linux-kernel - [PATCH 1/3] of: add device node status update APIs

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Date:	Thu, 15 Aug 2013 18:55:31 +0800
From:	Dong Aisheng <b29396@...escale.com>
To:	<devicetree-discuss@...ts.ozlabs.org>,
	<linux-kernel@...r.kernel.org>
CC:	<grant.likely@...aro.org>, <rob.herring@...xeda.com>,
	<rob@...dley.net>, <linux-arm-kernel@...ts.infradead.org>
Subject: [PATCH 1/3] of: add device node status update APIs

Used for convineniently update the device node status.

Signed-off-by: Dong Aisheng <b29396@...escale.com>
---
 drivers/of/base.c  |   74 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/of.h |    5 +++
 2 files changed, 79 insertions(+), 0 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 5c54279..f944a54 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1424,6 +1424,80 @@ int of_update_property(struct device_node *np, struct property *newprop)
 	return 0;
 }
 
+/* update the node status property to be "enabled" or "disabled" */
+static int of_node_status_update(struct device_node *np, bool enable)
+{
+	struct property *oldprop;
+	struct property *newprop;
+	int ret;
+
+	if (of_device_is_available(np) == enable)
+		return 0;
+
+	oldprop = of_find_property(np, "status", NULL);
+
+	if (enable) {
+		/* for disabled node, there must be a status property with "disabled" state */
+		ret = of_remove_property(np, oldprop);
+	} else {
+		newprop = kzalloc(sizeof(*newprop), GFP_KERNEL);
+		if (!newprop)
+			return -ENOMEM;
+
+		newprop->name = kstrdup("status", GFP_KERNEL);
+		newprop->value = kstrdup("disabled", GFP_KERNEL);
+		newprop->length = 9;
+		if (!newprop->name || !newprop->value) {
+			kfree(newprop->name);
+			kfree(newprop->value);
+			kfree(newprop);
+			return -ENOMEM;
+		}
+
+		ret = of_update_property(np, newprop);
+	}
+
+	pr_debug("%s:  %s --> %s %s\n", np->full_name, enable ?
+		"disabled" : "enabled", enable ? "enabled" : "disabled",
+		ret ? "failed" : "okay");
+
+	return ret;
+}
+
+int of_node_status_disable(struct device_node *np)
+{
+	return of_node_status_update(np, 0);
+}
+
+int of_node_status_enable(struct device_node *np)
+{
+	return of_node_status_update(np, 1);
+}
+
+int of_node_status_disable_by_path(const char *path)
+{
+	struct device_node *np;
+
+	pr_debug("disable node: %s\n", path);
+	np = of_find_node_by_path(path);
+	if (!np)
+		return -ENODEV;
+
+	return of_node_status_update(np, 0);
+}
+
+int of_node_status_enable_by_path(const char *path)
+{
+	struct device_node *np;
+
+	pr_debug("enable node: %s\n", path);
+	np = of_find_node_by_path(path);
+	if (!np)
+		return -ENODEV;
+
+	return of_node_status_update(np, 1);
+}
+
 #if defined(CONFIG_OF_DYNAMIC)
 /*
  * Support for dynamic device trees.
diff --git a/include/linux/of.h b/include/linux/of.h
index 1fd08ca..61b35fe 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -292,6 +292,11 @@ extern int of_add_property(struct device_node *np, struct property *prop);
 extern int of_remove_property(struct device_node *np, struct property *prop);
 extern int of_update_property(struct device_node *np, struct property *newprop);
 
+extern int of_node_status_disable(struct device_node *np);
+extern int of_node_status_enable(struct device_node *np);
+extern int of_node_status_disable_by_path(const char *path);
+extern int of_node_status_enable_by_path(const char *path);
+
 /* For updating the device tree at runtime */
 #define OF_RECONFIG_ATTACH_NODE		0x0001
 #define OF_RECONFIG_DETACH_NODE		0x0002
-- 
1.7.1


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