isdn/gigaset: unify function return values

Various functions in the Gigaset driver were using different
conventions for the meaning of their int return values.
Align them to the usual negative error numbers convention.

Inspired-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/isdn/gigaset/usb-gigaset.c b/drivers/isdn/gigaset/usb-gigaset.c
index 049da67..bb12d80 100644
--- a/drivers/isdn/gigaset/usb-gigaset.c
+++ b/drivers/isdn/gigaset/usb-gigaset.c
@@ -549,10 +549,9 @@
 			       0, 0, &buf, 6, 2000);
 }
 
-static int gigaset_freebcshw(struct bc_state *bcs)
+static void gigaset_freebcshw(struct bc_state *bcs)
 {
 	/* unused */
-	return 1;
 }
 
 /* Initialize the b-channel structure */
@@ -560,7 +559,7 @@
 {
 	/* unused */
 	bcs->hw.usb = NULL;
-	return 1;
+	return 0;
 }
 
 static void gigaset_reinitbcshw(struct bc_state *bcs)
@@ -582,7 +581,7 @@
 		kmalloc(sizeof(struct usb_cardstate), GFP_KERNEL);
 	if (!ucs) {
 		pr_err("out of memory\n");
-		return 0;
+		return -ENOMEM;
 	}
 
 	ucs->bchars[0] = 0;
@@ -597,7 +596,7 @@
 	tasklet_init(&cs->write_tasklet,
 		     gigaset_modem_fill, (unsigned long) cs);
 
-	return 1;
+	return 0;
 }
 
 /* Send data from current skb to the device. */
@@ -766,9 +765,9 @@
 	if (startmode == SM_LOCKED)
 		cs->mstate = MS_LOCKED;
 
-	if (!gigaset_start(cs)) {
+	retval = gigaset_start(cs);
+	if (retval < 0) {
 		tasklet_kill(&cs->write_tasklet);
-		retval = -ENODEV;
 		goto error;
 	}
 	return 0;
@@ -898,8 +897,10 @@
 	driver = gigaset_initdriver(GIGASET_MINOR, GIGASET_MINORS,
 				    GIGASET_MODULENAME, GIGASET_DEVNAME,
 				    &ops, THIS_MODULE);
-	if (driver == NULL)
+	if (driver == NULL) {
+		result = -ENOMEM;
 		goto error;
+	}
 
 	/* register this driver with the USB subsystem */
 	result = usb_register(&gigaset_usb_driver);
@@ -915,7 +916,7 @@
 	if (driver)
 		gigaset_freedriver(driver);
 	driver = NULL;
-	return -1;
+	return result;
 }
 
 /*