[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
 */

/* Note: This driver doesn't compile, analog support in sigrok is WIP. */

#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <alsa/asoundlib.h>
#include "libsigrok.h"
#include "libsigrok-internal.h"

/* Message logging helpers with driver-specific prefix string. */
#define DRIVER_LOG_DOMAIN "alsa: "
#define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args)
#define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args)
#define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args)
#define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args)
#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)

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

struct sr_analog_probe {
	uint8_t att;
	uint8_t res;    /* Needs to be a power of 2, FIXME */
	uint16_t val;   /* Max hardware ADC width is 16bits */
};

struct sr_analog_sample {
	uint8_t num_probes; /* Max hardware probes is 256 */
	struct sr_analog_probe probes[];
};

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

/* TODO: Which probe names/numbers to use? */
static const char *probe_names[NUM_PROBES + 1] = {
	"0",
	"1",
	NULL,
};

static GSList *dev_insts = NULL;

/* Private, per-device-instance driver context. */
struct context {
	uint64_t cur_rate;
	uint64_t limit_samples;
	snd_pcm_t *capture_handle;
	snd_pcm_hw_params_t *hw_params;
	void *session_dev_id;
};

static int hw_init(struct sr_context *sr_ctx)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;

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

	if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL))) {
		sr_err("%s: sdi was NULL", __func__);
		goto free_ctx;
	}

	sdi->priv = ctx;

	dev_insts = g_slist_append(dev_insts, sdi);

	return 1;

free_ctx:
	g_free(ctx);
	return 0;
}

static int hw_dev_open(int dev_index)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;
	int ret;

	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
		return SR_ERR;
	ctx = sdi->priv;

	ret = snd_pcm_open(&ctx->capture_handle, AUDIO_DEV,
			   SND_PCM_STREAM_CAPTURE, 0);
	if (ret < 0) {
		sr_err("Can't open audio device %s (%s).", AUDIO_DEV,
		       snd_strerror(ret));
		return SR_ERR;
	}

	ret = snd_pcm_hw_params_malloc(&ctx->hw_params);
	if (ret < 0) {
		sr_err("Can't allocate hardware parameter structure (%s).",
		       snd_strerror(ret));
		return SR_ERR_MALLOC;
	}

	ret = snd_pcm_hw_params_any(ctx->capture_handle, ctx->hw_params);
	if (ret < 0) {
		sr_err("Can't initialize hardware parameter structure (%s)",
		       snd_strerror(ret));
		return SR_ERR;
	}

	return SR_OK;
}

static int hw_dev_close(int dev_index)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;

	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
		sr_err("%s: sdi was NULL", __func__);
		return SR_ERR_BUG;
	}

	if (!(ctx = sdi->priv)) {
		sr_err("%s: sdi->priv was NULL", __func__);
		return SR_ERR_BUG;
	}

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

	return SR_OK;
}

static int hw_cleanup(void)
{
	struct sr_dev_inst *sdi;

	if (!(sdi = sr_dev_inst_get(dev_insts, 0))) {
		sr_err("%s: sdi was NULL", __func__);
		return SR_ERR_BUG;
	}

	sr_dev_inst_free(sdi);

	return SR_OK;
}

static const void *hw_dev_info_get(int dev_index, int dev_info_id)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;
	void *info = NULL;

	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
		return NULL;
	ctx = sdi->priv;

	switch (dev_info_id) {
	case SR_DI_INST:
		info = sdi;
		break;
	case SR_DI_NUM_PROBES:
		info = GINT_TO_POINTER(NUM_PROBES);
		break;
	case SR_DI_PROBE_NAMES:
		info = probe_names;
		break;
	case SR_DI_CUR_SAMPLERATE:
		info = &ctx->cur_rate;
		break;
	// case SR_DI_PROBE_TYPE:
	// 	info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
	// 	break;
	}

	return info;
}

static int hw_dev_status_get(int dev_index)
{
	(void)dev_index;

	return SR_ST_ACTIVE;
}

static const int *hw_hwcap_get_all(void)
{
	return hwcaps;
}

static int hw_dev_config_set(int dev_index, int hwcap, const void *value)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;

	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
		return SR_ERR;
	ctx = sdi->priv;

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

static int receive_data(int fd, int revents, void *cb_data)
{
	struct sr_dev_inst *sdi = cb_data;
	struct context *ctx = 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(ctx->capture_handle, inb,
			MIN(4096 / 4, ctx->limit_samples));
		if (count < 1) {
			sr_err("Failed to read samples");
			return FALSE;
		}

		if (!(outb = g_try_malloc(sample_size * count))) {
			sr_err("%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_send(sdi, &packet);
		g_free(outb);
		ctx->limit_samples -= count;

	} while (ctx->limit_samples > 0);

	packet.type = SR_DF_END;
	sr_session_send(sdi, &packet);

	return TRUE;
}

static int hw_dev_acquisition_start(int dev_index, void *cb_data)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;
	struct sr_datafeed_packet packet;
	struct sr_datafeed_header header;
	struct pollfd *ufds;
	int count;
	int ret;

	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
		return SR_ERR;
	ctx = sdi->priv;

	ret = snd_pcm_hw_params_set_access(ctx->capture_handle,
			ctx->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	if (ret < 0) {
		sr_err("Can't set access type (%s).", snd_strerror(ret));
		return SR_ERR;
	}

	/* FIXME: Hardcoded for 16bits */
	ret = snd_pcm_hw_params_set_format(ctx->capture_handle,
			ctx->hw_params, SND_PCM_FORMAT_S16_LE);
	if (ret < 0) {
		sr_err("Can't set sample format (%s).", snd_strerror(ret));
		return SR_ERR;
	}

	ret = snd_pcm_hw_params_set_rate_near(ctx->capture_handle,
			ctx->hw_params, (unsigned int *)&ctx->cur_rate, 0);
	if (ret < 0) {
		sr_err("Can't set sample rate (%s).", snd_strerror(ret));
		return SR_ERR;
	}

	ret = snd_pcm_hw_params_set_channels(ctx->capture_handle,
			ctx->hw_params, NUM_PROBES);
	if (ret < 0) {
		sr_err("Can't set channel count (%s).", snd_strerror(ret));
		return SR_ERR;
	}

	ret = snd_pcm_hw_params(ctx->capture_handle, ctx->hw_params);
	if (ret < 0) {
		sr_err("Can't set parameters (%s).", snd_strerror(ret));
		return SR_ERR;
	}

	ret = snd_pcm_prepare(ctx->capture_handle);
	if (ret < 0) {
		sr_err("Can't prepare audio interface for use (%s).",
		       snd_strerror(ret));
		return SR_ERR;
	}

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

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

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

	ctx->session_dev_id = cb_data;
	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 = ctx->cur_rate;
	header.num_analog_probes = NUM_PROBES;
	header.num_logic_probes = 0;
	header.protocol_id = SR_PROTO_RAW;
	sr_session_send(cb_data, &packet);
	g_free(ufds);

	return SR_OK;
}

/* TODO: This stops acquisition on ALL devices, ignoring dev_index. */
static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
{
	(void)dev_index;
	(void)cb_data;

	return SR_OK;
}

SR_PRIV struct sr_dev_driver alsa_driver_info = {
	.name = "alsa",
	.longname = "ALSA driver",
	.api_version = 1,
	.init = hw_init,
	.cleanup = hw_cleanup,
	.dev_open = hw_dev_open,
	.dev_close = hw_dev_close,
	.dev_info_get = hw_dev_info_get,
	.dev_status_get = hw_dev_status_get,
	.hwcap_get_all = hw_hwcap_get_all,
	.dev_config_set = hw_dev_config_set,
	.dev_acquisition_start = hw_dev_acquisition_start,
	.dev_acquisition_stop = hw_dev_acquisition_stop,
};
Commit	Line	Data
	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
	21	/* Note: This driver doesn't compile, analog support in sigrok is WIP. */
	22
	23	#include <stdlib.h>
	24	#include <unistd.h>
	25	#include <string.h>
	26	#include <alsa/asoundlib.h>
	27	#include "libsigrok.h"
	28	#include "libsigrok-internal.h"
	29
	30	/* Message logging helpers with driver-specific prefix string. */
	31	#define DRIVER_LOG_DOMAIN "alsa: "
	32	#define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args)
	33	#define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args)
	34	#define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args)
	35	#define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args)
	36	#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
	37	#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)
	38
	39	#define NUM_PROBES 2
	40	#define SAMPLE_WIDTH 16
	41	#define AUDIO_DEV "plughw:0,0"
	42
	43	struct sr_analog_probe {
	44	uint8_t att;
	45	uint8_t res; /* Needs to be a power of 2, FIXME */
	46	uint16_t val; /* Max hardware ADC width is 16bits */
	47	};
	48
	49	struct sr_analog_sample {
	50	uint8_t num_probes; /* Max hardware probes is 256 */
	51	struct sr_analog_probe probes[];
	52	};
	53
	54	static const int hwcaps[] = {
	55	SR_HWCAP_SAMPLERATE,
	56	SR_HWCAP_LIMIT_SAMPLES,
	57	SR_HWCAP_CONTINUOUS,
	58	};
	59
	60	/* TODO: Which probe names/numbers to use? */
	61	static const char *probe_names[NUM_PROBES + 1] = {
	62	"0",
	63	"1",
	64	NULL,
	65	};
	66
	67	static GSList *dev_insts = NULL;
	68
	69	/* Private, per-device-instance driver context. */
	70	struct context {
	71	uint64_t cur_rate;
	72	uint64_t limit_samples;
	73	snd_pcm_t *capture_handle;
	74	snd_pcm_hw_params_t *hw_params;
	75	void *session_dev_id;
	76	};
	77
	78	static int hw_init(struct sr_context *sr_ctx)
	79	{
	80	struct sr_dev_inst *sdi;
	81	struct context *ctx;
	82
	83	if (!(ctx = g_try_malloc0(sizeof(struct context)))) {
	84	sr_err("%s: ctx malloc failed", __func__);
	85	return SR_ERR_MALLOC;
	86	}
	87
	88	if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL))) {
	89	sr_err("%s: sdi was NULL", __func__);
	90	goto free_ctx;
	91	}
	92
	93	sdi->priv = ctx;
	94
	95	dev_insts = g_slist_append(dev_insts, sdi);
	96
	97	return 1;
	98
	99	free_ctx:
	100	g_free(ctx);
	101	return 0;
	102	}
	103
	104	static int hw_dev_open(int dev_index)
	105	{
	106	struct sr_dev_inst *sdi;
	107	struct context *ctx;
	108	int ret;
	109
	110	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	111	return SR_ERR;
	112	ctx = sdi->priv;
	113
	114	ret = snd_pcm_open(&ctx->capture_handle, AUDIO_DEV,
	115	SND_PCM_STREAM_CAPTURE, 0);
	116	if (ret < 0) {
	117	sr_err("Can't open audio device %s (%s).", AUDIO_DEV,
	118	snd_strerror(ret));
	119	return SR_ERR;
	120	}
	121
	122	ret = snd_pcm_hw_params_malloc(&ctx->hw_params);
	123	if (ret < 0) {
	124	sr_err("Can't allocate hardware parameter structure (%s).",
	125	snd_strerror(ret));
	126	return SR_ERR_MALLOC;
	127	}
	128
	129	ret = snd_pcm_hw_params_any(ctx->capture_handle, ctx->hw_params);
	130	if (ret < 0) {
	131	sr_err("Can't initialize hardware parameter structure (%s)",
	132	snd_strerror(ret));
	133	return SR_ERR;
	134	}
	135
	136	return SR_OK;
	137	}
	138
	139	static int hw_dev_close(int dev_index)
	140	{
	141	struct sr_dev_inst *sdi;
	142	struct context *ctx;
	143
	144	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
	145	sr_err("%s: sdi was NULL", __func__);
	146	return SR_ERR_BUG;
	147	}
	148
	149	if (!(ctx = sdi->priv)) {
	150	sr_err("%s: sdi->priv was NULL", __func__);
	151	return SR_ERR_BUG;
	152	}
	153
	154	// TODO: Return values of snd_*?
	155	if (ctx->hw_params)
	156	snd_pcm_hw_params_free(ctx->hw_params);
	157	if (ctx->capture_handle)
	158	snd_pcm_close(ctx->capture_handle);
	159
	160	return SR_OK;
	161	}
	162
	163	static int hw_cleanup(void)
	164	{
	165	struct sr_dev_inst *sdi;
	166
	167	if (!(sdi = sr_dev_inst_get(dev_insts, 0))) {
	168	sr_err("%s: sdi was NULL", __func__);
	169	return SR_ERR_BUG;
	170	}
	171
	172	sr_dev_inst_free(sdi);
	173
	174	return SR_OK;
	175	}
	176
	177	static const void *hw_dev_info_get(int dev_index, int dev_info_id)
	178	{
	179	struct sr_dev_inst *sdi;
	180	struct context *ctx;
	181	void *info = NULL;
	182
	183	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	184	return NULL;
	185	ctx = sdi->priv;
	186
	187	switch (dev_info_id) {
	188	case SR_DI_INST:
	189	info = sdi;
	190	break;
	191	case SR_DI_NUM_PROBES:
	192	info = GINT_TO_POINTER(NUM_PROBES);
	193	break;
	194	case SR_DI_PROBE_NAMES:
	195	info = probe_names;
	196	break;
	197	case SR_DI_CUR_SAMPLERATE:
	198	info = &ctx->cur_rate;
	199	break;
	200	// case SR_DI_PROBE_TYPE:
	201	// info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
	202	// break;
	203	}
	204
	205	return info;
	206	}
	207
	208	static int hw_dev_status_get(int dev_index)
	209	{
	210	(void)dev_index;
	211
	212	return SR_ST_ACTIVE;
	213	}
	214
	215	static const int *hw_hwcap_get_all(void)
	216	{
	217	return hwcaps;
	218	}
	219
	220	static int hw_dev_config_set(int dev_index, int hwcap, const void *value)
	221	{
	222	struct sr_dev_inst *sdi;
	223	struct context *ctx;
	224
	225	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	226	return SR_ERR;
	227	ctx = sdi->priv;
	228
	229	switch (hwcap) {
	230	case SR_HWCAP_PROBECONFIG:
	231	return SR_OK;
	232	case SR_HWCAP_SAMPLERATE:
	233	ctx->cur_rate = (const uint64_t )value;
	234	return SR_OK;
	235	case SR_HWCAP_LIMIT_SAMPLES:
	236	ctx->limit_samples = (const uint64_t )value;
	237	return SR_OK;
	238	default:
	239	return SR_ERR;
	240	}
	241	}
	242
	243	static int receive_data(int fd, int revents, void *cb_data)
	244	{
	245	struct sr_dev_inst *sdi = cb_data;
	246	struct context *ctx = sdi->priv;
	247	struct sr_datafeed_packet packet;
	248	struct sr_analog_sample *sample;
	249	unsigned int sample_size = sizeof(struct sr_analog_sample) +
	250	(NUM_PROBES * sizeof(struct sr_analog_probe));
	251	char *outb;
	252	char inb[4096];
	253	int i, x, count;
	254
	255	fd = fd;
	256	revents = revents;
	257
	258	do {
	259	memset(inb, 0, sizeof(inb));
	260	count = snd_pcm_readi(ctx->capture_handle, inb,
	261	MIN(4096 / 4, ctx->limit_samples));
	262	if (count < 1) {
	263	sr_err("Failed to read samples");
	264	return FALSE;
	265	}
	266
	267	if (!(outb = g_try_malloc(sample_size * count))) {
	268	sr_err("%s: outb malloc failed", __func__);
	269	return FALSE;
	270	}
	271
	272	for (i = 0; i < count; i++) {
	273	sample = (struct sr_analog_sample *)
	274	(outb + (i * sample_size));
	275	sample->num_probes = NUM_PROBES;
	276
	277	for (x = 0; x < NUM_PROBES; x++) {
	278	sample->probes[x].val =
	279	(uint16_t )(inb + (i * 4) + (x * 2));
	280	sample->probes[x].val &= ((1 << 16) - 1);
	281	sample->probes[x].res = 16;
	282	}
	283	}
	284
	285	packet.type = SR_DF_ANALOG;
	286	packet.length = count * sample_size;
	287	packet.unitsize = sample_size;
	288	packet.payload = outb;
	289	sr_session_send(sdi, &packet);
	290	g_free(outb);
	291	ctx->limit_samples -= count;
	292
	293	} while (ctx->limit_samples > 0);
	294
	295	packet.type = SR_DF_END;
	296	sr_session_send(sdi, &packet);
	297
	298	return TRUE;
	299	}
	300
	301	static int hw_dev_acquisition_start(int dev_index, void *cb_data)
	302	{
	303	struct sr_dev_inst *sdi;
	304	struct context *ctx;
	305	struct sr_datafeed_packet packet;
	306	struct sr_datafeed_header header;
	307	struct pollfd *ufds;
	308	int count;
	309	int ret;
	310
	311	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	312	return SR_ERR;
	313	ctx = sdi->priv;
	314
	315	ret = snd_pcm_hw_params_set_access(ctx->capture_handle,
	316	ctx->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	317	if (ret < 0) {
	318	sr_err("Can't set access type (%s).", snd_strerror(ret));
	319	return SR_ERR;
	320	}
	321
	322	/* FIXME: Hardcoded for 16bits */
	323	ret = snd_pcm_hw_params_set_format(ctx->capture_handle,
	324	ctx->hw_params, SND_PCM_FORMAT_S16_LE);
	325	if (ret < 0) {
	326	sr_err("Can't set sample format (%s).", snd_strerror(ret));
	327	return SR_ERR;
	328	}
	329
	330	ret = snd_pcm_hw_params_set_rate_near(ctx->capture_handle,
	331	ctx->hw_params, (unsigned int *)&ctx->cur_rate, 0);
	332	if (ret < 0) {
	333	sr_err("Can't set sample rate (%s).", snd_strerror(ret));
	334	return SR_ERR;
	335	}
	336
	337	ret = snd_pcm_hw_params_set_channels(ctx->capture_handle,
	338	ctx->hw_params, NUM_PROBES);
	339	if (ret < 0) {
	340	sr_err("Can't set channel count (%s).", snd_strerror(ret));
	341	return SR_ERR;
	342	}
	343
	344	ret = snd_pcm_hw_params(ctx->capture_handle, ctx->hw_params);
	345	if (ret < 0) {
	346	sr_err("Can't set parameters (%s).", snd_strerror(ret));
	347	return SR_ERR;
	348	}
	349
	350	ret = snd_pcm_prepare(ctx->capture_handle);
	351	if (ret < 0) {
	352	sr_err("Can't prepare audio interface for use (%s).",
	353	snd_strerror(ret));
	354	return SR_ERR;
	355	}
	356
	357	count = snd_pcm_poll_descriptors_count(ctx->capture_handle);
	358	if (count < 1) {
	359	sr_err("Unable to obtain poll descriptors count.");
	360	return SR_ERR;
	361	}
	362
	363	if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
	364	sr_err("%s: ufds malloc failed", __func__);
	365	return SR_ERR_MALLOC;
	366	}
	367
	368	ret = snd_pcm_poll_descriptors(ctx->capture_handle, ufds, count);
	369	if (ret < 0) {
	370	sr_err("Unable to obtain poll descriptors (%s)",
	371	snd_strerror(ret));
	372	g_free(ufds);
	373	return SR_ERR;
	374	}
	375
	376	ctx->session_dev_id = cb_data;
	377	sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
	378
	379	packet.type = SR_DF_HEADER;
	380	packet.length = sizeof(struct sr_datafeed_header);
	381	packet.payload = (unsigned char *)&header;
	382	header.feed_version = 1;
	383	gettimeofday(&header.starttime, NULL);
	384	header.samplerate = ctx->cur_rate;
	385	header.num_analog_probes = NUM_PROBES;
	386	header.num_logic_probes = 0;
	387	header.protocol_id = SR_PROTO_RAW;
	388	sr_session_send(cb_data, &packet);
	389	g_free(ufds);
	390
	391	return SR_OK;
	392	}
	393
	394	/* TODO: This stops acquisition on ALL devices, ignoring dev_index. */
	395	static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
	396	{
	397	(void)dev_index;
	398	(void)cb_data;
	399
	400	return SR_OK;
	401	}
	402
	403	SR_PRIV struct sr_dev_driver alsa_driver_info = {
	404	.name = "alsa",
	405	.longname = "ALSA driver",
	406	.api_version = 1,
	407	.init = hw_init,
	408	.cleanup = hw_cleanup,
	409	.dev_open = hw_dev_open,
	410	.dev_close = hw_dev_close,
	411	.dev_info_get = hw_dev_info_get,
	412	.dev_status_get = hw_dev_status_get,
	413	.hwcap_get_all = hw_hwcap_get_all,
	414	.dev_config_set = hw_dev_config_set,
	415	.dev_acquisition_start = hw_dev_acquisition_start,
	416	.dev_acquisition_stop = hw_dev_acquisition_stop,
	417	};