[PATCH 4/5] of: Add old prop argument on OF_RECONFIG_UPDATE_PROPERTY

[Pantelis Antoniou <pantelis.antoniou@konsulko.com>]

The notifier now includes the old_prop argument when updating
properties, propagate this API to changeset internals while
also retaining the old behaviour of retrieving the old_property
when NULL is passed.

Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
---
 drivers/of/dynamic.c  | 18 ++++++++++++++----
 drivers/of/selftest.c |  2 +-
 include/linux/of.h    | 20 +++++++++++++-------
 3 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 8e8b614..9eb8528 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -627,6 +627,7 @@ int of_changeset_revert(struct of_changeset *ocs)
  * @action:	action to perform
  * @np:		Pointer to device node
  * @prop:	Pointer to property
+ * @old_prop:	Pointer to old property (if updating)
  *
  * On action being one of:
  * + OF_RECONFIG_ATTACH_NODE
@@ -637,10 +638,21 @@ int of_changeset_revert(struct of_changeset *ocs)
  * Returns 0 on success, a negative error value in case of an error.
  */
 int of_changeset_action(struct of_changeset *ocs, unsigned long action,
-		struct device_node *np, struct property *prop)
+		struct device_node *np, struct property *prop,
+		struct property *oldprop)
 {
 	struct of_changeset_entry *ce;
 
+	/* in case someone passed NULL as old_prop, find it */
+	if (action == OF_RECONFIG_UPDATE_PROPERTY && prop && !oldprop) {
+		oldprop = of_find_property(np, prop->name, NULL);
+		if (!oldprop) {
+			pr_err("%s: Failed to find old_prop for \"%s/%s\"\n",
+					__func__, np->full_name, prop->name);
+			return -EINVAL;
+		}
+	}
+
 	ce = kzalloc(sizeof(*ce), GFP_KERNEL);
 	if (!ce) {
 		pr_err("%s: Failed to allocate\n", __func__);
@@ -650,9 +662,7 @@ int of_changeset_action(struct of_changeset *ocs, unsigned long action,
 	ce->action = action;
 	ce->np = of_node_get(np);
 	ce->prop = prop;
-
-	if (action == OF_RECONFIG_UPDATE_PROPERTY && prop)
-		ce->old_prop = of_find_property(np, prop->name, NULL);
+	ce->old_prop = oldprop;
 
 	/* add it to the list */
 	list_add_tail(&ce->node, &ocs->entries);
diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c
index 7800127..16102fd 100644
--- a/drivers/of/selftest.c
+++ b/drivers/of/selftest.c
@@ -427,7 +427,7 @@ static void __init of_selftest_changeset(void)
 	selftest(!of_changeset_detach_node(&chgset, nremove), "fail remove node\n");
 	selftest(!of_changeset_attach_node(&chgset, n21), "fail attach n21\n");
 	selftest(!of_changeset_add_property(&chgset, parent, ppadd), "fail add prop\n");
-	selftest(!of_changeset_update_property(&chgset, parent, ppupdate), "fail update prop\n");
+	selftest(!of_changeset_update_property(&chgset, parent, ppupdate, NULL), "fail update prop\n");
 	selftest(!of_changeset_remove_property(&chgset, parent, ppremove), "fail remove prop\n");
 	mutex_lock(&of_mutex);
 	selftest(!of_changeset_apply(&chgset), "apply failed\n");
diff --git a/include/linux/of.h b/include/linux/of.h
index 6545e7a..71d25aa 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -830,36 +830,42 @@ extern int of_changeset_apply(struct of_changeset *ocs);
 extern int of_changeset_revert(struct of_changeset *ocs);
 extern int of_changeset_action(struct of_changeset *ocs,
 		unsigned long action, struct device_node *np,
-		struct property *prop);
+		struct property *prop, struct property *old_prop);
 
 static inline int of_changeset_attach_node(struct of_changeset *ocs,
 		struct device_node *np)
 {
-	return of_changeset_action(ocs, OF_RECONFIG_ATTACH_NODE, np, NULL);
+	return of_changeset_action(ocs, OF_RECONFIG_ATTACH_NODE, np, NULL,
+			NULL);
 }
 
 static inline int of_changeset_detach_node(struct of_changeset *ocs,
 		struct device_node *np)
 {
-	return of_changeset_action(ocs, OF_RECONFIG_DETACH_NODE, np, NULL);
+	return of_changeset_action(ocs, OF_RECONFIG_DETACH_NODE, np, NULL,
+			NULL);
 }
 
 static inline int of_changeset_add_property(struct of_changeset *ocs,
 		struct device_node *np, struct property *prop)
 {
-	return of_changeset_action(ocs, OF_RECONFIG_ADD_PROPERTY, np, prop);
+	return of_changeset_action(ocs, OF_RECONFIG_ADD_PROPERTY, np, prop,
+			NULL);
 }
 
 static inline int of_changeset_remove_property(struct of_changeset *ocs,
 		struct device_node *np, struct property *prop)
 {
-	return of_changeset_action(ocs, OF_RECONFIG_REMOVE_PROPERTY, np, prop);
+	return of_changeset_action(ocs, OF_RECONFIG_REMOVE_PROPERTY, np, prop,
+			NULL);
 }
 
 static inline int of_changeset_update_property(struct of_changeset *ocs,
-		struct device_node *np, struct property *prop)
+		struct device_node *np, struct property *prop,
+		struct property *old_prop)
 {
-	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
+	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop,
+			old_prop);
 }
 #endif
 
-- 
1.7.12