[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(const char *devinfo)
{
	struct sr_dev_inst *sdi;
	struct context *ctx;

	(void)devinfo;

	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(const char *devinfo)
	79	{
	80	struct sr_dev_inst *sdi;
	81	struct context *ctx;
	82
	83	(void)devinfo;
	84
	85	if (!(ctx = g_try_malloc0(sizeof(struct context)))) {
	86	sr_err("%s: ctx malloc failed", __func__);
	87	return SR_ERR_MALLOC;
	88	}
	89
	90	if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE, "alsa", NULL, NULL))) {
	91	sr_err("%s: sdi was NULL", __func__);
	92	goto free_ctx;
	93	}
	94
	95	sdi->priv = ctx;
	96
	97	dev_insts = g_slist_append(dev_insts, sdi);
	98
	99	return 1;
	100
	101	free_ctx:
	102	g_free(ctx);
	103	return 0;
	104	}
	105
	106	static int hw_dev_open(int dev_index)
	107	{
	108	struct sr_dev_inst *sdi;
	109	struct context *ctx;
	110	int ret;
	111
	112	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	113	return SR_ERR;
	114	ctx = sdi->priv;
	115
	116	ret = snd_pcm_open(&ctx->capture_handle, AUDIO_DEV,
	117	SND_PCM_STREAM_CAPTURE, 0);
	118	if (ret < 0) {
	119	sr_err("Can't open audio device %s (%s).", AUDIO_DEV,
	120	snd_strerror(ret));
	121	return SR_ERR;
	122	}
	123
	124	ret = snd_pcm_hw_params_malloc(&ctx->hw_params);
	125	if (ret < 0) {
	126	sr_err("Can't allocate hardware parameter structure (%s).",
	127	snd_strerror(ret));
	128	return SR_ERR_MALLOC;
	129	}
	130
	131	ret = snd_pcm_hw_params_any(ctx->capture_handle, ctx->hw_params);
	132	if (ret < 0) {
	133	sr_err("Can't initialize hardware parameter structure (%s)",
	134	snd_strerror(ret));
	135	return SR_ERR;
	136	}
	137
	138	return SR_OK;
	139	}
	140
	141	static int hw_dev_close(int dev_index)
	142	{
	143	struct sr_dev_inst *sdi;
	144	struct context *ctx;
	145
	146	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index))) {
	147	sr_err("%s: sdi was NULL", __func__);
	148	return SR_ERR_BUG;
	149	}
	150
	151	if (!(ctx = sdi->priv)) {
	152	sr_err("%s: sdi->priv was NULL", __func__);
	153	return SR_ERR_BUG;
	154	}
	155
	156	// TODO: Return values of snd_*?
	157	if (ctx->hw_params)
	158	snd_pcm_hw_params_free(ctx->hw_params);
	159	if (ctx->capture_handle)
	160	snd_pcm_close(ctx->capture_handle);
	161
	162	return SR_OK;
	163	}
	164
	165	static int hw_cleanup(void)
	166	{
	167	struct sr_dev_inst *sdi;
	168
	169	if (!(sdi = sr_dev_inst_get(dev_insts, 0))) {
	170	sr_err("%s: sdi was NULL", __func__);
	171	return SR_ERR_BUG;
	172	}
	173
	174	sr_dev_inst_free(sdi);
	175
	176	return SR_OK;
	177	}
	178
	179	static const void *hw_dev_info_get(int dev_index, int dev_info_id)
	180	{
	181	struct sr_dev_inst *sdi;
	182	struct context *ctx;
	183	void *info = NULL;
	184
	185	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	186	return NULL;
	187	ctx = sdi->priv;
	188
	189	switch (dev_info_id) {
	190	case SR_DI_INST:
	191	info = sdi;
	192	break;
	193	case SR_DI_NUM_PROBES:
	194	info = GINT_TO_POINTER(NUM_PROBES);
	195	break;
	196	case SR_DI_PROBE_NAMES:
	197	info = probe_names;
	198	break;
	199	case SR_DI_CUR_SAMPLERATE:
	200	info = &ctx->cur_rate;
	201	break;
	202	// case SR_DI_PROBE_TYPE:
	203	// info = GINT_TO_POINTER(SR_PROBE_TYPE_ANALOG);
	204	// break;
	205	}
	206
	207	return info;
	208	}
	209
	210	static int hw_dev_status_get(int dev_index)
	211	{
	212	(void)dev_index;
	213
	214	return SR_ST_ACTIVE;
	215	}
	216
	217	static const int *hw_hwcap_get_all(void)
	218	{
	219	return hwcaps;
	220	}
	221
	222	static int hw_dev_config_set(int dev_index, int hwcap, const void *value)
	223	{
	224	struct sr_dev_inst *sdi;
	225	struct context *ctx;
	226
	227	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	228	return SR_ERR;
	229	ctx = sdi->priv;
	230
	231	switch (hwcap) {
	232	case SR_HWCAP_PROBECONFIG:
	233	return SR_OK;
	234	case SR_HWCAP_SAMPLERATE:
	235	ctx->cur_rate = (const uint64_t )value;
	236	return SR_OK;
	237	case SR_HWCAP_LIMIT_SAMPLES:
	238	ctx->limit_samples = (const uint64_t )value;
	239	return SR_OK;
	240	default:
	241	return SR_ERR;
	242	}
	243	}
	244
	245	static int receive_data(int fd, int revents, void *cb_data)
	246	{
	247	struct sr_dev_inst *sdi = cb_data;
	248	struct context *ctx = sdi->priv;
	249	struct sr_datafeed_packet packet;
	250	struct sr_analog_sample *sample;
	251	unsigned int sample_size = sizeof(struct sr_analog_sample) +
	252	(NUM_PROBES * sizeof(struct sr_analog_probe));
	253	char *outb;
	254	char inb[4096];
	255	int i, x, count;
	256
	257	fd = fd;
	258	revents = revents;
	259
	260	do {
	261	memset(inb, 0, sizeof(inb));
	262	count = snd_pcm_readi(ctx->capture_handle, inb,
	263	MIN(4096 / 4, ctx->limit_samples));
	264	if (count < 1) {
	265	sr_err("Failed to read samples");
	266	return FALSE;
	267	}
	268
	269	if (!(outb = g_try_malloc(sample_size * count))) {
	270	sr_err("%s: outb malloc failed", __func__);
	271	return FALSE;
	272	}
	273
	274	for (i = 0; i < count; i++) {
	275	sample = (struct sr_analog_sample *)
	276	(outb + (i * sample_size));
	277	sample->num_probes = NUM_PROBES;
	278
	279	for (x = 0; x < NUM_PROBES; x++) {
	280	sample->probes[x].val =
	281	(uint16_t )(inb + (i * 4) + (x * 2));
	282	sample->probes[x].val &= ((1 << 16) - 1);
	283	sample->probes[x].res = 16;
	284	}
	285	}
	286
	287	packet.type = SR_DF_ANALOG;
	288	packet.length = count * sample_size;
	289	packet.unitsize = sample_size;
	290	packet.payload = outb;
	291	sr_session_send(sdi, &packet);
	292	g_free(outb);
	293	ctx->limit_samples -= count;
	294
	295	} while (ctx->limit_samples > 0);
	296
	297	packet.type = SR_DF_END;
	298	sr_session_send(sdi, &packet);
	299
	300	return TRUE;
	301	}
	302
	303	static int hw_dev_acquisition_start(int dev_index, void *cb_data)
	304	{
	305	struct sr_dev_inst *sdi;
	306	struct context *ctx;
	307	struct sr_datafeed_packet packet;
	308	struct sr_datafeed_header header;
	309	struct pollfd *ufds;
	310	int count;
	311	int ret;
	312
	313	if (!(sdi = sr_dev_inst_get(dev_insts, dev_index)))
	314	return SR_ERR;
	315	ctx = sdi->priv;
	316
	317	ret = snd_pcm_hw_params_set_access(ctx->capture_handle,
	318	ctx->hw_params, SND_PCM_ACCESS_RW_INTERLEAVED);
	319	if (ret < 0) {
	320	sr_err("Can't set access type (%s).", snd_strerror(ret));
	321	return SR_ERR;
	322	}
	323
	324	/* FIXME: Hardcoded for 16bits */
	325	ret = snd_pcm_hw_params_set_format(ctx->capture_handle,
	326	ctx->hw_params, SND_PCM_FORMAT_S16_LE);
	327	if (ret < 0) {
	328	sr_err("Can't set sample format (%s).", snd_strerror(ret));
	329	return SR_ERR;
	330	}
	331
	332	ret = snd_pcm_hw_params_set_rate_near(ctx->capture_handle,
	333	ctx->hw_params, (unsigned int *)&ctx->cur_rate, 0);
	334	if (ret < 0) {
	335	sr_err("Can't set sample rate (%s).", snd_strerror(ret));
	336	return SR_ERR;
	337	}
	338
	339	ret = snd_pcm_hw_params_set_channels(ctx->capture_handle,
	340	ctx->hw_params, NUM_PROBES);
	341	if (ret < 0) {
	342	sr_err("Can't set channel count (%s).", snd_strerror(ret));
	343	return SR_ERR;
	344	}
	345
	346	ret = snd_pcm_hw_params(ctx->capture_handle, ctx->hw_params);
	347	if (ret < 0) {
	348	sr_err("Can't set parameters (%s).", snd_strerror(ret));
	349	return SR_ERR;
	350	}
	351
	352	ret = snd_pcm_prepare(ctx->capture_handle);
	353	if (ret < 0) {
	354	sr_err("Can't prepare audio interface for use (%s).",
	355	snd_strerror(ret));
	356	return SR_ERR;
	357	}
	358
	359	count = snd_pcm_poll_descriptors_count(ctx->capture_handle);
	360	if (count < 1) {
	361	sr_err("Unable to obtain poll descriptors count.");
	362	return SR_ERR;
	363	}
	364
	365	if (!(ufds = g_try_malloc(count * sizeof(struct pollfd)))) {
	366	sr_err("%s: ufds malloc failed", __func__);
	367	return SR_ERR_MALLOC;
	368	}
	369
	370	ret = snd_pcm_poll_descriptors(ctx->capture_handle, ufds, count);
	371	if (ret < 0) {
	372	sr_err("Unable to obtain poll descriptors (%s)",
	373	snd_strerror(ret));
	374	g_free(ufds);
	375	return SR_ERR;
	376	}
	377
	378	ctx->session_dev_id = cb_data;
	379	sr_source_add(ufds[0].fd, ufds[0].events, 10, receive_data, sdi);
	380
	381	packet.type = SR_DF_HEADER;
	382	packet.length = sizeof(struct sr_datafeed_header);
	383	packet.payload = (unsigned char *)&header;
	384	header.feed_version = 1;
	385	gettimeofday(&header.starttime, NULL);
	386	header.samplerate = ctx->cur_rate;
	387	header.num_analog_probes = NUM_PROBES;
	388	header.num_logic_probes = 0;
	389	header.protocol_id = SR_PROTO_RAW;
	390	sr_session_send(cb_data, &packet);
	391	g_free(ufds);
	392
	393	return SR_OK;
	394	}
	395
	396	/* TODO: This stops acquisition on ALL devices, ignoring dev_index. */
	397	static int hw_dev_acquisition_stop(int dev_index, void *cb_data)
	398	{
	399	(void)dev_index;
	400	(void)cb_data;
	401
	402	return SR_OK;
	403	}
	404
	405	SR_PRIV struct sr_dev_driver alsa_driver_info = {
	406	.name = "alsa",
	407	.longname = "ALSA driver",
	408	.api_version = 1,
	409	.init = hw_init,
	410	.cleanup = hw_cleanup,
	411	.dev_open = hw_dev_open,
	412	.dev_close = hw_dev_close,
	413	.dev_info_get = hw_dev_info_get,
	414	.dev_status_get = hw_dev_status_get,
	415	.hwcap_get_all = hw_hwcap_get_all,
	416	.dev_config_set = hw_dev_config_set,
	417	.dev_acquisition_start = hw_dev_acquisition_start,
	418	.dev_acquisition_stop = hw_dev_acquisition_stop,
	419	};