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Posted to commits@nuttx.apache.org by ac...@apache.org on 2020/06/05 18:54:28 UTC
[incubator-nuttx] 01/03: drivers/audio: Add CS4344 driver.
This is an automated email from the ASF dual-hosted git repository.
acassis pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git
commit 8da4b02350da5b0fe9dee1f70ce7f2b5730a89a7
Author: Ouss4 <ab...@gmail.com>
AuthorDate: Wed Jun 3 15:45:26 2020 +0100
drivers/audio: Add CS4344 driver.
---
drivers/audio/Kconfig | 33 +
drivers/audio/Make.defs | 4 +
drivers/audio/cs4344.c | 1370 ++++++++++++++++++++++++++++++++++++++++++
drivers/audio/cs4344.h | 98 +++
include/nuttx/audio/cs4344.h | 141 +++++
5 files changed, 1646 insertions(+)
diff --git a/drivers/audio/Kconfig b/drivers/audio/Kconfig
index 735718a..610109c 100644
--- a/drivers/audio/Kconfig
+++ b/drivers/audio/Kconfig
@@ -165,6 +165,39 @@ config CS43L22_CLKDEBUG
endif # AUDIO_CS43L22
+config AUDIO_CS4344
+ bool "CS4344 audio chip"
+ default n
+ depends on AUDIO
+ ---help---
+ Select to enable support for the CS4344 Audio codec by Cirrus Logic.
+ This chip is a lower level audio chip.. basically
+ an exotic D-to-A. It includes no built-in support for audio CODECS.
+
+if AUDIO_CS4344
+
+config CS4344_INFLIGHT
+ int "CS4344 maximum in-flight audio buffers"
+ default 2
+
+config CS4344_MSG_PRIO
+ int "CS4344 message priority"
+ default 1
+
+config CS4344_BUFFER_SIZE
+ int "CS4344 preferred buffer size"
+ default 8192
+
+config CS4344_NUM_BUFFERS
+ int "CS4344 preferred number of buffers"
+ default 4
+
+config CS4344_WORKER_STACKSIZE
+ int "CS4344 worker thread stack size"
+ default 768
+
+endif # AUDIO_CS4344
+
config AUDIO_WM8776
bool "WM8776 audio chip"
default n
diff --git a/drivers/audio/Make.defs b/drivers/audio/Make.defs
index a3b607c..b0c0535 100644
--- a/drivers/audio/Make.defs
+++ b/drivers/audio/Make.defs
@@ -58,6 +58,10 @@ endif
endif
endif
+ifeq ($(CONFIG_AUDIO_CS4344),y)
+CSRCS += cs4344.c
+endif
+
ifeq ($(CONFIG_AUDIO_WM8904),y)
CSRCS += wm8904.c
ifeq ($(CONFIG_WM8904_REGDUMP),y)
diff --git a/drivers/audio/cs4344.c b/drivers/audio/cs4344.c
new file mode 100644
index 0000000..0c2619b
--- /dev/null
+++ b/drivers/audio/cs4344.c
@@ -0,0 +1,1370 @@
+/****************************************************************************
+ * drivers/audio/cs4344.c
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <sys/ioctl.h>
+
+#include <stdint.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <fixedmath.h>
+#include <queue.h>
+#include <debug.h>
+
+#include <nuttx/kmalloc.h>
+#include <nuttx/mqueue.h>
+#include <nuttx/clock.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/fs/fs.h>
+#include <nuttx/fs/ioctl.h>
+#include <nuttx/audio/i2s.h>
+#include <nuttx/audio/audio.h>
+#include <nuttx/audio/cs4344.h>
+#include <nuttx/lib/math.h>
+
+#include "cs4344.h"
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+static int cs4344_takesem(FAR sem_t *sem);
+static int cs4344_forcetake(FAR sem_t *sem);
+#define cs4344_givesem(s) nxsem_post(s)
+
+static void cs4344_setdatawidth(FAR struct cs4344_dev_s *priv);
+static void cs4344_setbitrate(FAR struct cs4344_dev_s *priv);
+
+/* Audio lower half methods (and close friends) */
+
+static int cs4344_getcaps(FAR struct audio_lowerhalf_s *dev, int type,
+ FAR struct audio_caps_s *caps);
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_configure(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session,
+ FAR const struct audio_caps_s *caps);
+#else
+static int cs4344_configure(FAR struct audio_lowerhalf_s *dev,
+ FAR const struct audio_caps_s *caps);
+#endif
+static int cs4344_shutdown(FAR struct audio_lowerhalf_s *dev);
+static void cs4344_senddone(FAR struct i2s_dev_s *i2s,
+ FAR struct ap_buffer_s *apb, FAR void *arg,
+ int result);
+static void cs4344_returnbuffers(FAR struct cs4344_dev_s *priv);
+static int cs4344_sendbuffer(FAR struct cs4344_dev_s *priv);
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_start(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session);
+#else
+static int cs4344_start(FAR struct audio_lowerhalf_s *dev);
+#endif
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_stop(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session);
+#else
+static int cs4344_stop(FAR struct audio_lowerhalf_s *dev);
+#endif
+#endif
+#ifndef CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_pause(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session);
+static int cs4344_resume(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session);
+#else
+static int cs4344_pause(FAR struct audio_lowerhalf_s *dev);
+static int cs4344_resume(FAR struct audio_lowerhalf_s *dev);
+#endif
+#endif
+static int cs4344_enqueuebuffer(FAR struct audio_lowerhalf_s *dev,
+ FAR struct ap_buffer_s *apb);
+static int cs4344_cancelbuffer(FAR struct audio_lowerhalf_s *dev,
+ FAR struct ap_buffer_s *apb);
+static int cs4344_ioctl(FAR struct audio_lowerhalf_s *dev, int cmd,
+ unsigned long arg);
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_reserve(FAR struct audio_lowerhalf_s *dev,
+ FAR void **session);
+#else
+static int cs4344_reserve(FAR struct audio_lowerhalf_s *dev);
+#endif
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_release(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session);
+#else
+static int cs4344_release(FAR struct audio_lowerhalf_s *dev);
+#endif
+
+static void *cs4344_workerthread(pthread_addr_t pvarg);
+
+/* Initialization */
+
+static void cs4344_reset(FAR struct cs4344_dev_s *priv);
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+static const struct audio_ops_s g_audioops =
+{
+ cs4344_getcaps, /* getcaps */
+ cs4344_configure, /* configure */
+ cs4344_shutdown, /* shutdown */
+ cs4344_start, /* start */
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+ cs4344_stop, /* stop */
+#endif
+#ifndef CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME
+ cs4344_pause, /* pause */
+ cs4344_resume, /* resume */
+#endif
+ NULL, /* allocbuffer */
+ NULL, /* freebuffer */
+ cs4344_enqueuebuffer, /* enqueue_buffer */
+ cs4344_cancelbuffer, /* cancel_buffer */
+ cs4344_ioctl, /* ioctl */
+ NULL, /* read */
+ NULL, /* write */
+ cs4344_reserve, /* reserve */
+ cs4344_release /* release */
+};
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cs4344_takesem
+ *
+ * Description:
+ * Take a semaphore count, handling the nasty EINTR return if we are
+ * interrupted by a signal.
+ *
+ ****************************************************************************/
+
+static int cs4344_takesem(FAR sem_t *sem)
+{
+ return nxsem_wait_uninterruptible(sem);
+}
+
+/****************************************************************************
+ * Name: cs4344_forcetake
+ *
+ * Description:
+ * This is just another wrapper but this one continues even if the thread
+ * is canceled. This must be done in certain conditions where were must
+ * continue in order to clean-up resources.
+ *
+ ****************************************************************************/
+
+static int cs4344_forcetake(FAR sem_t *sem)
+{
+ int result;
+ int ret = OK;
+
+ do
+ {
+ result = nxsem_wait_uninterruptible(sem);
+
+ /* The only expected error would -ECANCELED meaning that the
+ * parent thread has been canceled. We have to continue and
+ * terminate the poll in this case.
+ */
+
+ DEBUGASSERT(result == OK || result == -ECANCELED);
+ if (ret == OK && result < 0)
+ {
+ /* Remember the first failure */
+
+ ret = result;
+ }
+ }
+ while (result < 0);
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_setdatawidth
+ *
+ * Description:
+ * Set the 8- or 16-bit data modes
+ *
+ ****************************************************************************/
+
+static void cs4344_setdatawidth(FAR struct cs4344_dev_s *priv)
+{
+ if (priv->bpsamp == 16)
+ {
+ /* Reset default default setting */
+
+ priv->i2s->ops->i2s_txdatawidth(priv->i2s, 16);
+ }
+ else
+ {
+ /* This should select 8-bit with no companding */
+
+ priv->i2s->ops->i2s_txdatawidth(priv->i2s, 8);
+ }
+}
+
+/****************************************************************************
+ * Name: cs4344_setbitrate
+ *
+ ****************************************************************************/
+
+static void cs4344_setbitrate(FAR struct cs4344_dev_s *priv)
+{
+ DEBUGASSERT(priv);
+
+ priv->i2s->ops->i2s_txsamplerate(priv->i2s, priv->samprate);
+
+ audinfo("sample rate=%u nchannels=%u bpsamp=%u\n",
+ priv->samprate, priv->nchannels, priv->bpsamp);
+}
+
+/****************************************************************************
+ * Name: cs4344_getcaps
+ *
+ * Description:
+ * Get the audio device capabilities
+ *
+ ****************************************************************************/
+
+static int cs4344_getcaps(FAR struct audio_lowerhalf_s *dev, int type,
+ FAR struct audio_caps_s *caps)
+{
+ /* Validate the structure */
+
+ DEBUGASSERT(caps && caps->ac_len >= sizeof(struct audio_caps_s));
+ audinfo("type=%d ac_type=%d\n", type, caps->ac_type);
+
+ /* Fill in the caller's structure based on requested info */
+
+ caps->ac_format.hw = 0;
+ caps->ac_controls.w = 0;
+
+ switch (caps->ac_type)
+ {
+ /* Caller is querying for the types of units we support */
+
+ case AUDIO_TYPE_QUERY:
+
+ /* Provide our overall capabilities. The interfacing software
+ * must then call us back for specific info for each capability.
+ */
+
+ caps->ac_channels = 2; /* Stereo output */
+
+ switch (caps->ac_subtype)
+ {
+ case AUDIO_TYPE_QUERY:
+
+ /* We don't decode any formats! Only something above us in
+ * the audio stream can perform decoding on our behalf.
+ */
+
+ /* The types of audio units we implement */
+
+ caps->ac_controls.b[0] =
+ AUDIO_TYPE_OUTPUT | AUDIO_TYPE_FEATURE |
+ AUDIO_TYPE_PROCESSING;
+ break;
+
+ case AUDIO_FMT_MIDI:
+
+ /* We only support Format 0 */
+
+ caps->ac_controls.b[0] = AUDIO_SUBFMT_END;
+ break;
+
+ default:
+ caps->ac_controls.b[0] = AUDIO_SUBFMT_END;
+ break;
+ }
+
+ break;
+
+ /* Provide capabilities of our OUTPUT unit */
+
+ case AUDIO_TYPE_OUTPUT:
+
+ caps->ac_channels = 2;
+
+ switch (caps->ac_subtype)
+ {
+ case AUDIO_TYPE_QUERY:
+
+ /* Report the Sample rates we support */
+
+ caps->ac_controls.b[0] =
+ AUDIO_SAMP_RATE_8K | AUDIO_SAMP_RATE_11K |
+ AUDIO_SAMP_RATE_16K | AUDIO_SAMP_RATE_22K |
+ AUDIO_SAMP_RATE_32K | AUDIO_SAMP_RATE_44K |
+ AUDIO_SAMP_RATE_48K;
+ break;
+
+ case AUDIO_FMT_MP3:
+ case AUDIO_FMT_WMA:
+ case AUDIO_FMT_PCM:
+ break;
+
+ default:
+ break;
+ }
+
+ break;
+
+ /* Provide capabilities of our FEATURE units */
+
+ case AUDIO_TYPE_FEATURE:
+
+ /* If the sub-type is UNDEF, then report the Feature Units we
+ * support.
+ */
+
+ if (caps->ac_subtype == AUDIO_FU_UNDEF)
+ {
+ /* Fill in the ac_controls section with the Feature Units we
+ * have.
+ */
+
+ caps->ac_controls.b[0] = AUDIO_FU_VOLUME | AUDIO_FU_BASS |
+ AUDIO_FU_TREBLE;
+ caps->ac_controls.b[1] = AUDIO_FU_BALANCE >> 8;
+ }
+ else
+ {
+ /* TODO: Do we need to provide specific info for the Feature
+ * Units, such as volume setting ranges, etc.?
+ */
+ }
+
+ break;
+
+ /* Provide capabilities of our PROCESSING unit */
+
+ case AUDIO_TYPE_PROCESSING:
+
+ switch (caps->ac_subtype)
+ {
+ case AUDIO_PU_UNDEF:
+
+ /* Provide the type of Processing Units we support */
+
+ caps->ac_controls.b[0] = AUDIO_PU_STEREO_EXTENDER;
+ break;
+
+ case AUDIO_PU_STEREO_EXTENDER:
+
+ /* Provide capabilities of our Stereo Extender */
+
+ caps->ac_controls.b[0] =
+ AUDIO_STEXT_ENABLE | AUDIO_STEXT_WIDTH;
+ break;
+
+ default:
+
+ /* Other types of processing uint we don't support */
+
+ break;
+ }
+ break;
+
+ /* All others we don't support */
+
+ default:
+
+ /* Zero out the fields to indicate no support */
+
+ caps->ac_subtype = 0;
+ caps->ac_channels = 0;
+
+ break;
+ }
+
+ /* Return the length of the audio_caps_s struct for validation of
+ * proper Audio device type.
+ */
+
+ return caps->ac_len;
+}
+
+/****************************************************************************
+ * Name: cs4344_configure
+ *
+ * Description:
+ * Configure the audio device for the specified mode of operation.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int
+cs4344_configure(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session, FAR const struct audio_caps_s *caps)
+#else
+static int
+cs4344_configure(FAR struct audio_lowerhalf_s *dev,
+ FAR const struct audio_caps_s *caps)
+#endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ int ret = OK;
+
+ DEBUGASSERT(priv != NULL && caps != NULL);
+ audinfo("ac_type: %d\n", caps->ac_type);
+
+ /* Process the configure operation */
+
+ switch (caps->ac_type)
+ {
+ case AUDIO_TYPE_FEATURE:
+ audinfo(" AUDIO_TYPE_FEATURE\n");
+
+ /* Process based on Feature Unit */
+
+ switch (caps->ac_format.hw)
+ {
+ default:
+ auderr(" ERROR: Unrecognized feature unit\n");
+ ret = -ENOTTY;
+ break;
+ }
+ break;
+
+ case AUDIO_TYPE_OUTPUT:
+ {
+ audinfo(" AUDIO_TYPE_OUTPUT:\n");
+ audinfo(" Number of channels: %u\n", caps->ac_channels);
+ audinfo(" Sample rate: %u\n", caps->ac_controls.hw[0]);
+ audinfo(" Sample width: %u\n", caps->ac_controls.b[2]);
+
+ /* Verify that all of the requested values are supported */
+
+ ret = -ERANGE;
+ if (caps->ac_channels != 1 && caps->ac_channels != 2)
+ {
+ auderr("ERROR: Unsupported number of channels: %d\n",
+ caps->ac_channels);
+ break;
+ }
+
+ if (caps->ac_controls.b[2] != 8 && caps->ac_controls.b[2] != 16)
+ {
+ auderr("ERROR: Unsupported bits per sample: %d\n",
+ caps->ac_controls.b[2]);
+ break;
+ }
+
+ /* Save the current stream configuration */
+
+ priv->samprate = caps->ac_controls.hw[0];
+ priv->nchannels = caps->ac_channels;
+ priv->bpsamp = caps->ac_controls.b[2];
+
+ /* Reconfigure the FLL to support the resulting number or channels,
+ * bits per sample, and bitrate.
+ */
+
+ cs4344_setdatawidth(priv);
+ cs4344_setbitrate(priv);
+ ret = OK;
+ }
+ break;
+
+ case AUDIO_TYPE_PROCESSING:
+ break;
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_shutdown
+ *
+ * Description:
+ * Shutdown the CS4344 chip and put it in the lowest power state possible.
+ *
+ ****************************************************************************/
+
+static int cs4344_shutdown(FAR struct audio_lowerhalf_s *dev)
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+
+ DEBUGASSERT(priv);
+
+ /* Now issue a software reset. This puts all CS4344 registers back in
+ * their default state.
+ */
+
+ cs4344_reset(priv);
+ return OK;
+}
+
+/****************************************************************************
+ * Name: cs4344_senddone
+ *
+ * Description:
+ * This is the I2S callback function that is invoked when the transfer
+ * completes.
+ *
+ ****************************************************************************/
+
+static void
+cs4344_senddone(FAR struct i2s_dev_s *i2s,
+ FAR struct ap_buffer_s *apb, FAR void *arg, int result)
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)arg;
+ struct audio_msg_s msg;
+ irqstate_t flags;
+ int ret;
+
+ DEBUGASSERT(i2s && priv && priv->running && apb);
+ audinfo("apb=%p inflight=%d result=%d\n", apb, priv->inflight, result);
+
+ /* We do not place any restriction on the context in which this function
+ * is called. It may be called from an interrupt handler. Therefore, the
+ * doneq and in-flight values might be accessed from the interrupt level.
+ * Not the best design. But we will use interrupt controls to protect
+ * against that possibility.
+ */
+
+ flags = enter_critical_section();
+
+ /* Add the completed buffer to the end of our doneq. We do not yet
+ * decrement the reference count.
+ */
+
+ dq_addlast((FAR dq_entry_t *)apb, &priv->doneq);
+
+ /* And decrement the number of buffers in-flight */
+
+ DEBUGASSERT(priv->inflight > 0);
+ priv->inflight--;
+
+ /* Save the result of the transfer */
+
+ /* REVISIT: This can be overwritten */
+
+ priv->result = result;
+ leave_critical_section(flags);
+
+ /* Now send a message to the worker thread, informing it that there are
+ * buffers in the done queue that need to be cleaned up.
+ */
+
+ msg.msg_id = AUDIO_MSG_COMPLETE;
+ ret = nxmq_send(priv->mq, (FAR const char *)&msg, sizeof(msg),
+ CONFIG_CS4344_MSG_PRIO);
+ if (ret < 0)
+ {
+ auderr("ERROR: nxmq_send failed: %d\n", ret);
+ }
+}
+
+/****************************************************************************
+ * Name: cs4344_returnbuffers
+ *
+ * Description:
+ * This function is called after the complete of one or more data
+ * transfers. This function will empty the done queue and release our
+ * reference to each buffer.
+ *
+ ****************************************************************************/
+
+static void cs4344_returnbuffers(FAR struct cs4344_dev_s *priv)
+{
+ FAR struct ap_buffer_s *apb;
+ irqstate_t flags;
+
+ /* The doneq and in-flight values might be accessed from the interrupt
+ * level in some implementations. Not the best design. But we will
+ * use interrupt controls to protect against that possibility.
+ */
+
+ flags = enter_critical_section();
+ while (dq_peek(&priv->doneq) != NULL)
+ {
+ /* Take the next buffer from the queue of completed transfers */
+
+ apb = (FAR struct ap_buffer_s *)dq_remfirst(&priv->doneq);
+ leave_critical_section(flags);
+
+ audinfo("Returning: apb=%p curbyte=%d nbytes=%d flags=%04x\n",
+ apb, apb->curbyte, apb->nbytes, apb->flags);
+
+ /* Are we returning the final buffer in the stream? */
+
+ if ((apb->flags & AUDIO_APB_FINAL) != 0)
+ {
+ /* Both the pending and the done queues should be empty and there
+ * should be no buffers in-flight.
+ */
+
+ DEBUGASSERT(dq_empty(&priv->doneq) && dq_empty(&priv->pendq) &&
+ priv->inflight == 0);
+
+ /* Set the terminating flag. This will, eventually, cause the
+ * worker thread to exit (if it is not already terminating).
+ */
+
+ audinfo("Terminating\n");
+ priv->terminating = true;
+ }
+
+ /* Release our reference to the audio buffer */
+
+ apb_free(apb);
+
+ /* Send the buffer back up to the previous level. */
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_DEQUEUE, apb, OK, NULL);
+#else
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_DEQUEUE, apb, OK);
+#endif
+ flags = enter_critical_section();
+ }
+
+ leave_critical_section(flags);
+}
+
+/****************************************************************************
+ * Name: cs4344_sendbuffer
+ *
+ * Description:
+ * Start the transfer an audio buffer to the CS4344 via I2S. This
+ * will not wait for the transfer to complete but will return immediately.
+ * the wmd8904_senddone called will be invoked when the transfer
+ * completes, stimulating the worker thread to call this function again.
+ *
+ ****************************************************************************/
+
+static int cs4344_sendbuffer(FAR struct cs4344_dev_s *priv)
+{
+ FAR struct ap_buffer_s *apb;
+ irqstate_t flags;
+ uint32_t timeout;
+ int shift;
+ int ret;
+
+ /* Loop while there are audio buffers to be sent and we have few than
+ * CONFIG_CS4344_INFLIGHT then "in-flight"
+ *
+ * The 'inflight' value might be modified from the interrupt level in some
+ * implementations. We will use interrupt controls to protect against
+ * that possibility.
+ *
+ * The 'pendq', on the other hand, is protected via a semaphore. Let's
+ * hold the semaphore while we are busy here and disable the interrupts
+ * only while accessing 'inflight'.
+ */
+
+ ret = cs4344_takesem(&priv->pendsem);
+ if (ret < 0)
+ {
+ return ret;
+ }
+
+ while (priv->inflight < CONFIG_CS4344_INFLIGHT &&
+ dq_peek(&priv->pendq) != NULL && !priv->paused)
+ {
+ /* Take next buffer from the queue of pending transfers */
+
+ apb = (FAR struct ap_buffer_s *)dq_remfirst(&priv->pendq);
+ audinfo("Sending apb=%p, size=%d inflight=%d\n",
+ apb, apb->nbytes, priv->inflight);
+
+ /* Increment the number of buffers in-flight before sending in order
+ * to avoid a possible race condition.
+ */
+
+ flags = enter_critical_section();
+ priv->inflight++;
+ leave_critical_section(flags);
+
+ /* Send the entire audio buffer via I2S. What is a reasonable timeout
+ * to use? This would depend on the bit rate and size of the buffer.
+ *
+ * Samples in the buffer (samples):
+ * = buffer_size * 8 / bpsamp samples
+ * Sample rate (samples/second):
+ * = samplerate * nchannels
+ * Expected transfer time (seconds):
+ * = (buffer_size * 8) / bpsamp / samplerate / nchannels
+ *
+ * We will set the timeout about twice that.
+ *
+ * NOTES:
+ * - The multiplier of 8 becomes 16000 for 2x and units of
+ * milliseconds.
+ * - 16000 is a approximately 16384 (1 << 14), bpsamp is either
+ * (1 << 3) or (1 << 4), and nchannels is either (1 << 0) or
+ * (1 << 1). So this can be simplifies to (milliseconds):
+ *
+ * = (buffer_size << shift) / samplerate
+ */
+
+ shift = (priv->bpsamp == 8) ? 14 - 3 : 14 - 4;
+ shift -= (priv->nchannels > 1) ? 1 : 0;
+
+ timeout = MSEC2TICK(((uint32_t)(apb->nbytes - apb->curbyte) << shift) /
+ (uint32_t)priv->samprate);
+
+ ret = I2S_SEND(priv->i2s, apb, cs4344_senddone, priv, timeout);
+ if (ret < 0)
+ {
+ auderr("ERROR: I2S_SEND failed: %d\n", ret);
+ break;
+ }
+ }
+
+ cs4344_givesem(&priv->pendsem);
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_start
+ *
+ * Description:
+ * Start the configured operation (audio streaming, volume enabled, etc.).
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_start(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session)
+#else
+static int cs4344_start(FAR struct audio_lowerhalf_s *dev)
+#endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ struct sched_param sparam;
+ struct mq_attr attr;
+ pthread_attr_t tattr;
+ FAR void *value;
+ int ret;
+
+ audinfo("Entry\n");
+
+ /* Create a message queue for the worker thread */
+
+ snprintf(priv->mqname, sizeof(priv->mqname), "/tmp/%X", priv);
+
+ attr.mq_maxmsg = 16;
+ attr.mq_msgsize = sizeof(struct audio_msg_s);
+ attr.mq_curmsgs = 0;
+ attr.mq_flags = 0;
+
+ priv->mq = mq_open(priv->mqname, O_RDWR | O_CREAT, 0644, &attr);
+ if (priv->mq == NULL)
+ {
+ /* Error creating message queue! */
+
+ auderr("ERROR: Couldn't allocate message queue\n");
+ return -ENOMEM;
+ }
+
+ /* Join any old worker thread we had created to prevent a memory leak */
+
+ if (priv->threadid != 0)
+ {
+ audinfo("Joining old thread\n");
+ pthread_join(priv->threadid, &value);
+ }
+
+ /* Start our thread for sending data to the device */
+
+ pthread_attr_init(&tattr);
+ sparam.sched_priority = sched_get_priority_max(SCHED_FIFO) - 3;
+ pthread_attr_setschedparam(&tattr, &sparam);
+ pthread_attr_setstacksize(&tattr, CONFIG_CS4344_WORKER_STACKSIZE);
+
+ audinfo("Starting worker thread\n");
+ ret = pthread_create(&priv->threadid, &tattr, cs4344_workerthread,
+ (pthread_addr_t)priv);
+ if (ret != OK)
+ {
+ auderr("ERROR: pthread_create failed: %d\n", ret);
+ }
+ else
+ {
+ pthread_setname_np(priv->threadid, "cs4344");
+ audinfo("Created worker thread\n");
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_stop
+ *
+ * Description:
+ * Stop the configured operation (audio streaming, volume disabled, etc.).
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+# ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_stop(FAR struct audio_lowerhalf_s *dev, FAR void *session)
+# else
+static int cs4344_stop(FAR struct audio_lowerhalf_s *dev)
+# endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ struct audio_msg_s term_msg;
+ FAR void *value;
+
+ /* Send a message to stop all audio streaming */
+
+ term_msg.msg_id = AUDIO_MSG_STOP;
+ term_msg.u.data = 0;
+ nxmq_send(priv->mq, (FAR const char *)&term_msg, sizeof(term_msg),
+ CONFIG_CS4344_MSG_PRIO);
+
+ /* Join the worker thread */
+
+ pthread_join(priv->threadid, &value);
+ priv->threadid = 0;
+
+ return OK;
+}
+#endif
+
+/****************************************************************************
+ * Name: cs4344_pause
+ *
+ * Description:
+ * Pauses the playback.
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME
+# ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_pause(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session)
+# else
+static int cs4344_pause(FAR struct audio_lowerhalf_s *dev)
+# endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+
+ if (priv->running && !priv->paused)
+ {
+ /* Disable interrupts to prevent us from suppling any more data */
+
+ priv->paused = true;
+ }
+
+ return OK;
+}
+#endif /* CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME */
+
+/****************************************************************************
+ * Name: cs4344_resume
+ *
+ * Description:
+ * Resumes the playback.
+ *
+ ****************************************************************************/
+
+#ifndef CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME
+# ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_resume(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session)
+# else
+static int cs4344_resume(FAR struct audio_lowerhalf_s *dev)
+# endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+
+ if (priv->running && priv->paused)
+ {
+ priv->paused = false;
+
+ /* Enable interrupts to allow sampling data */
+
+ cs4344_sendbuffer(priv);
+ }
+
+ return OK;
+}
+#endif /* CONFIG_AUDIO_EXCLUDE_PAUSE_RESUME */
+
+/****************************************************************************
+ * Name: cs4344_enqueuebuffer
+ *
+ * Description:
+ * Enqueue an Audio Pipeline Buffer for playback/ processing.
+ *
+ ****************************************************************************/
+
+static int cs4344_enqueuebuffer(FAR struct audio_lowerhalf_s *dev,
+ FAR struct ap_buffer_s *apb)
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ struct audio_msg_s term_msg;
+ int ret;
+
+ audinfo("Enqueueing: apb=%p curbyte=%d nbytes=%d flags=%04x\n",
+ apb, apb->curbyte, apb->nbytes, apb->flags);
+
+ ret = cs4344_takesem(&priv->pendsem);
+ if (ret < 0)
+ {
+ return ret;
+ }
+
+ /* Take a reference on the new audio buffer */
+
+ apb_reference(apb);
+
+ /* Add the new buffer to the tail of pending audio buffers */
+
+ apb->flags |= AUDIO_APB_OUTPUT_ENQUEUED;
+ dq_addlast(&apb->dq_entry, &priv->pendq);
+ cs4344_givesem(&priv->pendsem);
+
+ /* Send a message to the worker thread indicating that a new buffer has
+ * been enqueued. If mq is NULL, then the playing has not yet started.
+ * In that case we are just "priming the pump" and we don't need to send
+ * any message.
+ */
+
+ ret = OK;
+ if (priv->mq != NULL)
+ {
+ term_msg.msg_id = AUDIO_MSG_ENQUEUE;
+ term_msg.u.data = 0;
+
+ ret = nxmq_send(priv->mq, (FAR const char *)&term_msg,
+ sizeof(term_msg), CONFIG_CS4344_MSG_PRIO);
+ if (ret < 0)
+ {
+ auderr("ERROR: nxmq_send failed: %d\n", ret);
+ }
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_cancelbuffer
+ *
+ * Description:
+ * Called when an enqueued buffer is being cancelled.
+ *
+ ****************************************************************************/
+
+static int cs4344_cancelbuffer(FAR struct audio_lowerhalf_s *dev,
+ FAR struct ap_buffer_s *apb)
+{
+ audinfo("apb=%p\n", apb);
+ return OK;
+}
+
+/****************************************************************************
+ * Name: cs4344_ioctl
+ *
+ * Description:
+ * Perform a device ioctl
+ *
+ ****************************************************************************/
+
+static int cs4344_ioctl(FAR struct audio_lowerhalf_s *dev, int cmd,
+ unsigned long arg)
+{
+ int ret = OK;
+#ifdef CONFIG_AUDIO_DRIVER_SPECIFIC_BUFFERS
+ FAR struct ap_buffer_info_s *bufinfo;
+#endif
+
+ /* Deal with ioctls passed from the upper-half driver */
+
+ switch (cmd)
+ {
+ /* Check for AUDIOIOC_HWRESET ioctl. This ioctl is passed straight
+ * through from the upper-half audio driver.
+ */
+
+ case AUDIOIOC_HWRESET:
+ {
+ audinfo("AUDIOIOC_HWRESET:\n");
+ }
+ break;
+
+ /* Report our preferred buffer size and quantity */
+
+#ifdef CONFIG_AUDIO_DRIVER_SPECIFIC_BUFFERS
+ case AUDIOIOC_GETBUFFERINFO:
+ {
+ audinfo("AUDIOIOC_GETBUFFERINFO:\n");
+ bufinfo = (FAR struct ap_buffer_info_s *)arg;
+ bufinfo->buffer_size = CONFIG_CS4344_BUFFER_SIZE;
+ bufinfo->nbuffers = CONFIG_CS4344_NUM_BUFFERS;
+ }
+ break;
+#endif
+
+ default:
+ ret = -ENOTTY;
+ audinfo("Ignored\n");
+ break;
+ }
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_reserve
+ *
+ * Description:
+ * Reserves a session (the only one we have).
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int
+cs4344_reserve(FAR struct audio_lowerhalf_s *dev, FAR void **session)
+#else
+static int cs4344_reserve(FAR struct audio_lowerhalf_s *dev)
+#endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ int ret = OK;
+
+ /* Borrow the APBQ semaphore for thread sync */
+
+ ret = cs4344_takesem(&priv->pendsem);
+ if (ret < 0)
+ {
+ return ret;
+ }
+
+ if (priv->reserved)
+ {
+ ret = -EBUSY;
+ }
+ else
+ {
+ /* Initialize the session context */
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+ *session = NULL;
+#endif
+ priv->inflight = 0;
+ priv->running = false;
+ priv->paused = false;
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+ priv->terminating = false;
+#endif
+ priv->reserved = true;
+ }
+
+ cs4344_givesem(&priv->pendsem);
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_release
+ *
+ * Description:
+ * Releases the session (the only one we have).
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+static int cs4344_release(FAR struct audio_lowerhalf_s *dev,
+ FAR void *session)
+#else
+static int cs4344_release(FAR struct audio_lowerhalf_s *dev)
+#endif
+{
+ FAR struct cs4344_dev_s *priv = (FAR struct cs4344_dev_s *)dev;
+ FAR void *value;
+ int ret;
+
+ /* Join any old worker thread we had created to prevent a memory leak */
+
+ if (priv->threadid != 0)
+ {
+ pthread_join(priv->threadid, &value);
+ priv->threadid = 0;
+ }
+
+ /* Borrow the APBQ semaphore for thread sync */
+
+ ret = cs4344_forcetake(&priv->pendsem);
+
+ /* Really we should free any queued buffers here */
+
+ priv->reserved = false;
+ cs4344_givesem(&priv->pendsem);
+
+ return ret;
+}
+
+/****************************************************************************
+ * Name: cs4344_workerthread
+ *
+ * This is the thread that feeds data to the chip and keeps the audio
+ * stream going.
+ *
+ ****************************************************************************/
+
+static void *cs4344_workerthread(pthread_addr_t pvarg)
+{
+ FAR struct cs4344_dev_s *priv = (struct cs4344_dev_s *)pvarg;
+ struct audio_msg_s msg;
+ FAR struct ap_buffer_s *apb;
+ int msglen;
+ unsigned int prio;
+
+ audinfo("Entry\n");
+
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+ priv->terminating = false;
+#endif
+
+/* Mark ourself as running and make sure that CS4344 interrupts are
+ * enabled.
+ */
+
+ priv->running = true;
+
+ /* Loop as long as we are supposed to be running and as long as we have
+ * buffers in-flight.
+ */
+
+ while (priv->running || priv->inflight > 0)
+ {
+ /* Check if we have been asked to terminate. We have to check if we
+ * still have buffers in-flight. If we do, then we can't stop until
+ * birds come back to roost.
+ */
+
+ if (priv->terminating && priv->inflight <= 0)
+ {
+ /* We are IDLE. Break out of the loop and exit. */
+
+ break;
+ }
+ else
+ {
+ /* Check if we can send more audio buffers to the CS4344 */
+
+ cs4344_sendbuffer(priv);
+ }
+
+ /* Wait for messages from our message queue */
+
+ msglen = nxmq_receive(priv->mq, (FAR char *)&msg, sizeof(msg), &prio);
+
+ /* Handle the case when we return with no message */
+
+ if (msglen < sizeof(struct audio_msg_s))
+ {
+ auderr("ERROR: Message too small: %d\n", msglen);
+ continue;
+ }
+
+ /* Process the message */
+
+ switch (msg.msg_id)
+ {
+ /* The ISR has requested more data. We will catch this case at
+ * the top of the loop.
+ */
+
+ case AUDIO_MSG_DATA_REQUEST:
+ audinfo("AUDIO_MSG_DATA_REQUEST\n");
+ break;
+
+ /* Stop the playback */
+
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+ case AUDIO_MSG_STOP:
+
+ /* Indicate that we are terminating */
+
+ audinfo("AUDIO_MSG_STOP: Terminating\n");
+ priv->terminating = true;
+ break;
+#endif
+
+ /* We have a new buffer to send. We will catch this case at
+ * the top of the loop.
+ */
+
+ case AUDIO_MSG_ENQUEUE:
+ audinfo("AUDIO_MSG_ENQUEUE\n");
+ break;
+
+ /* We will wake up from the I2S callback with this message */
+
+ case AUDIO_MSG_COMPLETE:
+ audinfo("AUDIO_MSG_COMPLETE\n");
+ cs4344_returnbuffers(priv);
+ break;
+
+ default:
+ auderr("ERROR: Ignoring message ID %d\n", msg.msg_id);
+ break;
+ }
+ }
+
+ /* Reset the CS4344 hardware */
+
+ cs4344_reset(priv);
+
+ /* Return any pending buffers in our pending queue */
+
+ cs4344_forcetake(&priv->pendsem);
+ while ((apb = (FAR struct ap_buffer_s *)dq_remfirst(&priv->pendq)) != NULL)
+ {
+ /* Release our reference to the buffer */
+
+ apb_free(apb);
+
+ /* Send the buffer back up to the previous level. */
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_DEQUEUE, apb, OK, NULL);
+#else
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_DEQUEUE, apb, OK);
+#endif
+ }
+
+ cs4344_givesem(&priv->pendsem);
+
+ /* Return any pending buffers in our done queue */
+
+ cs4344_returnbuffers(priv);
+
+ /* Close the message queue */
+
+ mq_close(priv->mq);
+ mq_unlink(priv->mqname);
+ priv->mq = NULL;
+
+ /* Send an AUDIO_MSG_COMPLETE message to the client */
+
+#ifdef CONFIG_AUDIO_MULTI_SESSION
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_COMPLETE, NULL, OK, NULL);
+#else
+ priv->dev.upper(priv->dev.priv, AUDIO_CALLBACK_COMPLETE, NULL, OK);
+#endif
+
+ audinfo("Exit\n");
+ return NULL;
+}
+
+/****************************************************************************
+ * Name: cs4344_reset
+ *
+ * Description:
+ * Reset and re-initialize the CS4344
+ *
+ * Input Parameters:
+ * priv - A reference to the driver state structure
+ *
+ * Returned Value:
+ * None
+ *
+ ****************************************************************************/
+
+static void cs4344_reset(FAR struct cs4344_dev_s *priv)
+{
+ /* Put audio output back to its initial configuration */
+
+ priv->samprate = CS4344_DEFAULT_SAMPRATE;
+ priv->nchannels = CS4344_DEFAULT_NCHANNELS;
+ priv->bpsamp = CS4344_DEFAULT_BPSAMP;
+
+ /* Configure the FLL and the LRCLK */
+
+ cs4344_setbitrate(priv);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cs4344_initialize
+ *
+ * Description:
+ * Initialize the CS4344 device.
+ *
+ * Input Parameters:
+ * i2s - An I2S driver instance
+ *
+ * Returned Value:
+ * A new lower half audio interface for the CS4344 device is returned on
+ * success; NULL is returned on failure.
+ *
+ ****************************************************************************/
+
+FAR struct audio_lowerhalf_s *cs4344_initialize(FAR struct i2s_dev_s *i2s)
+{
+ FAR struct cs4344_dev_s *priv;
+
+ /* Sanity check */
+
+ DEBUGASSERT(i2s);
+
+ /* Allocate a CS4344 device structure */
+
+ priv = (FAR struct cs4344_dev_s *) kmm_zalloc(sizeof(struct cs4344_dev_s));
+ if (priv)
+ {
+ /* Initialize the CS4344 device structure. Since we used kmm_zalloc,
+ * only the non-zero elements of the structure need to be initialized.
+ */
+
+ priv->dev.ops = &g_audioops;
+ priv->i2s = i2s;
+
+ nxsem_init(&priv->pendsem, 0, 1);
+ dq_init(&priv->pendq);
+ dq_init(&priv->doneq);
+
+ /* Reset and reconfigure the CS4344 hardware */
+
+ cs4344_reset(priv);
+ return &priv->dev;
+ }
+
+ nxsem_destroy(&priv->pendsem);
+ kmm_free(priv);
+ return NULL;
+}
diff --git a/drivers/audio/cs4344.h b/drivers/audio/cs4344.h
new file mode 100644
index 0000000..44d914e
--- /dev/null
+++ b/drivers/audio/cs4344.h
@@ -0,0 +1,98 @@
+/****************************************************************************
+ * drivers/audio/cs4344.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __DRIVERS_AUDIO_CS4344_H
+#define __DRIVERS_AUDIO_CS4344_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <pthread.h>
+#include <mqueue.h>
+
+#include <nuttx/wqueue.h>
+#include <nuttx/fs/ioctl.h>
+
+#ifdef CONFIG_AUDIO
+
+/****************************************************************************
+ * Pre-Processor Definitions
+ ****************************************************************************/
+
+#define CS4344_DEFAULT_SAMPRATE 11025 /* Initial sample rate */
+#define CS4344_DEFAULT_NCHANNELS 1 /* Initial number of channels */
+#define CS4344_DEFAULT_BPSAMP 16 /* Initial bits per sample */
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+struct cs4344_dev_s
+{
+ /* We are an audio lower half driver (We are also the upper "half" of
+ * the CS4344 driver with respect to the board lower half driver).
+ *
+ * Terminology:
+ * Our "lower" half audio instances will be called dev for the publicly
+ * visible version and "priv" for the version that only this driver
+ * knows. From the point of view of this driver, it is the board lower
+ * "half" that is referred to as "lower".
+ */
+
+ struct audio_lowerhalf_s dev; /* CS4344 audio lower half (this device) */
+
+ /* Our specific driver data goes here */
+
+ FAR struct i2s_dev_s *i2s; /* I2S driver to use */
+ struct dq_queue_s pendq; /* Queue of pending buffers to be sent */
+ struct dq_queue_s doneq; /* Queue of sent buffers to be returned */
+ mqd_t mq; /* Message queue for receiving messages */
+ char mqname[16]; /* Our message queue name */
+ pthread_t threadid; /* ID of our thread */
+ uint32_t bitrate; /* Actual programmed bit rate */
+ sem_t pendsem; /* Protect pendq */
+ uint16_t samprate; /* Configured samprate (samples/sec) */
+ uint8_t nchannels; /* Number of channels (1 or 2) */
+ uint8_t bpsamp; /* Bits per sample (8 or 16) */
+ volatile uint8_t inflight; /* Number of audio buffers in-flight */
+ bool running; /* True: Worker thread is running */
+ bool paused; /* True: Playing is paused */
+ bool mute; /* True: Output is muted */
+#ifndef CONFIG_AUDIO_EXCLUDE_STOP
+ bool terminating; /* True: Stop requested */
+#endif
+ bool reserved; /* True: Device is reserved */
+ volatile int result; /* The result of the last transfer */
+};
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+#endif /* CONFIG_AUDIO */
+#endif /* __DRIVERS_AUDIO_CS4344_H */
diff --git a/include/nuttx/audio/cs4344.h b/include/nuttx/audio/cs4344.h
new file mode 100644
index 0000000..38b5fc9
--- /dev/null
+++ b/include/nuttx/audio/cs4344.h
@@ -0,0 +1,141 @@
+/****************************************************************************
+ * include/nuttx/audio/cs4344.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership. The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+#ifndef __INCLUDE_NUTTX_AUDIO_CS4344_H
+#define __INCLUDE_NUTTX_AUDIO_CS4344_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <nuttx/irq.h>
+
+#ifdef CONFIG_AUDIO_CS4344
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Configuration ************************************************************
+ *
+ * CONFIG_AUDIO_CS4344 - Enables CS4344 support
+ * CONFIG_CS4344_INFLIGHT - Maximum number of buffers that the CS4344
+ * driver will send to the I2S driver before any have completed.
+ * CONFIG_CS4344_MSG_PRIO - Priority of messages sent to the CS4344
+ * worker thread.
+ * CONFIG_CS4344_BUFFER_SIZE - Preferred buffer size
+ * CONFIG_CS4344_NUM_BUFFERS - Preferred number of buffers
+ * CONFIG_CS4344_WORKER_STACKSIZE - Stack size to use when creating the the
+ * CS4344 worker thread.
+ * CONFIG_CS4344_REGDUMP - Enable logic to dump all CS4344 registers to
+ * the SYSLOG device.
+ */
+
+/* Pre-requisites */
+
+#ifndef CONFIG_AUDIO
+# error CONFIG_AUDIO is required for audio subsystem support
+#endif
+
+#ifndef CONFIG_I2S
+# error CONFIG_I2S is required by the CS4344 driver
+#endif
+
+#ifndef CONFIG_SCHED_WORKQUEUE
+# error CONFIG_SCHED_WORKQUEUE is required by the CS4344 driver
+#endif
+
+/* Default configuration values */
+
+#ifndef CONFIG_CS4344_INFLIGHT
+# define CONFIG_CS4344_INFLIGHT 2
+#endif
+
+#if CONFIG_CS4344_INFLIGHT > 255
+# error CONFIG_CS4344_INFLIGHT must fit in a uint8_t
+#endif
+
+#ifndef CONFIG_CS4344_MSG_PRIO
+# define CONFIG_CS4344_MSG_PRIO 1
+#endif
+
+#ifndef CONFIG_CS4344_BUFFER_SIZE
+# define CONFIG_CS4344_BUFFER_SIZE 8192
+#endif
+
+#ifndef CONFIG_CS4344_NUM_BUFFERS
+# define CONFIG_CS4344_NUM_BUFFERS 4
+#endif
+
+#ifndef CONFIG_CS4344_WORKER_STACKSIZE
+# define CONFIG_CS4344_WORKER_STACKSIZE 768
+#endif
+
+/****************************************************************************
+ * Public Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+#ifdef __cplusplus
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: cs4344_initialize
+ *
+ * Description:
+ * Initialize the CS4344 device.
+ *
+ * Input Parameters:
+ * i2s - An I2S driver instance
+ * lower - Persistent board configuration data
+ *
+ * Returned Value:
+ * A new lower half audio interface for the CS4344 device is returned on
+ * success; NULL is returned on failure.
+ *
+ ****************************************************************************/
+
+struct i2s_dev_s; /* Forward reference. Defined in include/nuttx/audio/i2s.h */
+struct audio_lowerhalf_s; /* Forward reference. Defined in nuttx/audio/audio.h */
+
+FAR struct audio_lowerhalf_s * cs4344_initialize(FAR struct i2s_dev_s *i2s);
+
+#undef EXTERN
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* CONFIG_AUDIO_CS4344 */
+#endif /* __INCLUDE_NUTTX_AUDIO_CS4344_H */