[libsigrok.git] / hardware / gmc-mh-1x-2x / api.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2013 Matthias Heidbrink <m-sigrok@heidbrink.biz>
 *
 * 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 <string.h>
#include "protocol.h"

/* Serial communication parameters for Metrahit 1x/2x with 'RS232' adaptor */
#define SERIALCOMM_1X_RS232 "8228/6n1/dtr=1/rts=1/flow=0" /* =8192, closer with divider */
#define SERIALCOMM_2X_RS232 "9600/6n1/dtr=1/rts=1/flow=0"
#define VENDOR_GMC "Gossen Metrawatt"

SR_PRIV struct sr_dev_driver gmc_mh_1x_2x_rs232_driver_info;
static struct sr_dev_driver *di = &gmc_mh_1x_2x_rs232_driver_info;

static const int32_t hwopts[] = {
	SR_CONF_CONN,
	SR_CONF_SERIALCOMM,
};

static const int32_t hwcaps[] = {
	SR_CONF_MULTIMETER,
	SR_CONF_LIMIT_SAMPLES,
	SR_CONF_LIMIT_MSEC,
	SR_CONF_CONTINUOUS,
};

static int init_1x_2x_rs232(struct sr_context *sr_ctx)
{
	return std_init(sr_ctx, di, LOG_PREFIX);
}

/**
 * Read single byte from serial port.
 *
 * @retval -1 Timeout or error.
 * @retval other Byte.
 */
static int read_byte(struct sr_serial_dev_inst *serial, gint64 timeout)
{
	uint8_t result = 0;
	int rc = 0;

	for (;;) {
		rc = serial_read(serial, &result, 1);
		if (rc == 1) {
			sr_spew("read: 0x%02x/%d", result, result);
			return result;
		}
		if (g_get_monotonic_time() > timeout)
			return -1;
		g_usleep(2000);
	}
}

/**
 * Try to detect GMC 1x/2x multimeter model in send mode for max. 1 second.
 *
 * @param serial Configured, open serial port.
 *
 * @retval NULL Detection failed.
 * @retval other Model code.
 */
static enum model scan_model_sm(struct sr_serial_dev_inst *serial)
{
	int byte, bytecnt, cnt;
	enum model model;
	gint64 timeout_us;

	model = SR_METRAHIT_NONE;
	timeout_us = g_get_monotonic_time() + 1 * 1000 * 1000;

	/*
	 * Try to find message consisting of device code and several
	 * (at least 4) data bytes.
	 */
	for (bytecnt = 0; bytecnt < 100; bytecnt++) {
		byte = read_byte(serial, timeout_us);
		if ((byte == -1) || (timeout_us < g_get_monotonic_time()))
			break;
		if ((byte & MSGID_MASK) == MSGID_INF) {
			if (!(model = sr_gmc_decode_model_sm(byte & MSGC_MASK)))
				break;
			/* Now expect (at least) 4 data bytes. */
			for (cnt = 0; cnt < 4; cnt++) {
				byte = read_byte(serial, timeout_us);
				if ((byte == -1) ||
					((byte & MSGID_MASK) != MSGID_DATA))
				{
					model = SR_METRAHIT_NONE;
					bytecnt = 100;
					break;
				}
			}
			break;
		}
	}

	return model;
}

/**
 * Scan for Metrahit 1x and Metrahit 2x in send mode using Gossen Metrawatt
 * 'RS232' interface.
 *
 * The older 1x models use 8192 baud and the newer 2x 9600 baud.
 * The DMM usually sends up to about 20 messages per second. However, depending
 * on configuration and measurement mode the intervals can be much larger and
 * then the detection might not work.
 */
static GSList *scan_1x_2x_rs232(GSList *options)
{
	struct sr_dev_inst *sdi;
	struct drv_context *drvc;
	struct dev_context *devc;
	struct sr_config *src;
	struct sr_probe *probe;
	struct sr_serial_dev_inst *serial;
	GSList *l, *devices;
	const char *conn, *serialcomm;
	enum model model;
	gboolean serialcomm_given;

	devices = NULL;
	drvc = di->priv;
	drvc->instances = NULL;
	conn = serialcomm = NULL;
	model = SR_METRAHIT_NONE;
	serialcomm_given = FALSE;

	sr_spew("scan_1x_2x_rs232() called!");

	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;
		case SR_CONF_SERIALCOMM:
			serialcomm = g_variant_get_string(src->data, NULL);
			serialcomm_given = TRUE;
			break;
		}
	}
	if (!conn)
		return NULL;
	if (!serialcomm)
		serialcomm = SERIALCOMM_2X_RS232;

	if (!(serial = sr_serial_dev_inst_new(conn, serialcomm)))
		return NULL;

	if (serial_open(serial, SERIAL_RDWR | SERIAL_NONBLOCK) != SR_OK) {
		sr_serial_dev_inst_free(serial);
		return NULL;
	}

	serial_flush(serial);

	model = scan_model_sm(serial);

	/*
	 * If detection failed and no user-supplied parameters,
	 * try second baud rate.
	 */
	if ((model == SR_METRAHIT_NONE) && !serialcomm_given) {
		serialcomm = SERIALCOMM_1X_RS232;
		g_free(serial->serialcomm);
		serial->serialcomm = g_strdup(serialcomm);
		if (serial_set_paramstr(serial, serialcomm) == SR_OK) {
			serial_flush(serial);
			model = scan_model_sm(serial);
		}
	}

	if (model != SR_METRAHIT_NONE) {
		sr_spew("%s %s detected!", VENDOR_GMC, sr_gmc_model_str(model));
		if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, VENDOR_GMC,
				sr_gmc_model_str(model), "")))
			return NULL;
		if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
			sr_err("Device context malloc failed.");
			return NULL;
		}
		devc->model = model;
		devc->limit_samples = 0;
		devc->limit_msec = 0;
		devc->num_samples = 0;
		devc->elapsed_msec = g_timer_new();
		devc->settings_ok = FALSE;

		sdi->conn = serial;
		sdi->priv = devc;
		sdi->driver = di;
		if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
			return NULL;
		sdi->probes = g_slist_append(sdi->probes, probe);
		drvc->instances = g_slist_append(drvc->instances, sdi);
		devices = g_slist_append(devices, sdi);
	}

	return devices;
}

static GSList *dev_list_1x_2x_rs232(void)
{
	return ((struct drv_context *)(di->priv))->instances;
}

static int dev_clear_1x_2x_rs232(void)
{
	return std_dev_clear(di, NULL);
}

static int dev_close(struct sr_dev_inst *sdi)
{
	struct dev_context *devc;

	std_serial_dev_close(sdi);

	sdi->status = SR_ST_INACTIVE;

	/* Free dynamically allocated resources. */
	if ((devc = sdi->priv) && devc->elapsed_msec) {
		g_timer_destroy(devc->elapsed_msec);
		devc->elapsed_msec = NULL;
		devc->model = SR_METRAHIT_NONE;
	}

	return SR_OK;
}

static int cleanup_sm_rs232(void)
{
	return dev_clear_1x_2x_rs232();
}

/** TODO */
static int config_get(int key, GVariant **data, const struct sr_dev_inst *sdi,
		const struct sr_probe_group *probe_group)
{
	int ret;

	(void)sdi;
	(void)data;
	(void)probe_group;

	ret = SR_OK;
	switch (key) {
	/* TODO */
	default:
		return SR_ERR_NA;
	}

	return ret;
}

static int config_set(int key, GVariant *data, const struct sr_dev_inst *sdi,
		const struct sr_probe_group *probe_group)
{
	struct dev_context *devc;

	(void)probe_group;

	if (sdi->status != SR_ST_ACTIVE)
		return SR_ERR_DEV_CLOSED;

	if (!(devc = sdi->priv)) {
		sr_err("sdi->priv was NULL.");
		return SR_ERR_BUG;
	}

	switch (key) {
	case SR_CONF_LIMIT_MSEC:
		if (g_variant_get_uint64(data) == 0) {
			sr_err("LIMIT_MSEC can't be 0.");
			return SR_ERR;
		}
		devc->limit_msec = g_variant_get_uint64(data);
		sr_dbg("Setting time limit to %" PRIu64 "ms.",
		       devc->limit_msec);
		break;
	case SR_CONF_LIMIT_SAMPLES:
		devc->limit_samples = g_variant_get_uint64(data);
		sr_dbg("Setting sample limit to %" PRIu64 ".",
		       devc->limit_samples);
		break;
	default:
		return SR_ERR_NA;
	}

	return SR_OK;
}

static int config_list(int key, GVariant **data, const struct sr_dev_inst *sdi,
		const struct sr_probe_group *probe_group)
{
	(void)sdi;
	(void)probe_group;

	switch (key) {
	case SR_CONF_SCAN_OPTIONS:
		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
				hwopts, ARRAY_SIZE(hwopts), sizeof(int32_t));
		break;
	case SR_CONF_DEVICE_OPTIONS:
		*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
				hwcaps, ARRAY_SIZE(hwcaps), sizeof(int32_t));
		break;
	default:
		return SR_ERR_NA;
	}

	return SR_OK;
}

static int dev_acq_start_1x_2x_rs232(const struct sr_dev_inst *sdi,
				     void *cb_data)
{
	struct dev_context *devc;
	struct sr_serial_dev_inst *serial;

	if (!sdi || !cb_data || !(devc = sdi->priv))
		return SR_ERR_BUG;

	if (sdi->status != SR_ST_ACTIVE)
		return SR_ERR_DEV_CLOSED;

	devc->cb_data = cb_data;
	devc->settings_ok = FALSE;
	devc->buflen = 0;

	/* Send header packet to the session bus. */
	std_session_send_df_header(cb_data, LOG_PREFIX);

	/* Start timer, if required. */
	if (devc->limit_msec)
		g_timer_start(devc->elapsed_msec);

	/* Poll every 40ms, or whenever some data comes in. */
	serial = sdi->conn;
	serial_source_add(serial, G_IO_IN, 40, gmc_mh_1x_2x_receive_data,
		(void *)sdi);

	return SR_OK;
}

static int dev_acq_stop(struct sr_dev_inst *sdi, void *cb_data)
{
	struct dev_context *devc;

	/* Stop timer, if required. */
	if (sdi && (devc = sdi->priv) && devc->limit_msec)
		g_timer_stop(devc->elapsed_msec);

	return std_serial_dev_acquisition_stop(sdi, cb_data, dev_close,
			sdi->conn, LOG_PREFIX);
}

SR_PRIV struct sr_dev_driver gmc_mh_1x_2x_rs232_driver_info = {
	.name = "gmc-mh-1x-2x-rs232",
	.longname =
		"Gossen Metrawatt Metrahit 1x/2x DMMs, 'RS232' Interface",
	.api_version = 1,
	.init = init_1x_2x_rs232,
	.cleanup = cleanup_sm_rs232,
	.scan = scan_1x_2x_rs232,
	.dev_list = dev_list_1x_2x_rs232,
	.dev_clear = dev_clear_1x_2x_rs232,
	.config_get = config_get,
	.config_set = config_set,
	.config_list = config_list,
	.dev_open = std_serial_dev_open,
	.dev_close = dev_close,
	.dev_acquisition_start = dev_acq_start_1x_2x_rs232,
	.dev_acquisition_stop = dev_acq_stop,
	.priv = NULL,
};
Commit	Line	Data
	1	/*
	2	* This file is part of the libsigrok project.
	3	*
	4	* Copyright (C) 2013 Matthias Heidbrink <m-sigrok@heidbrink.biz>
	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 <string.h>
	21	#include "protocol.h"
	22
	23	/* Serial communication parameters for Metrahit 1x/2x with 'RS232' adaptor */
	24	#define SERIALCOMM_1X_RS232 "8228/6n1/dtr=1/rts=1/flow=0" /* =8192, closer with divider */
	25	#define SERIALCOMM_2X_RS232 "9600/6n1/dtr=1/rts=1/flow=0"
	26	#define VENDOR_GMC "Gossen Metrawatt"
	27
	28	SR_PRIV struct sr_dev_driver gmc_mh_1x_2x_rs232_driver_info;
	29	static struct sr_dev_driver *di = &gmc_mh_1x_2x_rs232_driver_info;
	30
	31	static const int32_t hwopts[] = {
	32	SR_CONF_CONN,
	33	SR_CONF_SERIALCOMM,
	34	};
	35
	36	static const int32_t hwcaps[] = {
	37	SR_CONF_MULTIMETER,
	38	SR_CONF_LIMIT_SAMPLES,
	39	SR_CONF_LIMIT_MSEC,
	40	SR_CONF_CONTINUOUS,
	41	};
	42
	43	static int init_1x_2x_rs232(struct sr_context *sr_ctx)
	44	{
	45	return std_init(sr_ctx, di, LOG_PREFIX);
	46	}
	47
	48	/**
	49	* Read single byte from serial port.
	50	*
	51	* @retval -1 Timeout or error.
	52	* @retval other Byte.
	53	*/
	54	static int read_byte(struct sr_serial_dev_inst *serial, gint64 timeout)
	55	{
	56	uint8_t result = 0;
	57	int rc = 0;
	58
	59	for (;;) {
	60	rc = serial_read(serial, &result, 1);
	61	if (rc == 1) {
	62	sr_spew("read: 0x%02x/%d", result, result);
	63	return result;
	64	}
	65	if (g_get_monotonic_time() > timeout)
	66	return -1;
	67	g_usleep(2000);
	68	}
	69	}
	70
	71	/**
	72	* Try to detect GMC 1x/2x multimeter model in send mode for max. 1 second.
	73	*
	74	* @param serial Configured, open serial port.
	75	*
	76	* @retval NULL Detection failed.
	77	* @retval other Model code.
	78	*/
	79	static enum model scan_model_sm(struct sr_serial_dev_inst *serial)
	80	{
	81	int byte, bytecnt, cnt;
	82	enum model model;
	83	gint64 timeout_us;
	84
	85	model = SR_METRAHIT_NONE;
	86	timeout_us = g_get_monotonic_time() + 1 * 1000 * 1000;
	87
	88	/*
	89	* Try to find message consisting of device code and several
	90	* (at least 4) data bytes.
	91	*/
	92	for (bytecnt = 0; bytecnt < 100; bytecnt++) {
	93	byte = read_byte(serial, timeout_us);
	94	if ((byte == -1) \|\| (timeout_us < g_get_monotonic_time()))
	95	break;
	96	if ((byte & MSGID_MASK) == MSGID_INF) {
	97	if (!(model = sr_gmc_decode_model_sm(byte & MSGC_MASK)))
	98	break;
	99	/* Now expect (at least) 4 data bytes. */
	100	for (cnt = 0; cnt < 4; cnt++) {
	101	byte = read_byte(serial, timeout_us);
	102	if ((byte == -1) \|\|
	103	((byte & MSGID_MASK) != MSGID_DATA))
	104	{
	105	model = SR_METRAHIT_NONE;
	106	bytecnt = 100;
	107	break;
	108	}
	109	}
	110	break;
	111	}
	112	}
	113
	114	return model;
	115	}
	116
	117	/**
	118	* Scan for Metrahit 1x and Metrahit 2x in send mode using Gossen Metrawatt
	119	* 'RS232' interface.
	120	*
	121	* The older 1x models use 8192 baud and the newer 2x 9600 baud.
	122	* The DMM usually sends up to about 20 messages per second. However, depending
	123	* on configuration and measurement mode the intervals can be much larger and
	124	* then the detection might not work.
	125	*/
	126	static GSList scan_1x_2x_rs232(GSList options)
	127	{
	128	struct sr_dev_inst *sdi;
	129	struct drv_context *drvc;
	130	struct dev_context *devc;
	131	struct sr_config *src;
	132	struct sr_probe *probe;
	133	struct sr_serial_dev_inst *serial;
	134	GSList l, devices;
	135	const char conn, serialcomm;
	136	enum model model;
	137	gboolean serialcomm_given;
	138
	139	devices = NULL;
	140	drvc = di->priv;
	141	drvc->instances = NULL;
	142	conn = serialcomm = NULL;
	143	model = SR_METRAHIT_NONE;
	144	serialcomm_given = FALSE;
	145
	146	sr_spew("scan_1x_2x_rs232() called!");
	147
	148	for (l = options; l; l = l->next) {
	149	src = l->data;
	150	switch (src->key) {
	151	case SR_CONF_CONN:
	152	conn = g_variant_get_string(src->data, NULL);
	153	break;
	154	case SR_CONF_SERIALCOMM:
	155	serialcomm = g_variant_get_string(src->data, NULL);
	156	serialcomm_given = TRUE;
	157	break;
	158	}
	159	}
	160	if (!conn)
	161	return NULL;
	162	if (!serialcomm)
	163	serialcomm = SERIALCOMM_2X_RS232;
	164
	165	if (!(serial = sr_serial_dev_inst_new(conn, serialcomm)))
	166	return NULL;
	167
	168	if (serial_open(serial, SERIAL_RDWR \| SERIAL_NONBLOCK) != SR_OK) {
	169	sr_serial_dev_inst_free(serial);
	170	return NULL;
	171	}
	172
	173	serial_flush(serial);
	174
	175	model = scan_model_sm(serial);
	176
	177	/*
	178	* If detection failed and no user-supplied parameters,
	179	* try second baud rate.
	180	*/
	181	if ((model == SR_METRAHIT_NONE) && !serialcomm_given) {
	182	serialcomm = SERIALCOMM_1X_RS232;
	183	g_free(serial->serialcomm);
	184	serial->serialcomm = g_strdup(serialcomm);
	185	if (serial_set_paramstr(serial, serialcomm) == SR_OK) {
	186	serial_flush(serial);
	187	model = scan_model_sm(serial);
	188	}
	189	}
	190
	191	if (model != SR_METRAHIT_NONE) {
	192	sr_spew("%s %s detected!", VENDOR_GMC, sr_gmc_model_str(model));
	193	if (!(sdi = sr_dev_inst_new(0, SR_ST_INACTIVE, VENDOR_GMC,
	194	sr_gmc_model_str(model), "")))
	195	return NULL;
	196	if (!(devc = g_try_malloc0(sizeof(struct dev_context)))) {
	197	sr_err("Device context malloc failed.");
	198	return NULL;
	199	}
	200	devc->model = model;
	201	devc->limit_samples = 0;
	202	devc->limit_msec = 0;
	203	devc->num_samples = 0;
	204	devc->elapsed_msec = g_timer_new();
	205	devc->settings_ok = FALSE;
	206
	207	sdi->conn = serial;
	208	sdi->priv = devc;
	209	sdi->driver = di;
	210	if (!(probe = sr_probe_new(0, SR_PROBE_ANALOG, TRUE, "P1")))
	211	return NULL;
	212	sdi->probes = g_slist_append(sdi->probes, probe);
	213	drvc->instances = g_slist_append(drvc->instances, sdi);
	214	devices = g_slist_append(devices, sdi);
	215	}
	216
	217	return devices;
	218	}
	219
	220	static GSList *dev_list_1x_2x_rs232(void)
	221	{
	222	return ((struct drv_context *)(di->priv))->instances;
	223	}
	224
	225	static int dev_clear_1x_2x_rs232(void)
	226	{
	227	return std_dev_clear(di, NULL);
	228	}
	229
	230	static int dev_close(struct sr_dev_inst *sdi)
	231	{
	232	struct dev_context *devc;
	233
	234	std_serial_dev_close(sdi);
	235
	236	sdi->status = SR_ST_INACTIVE;
	237
	238	/* Free dynamically allocated resources. */
	239	if ((devc = sdi->priv) && devc->elapsed_msec) {
	240	g_timer_destroy(devc->elapsed_msec);
	241	devc->elapsed_msec = NULL;
	242	devc->model = SR_METRAHIT_NONE;
	243	}
	244
	245	return SR_OK;
	246	}
	247
	248	static int cleanup_sm_rs232(void)
	249	{
	250	return dev_clear_1x_2x_rs232();
	251	}
	252
	253	/** TODO */
	254	static int config_get(int key, GVariant *data, const struct sr_dev_inst sdi,
	255	const struct sr_probe_group *probe_group)
	256	{
	257	int ret;
	258
	259	(void)sdi;
	260	(void)data;
	261	(void)probe_group;
	262
	263	ret = SR_OK;
	264	switch (key) {
	265	/* TODO */
	266	default:
	267	return SR_ERR_NA;
	268	}
	269
	270	return ret;
	271	}
	272
	273	static int config_set(int key, GVariant data, const struct sr_dev_inst sdi,
	274	const struct sr_probe_group *probe_group)
	275	{
	276	struct dev_context *devc;
	277
	278	(void)probe_group;
	279
	280	if (sdi->status != SR_ST_ACTIVE)
	281	return SR_ERR_DEV_CLOSED;
	282
	283	if (!(devc = sdi->priv)) {
	284	sr_err("sdi->priv was NULL.");
	285	return SR_ERR_BUG;
	286	}
	287
	288	switch (key) {
	289	case SR_CONF_LIMIT_MSEC:
	290	if (g_variant_get_uint64(data) == 0) {
	291	sr_err("LIMIT_MSEC can't be 0.");
	292	return SR_ERR;
	293	}
	294	devc->limit_msec = g_variant_get_uint64(data);
	295	sr_dbg("Setting time limit to %" PRIu64 "ms.",
	296	devc->limit_msec);
	297	break;
	298	case SR_CONF_LIMIT_SAMPLES:
	299	devc->limit_samples = g_variant_get_uint64(data);
	300	sr_dbg("Setting sample limit to %" PRIu64 ".",
	301	devc->limit_samples);
	302	break;
	303	default:
	304	return SR_ERR_NA;
	305	}
	306
	307	return SR_OK;
	308	}
	309
	310	static int config_list(int key, GVariant *data, const struct sr_dev_inst sdi,
	311	const struct sr_probe_group *probe_group)
	312	{
	313	(void)sdi;
	314	(void)probe_group;
	315
	316	switch (key) {
	317	case SR_CONF_SCAN_OPTIONS:
	318	*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
	319	hwopts, ARRAY_SIZE(hwopts), sizeof(int32_t));
	320	break;
	321	case SR_CONF_DEVICE_OPTIONS:
	322	*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
	323	hwcaps, ARRAY_SIZE(hwcaps), sizeof(int32_t));
	324	break;
	325	default:
	326	return SR_ERR_NA;
	327	}
	328
	329	return SR_OK;
	330	}
	331
	332	static int dev_acq_start_1x_2x_rs232(const struct sr_dev_inst *sdi,
	333	void *cb_data)
	334	{
	335	struct dev_context *devc;
	336	struct sr_serial_dev_inst *serial;
	337
	338	if (!sdi \|\| !cb_data \|\| !(devc = sdi->priv))
	339	return SR_ERR_BUG;
	340
	341	if (sdi->status != SR_ST_ACTIVE)
	342	return SR_ERR_DEV_CLOSED;
	343
	344	devc->cb_data = cb_data;
	345	devc->settings_ok = FALSE;
	346	devc->buflen = 0;
	347
	348	/* Send header packet to the session bus. */
	349	std_session_send_df_header(cb_data, LOG_PREFIX);
	350
	351	/* Start timer, if required. */
	352	if (devc->limit_msec)
	353	g_timer_start(devc->elapsed_msec);
	354
	355	/* Poll every 40ms, or whenever some data comes in. */
	356	serial = sdi->conn;
	357	serial_source_add(serial, G_IO_IN, 40, gmc_mh_1x_2x_receive_data,
	358	(void *)sdi);
	359
	360	return SR_OK;
	361	}
	362
	363	static int dev_acq_stop(struct sr_dev_inst sdi, void cb_data)
	364	{
	365	struct dev_context *devc;
	366
	367	/* Stop timer, if required. */
	368	if (sdi && (devc = sdi->priv) && devc->limit_msec)
	369	g_timer_stop(devc->elapsed_msec);
	370
	371	return std_serial_dev_acquisition_stop(sdi, cb_data, dev_close,
	372	sdi->conn, LOG_PREFIX);
	373	}
	374
	375	SR_PRIV struct sr_dev_driver gmc_mh_1x_2x_rs232_driver_info = {
	376	.name = "gmc-mh-1x-2x-rs232",
	377	.longname =
	378	"Gossen Metrawatt Metrahit 1x/2x DMMs, 'RS232' Interface",
	379	.api_version = 1,
	380	.init = init_1x_2x_rs232,
	381	.cleanup = cleanup_sm_rs232,
	382	.scan = scan_1x_2x_rs232,
	383	.dev_list = dev_list_1x_2x_rs232,
	384	.dev_clear = dev_clear_1x_2x_rs232,
	385	.config_get = config_get,
	386	.config_set = config_set,
	387	.config_list = config_list,
	388	.dev_open = std_serial_dev_open,
	389	.dev_close = dev_close,
	390	.dev_acquisition_start = dev_acq_start_1x_2x_rs232,
	391	.dev_acquisition_stop = dev_acq_stop,
	392	.priv = NULL,
	393	};