[libsigrok.git] / src / hardware / lascar-el-usb / api.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2012 Bert Vermeulen <bert@biot.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 3 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, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <glib.h>
#include <libusb.h>
#include <libsigrok/libsigrok.h>
#include "libsigrok-internal.h"
#include "protocol.h"

static const uint32_t scanopts[] = {
	SR_CONF_CONN,
};

static const uint32_t devopts[] = {
	SR_CONF_THERMOMETER,
	SR_CONF_HYGROMETER,
	SR_CONF_CONN | SR_CONF_GET,
	SR_CONF_LIMIT_SAMPLES | SR_CONF_GET | SR_CONF_SET,
	SR_CONF_DATALOG | SR_CONF_GET | SR_CONF_SET,
};

static GSList *scan(struct sr_dev_driver *di, GSList *options)
{
	struct drv_context *drvc;
	struct sr_dev_inst *sdi;
	struct sr_usb_dev_inst *usb;
	struct sr_config *src;
	GSList *usb_devices, *devices, *l;
	const char *conn;

	drvc = di->context;

	conn = NULL;
	for (l = options; l; l = l->next) {
		src = l->data;
		switch (src->key) {
		case SR_CONF_CONN:
			conn = g_variant_get_string(src->data, NULL);
			break;
		}
	}
	if (!conn)
		return NULL;

	devices = NULL;
	if ((usb_devices = sr_usb_find(drvc->sr_ctx->libusb_ctx, conn))) {
		/* We have a list of sr_usb_dev_inst matching the connection
		 * string. Wrap them in sr_dev_inst and we're done. */
		for (l = usb_devices; l; l = l->next) {
			usb = l->data;
			if (!(sdi = lascar_scan(usb->bus, usb->address))) {
				/* Not a Lascar EL-USB. */
				g_free(usb);
				continue;
			}
			sdi->inst_type = SR_INST_USB;
			sdi->conn = usb;
			devices = g_slist_append(devices, sdi);
		}
		g_slist_free(usb_devices);
	} else
		g_slist_free_full(usb_devices, g_free);

	return std_scan_complete(di, devices);
}

static int dev_open(struct sr_dev_inst *sdi)
{
	struct sr_dev_driver *di = sdi->driver;
	struct drv_context *drvc = di->context;;
	struct sr_usb_dev_inst *usb;
	int ret;

	usb = sdi->conn;

	if (sr_usb_open(drvc->sr_ctx->libusb_ctx, usb) != SR_OK)
		return SR_ERR;

	if ((ret = libusb_claim_interface(usb->devhdl, LASCAR_INTERFACE))) {
		sr_err("Failed to claim interface: %s.", libusb_error_name(ret));
		return SR_ERR;
	}
	sdi->status = SR_ST_ACTIVE;

	return ret;
}

static int dev_close(struct sr_dev_inst *sdi)
{
	struct sr_usb_dev_inst *usb;

	usb = sdi->conn;

	if (!usb->devhdl)
		/* Nothing to do. */
		return SR_OK;

	libusb_release_interface(usb->devhdl, LASCAR_INTERFACE);
	libusb_close(usb->devhdl);
	usb->devhdl = NULL;
	sdi->status = SR_ST_INACTIVE;

	return SR_OK;
}

static int config_get(uint32_t key, GVariant **data, const struct sr_dev_inst *sdi,
		const struct sr_channel_group *cg)
{
	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	int ret;
	char str[128];

	(void)cg;

	devc = sdi->priv;
	switch (key) {
	case SR_CONF_CONN:
		if (!sdi || !sdi->conn)
			return SR_ERR_ARG;
		usb = sdi->conn;
		snprintf(str, 128, "%d.%d", usb->bus, usb->address);
		*data = g_variant_new_string(str);
		break;
	case SR_CONF_DATALOG:
		if (!sdi)
			return SR_ERR_ARG;
		if ((ret = lascar_is_logging(sdi)) == -1)
			return SR_ERR;
		*data = g_variant_new_boolean(ret ? TRUE : FALSE);
		break;
	case SR_CONF_LIMIT_SAMPLES:
		*data = g_variant_new_uint64(devc->limit_samples);
		break;
	default:
		return SR_ERR_NA;
	}

	return SR_OK;
}

static int config_set(uint32_t key, GVariant *data, const struct sr_dev_inst *sdi,
		const struct sr_channel_group *cg)
{
	struct dev_context *devc;
	int ret;

	(void)cg;

	devc = sdi->priv;
	ret = SR_OK;
	switch (key) {
	case SR_CONF_DATALOG:
		if (g_variant_get_boolean(data))
			ret = lascar_start_logging(sdi);
		else
			ret = lascar_stop_logging(sdi);
		break;
	case SR_CONF_LIMIT_SAMPLES:
		devc->limit_samples = g_variant_get_uint64(data);
		break;
	default:
		ret = SR_ERR_NA;
	}

	return ret;
}

static int config_list(uint32_t key, GVariant **data, const struct sr_dev_inst *sdi,
		const struct sr_channel_group *cg)
{
	(void)sdi;
	(void)cg;

	switch (key) {
	case SR_CONF_SCAN_OPTIONS:
		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
				scanopts, ARRAY_SIZE(scanopts), sizeof(uint32_t));
		break;
	case SR_CONF_DEVICE_OPTIONS:
		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
				devopts, ARRAY_SIZE(devopts), sizeof(uint32_t));
		break;
	default:
		return SR_ERR_NA;
	}

	return SR_OK;
}

static void LIBUSB_CALL mark_xfer(struct libusb_transfer *xfer)
{

	if (xfer->status == LIBUSB_TRANSFER_COMPLETED)
		xfer->user_data = GINT_TO_POINTER(1);
	else
		xfer->user_data = GINT_TO_POINTER(-1);

}

/* The Lascar software, in its infinite ignorance, reads a set of four
 * bytes from the device config struct and interprets it as a float.
 * That only works because they only use windows, and only on x86. However
 * we may be running on any architecture, any operating system. So we have
 * to convert these four bytes as the Lascar software would on windows/x86,
 * to the local representation of a float.
 * The source format is little-endian, with IEEE 754-2008 BINARY32 encoding. */
static float binary32_le_to_float(unsigned char *buf)
{
	GFloatIEEE754 f;

	f.v_float = 0;
	f.mpn.sign = (buf[3] & 0x80) ? 1 : 0;
	f.mpn.biased_exponent = (buf[3] << 1) | (buf[2] >> 7);
	f.mpn.mantissa = buf[0] | (buf[1] << 8) | ((buf[2] & 0x7f) << 16);

	return f.v_float;
}

static int lascar_proc_config(const struct sr_dev_inst *sdi)
{
	struct dev_context *devc;
	struct sr_usb_dev_inst *usb;
	int dummy, ret;

	devc = sdi->priv;
	usb = sdi->conn;

	if (lascar_get_config(usb->devhdl, devc->config, &dummy) != SR_OK)
		return SR_ERR;

	ret = SR_OK;
	switch (devc->profile->logformat) {
	case LOG_TEMP_RH:
		devc->sample_size = 2;
		devc->temp_unit = devc->config[0x2e] | (devc->config[0x2f] << 8);
		if (devc->temp_unit != 0 && devc->temp_unit != 1) {
			sr_dbg("invalid temperature unit %d", devc->temp_unit);
			/* Default to Celsius, we're all adults here. */
			devc->temp_unit = 0;
		} else
			sr_dbg("temperature unit is %s", devc->temp_unit
					? "Fahrenheit" : "Celsius");
		break;
	case LOG_CO:
		devc->sample_size = 2;
		devc->co_high = binary32_le_to_float(devc->config + 0x24);
		devc->co_low = binary32_le_to_float(devc->config + 0x28);
		sr_dbg("EL-USB-CO calibration high %f low %f", devc->co_high,
				devc->co_low);
		break;
	default:
		ret = SR_ERR_ARG;
	}
	devc->logged_samples = devc->config[0x1e] | (devc->config[0x1f] << 8);
	sr_dbg("device log contains %d samples.", devc->logged_samples);

	return ret;
}

static int dev_acquisition_start(const struct sr_dev_inst *sdi)
{
	struct sr_dev_driver *di = sdi->driver;
	struct sr_datafeed_packet packet;
	struct sr_datafeed_meta meta;
	struct sr_config *src;
	struct dev_context *devc;
	struct drv_context *drvc;
	struct sr_usb_dev_inst *usb;
	struct libusb_transfer *xfer_in, *xfer_out;
	struct timeval tv;
	uint64_t interval;
	int ret;
	unsigned char cmd[3], resp[4], *buf;

	drvc = di->context;
	devc = sdi->priv;
	usb = sdi->conn;

	if (lascar_proc_config(sdi) != SR_OK)
		return SR_ERR;

	sr_dbg("Starting log retrieval.");

	std_session_send_df_header(sdi);

	interval = (devc->config[0x1c] | (devc->config[0x1d] << 8)) * 1000;
	packet.type = SR_DF_META;
	packet.payload = &meta;
	src = sr_config_new(SR_CONF_SAMPLE_INTERVAL, g_variant_new_uint64(interval));
	meta.config = g_slist_append(NULL, src);
	sr_session_send(sdi, &packet);
	g_free(src);

	if (devc->logged_samples == 0) {
		/* This ensures the frontend knows the session is done. */
		std_session_send_df_end(sdi);
		return SR_OK;
	}

	if (!(xfer_in = libusb_alloc_transfer(0)) ||
			!(xfer_out = libusb_alloc_transfer(0)))
		return SR_ERR;

	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
			0x00, 0xffff, 0x00, NULL, 0, 50);
	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
			0x02, 0x0002, 0x00, NULL, 0, 50);
	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
			0x02, 0x0001, 0x00, NULL, 0, 50);

	/* Flush input. The F321 requires this. */
	while (libusb_bulk_transfer(usb->devhdl, LASCAR_EP_IN, resp,
			256, &ret, 5) == 0 && ret > 0)
		;

	libusb_fill_bulk_transfer(xfer_in, usb->devhdl, LASCAR_EP_IN,
			resp, sizeof(resp), mark_xfer, 0, BULK_XFER_TIMEOUT);
	if (libusb_submit_transfer(xfer_in) != 0) {
		libusb_free_transfer(xfer_in);
		libusb_free_transfer(xfer_out);
		return SR_ERR;
	}

	cmd[0] = 0x03;
	cmd[1] = 0xff;
	cmd[2] = 0xff;
	libusb_fill_bulk_transfer(xfer_out, usb->devhdl, LASCAR_EP_OUT,
			cmd, 3, mark_xfer, 0, 100);
	if (libusb_submit_transfer(xfer_out) != 0) {
		libusb_free_transfer(xfer_in);
		libusb_free_transfer(xfer_out);
		return SR_ERR;
	}

	tv.tv_sec = 0;
	tv.tv_usec = 0;
	while (!xfer_in->user_data || !xfer_out->user_data) {
		g_usleep(SLEEP_US_LONG);
		libusb_handle_events_timeout(drvc->sr_ctx->libusb_ctx, &tv);
	}
	if (xfer_in->user_data != GINT_TO_POINTER(1) ||
			xfer_out->user_data != GINT_TO_POINTER(1)) {
		sr_dbg("no response to log transfer request");
		libusb_free_transfer(xfer_in);
		libusb_free_transfer(xfer_out);
		return SR_ERR;
	}
	if (xfer_in->actual_length != 3 || xfer_in->buffer[0] != 2) {
		sr_dbg("invalid response to log transfer request");
		libusb_free_transfer(xfer_in);
		libusb_free_transfer(xfer_out);
		return SR_ERR;
	}
	devc->log_size = xfer_in->buffer[1] + (xfer_in->buffer[2] << 8);
	libusb_free_transfer(xfer_out);

	usb_source_add(sdi->session, drvc->sr_ctx, 100,
			lascar_el_usb_handle_events, (void *)sdi);

	buf = g_malloc(4096);
	libusb_fill_bulk_transfer(xfer_in, usb->devhdl, LASCAR_EP_IN,
			buf, 4096, lascar_el_usb_receive_transfer,
			(struct sr_dev_inst *)sdi, 100);
	if ((ret = libusb_submit_transfer(xfer_in) != 0)) {
		sr_err("Unable to submit transfer: %s.", libusb_error_name(ret));
		libusb_free_transfer(xfer_in);
		g_free(buf);
		return SR_ERR;
	}

	return SR_OK;
}

static int dev_acquisition_stop(struct sr_dev_inst *sdi)
{
	sdi->status = SR_ST_STOPPING;
	/* TODO: free ongoing transfers? */

	return SR_OK;
}

SR_PRIV struct sr_dev_driver lascar_el_usb_driver_info = {
	.name = "lascar-el-usb",
	.longname = "Lascar EL-USB",
	.api_version = 1,
	.init = std_init,
	.cleanup = std_cleanup,
	.scan = scan,
	.dev_list = std_dev_list,
	.dev_clear = NULL,
	.config_get = config_get,
	.config_set = config_set,
	.config_list = config_list,
	.dev_open = dev_open,
	.dev_close = dev_close,
	.dev_acquisition_start = dev_acquisition_start,
	.dev_acquisition_stop = dev_acquisition_stop,
	.context = NULL,
};
SR_REGISTER_DEV_DRIVER(lascar_el_usb_driver_info);
Commit	Line	Data
	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2012 Bert Vermeulen <bert@biot.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 3 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, see <http://www.gnu.org/licenses/>.
	18	*/
	19
	20	#include <config.h>
	21	#include <glib.h>
	22	#include <libusb.h>
	23	#include <libsigrok/libsigrok.h>
	24	#include "libsigrok-internal.h"
	25	#include "protocol.h"
	26
	27	static const uint32_t scanopts[] = {
	28	SR_CONF_CONN,
	29	};
	30
	31	static const uint32_t devopts[] = {
	32	SR_CONF_THERMOMETER,
	33	SR_CONF_HYGROMETER,
	34	SR_CONF_CONN \| SR_CONF_GET,
	35	SR_CONF_LIMIT_SAMPLES \| SR_CONF_GET \| SR_CONF_SET,
	36	SR_CONF_DATALOG \| SR_CONF_GET \| SR_CONF_SET,
	37	};
	38
	39	static GSList scan(struct sr_dev_driver di, GSList *options)
	40	{
	41	struct drv_context *drvc;
	42	struct sr_dev_inst *sdi;
	43	struct sr_usb_dev_inst *usb;
	44	struct sr_config *src;
	45	GSList usb_devices, devices, *l;
	46	const char *conn;
	47
	48	drvc = di->context;
	49
	50	conn = NULL;
	51	for (l = options; l; l = l->next) {
	52	src = l->data;
	53	switch (src->key) {
	54	case SR_CONF_CONN:
	55	conn = g_variant_get_string(src->data, NULL);
	56	break;
	57	}
	58	}
	59	if (!conn)
	60	return NULL;
	61
	62	devices = NULL;
	63	if ((usb_devices = sr_usb_find(drvc->sr_ctx->libusb_ctx, conn))) {
	64	/* We have a list of sr_usb_dev_inst matching the connection
	65	* string. Wrap them in sr_dev_inst and we're done. */
	66	for (l = usb_devices; l; l = l->next) {
	67	usb = l->data;
	68	if (!(sdi = lascar_scan(usb->bus, usb->address))) {
	69	/* Not a Lascar EL-USB. */
	70	g_free(usb);
	71	continue;
	72	}
	73	sdi->inst_type = SR_INST_USB;
	74	sdi->conn = usb;
	75	devices = g_slist_append(devices, sdi);
	76	}
	77	g_slist_free(usb_devices);
	78	} else
	79	g_slist_free_full(usb_devices, g_free);
	80
	81	return std_scan_complete(di, devices);
	82	}
	83
	84	static int dev_open(struct sr_dev_inst *sdi)
	85	{
	86	struct sr_dev_driver *di = sdi->driver;
	87	struct drv_context *drvc = di->context;;
	88	struct sr_usb_dev_inst *usb;
	89	int ret;
	90
	91	usb = sdi->conn;
	92
	93	if (sr_usb_open(drvc->sr_ctx->libusb_ctx, usb) != SR_OK)
	94	return SR_ERR;
	95
	96	if ((ret = libusb_claim_interface(usb->devhdl, LASCAR_INTERFACE))) {
	97	sr_err("Failed to claim interface: %s.", libusb_error_name(ret));
	98	return SR_ERR;
	99	}
	100	sdi->status = SR_ST_ACTIVE;
	101
	102	return ret;
	103	}
	104
	105	static int dev_close(struct sr_dev_inst *sdi)
	106	{
	107	struct sr_usb_dev_inst *usb;
	108
	109	usb = sdi->conn;
	110
	111	if (!usb->devhdl)
	112	/* Nothing to do. */
	113	return SR_OK;
	114
	115	libusb_release_interface(usb->devhdl, LASCAR_INTERFACE);
	116	libusb_close(usb->devhdl);
	117	usb->devhdl = NULL;
	118	sdi->status = SR_ST_INACTIVE;
	119
	120	return SR_OK;
	121	}
	122
	123	static int config_get(uint32_t key, GVariant *data, const struct sr_dev_inst sdi,
	124	const struct sr_channel_group *cg)
	125	{
	126	struct dev_context *devc;
	127	struct sr_usb_dev_inst *usb;
	128	int ret;
	129	char str[128];
	130
	131	(void)cg;
	132
	133	devc = sdi->priv;
	134	switch (key) {
	135	case SR_CONF_CONN:
	136	if (!sdi \|\| !sdi->conn)
	137	return SR_ERR_ARG;
	138	usb = sdi->conn;
	139	snprintf(str, 128, "%d.%d", usb->bus, usb->address);
	140	*data = g_variant_new_string(str);
	141	break;
	142	case SR_CONF_DATALOG:
	143	if (!sdi)
	144	return SR_ERR_ARG;
	145	if ((ret = lascar_is_logging(sdi)) == -1)
	146	return SR_ERR;
	147	*data = g_variant_new_boolean(ret ? TRUE : FALSE);
	148	break;
	149	case SR_CONF_LIMIT_SAMPLES:
	150	*data = g_variant_new_uint64(devc->limit_samples);
	151	break;
	152	default:
	153	return SR_ERR_NA;
	154	}
	155
	156	return SR_OK;
	157	}
	158
	159	static int config_set(uint32_t key, GVariant data, const struct sr_dev_inst sdi,
	160	const struct sr_channel_group *cg)
	161	{
	162	struct dev_context *devc;
	163	int ret;
	164
	165	(void)cg;
	166
	167	devc = sdi->priv;
	168	ret = SR_OK;
	169	switch (key) {
	170	case SR_CONF_DATALOG:
	171	if (g_variant_get_boolean(data))
	172	ret = lascar_start_logging(sdi);
	173	else
	174	ret = lascar_stop_logging(sdi);
	175	break;
	176	case SR_CONF_LIMIT_SAMPLES:
	177	devc->limit_samples = g_variant_get_uint64(data);
	178	break;
	179	default:
	180	ret = SR_ERR_NA;
	181	}
	182
	183	return ret;
	184	}
	185
	186	static int config_list(uint32_t key, GVariant *data, const struct sr_dev_inst sdi,
	187	const struct sr_channel_group *cg)
	188	{
	189	(void)sdi;
	190	(void)cg;
	191
	192	switch (key) {
	193	case SR_CONF_SCAN_OPTIONS:
	194	*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
	195	scanopts, ARRAY_SIZE(scanopts), sizeof(uint32_t));
	196	break;
	197	case SR_CONF_DEVICE_OPTIONS:
	198	*data = g_variant_new_fixed_array(G_VARIANT_TYPE_UINT32,
	199	devopts, ARRAY_SIZE(devopts), sizeof(uint32_t));
	200	break;
	201	default:
	202	return SR_ERR_NA;
	203	}
	204
	205	return SR_OK;
	206	}
	207
	208	static void LIBUSB_CALL mark_xfer(struct libusb_transfer *xfer)
	209	{
	210
	211	if (xfer->status == LIBUSB_TRANSFER_COMPLETED)
	212	xfer->user_data = GINT_TO_POINTER(1);
	213	else
	214	xfer->user_data = GINT_TO_POINTER(-1);
	215
	216	}
	217
	218	/* The Lascar software, in its infinite ignorance, reads a set of four
	219	* bytes from the device config struct and interprets it as a float.
	220	* That only works because they only use windows, and only on x86. However
	221	* we may be running on any architecture, any operating system. So we have
	222	* to convert these four bytes as the Lascar software would on windows/x86,
	223	* to the local representation of a float.
	224	* The source format is little-endian, with IEEE 754-2008 BINARY32 encoding. */
	225	static float binary32_le_to_float(unsigned char *buf)
	226	{
	227	GFloatIEEE754 f;
	228
	229	f.v_float = 0;
	230	f.mpn.sign = (buf[3] & 0x80) ? 1 : 0;
	231	f.mpn.biased_exponent = (buf[3] << 1) \| (buf[2] >> 7);
	232	f.mpn.mantissa = buf[0] \| (buf[1] << 8) \| ((buf[2] & 0x7f) << 16);
	233
	234	return f.v_float;
	235	}
	236
	237	static int lascar_proc_config(const struct sr_dev_inst *sdi)
	238	{
	239	struct dev_context *devc;
	240	struct sr_usb_dev_inst *usb;
	241	int dummy, ret;
	242
	243	devc = sdi->priv;
	244	usb = sdi->conn;
	245
	246	if (lascar_get_config(usb->devhdl, devc->config, &dummy) != SR_OK)
	247	return SR_ERR;
	248
	249	ret = SR_OK;
	250	switch (devc->profile->logformat) {
	251	case LOG_TEMP_RH:
	252	devc->sample_size = 2;
	253	devc->temp_unit = devc->config[0x2e] \| (devc->config[0x2f] << 8);
	254	if (devc->temp_unit != 0 && devc->temp_unit != 1) {
	255	sr_dbg("invalid temperature unit %d", devc->temp_unit);
	256	/* Default to Celsius, we're all adults here. */
	257	devc->temp_unit = 0;
	258	} else
	259	sr_dbg("temperature unit is %s", devc->temp_unit
	260	? "Fahrenheit" : "Celsius");
	261	break;
	262	case LOG_CO:
	263	devc->sample_size = 2;
	264	devc->co_high = binary32_le_to_float(devc->config + 0x24);
	265	devc->co_low = binary32_le_to_float(devc->config + 0x28);
	266	sr_dbg("EL-USB-CO calibration high %f low %f", devc->co_high,
	267	devc->co_low);
	268	break;
	269	default:
	270	ret = SR_ERR_ARG;
	271	}
	272	devc->logged_samples = devc->config[0x1e] \| (devc->config[0x1f] << 8);
	273	sr_dbg("device log contains %d samples.", devc->logged_samples);
	274
	275	return ret;
	276	}
	277
	278	static int dev_acquisition_start(const struct sr_dev_inst *sdi)
	279	{
	280	struct sr_dev_driver *di = sdi->driver;
	281	struct sr_datafeed_packet packet;
	282	struct sr_datafeed_meta meta;
	283	struct sr_config *src;
	284	struct dev_context *devc;
	285	struct drv_context *drvc;
	286	struct sr_usb_dev_inst *usb;
	287	struct libusb_transfer xfer_in, xfer_out;
	288	struct timeval tv;
	289	uint64_t interval;
	290	int ret;
	291	unsigned char cmd[3], resp[4], *buf;
	292
	293	drvc = di->context;
	294	devc = sdi->priv;
	295	usb = sdi->conn;
	296
	297	if (lascar_proc_config(sdi) != SR_OK)
	298	return SR_ERR;
	299
	300	sr_dbg("Starting log retrieval.");
	301
	302	std_session_send_df_header(sdi);
	303
	304	interval = (devc->config[0x1c] \| (devc->config[0x1d] << 8)) * 1000;
	305	packet.type = SR_DF_META;
	306	packet.payload = &meta;
	307	src = sr_config_new(SR_CONF_SAMPLE_INTERVAL, g_variant_new_uint64(interval));
	308	meta.config = g_slist_append(NULL, src);
	309	sr_session_send(sdi, &packet);
	310	g_free(src);
	311
	312	if (devc->logged_samples == 0) {
	313	/* This ensures the frontend knows the session is done. */
	314	std_session_send_df_end(sdi);
	315	return SR_OK;
	316	}
	317
	318	if (!(xfer_in = libusb_alloc_transfer(0)) \|\|
	319	!(xfer_out = libusb_alloc_transfer(0)))
	320	return SR_ERR;
	321
	322	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
	323	0x00, 0xffff, 0x00, NULL, 0, 50);
	324	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
	325	0x02, 0x0002, 0x00, NULL, 0, 50);
	326	libusb_control_transfer(usb->devhdl, LIBUSB_REQUEST_TYPE_VENDOR,
	327	0x02, 0x0001, 0x00, NULL, 0, 50);
	328
	329	/* Flush input. The F321 requires this. */
	330	while (libusb_bulk_transfer(usb->devhdl, LASCAR_EP_IN, resp,
	331	256, &ret, 5) == 0 && ret > 0)
	332	;
	333
	334	libusb_fill_bulk_transfer(xfer_in, usb->devhdl, LASCAR_EP_IN,
	335	resp, sizeof(resp), mark_xfer, 0, BULK_XFER_TIMEOUT);
	336	if (libusb_submit_transfer(xfer_in) != 0) {
	337	libusb_free_transfer(xfer_in);
	338	libusb_free_transfer(xfer_out);
	339	return SR_ERR;
	340	}
	341
	342	cmd[0] = 0x03;
	343	cmd[1] = 0xff;
	344	cmd[2] = 0xff;
	345	libusb_fill_bulk_transfer(xfer_out, usb->devhdl, LASCAR_EP_OUT,
	346	cmd, 3, mark_xfer, 0, 100);
	347	if (libusb_submit_transfer(xfer_out) != 0) {
	348	libusb_free_transfer(xfer_in);
	349	libusb_free_transfer(xfer_out);
	350	return SR_ERR;
	351	}
	352
	353	tv.tv_sec = 0;
	354	tv.tv_usec = 0;
	355	while (!xfer_in->user_data \|\| !xfer_out->user_data) {
	356	g_usleep(SLEEP_US_LONG);
	357	libusb_handle_events_timeout(drvc->sr_ctx->libusb_ctx, &tv);
	358	}
	359	if (xfer_in->user_data != GINT_TO_POINTER(1) \|\|
	360	xfer_out->user_data != GINT_TO_POINTER(1)) {
	361	sr_dbg("no response to log transfer request");
	362	libusb_free_transfer(xfer_in);
	363	libusb_free_transfer(xfer_out);
	364	return SR_ERR;
	365	}
	366	if (xfer_in->actual_length != 3 \|\| xfer_in->buffer[0] != 2) {
	367	sr_dbg("invalid response to log transfer request");
	368	libusb_free_transfer(xfer_in);
	369	libusb_free_transfer(xfer_out);
	370	return SR_ERR;
	371	}
	372	devc->log_size = xfer_in->buffer[1] + (xfer_in->buffer[2] << 8);
	373	libusb_free_transfer(xfer_out);
	374
	375	usb_source_add(sdi->session, drvc->sr_ctx, 100,
	376	lascar_el_usb_handle_events, (void *)sdi);
	377
	378	buf = g_malloc(4096);
	379	libusb_fill_bulk_transfer(xfer_in, usb->devhdl, LASCAR_EP_IN,
	380	buf, 4096, lascar_el_usb_receive_transfer,
	381	(struct sr_dev_inst *)sdi, 100);
	382	if ((ret = libusb_submit_transfer(xfer_in) != 0)) {
	383	sr_err("Unable to submit transfer: %s.", libusb_error_name(ret));
	384	libusb_free_transfer(xfer_in);
	385	g_free(buf);
	386	return SR_ERR;
	387	}
	388
	389	return SR_OK;
	390	}
	391
	392	static int dev_acquisition_stop(struct sr_dev_inst *sdi)
	393	{
	394	sdi->status = SR_ST_STOPPING;
	395	/* TODO: free ongoing transfers? */
	396
	397	return SR_OK;
	398	}
	399
	400	SR_PRIV struct sr_dev_driver lascar_el_usb_driver_info = {
	401	.name = "lascar-el-usb",
	402	.longname = "Lascar EL-USB",
	403	.api_version = 1,
	404	.init = std_init,
	405	.cleanup = std_cleanup,
	406	.scan = scan,
	407	.dev_list = std_dev_list,
	408	.dev_clear = NULL,
	409	.config_get = config_get,
	410	.config_set = config_set,
	411	.config_list = config_list,
	412	.dev_open = dev_open,
	413	.dev_close = dev_close,
	414	.dev_acquisition_start = dev_acquisition_start,
	415	.dev_acquisition_stop = dev_acquisition_stop,
	416	.context = NULL,
	417	};
	418	SR_REGISTER_DEV_DRIVER(lascar_el_usb_driver_info);