[PATCH v5 0/7] Move device tree graph parsing helpers to drivers/of

@@ -2026,32 +2026,34 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 			pr_err("%s(): no endpoint nodes specified for %s\n",
 			       __func__, parent->full_name);
 		of_node_put(node);
-	} else {
-		port = of_get_parent(prev);
-		if (WARN_ONCE(!port, "%s(): endpoint has no parent node\n",
-			      __func__))
-			return NULL;
 
-		/* Avoid dropping prev node refcount to 0. */
-		of_node_get(prev);
-		endpoint = of_get_next_child(port, prev);
-		if (endpoint) {
-			of_node_put(port);
-			return endpoint;
-		}
+		return endpoint;
+	}
 
-		/* No more endpoints under this port, try the next one. */
-		do {
-			port = of_get_next_child(parent, port);
-			if (!port)
-				return NULL;
-		} while (of_node_cmp(port->name, "port"));
+	port = of_get_parent(prev);
+	if (WARN_ONCE(!port, "%s(): endpoint has no parent node\n",
+		      __func__))
+		return NULL;
 
-		/* Pick up the first endpoint in this port. */
-		endpoint = of_get_next_child(port, NULL);
+	/* Avoid dropping prev node refcount to 0. */
+	of_node_get(prev);
+	endpoint = of_get_next_child(port, prev);
+	if (endpoint) {
 		of_node_put(port);
+		return endpoint;
 	}
 
+	/* No more endpoints under this port, try the next one. */
+	do {
+		port = of_get_next_child(parent, port);
+		if (!port)
+			return NULL;
+	} while (of_node_cmp(port->name, "port"));
+
+	/* Pick up the first endpoint in this port. */
+	endpoint = of_get_next_child(port, NULL);
+	of_node_put(port);
+
 	return endpoint;
 }
 EXPORT_SYMBOL(of_graph_get_next_endpoint);

@@ -2028,8 +2028,8 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 		of_node_put(node);
 	} else {
 		port = of_get_parent(prev);
-		if (!port)
-			/* Hm, has someone given us the root node ?... */
+		if (WARN_ONCE(!port, "%s(): endpoint has no parent node\n",
+			      __func__))
 			return NULL;
 
 		/* Avoid dropping prev node refcount to 0. */

@@ -84,6 +84,14 @@ device {
         };
 };
 
+For devices with only a single port and a single endpoint, this can be further
+simplified by making the port implicit, and adding the endpoint node as a direct
+child of the device node.
+
+device {
+	endpoint { ... };
+};
+
 Links between endpoints
 -----------------------
 

@@ -469,10 +469,10 @@ static int fimc_md_parse_port_node(struct fimc_md *fmd,
 		return 0;
 
 	v4l2_of_parse_endpoint(ep, &endpoint);
-	if (WARN_ON(endpoint.port == 0) || index >= FIMC_MAX_SENSORS)
+	if (WARN_ON(endpoint.base.port == 0) || index >= FIMC_MAX_SENSORS)
 		return -EINVAL;
 
-	pd->mux_id = (endpoint.port - 1) & 0x1;
+	pd->mux_id = (endpoint.base.port - 1) & 0x1;
 
 	rem = of_graph_get_remote_port_parent(ep);
 	of_node_put(ep);

@@ -494,13 +494,13 @@ static int fimc_md_parse_port_node(struct fimc_md *fmd,
 		return -EINVAL;
 	}
 
-	if (fimc_input_is_parallel(endpoint.port)) {
+	if (fimc_input_is_parallel(endpoint.base.port)) {
 		if (endpoint.bus_type == V4L2_MBUS_PARALLEL)
 			pd->sensor_bus_type = FIMC_BUS_TYPE_ITU_601;
 		else
 			pd->sensor_bus_type = FIMC_BUS_TYPE_ITU_656;
 		pd->flags = endpoint.bus.parallel.flags;
-	} else if (fimc_input_is_mipi_csi(endpoint.port)) {
+	} else if (fimc_input_is_mipi_csi(endpoint.base.port)) {
 		/*
 		 * MIPI CSI-2: only input mux selection and
 		 * the sensor's clock frequency is needed.

@@ -508,7 +508,7 @@ static int fimc_md_parse_port_node(struct fimc_md *fmd,
 		pd->sensor_bus_type = FIMC_BUS_TYPE_MIPI_CSI2;
 	} else {
 		v4l2_err(&fmd->v4l2_dev, "Wrong port id (%u) at node %s\n",
-			 endpoint.port, rem->full_name);
+			 endpoint.base.port, rem->full_name);
 	}
 	/*
 	 * For FIMC-IS handled sensors, that are placed under i2c-isp device

@@ -772,7 +772,7 @@ static int s5pcsis_parse_dt(struct platform_device *pdev,
 	/* Get port node and validate MIPI-CSI channel id. */
 	v4l2_of_parse_endpoint(node, &endpoint);
 
-	state->index = endpoint.port - FIMC_INPUT_MIPI_CSI2_0;
+	state->index = endpoint.base.port - FIMC_INPUT_MIPI_CSI2_0;
 	if (state->index < 0 || state->index >= CSIS_MAX_ENTITIES)
 		return -ENXIO;
 

@@ -127,17 +127,9 @@ static void v4l2_of_parse_parallel_bus(const struct device_node *node,
 int v4l2_of_parse_endpoint(const struct device_node *node,
 			   struct v4l2_of_endpoint *endpoint)
 {
-	struct device_node *port_node = of_get_parent(node);
-
-	memset(endpoint, 0, offsetof(struct v4l2_of_endpoint, head));
-
-	endpoint->local_node = node;
-	/*
-	 * It doesn't matter whether the two calls below succeed.
-	 * If they don't then the default value 0 is used.
-	 */
-	of_property_read_u32(port_node, "reg", &endpoint->port);
-	of_property_read_u32(node, "reg", &endpoint->id);
+	of_graph_parse_endpoint(node, &endpoint->base);
+	endpoint->bus_type = 0;
+	memset(&endpoint->bus, 0, sizeof(endpoint->bus));
 
 	v4l2_of_parse_csi_bus(node, endpoint);
 	/*

@@ -147,8 +139,6 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
 	if (endpoint->bus.mipi_csi2.flags == 0)
 		v4l2_of_parse_parallel_bus(node, endpoint);
 
-	of_node_put(port_node);
-
 	return 0;
 }
 EXPORT_SYMBOL(v4l2_of_parse_endpoint);

@@ -1985,6 +1985,37 @@ struct device_node *of_find_next_cache_node(const struct device_node *np)
 }
 
 /**
+ * of_graph_parse_endpoint() - parse common endpoint node properties
+ * @node: pointer to endpoint device_node
+ * @endpoint: pointer to the OF endpoint data structure
+ *
+ * All properties are optional. If none are found, we don't set any flags.
+ * This means the port has a static configuration and no properties have
+ * to be specified explicitly.
+ * The caller should hold a reference to @node.
+ */
+int of_graph_parse_endpoint(const struct device_node *node,
+			    struct of_endpoint *endpoint)
+{
+	struct device_node *port_node = of_get_parent(node);
+
+	memset(endpoint, 0, sizeof(*endpoint));
+
+	endpoint->local_node = node;
+	/*
+	 * It doesn't matter whether the two calls below succeed.
+	 * If they don't then the default value 0 is used.
+	 */
+	of_property_read_u32(port_node, "reg", &endpoint->port);
+	of_property_read_u32(node, "reg", &endpoint->id);
+
+	of_node_put(port_node);
+
+	return 0;
+}
+EXPORT_SYMBOL(of_graph_parse_endpoint);
+
+/**
  * of_graph_get_next_endpoint() - get next endpoint node
  * @parent: pointer to the parent device node
  * @prev: previous endpoint node, or NULL to get first

@@ -14,7 +14,21 @@
 #ifndef __LINUX_OF_GRAPH_H
 #define __LINUX_OF_GRAPH_H
 
+/**
+ * struct of_endpoint - the OF graph endpoint data structure
+ * @port: identifier (value of reg property) of a port this endpoint belongs to
+ * @id: identifier (value of reg property) of this endpoint
+ * @local_node: pointer to device_node of this endpoint
+ */
+struct of_endpoint {
+	unsigned int port;
+	unsigned int id;
+	const struct device_node *local_node;
+};
+
 #ifdef CONFIG_OF
+int of_graph_parse_endpoint(const struct device_node *node,
+				struct of_endpoint *endpoint);
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
 struct device_node *of_graph_get_remote_port_parent(

@@ -22,6 +36,12 @@ struct device_node *of_graph_get_remote_port_parent(
 struct device_node *of_graph_get_remote_port(const struct device_node *node);
 #else
 
+static inline int of_graph_parse_endpoint(const struct device_node *node,
+					struct of_endpoint *endpoint);
+{
+	return -ENOSYS;
+}
+
 static inline struct device_node *of_graph_get_next_endpoint(
 					const struct device_node *parent,
 					struct device_node *previous)

@@ -51,17 +51,13 @@ struct v4l2_of_bus_parallel {
 
 /**
  * struct v4l2_of_endpoint - the endpoint data structure
- * @port: identifier (value of reg property) of a port this endpoint belongs to
- * @id: identifier (value of reg property) of this endpoint
- * @local_node: pointer to device_node of this endpoint
+ * @base: struct of_endpoint containing port, id, and local of_node
  * @bus_type: bus type
  * @bus: bus configuration data structure
  * @head: list head for this structure
  */
 struct v4l2_of_endpoint {
-	unsigned int port;
-	unsigned int id;
-	const struct device_node *local_node;
+	struct of_endpoint base;
 	enum v4l2_mbus_type bus_type;
 	union {
 		struct v4l2_of_bus_parallel parallel;

@@ -26,12 +26,12 @@
 #include <linux/videodev2.h>
 #include <linux/uaccess.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 
 #include <media/adv7343.h>
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-ctrls.h>
-#include <media/v4l2-of.h>
 
 #include "adv7343_regs.h"
 

@@ -410,7 +410,7 @@ adv7343_get_pdata(struct i2c_client *client)
 	if (!IS_ENABLED(CONFIG_OF) || !client->dev.of_node)
 		return client->dev.platform_data;
 
-	np = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
+	np = of_graph_get_next_endpoint(client->dev.of_node, NULL);
 	if (!np)
 		return NULL;
 

@@ -21,6 +21,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_gpio.h>
+#include <linux/of_graph.h>
 #include <linux/pm.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>

@@ -29,7 +30,6 @@
 #include <media/mt9p031.h>
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
-#include <media/v4l2-of.h>
 #include <media/v4l2-subdev.h>
 
 #include "aptina-pll.h"

@@ -943,7 +943,7 @@ mt9p031_get_pdata(struct i2c_client *client)
 	if (!IS_ENABLED(CONFIG_OF) || !client->dev.of_node)
 		return client->dev.platform_data;
 
-	np = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
+	np = of_graph_get_next_endpoint(client->dev.of_node, NULL);
 	if (!np)
 		return NULL;
 

@@ -21,6 +21,7 @@
 #include <linux/media.h>
 #include <linux/module.h>
 #include <linux/of_gpio.h>
+#include <linux/of_graph.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 

@@ -1855,7 +1856,7 @@ static int s5k5baf_parse_device_node(struct s5k5baf *state, struct device *dev)
 	if (ret < 0)
 		return ret;
 
-	node_ep = v4l2_of_get_next_endpoint(node, NULL);
+	node_ep = of_graph_get_next_endpoint(node, NULL);
 	if (!node_ep) {
 		dev_err(dev, "no endpoint defined at node %s\n",
 			node->full_name);

@@ -36,6 +36,7 @@
 #include <linux/module.h>
 #include <linux/v4l2-mediabus.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 
 #include <media/v4l2-async.h>
 #include <media/v4l2-device.h>

@@ -1068,7 +1069,7 @@ tvp514x_get_pdata(struct i2c_client *client)
 	if (!IS_ENABLED(CONFIG_OF) || !client->dev.of_node)
 		return client->dev.platform_data;
 
-	endpoint = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
+	endpoint = of_graph_get_next_endpoint(client->dev.of_node, NULL);
 	if (!endpoint)
 		return NULL;
 

@@ -30,6 +30,7 @@
 #include <linux/videodev2.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/v4l2-dv-timings.h>
 #include <media/tvp7002.h>
 #include <media/v4l2-async.h>

@@ -957,7 +958,7 @@ tvp7002_get_pdata(struct i2c_client *client)
 	if (!IS_ENABLED(CONFIG_OF) || !client->dev.of_node)
 		return client->dev.platform_data;
 
-	endpoint = v4l2_of_get_next_endpoint(client->dev.of_node, NULL);
+	endpoint = of_graph_get_next_endpoint(client->dev.of_node, NULL);
 	if (!endpoint)
 		return NULL;
 

@@ -24,13 +24,13 @@
 #include <linux/i2c.h>
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
+#include <linux/of_graph.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/videodev2.h>
-#include <media/v4l2-of.h>
 #include <media/videobuf2-dma-contig.h>
 
 #include "media-dev.h"

@@ -167,10 +167,10 @@ static int fimc_is_parse_sensor_config(struct fimc_is_sensor *sensor,
 	u32 tmp = 0;
 	int ret;
 
-	np = v4l2_of_get_next_endpoint(np, NULL);
+	np = of_graph_get_next_endpoint(np, NULL);
 	if (!np)
 		return -ENXIO;
-	np = v4l2_of_get_remote_port(np);
+	np = of_graph_get_remote_port(np);
 	if (!np)
 		return -ENXIO;
 

@@ -20,6 +20,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_device.h>
+#include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/types.h>

@@ -473,7 +474,7 @@ static int fimc_md_parse_port_node(struct fimc_md *fmd,
 
 	pd->mux_id = (endpoint.port - 1) & 0x1;
 
-	rem = v4l2_of_get_remote_port_parent(ep);
+	rem = of_graph_get_remote_port_parent(ep);
 	of_node_put(ep);
 	if (rem == NULL) {
 		v4l2_info(&fmd->v4l2_dev, "Remote device at %s not found\n",

@@ -20,6 +20,7 @@
 #include <linux/memory.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_data/mipi-csis.h>
 #include <linux/platform_device.h>

@@ -762,7 +763,7 @@ static int s5pcsis_parse_dt(struct platform_device *pdev,
 				 &state->max_num_lanes))
 		return -EINVAL;
 
-	node = v4l2_of_get_next_endpoint(node, NULL);
+	node = of_graph_get_next_endpoint(node, NULL);
 	if (!node) {
 		dev_err(&pdev->dev, "No port node at %s\n",
 				pdev->dev.of_node->full_name);

@@ -152,120 +152,3 @@ int v4l2_of_parse_endpoint(const struct device_node *node,
 	return 0;
 }
 EXPORT_SYMBOL(v4l2_of_parse_endpoint);
-
-/**
- * v4l2_of_get_next_endpoint() - get next endpoint node
- * @parent: pointer to the parent device node
- * @prev: previous endpoint node, or NULL to get first
- *
- * Return: An 'endpoint' node pointer with refcount incremented. Refcount
- * of the passed @prev node is not decremented, the caller have to use
- * of_node_put() on it when done.
- */
-struct device_node *v4l2_of_get_next_endpoint(const struct device_node *parent,
-					struct device_node *prev)
-{
-	struct device_node *endpoint;
-	struct device_node *port = NULL;
-
-	if (!parent)
-		return NULL;
-
-	if (!prev) {
-		struct device_node *node;
-		/*
-		 * It's the first call, we have to find a port subnode
-		 * within this node or within an optional 'ports' node.
-		 */
-		node = of_get_child_by_name(parent, "ports");
-		if (node)
-			parent = node;
-
-		port = of_get_child_by_name(parent, "port");
-
-		if (port) {
-			/* Found a port, get an endpoint. */
-			endpoint = of_get_next_child(port, NULL);
-			of_node_put(port);
-		} else {
-			endpoint = NULL;
-		}
-
-		if (!endpoint)
-			pr_err("%s(): no endpoint nodes specified for %s\n",
-			       __func__, parent->full_name);
-		of_node_put(node);
-	} else {
-		port = of_get_parent(prev);
-		if (!port)
-			/* Hm, has someone given us the root node ?... */
-			return NULL;
-
-		/* Avoid dropping prev node refcount to 0. */
-		of_node_get(prev);
-		endpoint = of_get_next_child(port, prev);
-		if (endpoint) {
-			of_node_put(port);
-			return endpoint;
-		}
-
-		/* No more endpoints under this port, try the next one. */
-		do {
-			port = of_get_next_child(parent, port);
-			if (!port)
-				return NULL;
-		} while (of_node_cmp(port->name, "port"));
-
-		/* Pick up the first endpoint in this port. */
-		endpoint = of_get_next_child(port, NULL);
-		of_node_put(port);
-	}
-
-	return endpoint;
-}
-EXPORT_SYMBOL(v4l2_of_get_next_endpoint);
-
-/**
- * v4l2_of_get_remote_port_parent() - get remote port's parent node
- * @node: pointer to a local endpoint device_node
- *
- * Return: Remote device node associated with remote endpoint node linked
- *	   to @node. Use of_node_put() on it when done.
- */
-struct device_node *v4l2_of_get_remote_port_parent(
-			       const struct device_node *node)
-{
-	struct device_node *np;
-	unsigned int depth;
-
-	/* Get remote endpoint node. */
-	np = of_parse_phandle(node, "remote-endpoint", 0);
-
-	/* Walk 3 levels up only if there is 'ports' node. */
-	for (depth = 3; depth && np; depth--) {
-		np = of_get_next_parent(np);
-		if (depth == 2 && of_node_cmp(np->name, "ports"))
-			break;
-	}
-	return np;
-}
-EXPORT_SYMBOL(v4l2_of_get_remote_port_parent);
-
-/**
- * v4l2_of_get_remote_port() - get remote port node
- * @node: pointer to a local endpoint device_node
- *
- * Return: Remote port node associated with remote endpoint node linked
- *	   to @node. Use of_node_put() on it when done.
- */
-struct device_node *v4l2_of_get_remote_port(const struct device_node *node)
-{
-	struct device_node *np;
-
-	/* Get remote endpoint node. */
-	np = of_parse_phandle(node, "remote-endpoint", 0);
-	if (!np)
-		return NULL;
-	return of_get_next_parent(np);
-}
-EXPORT_SYMBOL(v4l2_of_get_remote_port);

@@ -21,6 +21,7 @@
 #include <linux/cpu.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/spinlock.h>
 #include <linux/slab.h>
 #include <linux/proc_fs.h>

@@ -1982,3 +1983,120 @@ struct device_node *of_find_next_cache_node(const struct device_node *np)
 
 	return NULL;
 }
+
+/**
+ * of_graph_get_next_endpoint() - get next endpoint node
+ * @parent: pointer to the parent device node
+ * @prev: previous endpoint node, or NULL to get first
+ *
+ * Return: An 'endpoint' node pointer with refcount incremented. Refcount
+ * of the passed @prev node is not decremented, the caller have to use
+ * of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
+					struct device_node *prev)
+{
+	struct device_node *endpoint;
+	struct device_node *port = NULL;
+
+	if (!parent)
+		return NULL;
+
+	if (!prev) {
+		struct device_node *node;
+		/*
+		 * It's the first call, we have to find a port subnode
+		 * within this node or within an optional 'ports' node.
+		 */
+		node = of_get_child_by_name(parent, "ports");
+		if (node)
+			parent = node;
+
+		port = of_get_child_by_name(parent, "port");
+
+		if (port) {
+			/* Found a port, get an endpoint. */
+			endpoint = of_get_next_child(port, NULL);
+			of_node_put(port);
+		} else {
+			endpoint = NULL;
+		}
+
+		if (!endpoint)
+			pr_err("%s(): no endpoint nodes specified for %s\n",
+			       __func__, parent->full_name);
+		of_node_put(node);
+	} else {
+		port = of_get_parent(prev);
+		if (!port)
+			/* Hm, has someone given us the root node ?... */
+			return NULL;
+
+		/* Avoid dropping prev node refcount to 0. */
+		of_node_get(prev);
+		endpoint = of_get_next_child(port, prev);
+		if (endpoint) {
+			of_node_put(port);
+			return endpoint;
+		}
+
+		/* No more endpoints under this port, try the next one. */
+		do {
+			port = of_get_next_child(parent, port);
+			if (!port)
+				return NULL;
+		} while (of_node_cmp(port->name, "port"));
+
+		/* Pick up the first endpoint in this port. */
+		endpoint = of_get_next_child(port, NULL);
+		of_node_put(port);
+	}
+
+	return endpoint;
+}
+EXPORT_SYMBOL(of_graph_get_next_endpoint);
+
+/**
+ * of_graph_get_remote_port_parent() - get remote port's parent node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: Remote device node associated with remote endpoint node linked
+ *	   to @node. Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_remote_port_parent(
+			       const struct device_node *node)
+{
+	struct device_node *np;
+	unsigned int depth;
+
+	/* Get remote endpoint node. */
+	np = of_parse_phandle(node, "remote-endpoint", 0);
+
+	/* Walk 3 levels up only if there is 'ports' node. */
+	for (depth = 3; depth && np; depth--) {
+		np = of_get_next_parent(np);
+		if (depth == 2 && of_node_cmp(np->name, "ports"))
+			break;
+	}
+	return np;
+}
+EXPORT_SYMBOL(of_graph_get_remote_port_parent);
+
+/**
+ * of_graph_get_remote_port() - get remote port node
+ * @node: pointer to a local endpoint device_node
+ *
+ * Return: Remote port node associated with remote endpoint node linked
+ *	   to @node. Use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_remote_port(const struct device_node *node)
+{
+	struct device_node *np;
+
+	/* Get remote endpoint node. */
+	np = of_parse_phandle(node, "remote-endpoint", 0);
+	if (!np)
+		return NULL;
+	return of_get_next_parent(np);
+}
+EXPORT_SYMBOL(of_graph_get_remote_port);

@@ -0,0 +1,46 @@
+/*
+ * OF graph binding parsing helpers
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
+ *
+ * Copyright (C) 2012 Renesas Electronics Corp.
+ * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ */
+#ifndef __LINUX_OF_GRAPH_H
+#define __LINUX_OF_GRAPH_H
+
+#ifdef CONFIG_OF
+struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
+					struct device_node *previous);
+struct device_node *of_graph_get_remote_port_parent(
+					const struct device_node *node);
+struct device_node *of_graph_get_remote_port(const struct device_node *node);
+#else
+
+static inline struct device_node *of_graph_get_next_endpoint(
+					const struct device_node *parent,
+					struct device_node *previous)
+{
+	return NULL;
+}
+
+static inline struct device_node *of_graph_get_remote_port_parent(
+					const struct device_node *node)
+{
+	return NULL;
+}
+
+static inline struct device_node *of_graph_get_remote_port(
+					const struct device_node *node)
+{
+	return NULL;
+}
+
+#endif /* CONFIG_OF */
+
+#endif /* __LINUX_OF_GRAPH_H */

@@ -17,6 +17,7 @@
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/errno.h>
+#include <linux/of_graph.h>
 
 #include <media/v4l2-mediabus.h>
 

@@ -72,11 +73,6 @@ struct v4l2_of_endpoint {
 #ifdef CONFIG_OF
 int v4l2_of_parse_endpoint(const struct device_node *node,
 			   struct v4l2_of_endpoint *endpoint);
-struct device_node *v4l2_of_get_next_endpoint(const struct device_node *parent,
-					struct device_node *previous);
-struct device_node *v4l2_of_get_remote_port_parent(
-					const struct device_node *node);
-struct device_node *v4l2_of_get_remote_port(const struct device_node *node);
 #else /* CONFIG_OF */
 
 static inline int v4l2_of_parse_endpoint(const struct device_node *node,

@@ -85,25 +81,6 @@ static inline int v4l2_of_parse_endpoint(const struct device_node *node,
 	return -ENOSYS;
 }
 
-static inline struct device_node *v4l2_of_get_next_endpoint(
-					const struct device_node *parent,
-					struct device_node *previous)
-{
-	return NULL;
-}
-
-static inline struct device_node *v4l2_of_get_remote_port_parent(
-					const struct device_node *node)
-{
-	return NULL;
-}
-
-static inline struct device_node *v4l2_of_get_remote_port(
-					const struct device_node *node)
-{
-	return NULL;
-}
-
 #endif /* CONFIG_OF */
 
 #endif /* _V4L2_OF_H */

@@ -2037,8 +2037,13 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 		struct device_node *node;
 		/*
 		 * It's the first call, we have to find a port subnode
-		 * within this node or within an optional 'ports' node.
+		 * within this node or within an optional 'ports' node,
+		 * or at least a single endpoint.
 		 */
+		endpoint = of_get_child_by_name(parent, "endpoint");
+		if (endpoint)
+			return endpoint;
+
 		node = of_get_child_by_name(parent, "ports");
 		if (node)
 			parent = node;

@@ -2049,8 +2054,6 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 			/* Found a port, get an endpoint. */
 			endpoint = of_get_next_child(port, NULL);
 			of_node_put(port);
-		} else {
-			endpoint = NULL;
 		}
 
 		if (!endpoint)

@@ -2065,6 +2068,10 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 	if (WARN_ONCE(!port, "%s(): endpoint has no parent node\n",
 		      __func__))
 		return NULL;
+	if (port == parent) {
+		of_node_put(port);
+		return NULL;
+	}
 
 	/* Avoid dropping prev node refcount to 0. */
 	of_node_get(prev);

@@ -2105,9 +2112,11 @@ struct device_node *of_graph_get_remote_port_parent(
 	/* Get remote endpoint node. */
 	np = of_parse_phandle(node, "remote-endpoint", 0);
 
-	/* Walk 3 levels up only if there is 'ports' node. */
+	/* Walk 3 levels up only if there is 'ports' node */
 	for (depth = 3; depth && np; depth--) {
 		np = of_get_next_parent(np);
+		if (depth == 3 && of_node_cmp(np->name, "port"))
+			break;
 		if (depth == 2 && of_node_cmp(np->name, "ports"))
 			break;
 	}

@@ -2130,6 +2139,11 @@ struct device_node *of_graph_get_remote_port(const struct device_node *node)
 	np = of_parse_phandle(node, "remote-endpoint", 0);
 	if (!np)
 		return NULL;
-	return of_get_next_parent(np);
+	np = of_get_next_parent(np);
+	if (of_node_cmp(np->name, "port")) {
+		of_node_put(np);
+		return NULL;
+	}
+	return np;
 }
 EXPORT_SYMBOL(of_graph_get_remote_port);

@@ -0,0 +1,129 @@
+Common bindings for device graphs
+
+General concept
+---------------
+
+The hierarchical organisation of the device tree is well suited to describe
+control flow to devices, but there can be more complex connections between
+devices that work together to form a logical compound device, following an
+arbitrarily complex graph.
+There already is a simple directed graph between devices tree nodes using
+phandle properties pointing to other nodes to describe connections that
+can not be inferred from device tree parent-child relationships. The device
+tree graph bindings described herein abstract more complex devices that can
+have multiple specifiable ports, each of which can be linked to one or more
+ports of other devices.
+
+These common bindings do not contain any information about the direction of
+type of the connections, they just map their existence. Specific properties
+may be described by specialized bindings depending on the type of connection.
+
+To see how this binding applies to video pipelines, for example, see
+Documentation/device-tree/bindings/media/video-interfaces.txt.
+Here the ports describe data interfaces, and the links between them are
+the connecting data buses. A single port with multiple connections can
+correspond to multiple devices being connected to the same physical bus.
+
+Organisation of ports and endpoints
+-----------------------------------
+
+Ports are described by child 'port' nodes contained in the device node.
+Each port node contains an 'endpoint' subnode for each remote device port
+connected to this port. If a single port is connected to more than one
+remote device, an 'endpoint' child node must be provided for each link.
+If more than one port is present in a device node or there is more than one
+endpoint at a port, or a port node needs to be associated with a selected
+hardware interface, a common scheme using '#address-cells', '#size-cells'
+and 'reg' properties is used number the nodes.
+
+device {
+        ...
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        port@0 {
+	        #address-cells = <1>;
+	        #size-cells = <0>;
+		reg = <0>;
+
+                endpoint@0 {
+			reg = <0>;
+			...
+		};
+                endpoint@1 {
+			reg = <1>;
+			...
+		};
+        };
+
+        port@1 {
+		reg = <1>;
+
+		endpoint { ... };
+	};
+};
+
+All 'port' nodes can be grouped under an optional 'ports' node, which
+allows to specify #address-cells, #size-cells properties for the 'port'
+nodes independently from any other child device nodes a device might
+have.
+
+device {
+        ...
+        ports {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                port@0 {
+                        ...
+                        endpoint@0 { ... };
+                        endpoint@1 { ... };
+                };
+
+                port@1 { ... };
+        };
+};
+
+Links between endpoints
+-----------------------
+
+Each endpoint should contain a 'remote-endpoint' phandle property that points
+to the corresponding endpoint in the port of the remote device. In turn, the
+remote endpoint should contain a 'remote-endpoint' property. If it has one,
+it must not point to another than the local endpoint. Two endpoints with their
+'remote-endpoint' phandles pointing at each other form a link between the
+containing ports.
+
+device_1 {
+        port {
+                device_1_output: endpoint {
+                        remote-endpoint = <&device_2_input>;
+                };
+        };
+};
+
+device_1 {
+        port {
+                device_2_input: endpoint {
+                        remote-endpoint = <&device_1_output>;
+                };
+        };
+};
+
+
+Required properties
+-------------------
+
+If there is more than one 'port' or more than one 'endpoint' node or 'reg'
+property is present in port and/or endpoint nodes the following properties
+are required in a relevant parent node:
+
+ - #address-cells : number of cells required to define port/endpoint
+                    identifier, should be 1.
+ - #size-cells    : should be zero.
+
+Optional endpoint properties
+----------------------------
+
+- remote-endpoint: phandle to an 'endpoint' subnode of a remote device node.
+