Remove unnecessary call to libusb_get_device_descriptor().

[libsigrok.git] / src / device.c

diff --git a/src/device.c b/src/device.c
index fe3e231616e67c13989be8340cb74dcddd7195ae..537c89eff2ab353c167152de2af775a4317736a0 100644 (file)
--- a/src/device.c
+++ b/src/device.c
@@ -17,9 +17,9 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <config.h>
 #include <stdio.h>
 #include <glib.h>
-#include "config.h" /* Needed for HAVE_LIBUSB_1_0 and others. */
 #include <libsigrok/libsigrok.h>
 #include "libsigrok-internal.h"
 
@@ -133,6 +133,25 @@ SR_API int sr_dev_channel_enable(struct sr_channel *channel,
        return SR_OK;
 }
 
+/* Returns the next enabled channel, wrapping around if necessary. */
+SR_PRIV struct sr_channel *sr_next_enabled_channel(const struct sr_dev_inst *sdi,
+               struct sr_channel *cur_channel)
+{
+       struct sr_channel *next_channel;
+       GSList *l;
+
+       next_channel = cur_channel;
+       do {
+               l = g_slist_find(sdi->channels, next_channel);
+               if (l && l->next)
+                       next_channel = l->next->data;
+               else
+                       next_channel = sdi->channels->data;
+       } while (!next_channel->enabled);
+
+       return next_channel;
+}
+
 /**
  * Determine whether the specified device instance has the specified
  * capability.
@@ -522,11 +541,10 @@ SR_API const char *sr_dev_inst_connid_get(const struct sr_dev_inst *sdi)
 {
 #ifdef HAVE_LIBUSB_1_0
        struct drv_context *drvc;
-       int r, cnt, i, a, b;
+       int cnt, i, a, b;
        char connection_id[64];
        struct sr_usb_dev_inst *usb;
        struct libusb_device **devlist;
-       struct libusb_device_descriptor des;
 #endif
 
        if (!sdi)
@@ -557,12 +575,6 @@ SR_API const char *sr_dev_inst_connid_get(const struct sr_dev_inst *sdi)
                }
 
                for (i = 0; i < cnt; i++) {
-                       if ((r = libusb_get_device_descriptor(devlist[i], &des)) < 0) {
-                               sr_err("Failed to get device descriptor: %s.",
-                                      libusb_error_name(r));
-                               continue;
-                       }
-
                        /* Find the USB device by the logical address we know. */
                        b = libusb_get_bus_number(devlist[i]);
                        a = libusb_get_device_address(devlist[i]);