drivers: dai: Add driver for NXP's SAI

This commit introduces a new DAI driver used for NXP'S SAI IP.

Signed-off-by: Laurentiu Mihalcea <laurentiu.mihalcea@nxp.com>
This commit is contained in:
Laurentiu Mihalcea 2023-10-03 14:11:53 +03:00 committed by Carles Cufí
commit fe64d840cc
7 changed files with 1366 additions and 0 deletions

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@ -4,3 +4,4 @@ add_subdirectory_ifdef(CONFIG_DAI_INTEL_SSP intel/ssp)
add_subdirectory_ifdef(CONFIG_DAI_INTEL_ALH intel/alh)
add_subdirectory_ifdef(CONFIG_DAI_INTEL_DMIC intel/dmic)
add_subdirectory_ifdef(CONFIG_DAI_INTEL_HDA intel/hda)
add_subdirectory_ifdef(CONFIG_DAI_NXP_SAI nxp/sai)

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@ -29,5 +29,6 @@ source "drivers/dai/intel/ssp/Kconfig.ssp"
source "drivers/dai/intel/alh/Kconfig.alh"
source "drivers/dai/intel/dmic/Kconfig.dmic"
source "drivers/dai/intel/hda/Kconfig.hda"
source "drivers/dai/nxp/sai/Kconfig.sai"
endif # DAI

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@ -0,0 +1,5 @@
# Copyright 2023 NXP
# SPDX-License-Identifier: Apache-2.0
zephyr_library()
zephyr_library_sources(sai.c)

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@ -0,0 +1,30 @@
# Copyright 2023 NXP
# SPDX-License-Identifier: Apache-2.0
config DAI_NXP_SAI
bool "NXP Synchronous Audio Interface (SAI) driver"
default y
depends on DT_HAS_NXP_DAI_SAI_ENABLED
help
Select this to enable NXP SAI driver.
if DAI_NXP_SAI
config SAI_HAS_MCLK_CONFIG_OPTION
bool "Set if SAI has MCLK configuration options"
default n
help
Select this if the SAI IP allows configuration
of the master clock. Master clock configuration
refers to enabling/disabling the master clock,
setting the signal as input or output or dividing
the master clock output.
config SAI_FIFO_WORD_SIZE
int "Size (in bytes) of a FIFO word"
default 4
help
Use this to set the size (in bytes) of a SAI
FIFO word.
endif # DAI_NXP_SAI

758
drivers/dai/nxp/sai/sai.c Normal file
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@ -0,0 +1,758 @@
/*
* Copyright 2023 NXP
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <zephyr/drivers/dai.h>
#include <zephyr/device.h>
#include <zephyr/kernel.h>
#include "sai.h"
/* used for binding the driver */
#define DT_DRV_COMPAT nxp_dai_sai
#define SAI_TX_RX_HW_DISABLE_TIMEOUT 50
/* TODO list:
*
* 1) No busy waiting should be performed in any of the operations.
* In the case of STOP(), the operation should be split into TRIGGER_STOP
* and TRIGGER_POST_STOP. (SOF)
*
* 2) The SAI ISR should stop the SAI whenever a FIFO error interrupt
* is raised.
*
* 3) Transmitter/receiver may remain enabled after sai_tx_rx_disable().
* Fix this.
*/
#ifdef CONFIG_SAI_HAS_MCLK_CONFIG_OPTION
/* note: i.MX8 boards don't seem to support the MICS field in the MCR
* register. As such, the MCLK source field of sai_master_clock_t is
* useless. I'm assuming the source is selected through xCR2's MSEL.
*
* TODO: for now, this function will set MCR's MSEL to the same value
* as xCR2's MSEL or, rather, to the same MCLK as the one used for
* generating BCLK. Is there a need to support different MCLKs in
* xCR2 and MCR?
*/
static int sai_mclk_config(const struct device *dev,
sai_bclk_source_t bclk_source,
const struct sai_bespoke_config *bespoke)
{
const struct sai_config *cfg;
struct sai_data *data;
sai_master_clock_t mclk_config;
uint32_t msel, mclk_rate;
int ret;
cfg = dev->config;
data = dev->data;
mclk_config.mclkOutputEnable = cfg->mclk_is_output;
ret = get_msel(bclk_source, &msel);
if (ret < 0) {
LOG_ERR("invalid MCLK source %d for MSEL", bclk_source);
return ret;
}
/* get MCLK's rate */
ret = get_mclk_rate(&cfg->clk_data, bclk_source, &mclk_rate);
if (ret < 0) {
LOG_ERR("failed to query MCLK's rate");
return ret;
}
LOG_DBG("source MCLK is %u", mclk_rate);
LOG_DBG("target MCLK is %u", bespoke->mclk_rate);
/* source MCLK rate */
mclk_config.mclkSourceClkHz = mclk_rate;
/* target MCLK rate */
mclk_config.mclkHz = bespoke->mclk_rate;
/* commit configuration */
SAI_SetMasterClockConfig(UINT_TO_I2S(data->regmap), &mclk_config);
set_msel(data->regmap, msel);
return 0;
}
#endif /* CONFIG_SAI_HAS_MCLK_CONFIG_OPTION */
void sai_isr(const void *parameter)
{
const struct device *dev;
struct sai_data *data;
dev = parameter;
data = dev->data;
/* check for TX FIFO error */
if (SAI_TX_RX_STATUS_IS_SET(DAI_DIR_TX, data->regmap, kSAI_FIFOErrorFlag)) {
LOG_ERR("FIFO underrun detected");
/* TODO: this will crash the program and should be addressed as
* mentioned in TODO list's 2).
*/
z_irq_spurious(NULL);
}
/* check for RX FIFO error */
if (SAI_TX_RX_STATUS_IS_SET(DAI_DIR_RX, data->regmap, kSAI_FIFOErrorFlag)) {
LOG_ERR("FIFO overrun detected");
/* TODO: this will crash the program and should be addressed as
* mentioned in TODO list's 2).
*/
z_irq_spurious(NULL);
}
}
static int sai_config_get(const struct device *dev,
struct dai_config *cfg,
enum dai_dir dir)
{
struct sai_data *data = dev->data;
/* dump content of the DAI configuration */
memcpy(cfg, &data->cfg, sizeof(*cfg));
return 0;
}
static const struct dai_properties
*sai_get_properties(const struct device *dev, enum dai_dir dir, int stream_id)
{
const struct sai_config *cfg = dev->config;
switch (dir) {
case DAI_DIR_RX:
return cfg->rx_props;
case DAI_DIR_TX:
return cfg->tx_props;
default:
LOG_ERR("invalid direction: %d", dir);
return NULL;
}
CODE_UNREACHABLE;
}
static int sai_config_set(const struct device *dev,
const struct dai_config *cfg,
const void *bespoke_data)
{
const struct sai_bespoke_config *bespoke;
sai_transceiver_t *rx_config, *tx_config;
struct sai_data *data;
const struct sai_config *sai_cfg;
int ret;
if (cfg->type != DAI_IMX_SAI) {
LOG_ERR("wrong DAI type: %d", cfg->type);
return -EINVAL;
}
bespoke = bespoke_data;
data = dev->data;
sai_cfg = dev->config;
rx_config = &data->rx_config;
tx_config = &data->tx_config;
/* since this function configures the transmitter AND the receiver, that
* means both of them need to be stopped. As such, doing the state
* transition here will also result in a state check.
*/
ret = sai_update_state(DAI_DIR_TX, data, DAI_STATE_READY);
if (ret < 0) {
LOG_ERR("failed to update TX state. Reason: %d", ret);
return ret;
}
ret = sai_update_state(DAI_DIR_RX, data, DAI_STATE_READY);
if (ret < 0) {
LOG_ERR("failed to update RX state. Reason: %d", ret);
return ret;
}
/* condition: BCLK = FSYNC * TDM_SLOT_WIDTH * TDM_SLOTS */
if (bespoke->bclk_rate !=
(bespoke->fsync_rate * bespoke->tdm_slot_width * bespoke->tdm_slots)) {
LOG_ERR("bad BCLK value: %d", bespoke->bclk_rate);
return -EINVAL;
}
/* TODO: this should be removed if we're to support sw channels != hw channels */
if (count_leading_zeros(~bespoke->tx_slots) != bespoke->tdm_slots ||
count_leading_zeros(~bespoke->rx_slots) != bespoke->tdm_slots) {
LOG_ERR("number of TX/RX slots doesn't match number of TDM slots");
return -EINVAL;
}
/* get default configurations */
get_bclk_default_config(&tx_config->bitClock);
get_fsync_default_config(&tx_config->frameSync);
get_serial_default_config(&tx_config->serialData);
get_fifo_default_config(&tx_config->fifo);
/* note1: this may be obvious but enabling multiple SAI
* channels (or data lines) may lead to FIFO starvation/
* overflow if data is not written/read from the respective
* TDR/RDR registers.
*
* note2: the SAI data line should be enabled based on
* the direction (TX/RX) we're enabling. Enabling the
* data line for the opposite direction will lead to FIFO
* overrun/underrun when working with a SYNC direction.
*
* note3: the TX/RX data line shall be enabled/disabled
* via the sai_trigger_() suite to avoid scenarios in
* which one configures both direction but only starts
* the SYNC direction which would lead to a FIFO underrun.
*/
tx_config->channelMask = 0x0;
/* TODO: for now, only MCLK1 is supported */
tx_config->bitClock.bclkSource = kSAI_BclkSourceMclkOption1;
/* FSYNC is asserted for tdm_slot_width BCLKs */
tx_config->frameSync.frameSyncWidth = bespoke->tdm_slot_width;
/* serial data common configuration */
tx_config->serialData.dataWord0Length = bespoke->tdm_slot_width;
tx_config->serialData.dataWordNLength = bespoke->tdm_slot_width;
tx_config->serialData.dataFirstBitShifted = bespoke->tdm_slot_width;
tx_config->serialData.dataWordNum = bespoke->tdm_slots;
/* clock provider configuration */
switch (cfg->format & DAI_FORMAT_CLOCK_PROVIDER_MASK) {
case DAI_CBP_CFP:
tx_config->masterSlave = kSAI_Slave;
break;
case DAI_CBC_CFC:
tx_config->masterSlave = kSAI_Master;
break;
case DAI_CBC_CFP:
case DAI_CBP_CFC:
LOG_ERR("unsupported provider configuration: %d",
cfg->format & DAI_FORMAT_CLOCK_PROVIDER_MASK);
return -ENOTSUP;
default:
LOG_ERR("invalid provider configuration: %d",
cfg->format & DAI_FORMAT_CLOCK_PROVIDER_MASK);
return -EINVAL;
}
LOG_DBG("SAI is in %d mode", tx_config->masterSlave);
/* protocol configuration */
switch (cfg->format & DAI_FORMAT_PROTOCOL_MASK) {
case DAI_PROTO_I2S:
/* BCLK is active LOW */
tx_config->bitClock.bclkPolarity = kSAI_PolarityActiveLow;
/* FSYNC is active LOW */
tx_config->frameSync.frameSyncPolarity = kSAI_PolarityActiveLow;
break;
case DAI_PROTO_DSP_A:
/* FSYNC is asserted for a single BCLK */
tx_config->frameSync.frameSyncWidth = 1;
/* BCLK is active LOW */
tx_config->bitClock.bclkPolarity = kSAI_PolarityActiveLow;
break;
default:
LOG_ERR("unsupported DAI protocol: %d",
cfg->format & DAI_FORMAT_PROTOCOL_MASK);
return -EINVAL;
}
LOG_DBG("SAI uses protocol: %d",
cfg->format & DAI_FORMAT_PROTOCOL_MASK);
/* clock inversion configuration */
switch (cfg->format & DAI_FORMAT_CLOCK_INVERSION_MASK) {
case DAI_INVERSION_IB_IF:
SAI_INVERT_POLARITY(tx_config->bitClock.bclkPolarity);
SAI_INVERT_POLARITY(tx_config->frameSync.frameSyncPolarity);
break;
case DAI_INVERSION_IB_NF:
SAI_INVERT_POLARITY(tx_config->bitClock.bclkPolarity);
break;
case DAI_INVERSION_NB_IF:
SAI_INVERT_POLARITY(tx_config->frameSync.frameSyncPolarity);
break;
case DAI_INVERSION_NB_NF:
/* nothing to do here */
break;
default:
LOG_ERR("invalid clock inversion configuration: %d",
cfg->format & DAI_FORMAT_CLOCK_INVERSION_MASK);
return -EINVAL;
}
LOG_DBG("FSYNC polarity: %d", tx_config->frameSync.frameSyncPolarity);
LOG_DBG("BCLK polarity: %d", tx_config->bitClock.bclkPolarity);
/* duplicate TX configuration */
memcpy(rx_config, tx_config, sizeof(sai_transceiver_t));
tx_config->serialData.dataMaskedWord = ~bespoke->tx_slots;
rx_config->serialData.dataMaskedWord = ~bespoke->rx_slots;
tx_config->fifo.fifoWatermark = sai_cfg->tx_fifo_watermark - 1;
rx_config->fifo.fifoWatermark = sai_cfg->rx_fifo_watermark - 1;
LOG_DBG("RX watermark: %d", sai_cfg->rx_fifo_watermark);
LOG_DBG("TX watermark: %d", sai_cfg->tx_fifo_watermark);
/* TODO: for now, the only supported operation mode is RX sync with TX.
* Is there a need to support other modes?
*/
tx_config->syncMode = kSAI_ModeAsync;
rx_config->syncMode = kSAI_ModeSync;
/* commit configuration */
SAI_RxSetConfig(UINT_TO_I2S(data->regmap), rx_config);
SAI_TxSetConfig(UINT_TO_I2S(data->regmap), tx_config);
/* a few notes here:
* 1) TX and RX operate in the same mode: master or slave.
* 2) Setting BCLK's rate needs to be performed explicitly
* since SetConfig() doesn't do it for us.
* 3) Setting BCLK's rate has to be performed after the
* SetConfig() call as that resets the SAI registers.
*/
if (tx_config->masterSlave == kSAI_Master) {
SAI_TxSetBitClockRate(UINT_TO_I2S(data->regmap), bespoke->mclk_rate,
bespoke->fsync_rate, bespoke->tdm_slot_width,
bespoke->tdm_slots);
SAI_RxSetBitClockRate(UINT_TO_I2S(data->regmap), bespoke->mclk_rate,
bespoke->fsync_rate, bespoke->tdm_slot_width,
bespoke->tdm_slots);
}
#ifdef CONFIG_SAI_HAS_MCLK_CONFIG_OPTION
ret = sai_mclk_config(dev, tx_config->bitClock.bclkSource, bespoke);
if (ret < 0) {
LOG_ERR("failed to set MCLK configuration");
return ret;
}
#endif /* CONFIG_SAI_HAS_MCLK_CONFIG_OPTION */
/* this is needed so that rates different from FSYNC_RATE
* will not be allowed.
*
* this is because the hardware is configured to match
* the topology rates so attempting to play a file using
* a different rate from the one configured in the hardware
* doesn't work properly.
*
* if != 0, SOF will raise an error if the PCM rate is
* different than the hardware rate (a.k.a this one).
*/
data->cfg.rate = bespoke->fsync_rate;
/* SOF note: we don't support a variable number of channels
* at the moment so leaving the number of channels as 0 is
* unnecessary and leads to issues (e.g: the mixer buffers
* use this value to set the number of channels so having
* a 0 as this value leads to mixer buffers having 0 channels,
* which, in turn, leads to the DAI ending up with 0 channels,
* thus resulting in an error)
*/
data->cfg.channels = bespoke->tdm_slots;
sai_dump_register_data(data->regmap);
return 0;
}
/* SOF note: please be very careful with this function as it does
* busy waiting and may mess up your timing in time critial applications
* (especially with timer domain). If this becomes unusable, the busy
* waiting should be removed altogether and the HW state check should
* be performed in sai_trigger_start() or in sai_config_set().
*
* TODO: seems like the transmitter still remains active (even if 1ms
* has passed after doing a sai_trigger_stop()!). Most likely this is
* because sai_trigger_stop() immediately stops the data line w/o
* checking the HW state of the transmitter/receiver. As such, to get
* rid of the busy waiting, the STOP operation may have to be split into
* 2 operations: TRIG_STOP and TRIG_POST_STOP.
*/
static int sai_tx_rx_disable(struct sai_data *data, enum dai_dir dir)
{
bool ret;
/* sai_disable() should never be called from ISR context
* as it does some busy waiting.
*/
if (k_is_in_isr()) {
LOG_ERR("sai_disable() should never be called from ISR context");
return -EINVAL;
}
if ((dir == DAI_DIR_TX && !data->rx_enabled) || dir == DAI_DIR_RX) {
/* VERY IMPORTANT: DO NOT use SAI_TxEnable/SAI_RxEnable
* here as they do not disable the ASYNC direction.
* Since the software logic assures that the ASYNC direction
* is not disabled before the SYNC direction, we can force
* the disablement of the given direction.
*/
sai_tx_rx_force_disable(dir, data->regmap);
/* please note the difference between the transmitter/receiver's
* hardware states and their software states. The software
* states can be obtained by reading data->tx/rx_enabled, while
* the hardware states can be obtained by reading TCSR/RCSR. The
* hadrware state can actually differ from the software state.
* Here, we're interested in reading the hardware state which
* indicates if the transmitter/receiver was actually disabled
* or not.
*/
ret = WAIT_FOR(!SAI_TX_RX_IS_HW_ENABLED(dir, data->regmap),
SAI_TX_RX_HW_DISABLE_TIMEOUT, k_busy_wait(1));
if (!ret) {
LOG_ERR("timed out while waiting for dir %d disable", dir);
return -ETIMEDOUT;
}
}
/* if TX wasn't explicitly enabled (via sai_trigger_start(TX))
* then that means it was enabled by a sai_trigger_start(RX). As
* such, data->tx_enabled will be false.
*/
if (dir == DAI_DIR_RX && !data->tx_enabled) {
sai_tx_rx_force_disable(DAI_DIR_TX, data->regmap);
ret = WAIT_FOR(!SAI_TX_RX_IS_HW_ENABLED(DAI_DIR_TX, data->regmap),
SAI_TX_RX_HW_DISABLE_TIMEOUT, k_busy_wait(1));
if (!ret) {
LOG_ERR("timed out while waiting for dir TX disable");
return -ETIMEDOUT;
}
}
return 0;
}
static int sai_trigger_pause(const struct device *dev,
enum dai_dir dir)
{
struct sai_data *data;
int ret;
data = dev->data;
if (dir != DAI_DIR_RX && dir != DAI_DIR_TX) {
LOG_ERR("invalid direction: %d", dir);
return -EINVAL;
}
/* attempt to change state */
ret = sai_update_state(dir, data, DAI_STATE_PAUSED);
if (ret < 0) {
LOG_ERR("failed to transition to PAUSED from %d. Reason: %d",
sai_get_state(dir, data), ret);
return ret;
}
LOG_DBG("pause on direction %d", dir);
ret = sai_tx_rx_disable(data, dir);
if (ret < 0) {
return ret;
}
/* update the software state of TX/RX */
sai_tx_rx_sw_enable_disable(dir, data, false);
return 0;
}
static int sai_trigger_stop(const struct device *dev,
enum dai_dir dir)
{
struct sai_data *data;
int ret;
uint32_t old_state;
data = dev->data;
old_state = sai_get_state(dir, data);
if (dir != DAI_DIR_RX && dir != DAI_DIR_TX) {
LOG_ERR("invalid direction: %d", dir);
return -EINVAL;
}
/* attempt to change state */
ret = sai_update_state(dir, data, DAI_STATE_STOPPING);
if (ret < 0) {
LOG_ERR("failed to transition to STOPPING from %d. Reason: %d",
sai_get_state(dir, data), ret);
return ret;
}
LOG_DBG("stop on direction %d", dir);
if (old_state == DAI_STATE_PAUSED) {
/* if SAI was previously paused then all that's
* left to do is disable the DMA requests and
* the data line.
*/
goto out_dline_disable;
}
ret = sai_tx_rx_disable(data, dir);
if (ret < 0) {
return ret;
}
/* update the software state of TX/RX */
sai_tx_rx_sw_enable_disable(dir, data, false);
out_dline_disable:
/* disable TX/RX data line */
sai_tx_rx_set_dline_mask(dir, data->regmap, 0x0);
/* disable DMA requests */
SAI_TX_RX_DMA_ENABLE_DISABLE(dir, data->regmap, false);
/* disable error interrupt */
SAI_TX_RX_ENABLE_DISABLE_IRQ(dir, data->regmap,
kSAI_FIFOErrorInterruptEnable, false);
return 0;
}
static int sai_trigger_start(const struct device *dev,
enum dai_dir dir)
{
struct sai_data *data;
uint32_t old_state;
int ret;
data = dev->data;
old_state = sai_get_state(dir, data);
/* TX and RX should be triggered independently */
if (dir != DAI_DIR_RX && dir != DAI_DIR_TX) {
LOG_ERR("invalid direction: %d", dir);
return -EINVAL;
}
/* attempt to change state */
ret = sai_update_state(dir, data, DAI_STATE_RUNNING);
if (ret < 0) {
LOG_ERR("failed to transition to RUNNING from %d. Reason: %d",
sai_get_state(dir, data), ret);
return ret;
}
if (old_state == DAI_STATE_PAUSED) {
/* if the SAI has been paused then there's no
* point in issuing a software reset. As such,
* skip this part and go directly to the TX/RX
* enablement.
*/
goto out_enable_tx_rx;
}
LOG_DBG("start on direction %d", dir);
if (dir == DAI_DIR_RX) {
/* this is fine because TX is async so it won't be
* affected by an RX software reset.
*/
SAI_TX_RX_SW_RESET(dir, data->regmap);
/* do a TX software reset only if not already enabled */
if (!data->tx_enabled) {
SAI_TX_RX_SW_RESET(DAI_DIR_TX, data->regmap);
}
} else {
/* a software reset should be issued for TX
* only if RX was not already enabled.
*/
if (!data->rx_enabled) {
SAI_TX_RX_SW_RESET(dir, data->regmap);
}
}
/* enable error interrupt */
SAI_TX_RX_ENABLE_DISABLE_IRQ(dir, data->regmap,
kSAI_FIFOErrorInterruptEnable, true);
/* TODO: is there a need to write some words to the FIFO to avoid starvation? */
/* TODO: for now, only DMA mode is supported */
SAI_TX_RX_DMA_ENABLE_DISABLE(dir, data->regmap, true);
/* enable TX/RX data line. This translates to TX_DLINE0/RX_DLINE0
* being enabled.
*
* TODO: for now we only support 1 data line per direction.
*/
sai_tx_rx_set_dline_mask(dir, data->regmap, 0x1);
out_enable_tx_rx:
/* this will also enable the async side */
SAI_TX_RX_ENABLE_DISABLE(dir, data->regmap, true);
/* update the software state of TX/RX */
sai_tx_rx_sw_enable_disable(dir, data, true);
return 0;
}
static int sai_trigger(const struct device *dev,
enum dai_dir dir,
enum dai_trigger_cmd cmd)
{
switch (cmd) {
case DAI_TRIGGER_START:
return sai_trigger_start(dev, dir);
case DAI_TRIGGER_PAUSE:
return sai_trigger_pause(dev, dir);
case DAI_TRIGGER_STOP:
return sai_trigger_stop(dev, dir);
case DAI_TRIGGER_PRE_START:
case DAI_TRIGGER_COPY:
/* COPY and PRE_START don't require the SAI
* driver to do anything at the moment so
* mark them as successful via a NULL return
*
* note: although the rest of the unhandled
* trigger commands may be valid, return
* an error code for them as they aren't
* implemented ATM (since they're not
* mandatory for the SAI driver to work).
*/
return 0;
default:
LOG_ERR("invalid trigger command: %d", cmd);
return -EINVAL;
}
CODE_UNREACHABLE;
}
static int sai_probe(const struct device *dev)
{
/* nothing to be done here but sadly mandatory to implement */
return 0;
}
static int sai_remove(const struct device *dev)
{
/* nothing to be done here but sadly mandatory to implement */
return 0;
}
static const struct dai_driver_api sai_api = {
.config_set = sai_config_set,
.config_get = sai_config_get,
.trigger = sai_trigger,
.get_properties = sai_get_properties,
.probe = sai_probe,
.remove = sai_remove,
};
static int sai_init(const struct device *dev)
{
const struct sai_config *cfg;
struct sai_data *data;
int i, ret;
cfg = dev->config;
data = dev->data;
device_map(&data->regmap, cfg->regmap_phys, cfg->regmap_size, K_MEM_CACHE_NONE);
/* enable clocks if any */
for (i = 0; i < cfg->clk_data.clock_num; i++) {
ret = clock_control_on(cfg->clk_data.dev,
UINT_TO_POINTER(cfg->clk_data.clocks[i]));
if (ret < 0) {
return ret;
}
LOG_DBG("clock %s has been ungated", cfg->clk_data.clock_names[i]);
}
/* set TX/RX default states */
data->tx_state = DAI_STATE_NOT_READY;
data->rx_state = DAI_STATE_NOT_READY;
/* register ISR and enable IRQ */
cfg->irq_config();
return 0;
}
#define SAI_INIT(inst) \
\
BUILD_ASSERT(SAI_FIFO_DEPTH(inst) > 0 && \
SAI_FIFO_DEPTH(inst) <= _SAI_FIFO_DEPTH(inst), \
"invalid FIFO depth"); \
\
BUILD_ASSERT(SAI_RX_FIFO_WATERMARK(inst) > 0 && \
SAI_RX_FIFO_WATERMARK(inst) <= _SAI_FIFO_DEPTH(inst), \
"invalid RX FIFO watermark"); \
\
BUILD_ASSERT(SAI_TX_FIFO_WATERMARK(inst) > 0 && \
SAI_TX_FIFO_WATERMARK(inst) <= _SAI_FIFO_DEPTH(inst), \
"invalid TX FIFO watermark"); \
\
BUILD_ASSERT(IS_ENABLED(CONFIG_SAI_HAS_MCLK_CONFIG_OPTION) || \
!DT_INST_PROP(inst, mclk_is_output), \
"SAI doesn't support MCLK config but mclk_is_output is specified");\
\
static const struct dai_properties sai_tx_props_##inst = { \
.fifo_address = SAI_TX_FIFO_BASE(inst), \
.fifo_depth = SAI_FIFO_DEPTH(inst) * CONFIG_SAI_FIFO_WORD_SIZE, \
.dma_hs_id = SAI_TX_DMA_MUX(inst), \
}; \
\
static const struct dai_properties sai_rx_props_##inst = { \
.fifo_address = SAI_RX_FIFO_BASE(inst), \
.fifo_depth = SAI_FIFO_DEPTH(inst) * CONFIG_SAI_FIFO_WORD_SIZE, \
.dma_hs_id = SAI_RX_DMA_MUX(inst), \
}; \
\
void irq_config_##inst(void) \
{ \
IRQ_CONNECT(DT_INST_IRQN(inst), \
0, \
sai_isr, \
DEVICE_DT_INST_GET(inst), \
0); \
irq_enable(DT_INST_IRQN(inst)); \
} \
\
static struct sai_config sai_config_##inst = { \
.regmap_phys = DT_INST_REG_ADDR(inst), \
.regmap_size = DT_INST_REG_SIZE(inst), \
.clk_data = SAI_CLOCK_DATA_DECLARE(inst), \
.rx_fifo_watermark = SAI_RX_FIFO_WATERMARK(inst), \
.tx_fifo_watermark = SAI_TX_FIFO_WATERMARK(inst), \
.mclk_is_output = DT_INST_PROP_OR(inst, mclk_is_output, false), \
.tx_props = &sai_tx_props_##inst, \
.rx_props = &sai_rx_props_##inst, \
.irq_config = irq_config_##inst, \
}; \
\
static struct sai_data sai_data_##inst = { \
.cfg.type = DAI_IMX_SAI, \
.cfg.dai_index = DT_INST_PROP_OR(inst, dai_index, 0), \
}; \
\
DEVICE_DT_INST_DEFINE(inst, &sai_init, NULL, \
&sai_data_##inst, &sai_config_##inst, \
POST_KERNEL, CONFIG_DAI_INIT_PRIORITY, \
&sai_api); \
DT_INST_FOREACH_STATUS_OKAY(SAI_INIT);

511
drivers/dai/nxp/sai/sai.h Normal file
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/* Copyright 2023 NXP
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef ZEPHYR_DRIVERS_DAI_NXP_SAI_H_
#define ZEPHYR_DRIVERS_DAI_NXP_SAI_H_
#include <zephyr/drivers/clock_control.h>
#include <zephyr/logging/log.h>
#include <fsl_sai.h>
LOG_MODULE_REGISTER(nxp_dai_sai);
#ifdef CONFIG_SAI_HAS_MCLK_CONFIG_OPTION
#define SAI_MCLK_MCR_MSEL_SHIFT 24
#define SAI_MCLK_MCR_MSEL_MASK GENMASK(24, 25)
#endif /* CONFIG_SAI_HAS_MCLK_CONFIG_OPTION */
/* workaround the fact that device_map() doesn't exist for SoCs with no MMU */
#ifndef DEVICE_MMIO_IS_IN_RAM
#define device_map(virt, phys, size, flags) *(virt) = (phys)
#endif /* DEVICE_MMIO_IS_IN_RAM */
/* used to convert an uint to I2S_Type * */
#define UINT_TO_I2S(x) ((I2S_Type *)(uintptr_t)(x))
/* macros used for parsing DTS data */
/* used instead of IDENTITY because LISTIFY expects the used macro function
* to also take a variable number of arguments.
*/
#define IDENTITY_VARGS(V, ...) IDENTITY(V)
/* used to generate the list of clock indexes */
#define _SAI_CLOCK_INDEX_ARRAY(inst)\
LISTIFY(DT_INST_PROP_LEN_OR(inst, clocks, 0), IDENTITY_VARGS, (,))
/* used to retrieve a clock's ID using its index generated via _SAI_CLOCK_INDEX_ARRAY */
#define _SAI_GET_CLOCK_ID(clock_idx, inst)\
DT_INST_CLOCKS_CELL_BY_IDX(inst, clock_idx, name)
/* used to retrieve a clock's name using its index generated via _SAI_CLOCK_INDEX_ARRAY */
#define _SAI_GET_CLOCK_NAME(clock_idx, inst)\
DT_INST_PROP_BY_IDX(inst, clock_names, clock_idx)
/* used to convert the clocks property into an array of clock IDs */
#define _SAI_CLOCK_ID_ARRAY(inst)\
FOR_EACH_FIXED_ARG(_SAI_GET_CLOCK_ID, (,), inst, _SAI_CLOCK_INDEX_ARRAY(inst))
/* used to convert the clock-names property into an array of clock names */
#define _SAI_CLOCK_NAME_ARRAY(inst)\
FOR_EACH_FIXED_ARG(_SAI_GET_CLOCK_NAME, (,), inst, _SAI_CLOCK_INDEX_ARRAY(inst))
/* used to convert a clocks property into an array of clock IDs. If the property
* is not specified then this macro will return {}.
*/
#define _SAI_GET_CLOCK_ARRAY(inst)\
COND_CODE_1(DT_NODE_HAS_PROP(DT_INST(inst, nxp_dai_sai), clocks),\
({ _SAI_CLOCK_ID_ARRAY(inst) }),\
({ }))
/* used to retrieve a const struct device *dev pointing to the clock controller.
* It is assumed that all SAI clocks come from a single clock provider.
* This macro returns a NULL if the clocks property doesn't exist.
*/
#define _SAI_GET_CLOCK_CONTROLLER(inst)\
COND_CODE_1(DT_NODE_HAS_PROP(DT_INST(inst, nxp_dai_sai), clocks),\
(DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(inst))),\
(NULL))
/* used to convert a clock-names property into an array of clock names. If the
* property is not specified then this macro will return {}.
*/
#define _SAI_GET_CLOCK_NAMES(inst)\
COND_CODE_1(DT_NODE_HAS_PROP(DT_INST(inst, nxp_dai_sai), clocks),\
({ _SAI_CLOCK_NAME_ARRAY(inst) }),\
({ }))
/* used to declare a struct clock_data */
#define SAI_CLOCK_DATA_DECLARE(inst) \
{ \
.clocks = (uint32_t [])_SAI_GET_CLOCK_ARRAY(inst), \
.clock_num = DT_INST_PROP_LEN_OR(inst, clocks, 0), \
.dev = _SAI_GET_CLOCK_CONTROLLER(inst), \
.clock_names = (const char *[])_SAI_GET_CLOCK_NAMES(inst), \
}
/* used to parse the tx-fifo-watermark property. If said property is not
* specified then this macro will return half of the number of words in the
* FIFO.
*/
#define SAI_TX_FIFO_WATERMARK(inst)\
DT_INST_PROP_OR(inst, tx_fifo_watermark,\
FSL_FEATURE_SAI_FIFO_COUNTn(UINT_TO_I2S(DT_INST_REG_ADDR(inst))) / 2)
/* used to parse the rx-fifo-watermark property. If said property is not
* specified then this macro will return half of the number of words in the
* FIFO.
*/
#define SAI_RX_FIFO_WATERMARK(inst)\
DT_INST_PROP_OR(inst, rx_fifo_watermark,\
FSL_FEATURE_SAI_FIFO_COUNTn(UINT_TO_I2S(DT_INST_REG_ADDR(inst))) / 2)
/* used to retrieve TFR0's address based on SAI's physical address */
#define SAI_TX_FIFO_BASE(inst)\
FSL_FEATURE_SAI_TX_FIFO_BASEn(UINT_TO_I2S(DT_INST_REG_ADDR(inst)), 0)
/* used to retrieve RFR0's address based on SAI's physical address */
#define SAI_RX_FIFO_BASE(inst)\
FSL_FEATURE_SAI_RX_FIFO_BASEn(UINT_TO_I2S(DT_INST_REG_ADDR(inst)), 0)
/* internal macro used to retrieve the default TX/RX FIFO's size (in FIFO words) */
#define _SAI_FIFO_DEPTH(inst)\
FSL_FEATURE_SAI_FIFO_COUNTn(UINT_TO_I2S(DT_INST_REG_ADDR(inst)))
/* used to retrieve the TX/RX FIFO's size (in FIFO words) */
#define SAI_FIFO_DEPTH(inst)\
DT_INST_PROP_OR(inst, fifo_depth, _SAI_FIFO_DEPTH(inst))
/* used to retrieve the DMA MUX for transmitter */
#define SAI_TX_DMA_MUX(inst)\
FSL_FEATURE_SAI_TX_DMA_MUXn(UINT_TO_I2S(DT_INST_REG_ADDR(inst)))
/* used to retrieve the DMA MUX for receiver */
#define SAI_RX_DMA_MUX(inst)\
FSL_FEATURE_SAI_RX_DMA_MUXn(UINT_TO_I2S(DT_INST_REG_ADDR(inst)))
/* utility macros */
/* invert a clock's polarity. This works because a clock's polarity is expressed
* as a 0 or as a 1.
*/
#define SAI_INVERT_POLARITY(polarity) (polarity) = !(polarity)
/* used to issue a software reset of the transmitter/receiver */
#define SAI_TX_RX_SW_RESET(dir, regmap)\
((dir) == DAI_DIR_RX ? SAI_RxSoftwareReset(UINT_TO_I2S(regmap), kSAI_ResetTypeSoftware) :\
SAI_TxSoftwareReset(UINT_TO_I2S(regmap), kSAI_ResetTypeSoftware))
/* used to enable/disable the transmitter/receiver.
* When enabling the SYNC component, the ASYNC component will also be enabled.
* Attempting to disable the SYNC component will fail unless the SYNC bit is
* cleared. It is recommended to use sai_tx_rx_force_disable() instead of this
* macro when disabling transmitter/receiver.
*/
#define SAI_TX_RX_ENABLE_DISABLE(dir, regmap, enable)\
((dir) == DAI_DIR_RX ? SAI_RxEnable(UINT_TO_I2S(regmap), enable) :\
SAI_TxEnable(UINT_TO_I2S(regmap), enable))
/* used to enable/disable the DMA requests for transmitter/receiver */
#define SAI_TX_RX_DMA_ENABLE_DISABLE(dir, regmap, enable)\
((dir) == DAI_DIR_RX ? SAI_RxEnableDMA(UINT_TO_I2S(regmap),\
kSAI_FIFORequestDMAEnable, enable) :\
SAI_TxEnableDMA(UINT_TO_I2S(regmap), kSAI_FIFORequestDMAEnable, enable))
/* used to check if the hardware transmitter/receiver is enabled */
#define SAI_TX_RX_IS_HW_ENABLED(dir, regmap)\
((dir) == DAI_DIR_RX ? (UINT_TO_I2S(regmap)->RCSR & I2S_RCSR_RE_MASK) : \
(UINT_TO_I2S(regmap)->TCSR & I2S_TCSR_TE_MASK))
/* used to enable various transmitter/receiver interrupts */
#define _SAI_TX_RX_ENABLE_IRQ(dir, regmap, which)\
((dir) == DAI_DIR_RX ? SAI_RxEnableInterrupts(UINT_TO_I2S(regmap), which) : \
SAI_TxEnableInterrupts(UINT_TO_I2S(regmap), which))
/* used to disable various transmitter/receiver interrupts */
#define _SAI_TX_RX_DISABLE_IRQ(dir, regmap, which)\
((dir) == DAI_DIR_RX ? SAI_RxDisableInterrupts(UINT_TO_I2S(regmap), which) : \
SAI_TxDisableInterrupts(UINT_TO_I2S(regmap), which))
/* used to enable/disable various transmitter/receiver interrupts */
#define SAI_TX_RX_ENABLE_DISABLE_IRQ(dir, regmap, which, enable)\
((enable == true) ? _SAI_TX_RX_ENABLE_IRQ(dir, regmap, which) :\
_SAI_TX_RX_DISABLE_IRQ(dir, regmap, which))
/* used to check if a status flag is set */
#define SAI_TX_RX_STATUS_IS_SET(dir, regmap, which)\
((dir) == DAI_DIR_RX ? ((UINT_TO_I2S(regmap))->RCSR & (which)) : \
((UINT_TO_I2S(regmap))->TCSR & (which)))
struct sai_clock_data {
uint32_t *clocks;
uint32_t clock_num;
/* assumption: all clocks belong to the same producer */
const struct device *dev;
const char **clock_names;
};
struct sai_data {
mm_reg_t regmap;
sai_transceiver_t rx_config;
sai_transceiver_t tx_config;
bool tx_enabled;
bool rx_enabled;
enum dai_state tx_state;
enum dai_state rx_state;
struct dai_config cfg;
};
struct sai_config {
uint32_t regmap_phys;
uint32_t regmap_size;
struct sai_clock_data clk_data;
bool mclk_is_output;
/* if the tx/rx-fifo-watermark properties are not specified, it's going
* to be assumed that the watermark should be set to half of the FIFO
* size.
*/
uint32_t rx_fifo_watermark;
uint32_t tx_fifo_watermark;
const struct dai_properties *tx_props;
const struct dai_properties *rx_props;
uint32_t dai_index;
void (*irq_config)(void);
};
/* this needs to perfectly match SOF's struct sof_ipc_dai_sai_params */
struct sai_bespoke_config {
uint32_t reserved0;
uint16_t reserved1;
uint16_t mclk_id;
uint32_t mclk_direction;
/* CLOCK-related data */
uint32_t mclk_rate;
uint32_t fsync_rate;
uint32_t bclk_rate;
/* TDM-related data */
uint32_t tdm_slots;
uint32_t rx_slots;
uint32_t tx_slots;
uint16_t tdm_slot_width;
uint16_t reserved2;
};
#ifdef CONFIG_SAI_HAS_MCLK_CONFIG_OPTION
static int get_msel(sai_bclk_source_t bclk_source, uint32_t *msel)
{
switch (bclk_source) {
case kSAI_BclkSourceMclkOption1:
*msel = 0;
break;
case kSAI_BclkSourceMclkOption2:
*msel = (0x2 << SAI_MCLK_MCR_MSEL_SHIFT);
break;
case kSAI_BclkSourceMclkOption3:
*msel = (0x3 << SAI_MCLK_MCR_MSEL_SHIFT);
break;
default:
return -EINVAL;
}
return 0;
}
static void set_msel(uint32_t regmap, int msel)
{
UINT_TO_I2S(regmap)->MCR &= ~SAI_MCLK_MCR_MSEL_MASK;
UINT_TO_I2S(regmap)->MCR |= msel;
}
static int clk_lookup_by_name(const struct sai_clock_data *clk_data, char *name)
{
int i;
for (i = 0; i < clk_data->clock_num; i++) {
if (!strcmp(name, clk_data->clock_names[i])) {
return i;
}
}
return -EINVAL;
}
static int get_mclk_rate(const struct sai_clock_data *clk_data,
sai_bclk_source_t bclk_source,
uint32_t *rate)
{
int clk_idx;
char *clk_name;
switch (bclk_source) {
case kSAI_BclkSourceMclkOption1:
clk_name = "mclk1";
break;
case kSAI_BclkSourceMclkOption2:
clk_name = "mclk2";
break;
case kSAI_BclkSourceMclkOption3:
clk_name = "mclk3";
break;
default:
LOG_ERR("invalid bitclock source: %d", bclk_source);
return -EINVAL;
}
clk_idx = clk_lookup_by_name(clk_data, clk_name);
if (clk_idx < 0) {
LOG_ERR("failed to get clock index for %s", clk_name);
return clk_idx;
}
return clock_control_get_rate(clk_data->dev,
UINT_TO_POINTER(clk_data->clocks[clk_idx]),
rate);
}
#endif /* CONFIG_SAI_HAS_MCLK_CONFIG_OPTION */
static inline void get_bclk_default_config(sai_bit_clock_t *cfg)
{
memset(cfg, 0, sizeof(sai_bit_clock_t));
/* by default, BCLK has the following properties:
*
* 1) BCLK is active HIGH.
* 2) BCLK uses MCLK1 source. (only applicable to master mode)
* 3) No source swap.
* 4) No input delay.
*/
cfg->bclkPolarity = kSAI_PolarityActiveHigh;
cfg->bclkSource = kSAI_BclkSourceMclkOption1;
}
static inline void get_fsync_default_config(sai_frame_sync_t *cfg)
{
memset(cfg, 0, sizeof(sai_frame_sync_t));
/* by default, FSYNC has the following properties:
*
* 1) FSYNC is asserted one bit early with respect to the next
* frame.
* 2) FSYNC is active HIGH.
*/
cfg->frameSyncEarly = true;
cfg->frameSyncPolarity = kSAI_PolarityActiveHigh;
}
static inline void get_serial_default_config(sai_serial_data_t *cfg)
{
memset(cfg, 0, sizeof(sai_serial_data_t));
/* by default, the serial configuration has the following quirks:
*
* 1) Data pin is not tri-stated.
* 2) MSB is first.
*/
/* note: this is equivalent to checking if the SAI has xCR4's CHMOD bit */
#if FSL_FEATURE_SAI_HAS_CHANNEL_MODE
cfg->dataMode = kSAI_DataPinStateOutputZero;
#endif /* FSL_FEATURE_SAI_HAS_CHANNEL_MODE */
cfg->dataOrder = kSAI_DataMSB;
}
static inline void get_fifo_default_config(sai_fifo_t *cfg)
{
memset(cfg, 0, sizeof(sai_fifo_t));
}
static inline uint32_t sai_get_state(enum dai_dir dir,
struct sai_data *data)
{
if (dir == DAI_DIR_RX) {
return data->rx_state;
} else {
return data->tx_state;
}
}
static int sai_update_state(enum dai_dir dir,
struct sai_data *data,
enum dai_state new_state)
{
enum dai_state old_state = sai_get_state(dir, data);
LOG_DBG("attempting to transition from %d to %d", old_state, new_state);
/* check if transition is possible */
switch (new_state) {
case DAI_STATE_NOT_READY:
/* this shouldn't be possible */
return -EPERM;
case DAI_STATE_READY:
if (old_state != DAI_STATE_NOT_READY &&
old_state != DAI_STATE_READY &&
old_state != DAI_STATE_STOPPING) {
return -EPERM;
}
break;
case DAI_STATE_RUNNING:
if (old_state != DAI_STATE_PAUSED &&
old_state != DAI_STATE_STOPPING &&
old_state != DAI_STATE_READY) {
return -EPERM;
}
break;
case DAI_STATE_PAUSED:
if (old_state != DAI_STATE_RUNNING) {
return -EPERM;
}
break;
case DAI_STATE_STOPPING:
if (old_state != DAI_STATE_READY &&
old_state != DAI_STATE_RUNNING &&
old_state != DAI_STATE_PAUSED) {
return -EPERM;
}
break;
case DAI_STATE_ERROR:
case DAI_STATE_PRE_RUNNING:
/* these states are not used so transitioning to them
* is considered invalid.
*/
default:
return -EINVAL;
}
if (dir == DAI_DIR_RX) {
data->rx_state = new_state;
} else {
data->tx_state = new_state;
}
return 0;
}
static inline void sai_tx_rx_force_disable(enum dai_dir dir,
uint32_t regmap)
{
I2S_Type *base = UINT_TO_I2S(regmap);
if (dir == DAI_DIR_RX) {
base->RCSR = ((base->RCSR & 0xFFE3FFFFU) & (~I2S_RCSR_RE_MASK));
} else {
base->TCSR = ((base->TCSR & 0xFFE3FFFFU) & (~I2S_TCSR_TE_MASK));
}
}
static inline void sai_tx_rx_sw_enable_disable(enum dai_dir dir,
struct sai_data *data,
bool enable)
{
if (dir == DAI_DIR_RX) {
data->rx_enabled = enable;
} else {
data->tx_enabled = enable;
}
}
static inline int count_leading_zeros(uint32_t word)
{
int num = 0;
while (word) {
if (!(word & 0x1)) {
num++;
} else {
break;
}
word = word >> 1;
}
return num;
}
static inline void sai_tx_rx_set_dline_mask(enum dai_dir dir, uint32_t regmap, uint32_t mask)
{
I2S_Type *base = UINT_TO_I2S(regmap);
if (dir == DAI_DIR_RX) {
base->RCR3 &= ~I2S_RCR3_RCE_MASK;
base->RCR3 |= I2S_RCR3_RCE(mask);
} else {
base->TCR3 &= ~I2S_TCR3_TCE_MASK;
base->TCR3 |= I2S_TCR3_TCE(mask);
}
}
static inline void sai_dump_register_data(uint32_t regmap)
{
I2S_Type *base = UINT_TO_I2S(regmap);
LOG_DBG("TCSR: 0x%x", base->TCSR);
LOG_DBG("RCSR: 0x%x", base->RCSR);
LOG_DBG("TCR1: 0x%x", base->TCR1);
LOG_DBG("RCR1: 0x%x", base->RCR1);
LOG_DBG("TCR2: 0x%x", base->TCR2);
LOG_DBG("RCR2: 0x%x", base->RCR2);
LOG_DBG("TCR3: 0x%x", base->TCR3);
LOG_DBG("RCR3: 0x%x", base->RCR3);
LOG_DBG("TCR4: 0x%x", base->TCR4);
LOG_DBG("RCR4: 0x%x", base->RCR4);
LOG_DBG("TCR5: 0x%x", base->TCR5);
LOG_DBG("RCR5: 0x%x", base->RCR5);
LOG_DBG("TMR: 0x%x", base->TMR);
LOG_DBG("RMR: 0x%x", base->RMR);
#ifdef CONFIG_SAI_HAS_MCLK_CONFIG_OPTION
LOG_DBG("MCR: 0x%x", base->MCR);
#endif /* CONFIG_SAI_HAS_MCLK_CONFIG_OPTION */
}
#endif /* ZEPHYR_DRIVERS_DAI_NXP_SAI_H_ */

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# Copyright 2023 NXP
# SPDX-License-Identifier: Apache-2.0
description: NXP Synchronous Audio Interface (SAI) node
compatible: "nxp,dai-sai"
include: base.yaml
properties:
reg:
required: true
mclk-is-output:
type: boolean
description: |
Use this property to set the SAI MCLK as output or as input.
By default, if this property is not specified, MCLK will be
set as input. Setting the MCLK as output for SAIs which don't
support MCLK configuration will result in a BUILD_ASSERT()
failure.
rx-fifo-watermark:
type: int
description: |
Use this property to specify the watermark value for the TX
FIFO. This value needs to be in FIFO words (NOT BYTES). This
value needs to be in the following interval: (0, DEFAULT_FIFO_DEPTH],
otherwise a BUILD_ASSERT() failure will be raised.
tx-fifo-watermark:
type: int
description: |
Use this property to specify the watermark value for the RX
FIFO. This value needs to be in FIFO words (NOT BYTES). This
value needs to be in the following interval: (0, DEFAULT_FIFO_DEPTH],
otherwise a BUILD_ASSERT() failure will be raised.
interrupts:
required: true
fifo-depth:
type: int
description: |
Use this property to set the FIFO depth that will be reported
to other applications calling dai_get_properties(). This value
should be in the following interval: (0, DEFAULT_FIFO_DEPTH],
otherwise a BUILD_ASSERT() failure will be raised.
By DEFAULT_FIFO_DEPTH we mean the actual (hardware) value of
the FIFO depth. This is needed because some applications (e.g: SOF)
use this value to compute the DMA burst size, in which case
DEFAULT_FIFO_DEPTH cannot be used. Generally, reporting a false
FIFO depth should be avoided. Please note that the sanity check
for tx/rx-fifo-watermark uses DEFAULT_FIFO_DEPTH instead of this
value so use with caution. If unsure, it's better to simply not
use this property, in which case the reported value will be
DEFAULT_FIFO_DEPTH.
dai-index:
type: int
description: |
Use this property to specify the index of the DAI. At the
moment, this is only used by SOF to fetch the "struct device"
associated with the DAI whose index Linux passes to SOF
through an IPC. If this property is not specified, the DAI
index will be considered 0.