greybus: control: add error message to mode-switch helper

Print an informative error message in case sending the mode-switch
request fails.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/control.c b/drivers/staging/greybus/control.c
index c5cdf3c..3e02bbb 100644 (file)
--- a/drivers/staging/greybus/control.c
+++ b/drivers/staging/greybus/control.c
@@ -163,9 +163,18 @@ int gb_control_disconnecting_operation(struct gb_control *control,
 
 int gb_control_mode_switch_operation(struct gb_control *control)
 {
-       return gb_operation_unidirectional(control->connection,
+       int ret;
+
+       ret = gb_operation_unidirectional(control->connection,
                                                GB_CONTROL_TYPE_MODE_SWITCH,
                                                NULL, 0);
+       if (ret) {
+               dev_err(&control->dev, "failed to send mode switch: %d\n",
+                               ret);
+               return ret;
+       }
+
+       return 0;
 }
 
 int gb_control_timesync_enable(struct gb_control *control, u8 count,