bool abort = false;
bool timeout = false;
uint32_t abort_reason;
uint32_t abort_reason = 0;
int byte_ctr;
int ilen = (int)len;
@ -158,17 +159,50 @@ static int i2c_write_blocking_internal(i2c_inst_t *i2c, uint8_t addr, const uint
bool_to_bit(last && !nostop) << I2C_IC_DATA_CMD_STOP_LSB |
*src++;
// Wait until the transmission of the address/data from the internal
// shift register has completed. For this to function correctly, the
// TX_EMPTY_CTRL flag in IC_CON must be set. The TX_EMPTY_CTRL flag
// was set in i2c_init.
do {
// Note clearing the abort flag also clears the reason, and this
// instance of flag is clear-on-read!
abort_reason = i2c->hw->tx_abrt_source;
abort = (bool) i2c->hw->clr_tx_abrt;
if (timeout_check) {
timeout = timeout_check(ts);
abort |= timeout;
}
tight_loop_contents();
} while (!abort && !(i2c->hw->status & I2C_IC_STATUS_TFE_BITS));
} while (!timeout && !(i2c->hw->raw_intr_stat & I2C_IC_RAW_INTR_STAT_TX_EMPTY_BITS));
// If there was a timeout, don't attempt to do anything else.
if (!timeout) {
abort_reason = i2c->hw->tx_abrt_source;
if (abort_reason) {
// Note clearing the abort flag also clears the reason, and
// this instance of flag is clear-on-read! Note also the
// IC_CLR_TX_ABRT register always reads as 0.
i2c->hw->clr_tx_abrt;
abort = true;
}
if (abort || (last && !nostop)) {
// If the transaction was aborted or if it completed
// successfully wait until the STOP condition has occured.
// TODO Could there be an abort while waiting for the STOP
// condition here? If so, additional code would be needed here
// to take care of the abort.
do {
if (timeout_check) {
timeout = timeout_check(ts);
abort |= timeout;
}
tight_loop_contents();
} while (!timeout && !(i2c->hw->raw_intr_stat & I2C_IC_RAW_INTR_STAT_STOP_DET_BITS));
// If there was a timeout, don't attempt to do anything else.
if (!timeout) {
i2c->hw->clr_stop_det;
}
}
}
// Note the hardware issues a STOP automatically on an abort condition.
// Note also the hardware clears RX FIFO as well as TX on abort,