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Subject[RFC PATCH] [media]: of: move graph helpers from drivers/media/v4l2-core to drivers/of
Date
From: Philipp Zabel <philipp.zabel@gmail.com>

This patch moves the parsing helpers used to parse connected graphs
in the device tree, like the video interface bindings documented in
Documentation/devicetree/bindings/media/video-interfaces.txt, from
drivers/media/v4l2-core to drivers/of.

This allows to reuse the same parser code from outside the V4L2 framework,
most importantly from display drivers. There have been patches that duplicate
the code (and I am going to send one of my own), such as
http://lists.freedesktop.org/archives/dri-devel/2013-August/043308.html
and others that parse the same binding in a different way:
https://www.mail-archive.com/linux-omap@vger.kernel.org/msg100761.html

I think that all common video interface parsing helpers should be moved to a
single place, outside of the specific subsystems, so that it can be reused
by all drivers.

I moved v4l2_of_get_next_endpoint, v4l2_of_get_remote_port,
and v4l2_of_get_remote_port_parent. They are renamed to
of_graph_get_next_endpoint, of_graph_get_remote_port, and
of_graph_get_remote_port_parent, respectively.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
drivers/media/Kconfig | 1 +
drivers/media/v4l2-core/v4l2-of.c | 117 ---------------------------------
drivers/of/Kconfig | 3 +
drivers/of/Makefile | 1 +
drivers/of/of_graph.c | 133 ++++++++++++++++++++++++++++++++++++++
include/linux/of_graph.h | 23 +++++++
include/media/v4l2-of.h | 16 ++---
7 files changed, 167 insertions(+), 127 deletions(-)
create mode 100644 drivers/of/of_graph.c
create mode 100644 include/linux/of_graph.h

diff --git a/drivers/media/Kconfig b/drivers/media/Kconfig
index 1d0758a..882faeb 100644
--- a/drivers/media/Kconfig
+++ b/drivers/media/Kconfig
@@ -96,6 +96,7 @@ config VIDEO_DEV
tristate
depends on MEDIA_SUPPORT
depends on MEDIA_CAMERA_SUPPORT || MEDIA_ANALOG_TV_SUPPORT || MEDIA_RADIO_SUPPORT
+ select OF_GRAPH if OF
default y

config VIDEO_V4L2_SUBDEV_API
diff --git a/drivers/media/v4l2-core/v4l2-of.c b/drivers/media/v4l2-core/v4l2-of.c
index 42e3e8a..f919db3 100644
--- a/drivers/media/v4l2-core/v4l2-of.c
+++ b/drivers/media/v4l2-core/v4l2-of.c
@@ -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);
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index c6973f1..1bfbb0e 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -75,4 +75,7 @@ config OF_MTD
depends on MTD
def_bool y

+config OF_GRAPH
+ bool
+
endmenu # OF
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index efd0510..7ee8ab3 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_OF_MDIO) += of_mdio.o
obj-$(CONFIG_OF_PCI) += of_pci.o
obj-$(CONFIG_OF_PCI_IRQ) += of_pci_irq.o
obj-$(CONFIG_OF_MTD) += of_mtd.o
+obj-$(CONFIG_OF_GRAPH) += of_graph.o
diff --git a/drivers/of/of_graph.c b/drivers/of/of_graph.c
new file mode 100644
index 0000000..aa526d7
--- /dev/null
+++ b/drivers/of/of_graph.c
@@ -0,0 +1,133 @@
+/*
+ * OF graph binding parsing library
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/of.h>
+#include <linux/types.h>
+
+/**
+ * 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);
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
new file mode 100644
index 0000000..352306a
--- /dev/null
+++ b/include/linux/of_graph.h
@@ -0,0 +1,23 @@
+/*
+ * 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
+
+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);
+
+#endif /* __LINUX_OF_GRAPH_H */
diff --git a/include/media/v4l2-of.h b/include/media/v4l2-of.h
index 541cea4..404a493 100644
--- a/include/media/v4l2-of.h
+++ b/include/media/v4l2-of.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 +81,25 @@ static inline int v4l2_of_parse_endpoint(const struct device_node *node,
return -ENOSYS;
}

+#endif /* CONFIG_OF */
+
static inline struct device_node *v4l2_of_get_next_endpoint(
const struct device_node *parent,
struct device_node *previous)
{
- return NULL;
+ return of_graph_get_next_endpoint(parent, previous);
}

static inline struct device_node *v4l2_of_get_remote_port_parent(
const struct device_node *node)
{
- return NULL;
+ return of_graph_get_remote_port_parent(node);
}

static inline struct device_node *v4l2_of_get_remote_port(
const struct device_node *node)
{
- return NULL;
+ return of_graph_get_remote_port(node);
}

-#endif /* CONFIG_OF */
-
#endif /* _V4L2_OF_H */
--
1.8.5.3


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