+/**
+ * Lookup a channel group from its name.
+ *
+ * Uses the previously stored option value to lookup a channel group.
+ * Returns a reference to the channel group when the lookup succeeded,
+ * or #NULL after lookup failure, or #NULL for the global channel group
+ * (the device's global parameters). Emits an error message when the
+ * lookup failed while a channel group's name was specified.
+ *
+ * @param[in] sdi Device instance.
+ *
+ * @returns The channel group, or #NULL for failed lookup.
+ */
+struct sr_channel_group *lookup_channel_group(struct sr_dev_inst *sdi)