hameg-hmo: Add support for sample rate fetching.

[libsigrok.git] / hardware / hameg-hmo / api.c

/*
 * This file is part of the libsigrok project.
 *
 * Copyright (C) 2013 poljar (Damir Jelić) <poljarinho@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 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 <stdlib.h>
#include <glib/gstdio.h>
#include "protocol.h"

#define SERIALCOMM "115200/8n1/flow=1"

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

static const char *manufacturers[] = {
	"HAMEG",
};

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

struct usb_id_info {
	uint16_t vendor_id;
	uint16_t product_id;
};

static struct usb_id_info ho_models[] = {
	{ 0x0403, 0xed72 }, /* HO720 */
	{ 0x0403, 0xed73 }, /* HO730 */
};

enum {
	PG_INVALID = -1,
	PG_NONE,
	PG_ANALOG,
	PG_DIGITAL,
};

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

/**
 * Find USB serial devices via the USB vendor ID and product ID.
 *
 * @param vendor_id Vendor ID of the USB device.
 * @param product_id Product ID of the USB device.
 *
 * @return A GSList of strings containing the path of the serial device or
 *         NULL if no serial device is found. The returned list must be freed
 *         by the caller.
 */
static GSList *auto_find_usb(uint16_t vendor_id, uint16_t product_id)
{
#ifdef __linux__
	const gchar *usb_dev;
	const char device_tree[] = "/sys/bus/usb/devices/";
	GDir *devices_dir, *device_dir;
	GSList *l = NULL;
	GSList *tty_devs;
	GSList *matched_paths;
	FILE *fd;
	char tmp[5];
	gchar *vendor_path, *product_path, *path_copy;
	gchar *prefix, *subdir_path, *device_path, *tty_path;
	unsigned long read_vendor_id, read_product_id;
	const char *file;

	l = NULL;
	tty_devs = NULL;
	matched_paths = NULL;

	if (!(devices_dir = g_dir_open(device_tree, 0, NULL)))
		return NULL;

	/*
	 * Find potential candidates using the vendor ID and product ID
	 * and store them in matched_paths.
	 */
	while ((usb_dev = g_dir_read_name(devices_dir))) {
		vendor_path = g_strconcat(device_tree,
					  usb_dev, "/idVendor", NULL);
		product_path = g_strconcat(device_tree,
					   usb_dev, "/idProduct", NULL);

		if (!g_file_test(vendor_path, G_FILE_TEST_EXISTS) ||
		    !g_file_test(product_path, G_FILE_TEST_EXISTS))
			goto skip_device;

		if ((fd = g_fopen(vendor_path, "r")) == NULL)
			goto skip_device;

		if (fgets(tmp, sizeof(tmp), fd) == NULL) {
			fclose(fd);
			goto skip_device;
		}
		read_vendor_id = strtoul(tmp, NULL, 16);

		fclose(fd);

		if ((fd = g_fopen(product_path, "r")) == NULL)
			goto skip_device;

		if (fgets(tmp, sizeof(tmp), fd) == NULL) {
			fclose(fd);
			goto skip_device;
		}
		read_product_id = strtoul(tmp, NULL, 16);

		fclose(fd);

		if (vendor_id == read_vendor_id &&
		    product_id == read_product_id) {
			path_copy = g_strdup(usb_dev);
			matched_paths = g_slist_prepend(matched_paths,
							path_copy);
		}

skip_device:
		g_free(vendor_path);
		g_free(product_path);
	}
	g_dir_close(devices_dir);

	/* For every matched device try to find a ttyUSBX subfolder. */
	for (l = matched_paths; l; l = l->next) {
		subdir_path = NULL;

		device_path = g_strconcat(device_tree, l->data, NULL);

		if (!(device_dir = g_dir_open(device_path, 0, NULL))) {
			g_free(device_path);
			continue;
		}

		prefix = g_strconcat(l->data, ":", NULL);

		while ((file = g_dir_read_name(device_dir))) {
			if (g_str_has_prefix(file, prefix)) {
				subdir_path = g_strconcat(device_path,
						"/", file, NULL);
				break;
			}
		}
		g_dir_close(device_dir);

		g_free(prefix);
		g_free(device_path);

		if (subdir_path) {
			if (!(device_dir = g_dir_open(subdir_path, 0, NULL))) {
				g_free(subdir_path);
				continue;
			}
			g_free(subdir_path);

			while ((file = g_dir_read_name(device_dir))) {
				if (g_str_has_prefix(file, "ttyUSB")) {
					tty_path = g_strconcat("/dev/",
							       file, NULL);
					sr_dbg("Found USB device %04x:%04x attached to %s.",
					       vendor_id, product_id, tty_path);
					tty_devs = g_slist_prepend(tty_devs,
							tty_path);
					break;
				}
			}
			g_dir_close(device_dir);
		}
	}
	g_slist_free_full(matched_paths, g_free);

	return tty_devs;
#else
	return NULL;
#endif
}

static int check_manufacturer(const char *manufacturer)
{
	unsigned int i;

	for (i = 0; i < ARRAY_SIZE(manufacturers); ++i)
		if (!strcmp(manufacturer, manufacturers[i]))
			return SR_OK;

	return SR_ERR;
}

static struct sr_dev_inst *hmo_probe_serial_device(const char *serial_device,
						    const char *serial_options)
{
	struct sr_dev_inst *sdi;
	struct dev_context *devc;
	struct sr_scpi_hw_info *hw_info;
	struct sr_scpi_dev_inst *scpi;

	sdi = NULL;
	devc = NULL;
	scpi = NULL;
	hw_info = NULL;

	if (!(scpi = scpi_dev_inst_new(serial_device, serial_options)))
		goto fail;

	sr_info("Probing %s.", serial_device);
	if (sr_scpi_open(scpi) != SR_OK)
		goto fail;

	if (sr_scpi_get_hw_id(scpi, &hw_info) != SR_OK) {
		sr_info("Couldn't get IDN response.");
		goto fail;
	}

	if (check_manufacturer(hw_info->manufacturer) != SR_OK)
		goto fail;

	if (!(sdi = sr_dev_inst_new(0, SR_ST_ACTIVE,
				    hw_info->manufacturer, hw_info->model,
				    hw_info->firmware_version))) {
		goto fail;
	}
	sr_scpi_hw_info_free(hw_info);
	hw_info = NULL;

	if (!(devc = g_try_malloc0(sizeof(struct dev_context))))
		goto fail;

	sdi->driver = di;
	sdi->priv = devc;
	sdi->inst_type = SR_INST_SCPI;
	sdi->conn = scpi;

	if (hmo_init_device(sdi) != SR_OK)
		goto fail;

	sr_scpi_close(sdi->conn);

	sdi->status = SR_ST_INACTIVE;

	return sdi;

fail:
	if (hw_info)
		sr_scpi_hw_info_free(hw_info);
	if (scpi)
		sr_scpi_free(scpi);
	if (sdi)
		sr_dev_inst_free(sdi);
	if (devc)
		g_free(devc);

	return NULL;
}

static GSList *scan(GSList *options)
{
	GSList *devices;
	struct drv_context *drvc;
	struct sr_dev_inst *sdi;
	const char *serial_device, *serial_options;
	GSList *l, *tty_devs;
	unsigned int i;

	serial_device = NULL;
	serial_options = SERIALCOMM;
	sdi = NULL;
	devices = NULL;
	drvc = di->priv;
	drvc->instances = NULL;

	if (sr_serial_extract_options(options, &serial_device,
				      &serial_options) == SR_OK) {
		sdi = hmo_probe_serial_device(serial_device, serial_options);
		if (sdi != NULL) {
			devices = g_slist_append(devices, sdi);
			drvc->instances = g_slist_append(drvc->instances, sdi);
		}
	} else {
		tty_devs = NULL;

		for (i = 0; i < ARRAY_SIZE(ho_models); i++) {
			if ((l = auto_find_usb(ho_models[i].vendor_id,
					   ho_models[i].product_id)) == NULL)
				continue;
			tty_devs = g_slist_concat(tty_devs, l);
		}

		for (l = tty_devs; l; l = l->next) {
			sdi = hmo_probe_serial_device(l->data, serial_options);
			if (sdi != NULL) {
				devices = g_slist_append(devices, sdi);
				drvc->instances = g_slist_append(drvc->instances, sdi);
			}
		}

		g_slist_free_full(tty_devs, g_free);
	}

	return devices;
}

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

static void clear_helper(void *priv)
{
	unsigned int i;
	struct dev_context *devc;
	struct scope_config *model;

	devc = priv;
	model = devc->model_config;

	hmo_scope_state_free(devc->model_state);

	for (i = 0; i < model->analog_channels; ++i)
		g_slist_free(devc->analog_groups[i].probes);

	for (i = 0; i < model->digital_pods; ++i) {
		g_slist_free(devc->digital_groups[i].probes);
		g_free(devc->digital_groups[i].name);
	}

	g_free(devc->analog_groups);
	g_free(devc->digital_groups);

	g_free(devc);
}

static int dev_clear(void)
{
	return std_dev_clear(di, clear_helper);
}

static int dev_open(struct sr_dev_inst *sdi)
{
	if (sdi->status != SR_ST_ACTIVE && sr_scpi_open(sdi->conn) != SR_OK)
		return SR_ERR;

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

	sdi->status = SR_ST_ACTIVE;

	return SR_OK;
}

static int dev_close(struct sr_dev_inst *sdi)
{
	if (sdi->status == SR_ST_INACTIVE)
		return SR_OK;

	sr_scpi_close(sdi->conn);

	sdi->status = SR_ST_INACTIVE;

	return SR_OK;
}

static int cleanup(void)
{
	dev_clear();

	return SR_OK;
}

static int check_probe_group(struct dev_context *devc,
			     const struct sr_probe_group *probe_group)
{
	unsigned int i;
	struct scope_config *model;

	model = devc->model_config;

	if (!probe_group)
		return PG_NONE;

	for (i = 0; i < model->analog_channels; ++i)
		if (probe_group == &devc->analog_groups[i])
			return PG_ANALOG;

	for (i = 0; i < model->digital_pods; ++i)
		if (probe_group == &devc->digital_groups[i])
			return PG_DIGITAL;

	sr_err("Invalid probe group specified.");

	return PG_INVALID;
}

static int config_get(int key, GVariant **data, const struct sr_dev_inst *sdi,
		      const struct sr_probe_group *probe_group)
{
	int ret, pg_type;
	unsigned int i;
	struct dev_context *devc;
	struct scope_config *model;
	struct scope_state *state;

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

	if ((pg_type = check_probe_group(devc, probe_group)) == PG_INVALID)
		return SR_ERR;

	ret = SR_ERR_NA;
	model = devc->model_config;
	state = devc->model_state;

	switch (key) {
	case SR_CONF_NUM_TIMEBASE:
		*data = g_variant_new_int32(model->num_xdivs);
		ret = SR_OK;
		break;
	case SR_CONF_NUM_VDIV:
		if (pg_type == PG_NONE) {
			sr_err("No probe group specified.");
			return SR_ERR_PROBE_GROUP;
		} else if (pg_type == PG_ANALOG) {
			for (i = 0; i < model->analog_channels; ++i) {
				if (probe_group != &devc->analog_groups[i])
					continue;
				*data = g_variant_new_int32(model->num_ydivs);
				ret = SR_OK;
				break;
			}

		} else {
			ret = SR_ERR_NA;
		}
		break;
	case SR_CONF_SAMPLERATE:
		*data = g_variant_new_uint64(state->sample_rate);
		ret = SR_OK;
		break;
	default:
		ret = SR_ERR_NA;
	}

	return ret;
}

static GVariant *build_tuples(const uint64_t (*array)[][2], unsigned int n)
{
	unsigned int i;
	GVariant *rational[2];
	GVariantBuilder gvb;

	g_variant_builder_init(&gvb, G_VARIANT_TYPE_ARRAY);

	for (i = 0; i < n; i++) {
		rational[0] = g_variant_new_uint64((*array)[i][0]);
		rational[1] = g_variant_new_uint64((*array)[i][1]);

		/* FIXME: Valgrind reports a memory leak here. */
		g_variant_builder_add_value(&gvb, g_variant_new_tuple(rational, 2));
	}

	return g_variant_builder_end(&gvb);
}

static int config_set(int key, GVariant *data, const struct sr_dev_inst *sdi,
		      const struct sr_probe_group *probe_group)
{
	int ret, pg_type;
	unsigned int i, j;
	char command[MAX_COMMAND_SIZE], float_str[30];
	struct dev_context *devc;
	struct scope_config *model;
	struct scope_state *state;
	const char *tmp;
	uint64_t p, q, tmp_u64;
	double tmp_d;

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

	if ((pg_type = check_probe_group(devc, probe_group)) == PG_INVALID)
		return SR_ERR;

	model = devc->model_config;
	state = devc->model_state;

	ret = SR_ERR_NA;

	switch (key) {
	case SR_CONF_LIMIT_FRAMES:
		devc->frame_limit = g_variant_get_uint64(data);
		ret = SR_OK;
		break;
	case SR_CONF_TRIGGER_SOURCE:
		tmp = g_variant_get_string(data, NULL);
		for (i = 0; (*model->trigger_sources)[i]; i++) {
			if (g_strcmp0(tmp, (*model->trigger_sources)[i]) != 0)
				continue;
			state->trigger_source = i;
			g_snprintf(command, sizeof(command),
				   (*model->scpi_dialect)[SCPI_CMD_SET_TRIGGER_SOURCE],
				   (*model->trigger_sources)[i]);

			ret = sr_scpi_send(sdi->conn, command);
			break;
		}
		break;
	case SR_CONF_VDIV:
		if (pg_type == PG_NONE) {
			sr_err("No probe group specified.");
			return SR_ERR_PROBE_GROUP;
		}

		g_variant_get(data, "(tt)", &p, &q);

		for (i = 0; i < model->num_vdivs; i++) {
			if (p != (*model->vdivs)[i][0] ||
			    q != (*model->vdivs)[i][1])
				continue;
			for (j = 1; j <= model->analog_channels; ++j) {
				if (probe_group != &devc->analog_groups[j - 1])
					continue;
				state->analog_channels[j - 1].vdiv = i;
				g_ascii_formatd(float_str, sizeof(float_str), "%E", (float) p / q);
				g_snprintf(command, sizeof(command),
					   (*model->scpi_dialect)[SCPI_CMD_SET_VERTICAL_DIV],
					   j, float_str);

				if (sr_scpi_send(sdi->conn, command) != SR_OK ||
				    sr_scpi_get_opc(sdi->conn) != SR_OK)
					return SR_ERR;

				break;
			}

			ret = SR_OK;
			break;
		}
		break;
	case SR_CONF_TIMEBASE:
		g_variant_get(data, "(tt)", &p, &q);

		for (i = 0; i < model->num_timebases; i++) {
			if (p != (*model->timebases)[i][0] ||
			    q != (*model->timebases)[i][1])
				continue;
			state->timebase = i;
			g_ascii_formatd(float_str, sizeof(float_str), "%E", (float) p / q);
			g_snprintf(command, sizeof(command),
				   (*model->scpi_dialect)[SCPI_CMD_SET_TIMEBASE],
				   float_str);

			ret = sr_scpi_send(sdi->conn, command);
			break;
		}
		break;
	case SR_CONF_HORIZ_TRIGGERPOS:
		tmp_d = g_variant_get_double(data);

		if (tmp_d < 0.0 || tmp_d > 1.0)
			return SR_ERR;

		state->horiz_triggerpos = -(tmp_d - 0.5) * state->timebase * model->num_xdivs;
		g_snprintf(command, sizeof(command),
			   (*model->scpi_dialect)[SCPI_CMD_SET_HORIZ_TRIGGERPOS],
			   state->horiz_triggerpos);

		ret = sr_scpi_send(sdi->conn, command);
		break;
	case SR_CONF_TRIGGER_SLOPE:
		tmp_u64 = g_variant_get_uint64(data);

		if (tmp_u64 != 0 && tmp_u64 != 1)
			return SR_ERR;

		state->trigger_slope = tmp_u64;

		g_snprintf(command, sizeof(command),
			   (*model->scpi_dialect)[SCPI_CMD_SET_TRIGGER_SLOPE],
			   tmp_u64 ? "POS" : "NEG");

		ret = sr_scpi_send(sdi->conn, command);
		break;
	case SR_CONF_COUPLING:
		if (pg_type == PG_NONE) {
			sr_err("No probe group specified.");
			return SR_ERR_PROBE_GROUP;
		}

		tmp = g_variant_get_string(data, NULL);

		for (i = 0; (*model->coupling_options)[i]; i++) {
			if (strcmp(tmp, (*model->coupling_options)[i]) != 0)
				continue;
			for (j = 1; j <= model->analog_channels; ++j) {
				if (probe_group != &devc->analog_groups[j - 1])
					continue;
				state->analog_channels[j-1].coupling = i;

				g_snprintf(command, sizeof(command),
					   (*model->scpi_dialect)[SCPI_CMD_SET_COUPLING],
					   j, tmp);

				if (sr_scpi_send(sdi->conn, command) != SR_OK ||
				    sr_scpi_get_opc(sdi->conn) != SR_OK)
					return SR_ERR;
				break;
			}

			ret = SR_OK;
			break;
		}
		break;
	default:
		ret = SR_ERR_NA;
		break;
	}

	if (ret == SR_OK)
		ret = sr_scpi_get_opc(sdi->conn);

	return ret;
}

static int config_list(int key, GVariant **data, const struct sr_dev_inst *sdi,
		       const struct sr_probe_group *probe_group)
{
	int pg_type;
	struct dev_context *devc;
	struct scope_config *model;

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

	if ((pg_type = check_probe_group(devc, probe_group)) == PG_INVALID)
		return SR_ERR;

	model = devc->model_config;

	switch (key) {
	case SR_CONF_DEVICE_OPTIONS:
		if (pg_type == PG_NONE) {
			*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
				model->hw_caps, model->num_hwcaps,
				sizeof(int32_t));
		} else if (pg_type == PG_ANALOG) {
			*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
				model->analog_hwcaps, model->num_analog_hwcaps,
				sizeof(int32_t));
		} else {
			*data = g_variant_new_fixed_array(G_VARIANT_TYPE_INT32,
				NULL, 0, sizeof(int32_t));
		}
		break;
	case SR_CONF_COUPLING:
		if (pg_type == PG_NONE)
			return SR_ERR_PROBE_GROUP;
		*data = g_variant_new_strv(*model->coupling_options,
			   g_strv_length((char **)*model->coupling_options));
		break;
	case SR_CONF_TRIGGER_SOURCE:
		*data = g_variant_new_strv(*model->trigger_sources,
			   g_strv_length((char **)*model->trigger_sources));
		break;
	case SR_CONF_TIMEBASE:
		*data = build_tuples(model->timebases, model->num_timebases);
		break;
	case SR_CONF_VDIV:
		if (pg_type == PG_NONE)
			return SR_ERR_PROBE_GROUP;
		*data = build_tuples(model->vdivs, model->num_vdivs);
		break;
	default:
		return SR_ERR_NA;
	}

	return SR_OK;
}

SR_PRIV int hmo_request_data(const struct sr_dev_inst *sdi)
{
	char command[MAX_COMMAND_SIZE];
	struct sr_probe *probe;
	struct dev_context *devc;
	struct scope_config *model;

	devc = sdi->priv;
	model = devc->model_config;

	probe = devc->current_probe->data;

	switch (probe->type) {
	case SR_PROBE_ANALOG:
		g_snprintf(command, sizeof(command),
			   (*model->scpi_dialect)[SCPI_CMD_GET_ANALOG_DATA],
			   probe->index + 1);
		break;
	case SR_PROBE_LOGIC:
		g_snprintf(command, sizeof(command),
			   (*model->scpi_dialect)[SCPI_CMD_GET_DIG_DATA],
			   probe->index < 8 ? 1 : 2);
		break;
	default:
		sr_err("Invalid probe type.");
		break;
	}

	return sr_scpi_send(sdi->conn, command);
}

static int hmo_check_probes(GSList *probes)
{
	GSList *l;
	struct sr_probe *probe;
	gboolean enabled_pod1, enabled_pod2, enabled_chan3, enabled_chan4;

	enabled_pod1 = enabled_pod2 = enabled_chan3 = enabled_chan4 = FALSE;

	for (l = probes; l; l = l->next) {
		probe = l->data;
		switch (probe->type) {
		case SR_PROBE_ANALOG:
			if (probe->index == 2)
				enabled_chan3 = TRUE;
			else if (probe->index == 3)
				enabled_chan4 = TRUE;
			break;
		case SR_PROBE_LOGIC:
			if (probe->index < 8)
				enabled_pod1 = TRUE;
			else
				enabled_pod2 = TRUE;
			break;
		default:
			return SR_ERR;
		}
	}

	if ((enabled_pod1 && enabled_chan3) ||
	    (enabled_pod2 && enabled_chan4))
		return SR_ERR;

	return SR_OK;
}

static int hmo_setup_probes(const struct sr_dev_inst *sdi)
{
	GSList *l;
	unsigned int i;
	gboolean *pod_enabled;
	char command[MAX_COMMAND_SIZE];
	struct scope_state *state;
	struct scope_config *model;
	struct sr_probe *probe;
	struct dev_context *devc;
	struct sr_scpi_dev_inst *scpi;

	devc = sdi->priv;
	scpi = sdi->conn;
	state = devc->model_state;
	model = devc->model_config;

	pod_enabled = g_try_malloc0(sizeof(gboolean) * model->digital_pods);

	for (l = sdi->probes; l; l = l->next) {
		probe = l->data;
		switch (probe->type) {
		case SR_PROBE_ANALOG:
			if (probe->enabled == state->analog_channels[probe->index].state)
				break;
			g_snprintf(command, sizeof(command),
				   (*model->scpi_dialect)[SCPI_CMD_SET_ANALOG_CHAN_STATE],
				   probe->index + 1, probe->enabled);

			if (sr_scpi_send(scpi, command) != SR_OK)
				return SR_ERR;
			state->analog_channels[probe->index].state = probe->enabled;
			break;
		case SR_PROBE_LOGIC:
			/*
			 * A digital POD needs to be enabled for every group of
			 * 8 probes.
			 */
			if (probe->enabled)
				pod_enabled[probe->index < 8 ? 0 : 1] = TRUE;

			if (probe->enabled == state->digital_channels[probe->index])
				break;
			g_snprintf(command, sizeof(command),
				   (*model->scpi_dialect)[SCPI_CMD_SET_DIG_CHAN_STATE],
				   probe->index, probe->enabled);

			if (sr_scpi_send(scpi, command) != SR_OK)
				return SR_ERR;

			state->digital_channels[probe->index] = probe->enabled;
			break;
		default:
			return SR_ERR;
		}
	}

	for (i = 1; i <= model->digital_pods; ++i) {
		if (state->digital_pods[i - 1] == pod_enabled[i - 1])
			continue;
		g_snprintf(command, sizeof(command),
			   (*model->scpi_dialect)[SCPI_CMD_SET_DIG_POD_STATE],
			   i, pod_enabled[i - 1]);
		if (sr_scpi_send(scpi, command) != SR_OK)
			return SR_ERR;
		state->digital_pods[i - 1] = pod_enabled[i - 1];
	}

	g_free(pod_enabled);

	return SR_OK;
}

static int dev_acquisition_start(const struct sr_dev_inst *sdi, void *cb_data)
{
	GSList *l;
	gboolean digital_added;
	struct sr_probe *probe;
	struct dev_context *devc;
	struct sr_scpi_dev_inst *scpi;

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

	scpi = sdi->conn;
	devc = sdi->priv;
	digital_added = FALSE;

	for (l = sdi->probes; l; l = l->next) {
		probe = l->data;
		if (!probe->enabled)
			continue;
		/* Only add a single digital probe. */
		if (probe->type != SR_PROBE_LOGIC || !digital_added) {
			devc->enabled_probes = g_slist_append(
					devc->enabled_probes, probe);
			if (probe->type == SR_PROBE_LOGIC)
				digital_added = TRUE;
		}
	}

	if (!devc->enabled_probes)
		return SR_ERR;

	if (hmo_check_probes(devc->enabled_probes) != SR_OK) {
		sr_err("Invalid probe configuration specified!");
		return SR_ERR_NA;
	}

	if (hmo_setup_probes(sdi) != SR_OK) {
		sr_err("Failed to setup probe configuration!");
		return SR_ERR;
	}

	sr_scpi_source_add(scpi, G_IO_IN, 50, hmo_receive_data, (void *)sdi);

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

	devc->current_probe = devc->enabled_probes;

	return hmo_request_data(sdi);
}

static int dev_acquisition_stop(struct sr_dev_inst *sdi, void *cb_data)
{
	struct dev_context *devc;
	struct sr_scpi_dev_inst *scpi;
	struct sr_datafeed_packet packet;

	(void)cb_data;

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

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

	devc = sdi->priv;

	g_slist_free(devc->enabled_probes);
	devc->enabled_probes = NULL;
	scpi = sdi->conn;
	sr_scpi_source_remove(scpi);

	return SR_OK;
}

SR_PRIV struct sr_dev_driver hameg_hmo_driver_info = {
	.name = "hameg-hmo",
	.longname = "Hameg HMO",
	.api_version = 1,
	.init = init,
	.cleanup = cleanup,
	.scan = scan,
	.dev_list = dev_list,
	.dev_clear = dev_clear,
	.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,
	.priv = NULL,
};