From c9f75ae1adefa54612bef6203f2459e337076572 Mon Sep 17 00:00:00 2001
From: Jan Kriz <krizj1@fel.cvut.cz>
Date: Thu, 24 Jul 2008 11:44:01 +0200
Subject: [PATCH] Added check of usbcan device presence on registration

---
 lincan/src/usbcan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lincan/src/usbcan.c b/lincan/src/usbcan.c
index 1be7a90..7980cc3 100644
--- a/lincan/src/usbcan.c
+++ b/lincan/src/usbcan.c
@@ -47,6 +47,12 @@ int usbcan_request_io(struct candevice_t *candev)
 {
 	struct usbcan_usb *dev = (struct usbcan_usb*)candev->sysdevptr.anydev;
 
+	if (!dev){
+		CANMSG("Cannot register usbcan while usb device is not present.\n");
+		CANMSG("Usbcan registers automatically on device insertion.\n");
+		return -ENODEV;
+	}
+
 	/* start kernel thread */
 	dev->rcvthread.arg = dev;
 	start_kthread(usbcan_read_kthread, &dev->rcvthread);
-- 
2.39.2