powerpc/vas: Fix cleanup when VAS is not configured

When VAS is not configured, unregister the platform driver. Also simplify
cleanup by delaying vas debugfs init until we know VAS is configured.
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/vas-debug.c

@@ -179,6 +179,7 @@ void vas_instance_init_dbgdir(struct vas_instance *vinst)
 {
 	struct dentry *d;
 
+	vas_init_dbgdir();
 	if (!vas_debugfs)
 		return;
 
@@ -201,8 +202,18 @@ void vas_instance_init_dbgdir(struct vas_instance *vinst)
 	vinst->dbgdir = NULL;
 }
 
+/*
+ * Set up the "root" VAS debugfs dir. Return if we already set it up
+ * (or failed to) in an earlier instance of VAS.
+ */
 void vas_init_dbgdir(void)
 {
+	static bool first_time = true;
+
+	if (!first_time)
+		return;
+
+	first_time = false;
 	vas_debugfs = debugfs_create_dir("vas", NULL);
 	if (IS_ERR(vas_debugfs))
 		vas_debugfs = NULL;

arch/powerpc/platforms/powernv/vas.c

@@ -160,8 +160,6 @@ static int __init vas_init(void)
 	int found = 0;
 	struct device_node *dn;
 
-	vas_init_dbgdir();
-
 	platform_driver_register(&vas_driver);
 
 	for_each_compatible_node(dn, NULL, "ibm,vas") {
@@ -169,8 +167,10 @@ static int __init vas_init(void)
 		found++;
 	}
 
-	if (!found)
+	if (!found) {
+		platform_driver_unregister(&vas_driver);
 		return -ENODEV;
+	}
 
 	pr_devel("Found %d instances\n", found);