drivers: i2s: Introduce the I2S_DIR_BOTH enumeration value

Introduce a new enumeration value that allows setting configuration
and triggering commands for both I2S streams simultaneously.
Such possibility is especially important on hardware where the streams
can be only enabled/disabled (but not started/stopped) independently,
like it is in nRF SoCs.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>

drivers/i2s/i2s_cavs.c

@@ -642,6 +642,10 @@ static int i2s_cavs_trigger(const struct device *dev, enum i2s_dir dir,
 	unsigned int key;
 	int ret = 0;
 
+	if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
+	}
+
 	strm = (dir == I2S_DIR_TX) ? &dev_data->tx : &dev_data->rx;
 
 	key = irq_lock();

drivers/i2s/i2s_litex.c

@@ -351,6 +351,8 @@ static int i2s_litex_configure(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->tx;
 		channels_concatenated = litex_read8(I2S_TX_STATUS_REG) &
 					I2S_TX_STAT_CHANNEL_CONCATENATED_MASK;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("either RX or TX direction must be selected");
 		return -EINVAL;
@@ -498,6 +500,8 @@ static int i2s_litex_trigger(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("either RX or TX direction must be selected");
 		return -EINVAL;

drivers/i2s/i2s_ll_stm32.c

@@ -193,6 +193,8 @@ static int i2s_stm32_configure(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;
@@ -296,6 +298,8 @@ static int i2s_stm32_trigger(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;

drivers/i2s/i2s_mcux_flexcomm.c

@@ -185,6 +185,8 @@ static int i2s_mcux_configure(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;
@@ -643,6 +645,8 @@ static int i2s_mcux_trigger(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;

drivers/i2s/i2s_sam_ssc.c

@@ -551,6 +551,8 @@ static int i2s_sam_configure(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;
@@ -763,6 +765,8 @@ static int i2s_sam_trigger(const struct device *dev, enum i2s_dir dir,
 		stream = &dev_data->rx;
 	} else if (dir == I2S_DIR_TX) {
 		stream = &dev_data->tx;
+	} else if (dir == I2S_DIR_BOTH) {
+		return -ENOSYS;
 	} else {
 		LOG_ERR("Either RX or TX direction must be selected");
 		return -EINVAL;

include/drivers/i2s.h

@@ -207,6 +207,8 @@ enum i2s_dir {
 	I2S_DIR_RX,
 	/** Transmit data */
 	I2S_DIR_TX,
+	/** Both receive and transmit data */
+	I2S_DIR_BOTH,
 };
 
 /** Interface state */
@@ -339,11 +341,14 @@ __subsystem struct i2s_driver_api {
  * the interface state will be changed to NOT_READY.
  *
  * @param dev Pointer to the device structure for the driver instance.
- * @param dir Stream direction: RX or TX as defined by I2S_DIR_*
+ * @param dir Stream direction: RX, TX, or both, as defined by I2S_DIR_*.
+ *            The I2S_DIR_BOTH value may not be supported by some drivers.
+ *            For those, the RX and TX streams need to be configured separately.
  * @param cfg Pointer to the structure containing configuration parameters.
  *
  * @retval 0 If successful.
  * @retval -EINVAL Invalid argument.
+ * @retval -ENOSYS I2S_DIR_BOTH value is not supported.
  */
 __syscall int i2s_configure(const struct device *dev, enum i2s_dir dir,
 			    struct i2s_config *cfg);
@@ -501,7 +506,10 @@ __syscall int i2s_buf_write(const struct device *dev, void *buf, size_t size);
  * @brief Send a trigger command.
  *
  * @param dev Pointer to the device structure for the driver instance.
- * @param dir Stream direction: RX or TX.
+ * @param dir Stream direction: RX, TX, or both, as defined by I2S_DIR_*.
+ *            The I2S_DIR_BOTH value may not be supported by some drivers.
+ *            For those, triggering need to be done separately for the RX
+ *            and TX streams.
  * @param cmd Trigger command.
  *
  * @retval 0 If successful.
@@ -509,6 +517,7 @@ __syscall int i2s_buf_write(const struct device *dev, void *buf, size_t size);
  * @retval -EIO The trigger cannot be executed in the current state or a DMA
  *         channel cannot be allocated.
  * @retval -ENOMEM RX/TX memory block not available.
+ * @retval -ENOSYS I2S_DIR_BOTH value is not supported.
  */
 __syscall int i2s_trigger(const struct device *dev, enum i2s_dir dir,
 			  enum i2s_trigger_cmd cmd);