X-Git-Url: https://sigrok.org/gitweb/?a=blobdiff_plain;f=src%2Fhardware%2Fhp-3457a%2Fapi.c;h=4cfc2d758b54e79625609d408ef0f506d028a5b7;hb=713a3f352496f928b9911bfdc7e87a67134113df;hp=23ac98517fbcc94c06744cea82ee45e66cf76714;hpb=e66d1892d0dd16ed166fc8f13493f95de0607362;p=libsigrok.git

diff --git a/src/hardware/hp-3457a/api.c b/src/hardware/hp-3457a/api.c
index 23ac9851..4cfc2d75 100644
--- a/src/hardware/hp-3457a/api.c
+++ b/src/hardware/hp-3457a/api.c
@@ -127,6 +127,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 	struct sr_dev_inst *sdi;
 	struct dev_context *devc;
 
+	/*
+	 * The device cannot get identified by means of SCPI queries.
+	 * Neither shall non-SCPI requests get emitted before reliable
+	 * identification of the device. Assume that we only get here
+	 * when user specs led us to believe it's safe to communicate
+	 * to the expected kind of device.
+	 */
+
 	/*
 	 * This command ensures we receive an EOI after every response, so that
 	 * we don't wait the entire timeout after the response is received.
@@ -138,13 +146,15 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 	if ((ret != SR_OK) || !response)
 		return NULL;
 
-	if (strcmp(response, "HP3457A"))
+	if (strcmp(response, "HP3457A") != 0) {
+		g_free(response);
 		return NULL;
+	}
 
 	g_free(response);
 
-	devc = g_malloc0(sizeof(struct dev_context));
-	sdi = g_malloc0(sizeof(struct sr_dev_inst));
+	devc = g_malloc0(sizeof(*devc));
+	sdi = g_malloc0(sizeof(*sdi));
 	sdi->vendor = g_strdup("Hewlett-Packard");
 	sdi->model = g_strdup("3457A");
 	sdi->version = get_revision(scpi);
@@ -168,6 +178,14 @@ static struct sr_dev_inst *probe_device(struct sr_scpi_dev_inst *scpi)
 
 static GSList *scan(struct sr_dev_driver *di, GSList *options)
 {
+	const char *conn;
+
+	/* Only scan for a device when conn= was specified. */
+	conn = NULL;
+	(void)sr_serial_extract_options(options, &conn, NULL);
+	if (!conn)
+		return NULL;
+
 	return sr_scpi_scan(di->context, options, probe_device);
 }
 
@@ -243,10 +261,8 @@ static int config_get(uint32_t key, GVariant **data,
 }
 
 static int config_set(uint32_t key, GVariant *data,
-		      const struct sr_dev_inst *sdi,
-		      const struct sr_channel_group *cg)
+	const struct sr_dev_inst *sdi, const struct sr_channel_group *cg)
 {
-	int ret;
 	enum sr_mq mq;
 	enum sr_mqflag mq_flags;
 	struct dev_context *devc;
@@ -256,7 +272,6 @@ static int config_set(uint32_t key, GVariant *data,
 
 	devc = sdi->priv;
 
-	ret = SR_OK;
 	switch (key) {
 	case SR_CONF_LIMIT_SAMPLES:
 		devc->limit_samples = g_variant_get_uint64(data);
@@ -266,17 +281,15 @@ static int config_set(uint32_t key, GVariant *data,
 		mq = g_variant_get_uint32(tuple_child);
 		tuple_child = g_variant_get_child_value(data, 1);
 		mq_flags = g_variant_get_uint64(tuple_child);
-		ret = hp_3457a_set_mq(sdi, mq, mq_flags);
 		g_variant_unref(tuple_child);
-		break;
+		return hp_3457a_set_mq(sdi, mq, mq_flags);
 	case SR_CONF_ADC_POWERLINE_CYCLES:
-		ret = hp_3457a_set_nplc(sdi, g_variant_get_double(data));
-		break;
+		return hp_3457a_set_nplc(sdi, g_variant_get_double(data));
 	default:
-		ret = SR_ERR_NA;
+		return SR_ERR_NA;
 	}
 
-	return ret;
+	return SR_OK;
 }
 
 static int config_list(uint32_t key, GVariant **data,
@@ -364,8 +377,13 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi)
 		return SR_ERR_ARG;
 	}
 
-	devc->current_channel = devc->active_channels->data;
 	devc->num_active_channels = g_slist_length(devc->active_channels);
+	if (!devc->num_active_channels) {
+		sr_err("Need at least one active channel!");
+		g_slist_free(devc->active_channels);
+		return SR_ERR_ARG;
+	}
+	devc->current_channel = devc->active_channels->data;
 
 	hp_3457a_select_input(sdi, front_selected ? CONN_FRONT : CONN_REAR);