greybus: Merge branch 'master' of github.com:gregkh/greybus

diff --cc drivers/staging/greybus/core.c
index 91dcc5b,6106175..0a24822
--- 1/drivers/staging/greybus/core.c
--- 2/drivers/staging/greybus/core.c
+++ b/drivers/staging/greybus/core.c
@@@ -185,14 -185,9 +185,14 @@@ struct greybus_host_device *greybus_cre
        if ((!driver->message_send) || (!driver->message_cancel) ||
            (!driver->submit_svc)) {
                pr_err("Must implement all greybus_host_driver callbacks!\n");
-               return NULL;
+               return ERR_PTR(-EINVAL);
        }
  
 +      if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
 +              dev_err(parent, "greybus host-device buffers too small\n");
 +              return NULL;
 +      }
 +
        /*
         * Make sure to never allocate messages larger than what the Greybus
         * protocol supports.