[libsigrok.git] / hardware / alsa / alsa.c

/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include "config.h" /* Must come before sigrok.h */
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sigrok.h>
#include <sigrok-internal.h>
#include <alsa/asoundlib.h>

#define NUM_PROBES 2
#define SAMPLE_WIDTH 16
#define AUDIO_DEV "plughw:0,0"

static int capabilities[] = {
	SR_HWCAP_SAMPLERATE,
	SR_HWCAP_LIMIT_SAMPLES,
	SR_HWCAP_CONTINUOUS,
};

static GSList *device_instances = NULL;

struct alsa {
	uint64_t cur_rate;
	uint64_t limit_samples;
	snd_pcm_t *capture_handle;
	snd_pcm_hw_params_t *hw_params;
	gpointer session_id;
};

static int hw_init(const char *deviceinfo)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;

	/* Avoid compiler warnings. */
	deviceinfo = deviceinfo;

	if (!(alsa = g_try_malloc0(sizeof(struct alsa)))) {
		sr_err("alsa: %s: alsa malloc failed", __func__);
		return 0;
	}

	sdi = sr_device_instance_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL);
	if (!sdi)
		goto free_alsa;

	sdi->priv = alsa;

	device_instances = g_slist_append(device_instances, sdi);

	return 1;
free_alsa:
	g_free(alsa);
	return 0;
}

static int hw_opendev(int device_index)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;
	int err;

	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
		return SR_ERR;
	alsa = sdi->priv;

	err = snd_pcm_open(&alsa->capture_handle, AUDIO_DEV,
					SND_PCM_STREAM_CAPTURE, 0);
	if (err < 0) {
		sr_warn("cannot open audio device %s (%s)", AUDIO_DEV,
			snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_hw_params_malloc(&alsa->hw_params);
	if (err < 0) {
		sr_warn("cannot allocate hardware parameter structure (%s)",
			snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_hw_params_any(alsa->capture_handle, alsa->hw_params);
	if (err < 0) {
		sr_warn("cannot initialize hardware parameter structure (%s)",
				snd_strerror(err));
		return SR_ERR;
	}

	return SR_OK;
}

static int hw_closedev(int device_index)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;

	if (!(sdi = sr_get_device_instance(device_instances, device_index))) {
		sr_err("alsa: %s: sdi was NULL", __func__);
		return SR_ERR; /* TODO: SR_ERR_ARG? */
	}

	if (!(alsa = sdi->priv)) {
		sr_err("alsa: %s: sdi->priv was NULL", __func__);
		return SR_ERR; /* TODO: SR_ERR_ARG? */
	}

	// TODO: Return values of snd_*?
	if (alsa->hw_params)
		snd_pcm_hw_params_free(alsa->hw_params);
	if (alsa->capture_handle)
		snd_pcm_close(alsa->capture_handle);

	return SR_OK;
}

static void hw_cleanup(void)
{
	struct sr_device_instance *sdi;

	if (!(sdi = sr_get_device_instance(device_instances, 0)))
		return;

	free(sdi->priv);
	sr_device_instance_free(sdi);
}

static void *hw_get_device_info(int device_index, int device_info_id)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;
	void *info = NULL;

	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
		return NULL;
	alsa = sdi->priv;

	switch (device_info_id) {
	case SR_DI_INSTANCE:
		info = sdi;
		break;
	case SR_DI_NUM_PROBES:
		info = GINT_TO_POINTER(NUM_PROBES);
		break;
	case SR_DI_CUR_SAMPLERATE:
		info = &alsa->cur_rate;
		break;
	// case SR_DI_PROBE_TYPE:
	// 	info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
	// 	break;
	}

	return info;
}

static int hw_get_status(int device_index)
{
	/* Avoid compiler warnings. */
	device_index = device_index;

	return SR_ST_ACTIVE;
}

static int *hw_get_capabilities(void)
{
	return capabilities;
}

static int hw_set_configuration(int device_index, int capability, void *value)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;

	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
		return SR_ERR;
	alsa = sdi->priv;

	switch (capability) {
	case SR_HWCAP_PROBECONFIG:
		return SR_OK;
	case SR_HWCAP_SAMPLERATE:
		alsa->cur_rate = *(uint64_t *) value;
		return SR_OK;
	case SR_HWCAP_LIMIT_SAMPLES:
		alsa->limit_samples = *(uint64_t *) value;
		return SR_OK;
	default:
		return SR_ERR;
	}
}

static int receive_data(int fd, int revents, void *user_data)
{
	struct sr_device_instance *sdi = user_data;
	struct alsa *alsa = sdi->priv;
	struct sr_datafeed_packet packet;
	struct sr_analog_sample *sample;
	unsigned int sample_size = sizeof(struct sr_analog_sample) +
		(NUM_PROBES * sizeof(struct sr_analog_probe));
	char *outb;
	char inb[4096];
	int i, x, count;

	fd = fd;
	revents = revents;

	do {
		memset(inb, 0, sizeof(inb));
		count = snd_pcm_readi(alsa->capture_handle, inb,
			MIN(4096/4, alsa->limit_samples));
		if (count < 1) {
			sr_warn("Failed to read samples");
			return FALSE;
		}

		if (!(outb = g_try_malloc(sample_size * count))) {
			sr_err("alsa: %s: outb malloc failed", __func__);
			return FALSE;
		}

		for (i = 0; i < count; i++) {
			sample = (struct sr_analog_sample *)
						(outb + (i * sample_size));
			sample->num_probes = NUM_PROBES;

			for (x = 0; x < NUM_PROBES; x++) {
				sample->probes[x].val =
					*(uint16_t *) (inb + (i * 4) + (x * 2));
				sample->probes[x].val &= ((1 << 16) - 1);
				sample->probes[x].res = 16;
			}
		}

		packet.type = SR_DF_ANALOG;
		packet.length = count * sample_size;
		packet.unitsize = sample_size;
		packet.payload = outb;
		sr_session_bus(user_data, &packet);
		g_free(outb);
		alsa->limit_samples -= count;

	} while (alsa->limit_samples > 0);

	packet.type = SR_DF_END;
	sr_session_bus(user_data, &packet);

	return TRUE;
}

static int hw_start_acquisition(int device_index, gpointer session_device_id)
{
	struct sr_device_instance *sdi;
	struct alsa *alsa;
	struct sr_datafeed_packet packet;
	struct sr_datafeed_header header;
	struct pollfd *ufds;
	int count;
	int err;

	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
		return SR_ERR;
	alsa = sdi->priv;

	err = snd_pcm_hw_params_set_access(alsa->capture_handle,
			alsa->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	if (err < 0) {
		sr_warn("cannot set access type (%s)", snd_strerror(err));
		return SR_ERR;
	}

	/* FIXME: Hardcoded for 16bits */
	err = snd_pcm_hw_params_set_format(alsa->capture_handle,
			alsa->hw_params, SND_PCM_FORMAT_S16_LE);
	if (err < 0) {
		sr_warn("cannot set sample format (%s)", snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_hw_params_set_rate_near(alsa->capture_handle,
			alsa->hw_params, (unsigned int *) &alsa->cur_rate, 0);
	if (err < 0) {
		sr_warn("cannot set sample rate (%s)", snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_hw_params_set_channels(alsa->capture_handle,
			alsa->hw_params, NUM_PROBES);
	if (err < 0) {
		sr_warn("cannot set channel count (%s)", snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_hw_params(alsa->capture_handle, alsa->hw_params);
	if (err < 0) {
		sr_warn("cannot set parameters (%s)", snd_strerror(err));
		return SR_ERR;
	}

	err = snd_pcm_prepare(alsa->capture_handle);
	if (err < 0) {
		sr_warn("cannot prepare audio interface for use (%s)",
				snd_strerror(err));
		return SR_ERR;
	}

	count = snd_pcm_poll_descriptors_count(alsa->capture_handle);
	if (count < 1) {
		sr_warn("Unable to obtain poll descriptors count");
		return SR_ERR;
	}

	if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
		sr_warn("alsa: %s: ufds malloc failed", __func__);
		return SR_ERR_MALLOC;
	}

	err = snd_pcm_poll_descriptors(alsa->capture_handle, ufds, count);
	if (err < 0) {
		sr_warn("Unable to obtain poll descriptors (%s)",
				snd_strerror(err));
		g_free(ufds);
		return SR_ERR;
	}

	alsa->session_id = session_device_id;
	sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);

	packet.type = SR_DF_HEADER;
	packet.length = sizeof(struct sr_datafeed_header);
	packet.payload = (unsigned char *) &header;
	header.feed_version = 1;
	gettimeofday(&header.starttime, NULL);
	header.samplerate = alsa->cur_rate;
	header.num_analog_probes = NUM_PROBES;
	header.num_logic_probes = 0;
	header.protocol_id = SR_PROTO_RAW;
	sr_session_bus(session_device_id, &packet);
	g_free(ufds);

	return SR_OK;
}

static void hw_stop_acquisition(int device_index, gpointer session_device_id)
{
	/* Avoid compiler warnings. */
	device_index = device_index;
	session_device_id = session_device_id;
}

struct sr_device_plugin alsa_plugin_info = {
	.name = "alsa",
	.longname = "ALSA driver",
	.api_version = 1,
	.init = hw_init,
	.cleanup = hw_cleanup,
	.opendev = hw_opendev,
	.closedev = hw_closedev,
	.get_device_info = hw_get_device_info,
	.get_status = hw_get_status,
	.get_capabilities = hw_get_capabilities,
	.set_configuration = hw_set_configuration,
	.start_acquisition = hw_start_acquisition,
	.stop_acquisition = hw_stop_acquisition,
};
Commit	Line	Data
6ed4f044 DR	1	/*
	2	* This file is part of the sigrok project.
	3	*
	4	* Copyright (C) 2011 Daniel Ribeiro <drwyrm@gmail.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License as published by
	8	* the Free Software Foundation; either version 2 of the License, or
	9	* (at your option) any later version.
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
92b3101c	21	#include "config.h" /* Must come before sigrok.h */
6ed4f044 DR	22	#include <stdlib.h>
	23	#include <unistd.h>
	24	#include <string.h>
	25	#include <sigrok.h>
92b3101c	26	#include <sigrok-internal.h>
6ed4f044	27	#include <alsa/asoundlib.h>
6ed4f044 DR	28
	29	#define NUM_PROBES 2
	30	#define SAMPLE_WIDTH 16
	31	#define AUDIO_DEV "plughw:0,0"
	32
	33	static int capabilities[] = {
5a2326a7 UH	34	SR_HWCAP_SAMPLERATE,
	35	SR_HWCAP_LIMIT_SAMPLES,
	36	SR_HWCAP_CONTINUOUS,
6ed4f044 DR	37	};
	38
	39	static GSList *device_instances = NULL;
	40
	41	struct alsa {
	42	uint64_t cur_rate;
	43	uint64_t limit_samples;
	44	snd_pcm_t *capture_handle;
	45	snd_pcm_hw_params_t *hw_params;
	46	gpointer session_id;
	47	};
	48
54ac5277	49	static int hw_init(const char *deviceinfo)
6ed4f044	50	{
a00ba012	51	struct sr_device_instance *sdi;
6ed4f044 DR	52	struct alsa *alsa;
	53
	54	/* Avoid compiler warnings. */
	55	deviceinfo = deviceinfo;
	56
92b3101c UH	57	if (!(alsa = g_try_malloc0(sizeof(struct alsa)))) {
92b3101c UH	58	sr_err("alsa: %s: alsa malloc failed", __func__);
6ed4f044	59	return 0;
92b3101c	60	}
6ed4f044	61
5a2326a7	62	sdi = sr_device_instance_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL);
6ed4f044 DR	63	if (!sdi)
	64	goto free_alsa;
	65
	66	sdi->priv = alsa;
	67
	68	device_instances = g_slist_append(device_instances, sdi);
	69
	70	return 1;
	71	free_alsa:
92b3101c	72	g_free(alsa);
6ed4f044 DR	73	return 0;
	74	}
	75
	76	static int hw_opendev(int device_index)
	77	{
a00ba012	78	struct sr_device_instance *sdi;
6ed4f044 DR	79	struct alsa *alsa;
	80	int err;
	81
d32d961d	82	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
e46b8fb1	83	return SR_ERR;
6ed4f044 DR	84	alsa = sdi->priv;
	85
	86	err = snd_pcm_open(&alsa->capture_handle, AUDIO_DEV,
	87	SND_PCM_STREAM_CAPTURE, 0);
	88	if (err < 0) {
b08024a8	89	sr_warn("cannot open audio device %s (%s)", AUDIO_DEV,
92b3101c	90	snd_strerror(err));
e46b8fb1	91	return SR_ERR;
6ed4f044 DR	92	}
	93
	94	err = snd_pcm_hw_params_malloc(&alsa->hw_params);
	95	if (err < 0) {
b08024a8	96	sr_warn("cannot allocate hardware parameter structure (%s)",
92b3101c	97	snd_strerror(err));
e46b8fb1	98	return SR_ERR;
6ed4f044 DR	99	}
	100
	101	err = snd_pcm_hw_params_any(alsa->capture_handle, alsa->hw_params);
	102	if (err < 0) {
b08024a8	103	sr_warn("cannot initialize hardware parameter structure (%s)",
6ed4f044	104	snd_strerror(err));
e46b8fb1	105	return SR_ERR;
6ed4f044 DR	106	}
6ed4f044 DR	107
e46b8fb1	108	return SR_OK;
6ed4f044 DR	109	}
6ed4f044 DR	110
697785d1	111	static int hw_closedev(int device_index)
6ed4f044	112	{
a00ba012	113	struct sr_device_instance *sdi;
6ed4f044 DR	114	struct alsa *alsa;
6ed4f044 DR	115
697785d1 UH	116	if (!(sdi = sr_get_device_instance(device_instances, device_index))) {
	117	sr_err("alsa: %s: sdi was NULL", __func__);
	118	return SR_ERR; /* TODO: SR_ERR_ARG? */
	119	}
6ed4f044	120
697785d1 UH	121	if (!(alsa = sdi->priv)) {
	122	sr_err("alsa: %s: sdi->priv was NULL", __func__);
	123	return SR_ERR; /* TODO: SR_ERR_ARG? */
	124	}
	125
	126	// TODO: Return values of snd_*?
6ed4f044 DR	127	if (alsa->hw_params)
	128	snd_pcm_hw_params_free(alsa->hw_params);
	129	if (alsa->capture_handle)
	130	snd_pcm_close(alsa->capture_handle);
697785d1 UH	131
697785d1 UH	132	return SR_OK;
6ed4f044 DR	133	}
	134
	135	static void hw_cleanup(void)
	136	{
a00ba012	137	struct sr_device_instance *sdi;
6ed4f044	138
d32d961d	139	if (!(sdi = sr_get_device_instance(device_instances, 0)))
6ed4f044 DR	140	return;
	141
	142	free(sdi->priv);
a00ba012	143	sr_device_instance_free(sdi);
6ed4f044 DR	144	}
	145
	146	static void *hw_get_device_info(int device_index, int device_info_id)
	147	{
a00ba012	148	struct sr_device_instance *sdi;
6ed4f044 DR	149	struct alsa *alsa;
	150	void *info = NULL;
	151
d32d961d	152	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
6ed4f044 DR	153	return NULL;
	154	alsa = sdi->priv;
	155
	156	switch (device_info_id) {
5a2326a7	157	case SR_DI_INSTANCE:
6ed4f044 DR	158	info = sdi;
6ed4f044 DR	159	break;
5a2326a7	160	case SR_DI_NUM_PROBES:
6ed4f044 DR	161	info = GINT_TO_POINTER(NUM_PROBES);
6ed4f044 DR	162	break;
5a2326a7	163	case SR_DI_CUR_SAMPLERATE:
6ed4f044 DR	164	info = &alsa->cur_rate;
6ed4f044 DR	165	break;
5a2326a7 UH	166	// case SR_DI_PROBE_TYPE:
5a2326a7 UH	167	// info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
da692373	168	// break;
6ed4f044 DR	169	}
	170
	171	return info;
	172	}
	173
	174	static int hw_get_status(int device_index)
	175	{
	176	/* Avoid compiler warnings. */
	177	device_index = device_index;
	178
5a2326a7	179	return SR_ST_ACTIVE;
6ed4f044 DR	180	}
	181
	182	static int *hw_get_capabilities(void)
	183	{
	184	return capabilities;
	185	}
	186
	187	static int hw_set_configuration(int device_index, int capability, void *value)
	188	{
a00ba012	189	struct sr_device_instance *sdi;
6ed4f044 DR	190	struct alsa *alsa;
6ed4f044 DR	191
d32d961d	192	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
e46b8fb1	193	return SR_ERR;
6ed4f044 DR	194	alsa = sdi->priv;
	195
	196	switch (capability) {
5a2326a7	197	case SR_HWCAP_PROBECONFIG:
e46b8fb1	198	return SR_OK;
5a2326a7	199	case SR_HWCAP_SAMPLERATE:
6ed4f044	200	alsa->cur_rate = (uint64_t ) value;
e46b8fb1	201	return SR_OK;
5a2326a7	202	case SR_HWCAP_LIMIT_SAMPLES:
6ed4f044	203	alsa->limit_samples = (uint64_t ) value;
e46b8fb1	204	return SR_OK;
6ed4f044	205	default:
e46b8fb1	206	return SR_ERR;
6ed4f044 DR	207	}
	208	}
	209
6ed4f044 DR	210	static int receive_data(int fd, int revents, void *user_data)
6ed4f044 DR	211	{
a00ba012	212	struct sr_device_instance *sdi = user_data;
6ed4f044	213	struct alsa *alsa = sdi->priv;
b9c735a2	214	struct sr_datafeed_packet packet;
809c5f20 UH	215	struct sr_analog_sample *sample;
	216	unsigned int sample_size = sizeof(struct sr_analog_sample) +
	217	(NUM_PROBES * sizeof(struct sr_analog_probe));
58330ab8 DR	218	char *outb;
	219	char inb[4096];
	220	int i, x, count;
	221
cdbc51d9 DR	222	fd = fd;
	223	revents = revents;
	224
58330ab8 DR	225	do {
	226	memset(inb, 0, sizeof(inb));
	227	count = snd_pcm_readi(alsa->capture_handle, inb,
	228	MIN(4096/4, alsa->limit_samples));
	229	if (count < 1) {
b08024a8	230	sr_warn("Failed to read samples");
58330ab8 DR	231	return FALSE;
58330ab8 DR	232	}
6ed4f044	233
92b3101c UH	234	if (!(outb = g_try_malloc(sample_size * count))) {
92b3101c UH	235	sr_err("alsa: %s: outb malloc failed", __func__);
6ed4f044	236	return FALSE;
92b3101c	237	}
58330ab8 DR	238
58330ab8 DR	239	for (i = 0; i < count; i++) {
809c5f20	240	sample = (struct sr_analog_sample *)
58330ab8 DR	241	(outb + (i * sample_size));
	242	sample->num_probes = NUM_PROBES;
	243
	244	for (x = 0; x < NUM_PROBES; x++) {
	245	sample->probes[x].val =
	246	(uint16_t ) (inb + (i * 4) + (x * 2));
	247	sample->probes[x].val &= ((1 << 16) - 1);
	248	sample->probes[x].res = 16;
	249	}
6ed4f044	250	}
58330ab8	251
5a2326a7	252	packet.type = SR_DF_ANALOG;
58330ab8 DR	253	packet.length = count * sample_size;
	254	packet.unitsize = sample_size;
	255	packet.payload = outb;
8a2efef2	256	sr_session_bus(user_data, &packet);
92b3101c	257	g_free(outb);
58330ab8 DR	258	alsa->limit_samples -= count;
	259
	260	} while (alsa->limit_samples > 0);
	261
5a2326a7	262	packet.type = SR_DF_END;
8a2efef2	263	sr_session_bus(user_data, &packet);
6ed4f044 DR	264
	265	return TRUE;
	266	}
	267
	268	static int hw_start_acquisition(int device_index, gpointer session_device_id)
	269	{
a00ba012	270	struct sr_device_instance *sdi;
6ed4f044	271	struct alsa *alsa;
b9c735a2 UH	272	struct sr_datafeed_packet packet;
b9c735a2 UH	273	struct sr_datafeed_header header;
6ed4f044 DR	274	struct pollfd *ufds;
	275	int count;
	276	int err;
	277
d32d961d	278	if (!(sdi = sr_get_device_instance(device_instances, device_index)))
e46b8fb1	279	return SR_ERR;
6ed4f044 DR	280	alsa = sdi->priv;
	281
	282	err = snd_pcm_hw_params_set_access(alsa->capture_handle,
	283	alsa->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	284	if (err < 0) {
b08024a8	285	sr_warn("cannot set access type (%s)", snd_strerror(err));
e46b8fb1	286	return SR_ERR;
6ed4f044 DR	287	}
	288
	289	/* FIXME: Hardcoded for 16bits */
	290	err = snd_pcm_hw_params_set_format(alsa->capture_handle,
	291	alsa->hw_params, SND_PCM_FORMAT_S16_LE);
	292	if (err < 0) {
b08024a8	293	sr_warn("cannot set sample format (%s)", snd_strerror(err));
e46b8fb1	294	return SR_ERR;
6ed4f044 DR	295	}
	296
	297	err = snd_pcm_hw_params_set_rate_near(alsa->capture_handle,
	298	alsa->hw_params, (unsigned int *) &alsa->cur_rate, 0);
	299	if (err < 0) {
b08024a8	300	sr_warn("cannot set sample rate (%s)", snd_strerror(err));
e46b8fb1	301	return SR_ERR;
6ed4f044 DR	302	}
	303
	304	err = snd_pcm_hw_params_set_channels(alsa->capture_handle,
	305	alsa->hw_params, NUM_PROBES);
	306	if (err < 0) {
b08024a8	307	sr_warn("cannot set channel count (%s)", snd_strerror(err));
e46b8fb1	308	return SR_ERR;
6ed4f044 DR	309	}
	310
	311	err = snd_pcm_hw_params(alsa->capture_handle, alsa->hw_params);
	312	if (err < 0) {
b08024a8	313	sr_warn("cannot set parameters (%s)", snd_strerror(err));
e46b8fb1	314	return SR_ERR;
6ed4f044 DR	315	}
	316
	317	err = snd_pcm_prepare(alsa->capture_handle);
	318	if (err < 0) {
b08024a8	319	sr_warn("cannot prepare audio interface for use (%s)",
6ed4f044	320	snd_strerror(err));
e46b8fb1	321	return SR_ERR;
6ed4f044 DR	322	}
	323
	324	count = snd_pcm_poll_descriptors_count(alsa->capture_handle);
	325	if (count < 1) {
b08024a8	326	sr_warn("Unable to obtain poll descriptors count");
e46b8fb1	327	return SR_ERR;
6ed4f044 DR	328	}
6ed4f044 DR	329
92b3101c UH	330	if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
92b3101c UH	331	sr_warn("alsa: %s: ufds malloc failed", __func__);
e46b8fb1	332	return SR_ERR_MALLOC;
92b3101c	333	}
6ed4f044 DR	334
	335	err = snd_pcm_poll_descriptors(alsa->capture_handle, ufds, count);
	336	if (err < 0) {
b08024a8	337	sr_warn("Unable to obtain poll descriptors (%s)",
6ed4f044	338	snd_strerror(err));
92b3101c	339	g_free(ufds);
e46b8fb1	340	return SR_ERR;
6ed4f044 DR	341	}
	342
	343	alsa->session_id = session_device_id;
6f1be0a2	344	sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
6ed4f044	345
5a2326a7	346	packet.type = SR_DF_HEADER;
b9c735a2	347	packet.length = sizeof(struct sr_datafeed_header);
6ed4f044 DR	348	packet.payload = (unsigned char *) &header;
	349	header.feed_version = 1;
	350	gettimeofday(&header.starttime, NULL);
	351	header.samplerate = alsa->cur_rate;
	352	header.num_analog_probes = NUM_PROBES;
	353	header.num_logic_probes = 0;
5a2326a7	354	header.protocol_id = SR_PROTO_RAW;
8a2efef2	355	sr_session_bus(session_device_id, &packet);
92b3101c	356	g_free(ufds);
6ed4f044	357
e46b8fb1	358	return SR_OK;
6ed4f044 DR	359	}
	360
	361	static void hw_stop_acquisition(int device_index, gpointer session_device_id)
	362	{
	363	/* Avoid compiler warnings. */
	364	device_index = device_index;
	365	session_device_id = session_device_id;
	366	}
	367
5c2d46d1	368	struct sr_device_plugin alsa_plugin_info = {
e519ba86 UH	369	.name = "alsa",
	370	.longname = "ALSA driver",
	371	.api_version = 1,
	372	.init = hw_init,
	373	.cleanup = hw_cleanup,
86f5e3d8 UH	374	.opendev = hw_opendev,
86f5e3d8 UH	375	.closedev = hw_closedev,
e519ba86 UH	376	.get_device_info = hw_get_device_info,
	377	.get_status = hw_get_status,
	378	.get_capabilities = hw_get_capabilities,
	379	.set_configuration = hw_set_configuration,
	380	.start_acquisition = hw_start_acquisition,
	381	.stop_acquisition = hw_stop_acquisition,
6ed4f044	382	};