[media] Add a V4L2 OF parser

Add a V4L2 OF parser, implementing bindings documented in
Documentation/devicetree/bindings/media/video-interfaces.txt.
[s.nawrocki@samsung.com: various corrections and improvements
since the initial version]
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/v4l2-core/Makefile

@@ -9,6 +9,9 @@ videodev-objs	:=	v4l2-dev.o v4l2-ioctl.o v4l2-device.o v4l2-fh.o \
 ifeq ($(CONFIG_COMPAT),y)
   videodev-objs += v4l2-compat-ioctl32.o
 endif
+ifeq ($(CONFIG_OF),y)
+  videodev-objs += v4l2-of.o
+endif
 
 obj-$(CONFIG_VIDEO_DEV) += videodev.o
 obj-$(CONFIG_VIDEO_V4L2_INT_DEVICE) += v4l2-int-device.o

drivers/media/v4l2-core/v4l2-of.c

+/*
+ * V4L2 OF binding parsing library
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * 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/module.h>
+#include <linux/of.h>
+#include <linux/string.h>
+#include <linux/types.h>
+
+#include <media/v4l2-of.h>
+
+static void v4l2_of_parse_csi_bus(const struct device_node *node,
+				  struct v4l2_of_endpoint *endpoint)
+{
+	struct v4l2_of_bus_mipi_csi2 *bus = &endpoint->bus.mipi_csi2;
+	u32 data_lanes[ARRAY_SIZE(bus->data_lanes)];
+	struct property *prop;
+	bool have_clk_lane = false;
+	unsigned int flags = 0;
+	u32 v;
+
+	prop = of_find_property(node, "data-lanes", NULL);
+	if (prop) {
+		const __be32 *lane = NULL;
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(data_lanes); i++) {
+			lane = of_prop_next_u32(prop, lane, &data_lanes[i]);
+			if (!lane)
+				break;
+		}
+		bus->num_data_lanes = i;
+		while (i--)
+			bus->data_lanes[i] = data_lanes[i];
+	}
+
+	if (!of_property_read_u32(node, "clock-lanes", &v)) {
+		bus->clock_lane = v;
+		have_clk_lane = true;
+	}
+
+	if (of_get_property(node, "clock-noncontinuous", &v))
+		flags |= V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
+	else if (have_clk_lane || bus->num_data_lanes > 0)
+		flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
+
+	bus->flags = flags;
+	endpoint->bus_type = V4L2_MBUS_CSI2;
+}
+
+static void v4l2_of_parse_parallel_bus(const struct device_node *node,
+				       struct v4l2_of_endpoint *endpoint)
+{
+	struct v4l2_of_bus_parallel *bus = &endpoint->bus.parallel;
+	unsigned int flags = 0;
+	u32 v;
+
+	if (!of_property_read_u32(node, "hsync-active", &v))
+		flags |= v ? V4L2_MBUS_HSYNC_ACTIVE_HIGH :
+			V4L2_MBUS_HSYNC_ACTIVE_LOW;
+
+	if (!of_property_read_u32(node, "vsync-active", &v))
+		flags |= v ? V4L2_MBUS_VSYNC_ACTIVE_HIGH :
+			V4L2_MBUS_VSYNC_ACTIVE_LOW;
+
+	if (!of_property_read_u32(node, "pclk-sample", &v))
+		flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
+			V4L2_MBUS_PCLK_SAMPLE_FALLING;
+
+	if (!of_property_read_u32(node, "field-even-active", &v))
+		flags |= v ? V4L2_MBUS_FIELD_EVEN_HIGH :
+			V4L2_MBUS_FIELD_EVEN_LOW;
+	if (flags)
+		endpoint->bus_type = V4L2_MBUS_PARALLEL;
+	else
+		endpoint->bus_type = V4L2_MBUS_BT656;
+
+	if (!of_property_read_u32(node, "data-active", &v))
+		flags |= v ? V4L2_MBUS_DATA_ACTIVE_HIGH :
+			V4L2_MBUS_DATA_ACTIVE_LOW;
+
+	if (of_get_property(node, "slave-mode", &v))
+		flags |= V4L2_MBUS_SLAVE;
+	else
+		flags |= V4L2_MBUS_MASTER;
+
+	if (!of_property_read_u32(node, "bus-width", &v))
+		bus->bus_width = v;
+
+	if (!of_property_read_u32(node, "data-shift", &v))
+		bus->data_shift = v;
+
+	bus->flags = flags;
+
+}
+EXPORT_SYMBOL(v4l2_of_parse_parallel_bus);
+
+/**
+ * v4l2_of_parse_endpoint() - parse all endpoint node properties
+ * @node: pointer to endpoint device_node
+ * @endpoint: pointer to the V4L2 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.
+ * If any properties that identify the bus as parallel are found and
+ * slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if we recognise
+ * the bus as serial CSI-2 and clock-noncontinuous isn't set, we set the
+ * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
+ * The caller should hold a reference to @node.
+ */
+void 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);
+
+	v4l2_of_parse_csi_bus(node, endpoint);
+	/*
+	 * Parse the parallel video bus properties only if none
+	 * of the MIPI CSI-2 specific properties were found.
+	 */
+	if (endpoint->bus.mipi_csi2.flags == 0)
+		v4l2_of_parse_parallel_bus(node, endpoint);
+
+	of_node_put(port_node);
+}
+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;
+
+		for_each_child_of_node(parent, node) {
+			if (!of_node_cmp(node->name, "port")) {
+				port = node;
+				break;
+			}
+		}
+		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);
+	} 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_parent(np);
+}
+EXPORT_SYMBOL(v4l2_of_get_remote_port);

include/media/v4l2-of.h

+/*
+ * V4L2 OF binding parsing library
+ *
+ * Copyright (C) 2012 Renesas Electronics Corp.
+ * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
+ *
+ * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
+ * Sylwester Nawrocki <s.nawrocki@samsung.com>
+ *
+ * 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 _V4L2_OF_H
+#define _V4L2_OF_H
+
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+
+#include <media/v4l2-mediabus.h>
+
+struct device_node;
+
+/**
+ * struct v4l2_of_bus_mipi_csi2 - MIPI CSI-2 bus data structure
+ * @flags: media bus (V4L2_MBUS_*) flags
+ * @data_lanes: an array of physical data lane indexes
+ * @clock_lane: physical lane index of the clock lane
+ * @num_data_lanes: number of data lanes
+ */
+struct v4l2_of_bus_mipi_csi2 {
+	unsigned int flags;
+	unsigned char data_lanes[4];
+	unsigned char clock_lane;
+	unsigned short num_data_lanes;
+};
+
+/**
+ * struct v4l2_of_bus_parallel - parallel data bus data structure
+ * @flags: media bus (V4L2_MBUS_*) flags
+ * @bus_width: bus width in bits
+ * @data_shift: data shift in bits
+ */
+struct v4l2_of_bus_parallel {
+	unsigned int flags;
+	unsigned char bus_width;
+	unsigned char data_shift;
+};
+
+/**
+ * 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
+ * @remote: phandle to remote endpoint 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;
+	const __be32 *remote;
+	enum v4l2_mbus_type bus_type;
+	union {
+		struct v4l2_of_bus_parallel parallel;
+		struct v4l2_of_bus_mipi_csi2 mipi_csi2;
+	} bus;
+	struct list_head head;
+};
+
+#ifdef CONFIG_OF
+void v4l2_of_parse_endpoint(const struct device_node *node,
+				struct v4l2_of_endpoint *link);
+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,
+					struct v4l2_of_endpoint *link)
+{
+	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 */