int i2c_master_read()

in common/util/hal_i2c.c [44:107]

• 55 lines of code
• 11 McCabe index (conditional complexity)

int i2c_master_read(I2C_MSG *msg, uint8_t retry)
{
	uint8_t i;
	uint8_t *txbuf, *rxbuf;
	int ret, status;
	if (DEBUG_I2C) {
		printf("i2c_master_read: bus %d, addr %x, rxlen %d, txlen %d, txbuf:", msg->bus,
		       msg->slave_addr, msg->rx_len, msg->tx_len);
		for (int i = 0; i < msg->tx_len; i++) {
			printf(" %x", msg->data[i]);
		}
		printf("\n");
	}

	if (msg->rx_len == 0) {
		printf("i2c_master_read with rx_len = 0\n");
		return EMSGSIZE;
	}

	do { // break while getting mutex success but tranmission fail
		status = k_mutex_lock(&i2c_mutex[msg->bus], K_MSEC(1000));
		if (status == osOK) {
			for (i = 0; i < retry; i++) {
				txbuf = (uint8_t *)malloc(I2C_BUFF_SIZE * sizeof(uint8_t));
				rxbuf = (uint8_t *)malloc(I2C_BUFF_SIZE * sizeof(uint8_t));

				memcpy(txbuf, &msg->data[0], msg->tx_len);

				ret = i2c_write_read(dev_i2c[msg->bus], msg->slave_addr, txbuf,
						     msg->tx_len, rxbuf, msg->rx_len);

				memcpy(&msg->data[0], rxbuf, msg->rx_len);

				if (DEBUG_I2C) {
					printf("rxbuf:");
					for (int i = 0; i < msg->rx_len; i++) {
						printf(" %x", msg->data[i]);
					}
					printf("\n");
				}

				free(txbuf);
				free(rxbuf);

				status = k_mutex_unlock(&i2c_mutex[msg->bus]);
				if (status != osOK) {
					printf("I2C %d master read release mutex fail\n", msg->bus);
				}
				return ret; // i2c write and read success
			}
			printf("I2C %d master read retry reach max\n", msg->bus);
			status = k_mutex_unlock(&i2c_mutex[msg->bus]);
			if (status != osOK) {
				printf("I2C %d master read release mutex fail\n", msg->bus);
			}
			return EPIPE;
		} else {
			printf("I2C %d master read get mutex timeout\n", msg->bus);
			return ENOLCK;
		}
	} while (0);

	return ECANCELED; // should not reach here
}