alistair23-linux/drivers/media/v4l2-core/v4l2-of.c

/*
 * V4L2 OF 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/module.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>

#include <media/v4l2-of.h>

static int 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;
	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;
		unsigned int i;

		for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
			lane = of_prop_next_u32(prop, lane, &v);
			if (!lane)
				break;
			bus->data_lanes[i] = v;
		}
		bus->num_data_lanes = i;
	}

	prop = of_find_property(node, "lane-polarities", NULL);
	if (prop) {
		const __be32 *polarity = NULL;
		unsigned int i;

		for (i = 0; i < ARRAY_SIZE(bus->lane_polarities); i++) {
			polarity = of_prop_next_u32(prop, polarity, &v);
			if (!polarity)
				break;
			bus->lane_polarities[i] = v;
		}

		if (i < 1 + bus->num_data_lanes /* clock + data */) {
			pr_warn("%s: too few lane-polarities entries (need %u, got %u)\n",
				node->full_name, 1 + bus->num_data_lanes, i);
			return -EINVAL;
		}
	}

	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;

	return 0;
}

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, "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, "pclk-sample", &v))
		flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
			V4L2_MBUS_PCLK_SAMPLE_FALLING;

	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;

	if (!of_property_read_u32(node, "sync-on-green-active", &v))
		flags |= v ? V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH :
			V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW;

	bus->flags = flags;

}

/**
 * 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.
 *
 * NOTE: This function does not parse properties the size of which is
 * variable without a low fixed limit. Please use
 * v4l2_of_alloc_parse_endpoint() in new drivers instead.
 *
 * Return: 0 on success or a negative error code on failure.
 */
int v4l2_of_parse_endpoint(const struct device_node *node,
			   struct v4l2_of_endpoint *endpoint)
{
	int rval;

	of_graph_parse_endpoint(node, &endpoint->base);
	/* Zero fields from bus_type to until the end */
	memset(&endpoint->bus_type, 0, sizeof(*endpoint) -
	       offsetof(typeof(*endpoint), bus_type));

	rval = v4l2_of_parse_csi_bus(node, endpoint);
	if (rval)
		return rval;
	/*
	 * 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);

	return 0;
}
EXPORT_SYMBOL(v4l2_of_parse_endpoint);

/*
 * v4l2_of_free_endpoint() - free the endpoint acquired by
 * v4l2_of_alloc_parse_endpoint()
 * @endpoint - the endpoint the resources of which are to be released
 *
 * It is safe to call this function with NULL argument or on an
 * endpoint the parsing of which failed.
 */
void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
{
	if (IS_ERR_OR_NULL(endpoint))
		return;

	kfree(endpoint->link_frequencies);
	kfree(endpoint);
}
EXPORT_SYMBOL(v4l2_of_free_endpoint);

/**
 * v4l2_of_alloc_parse_endpoint() - parse all endpoint node properties
 * @node: pointer to endpoint device_node
 *
 * 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.
 *
 * v4l2_of_alloc_parse_endpoint() has two important differences to
 * v4l2_of_parse_endpoint():
 *
 * 1. It also parses variable size data and
 *
 * 2. The memory it has allocated to store the variable size data must
 *    be freed using v4l2_of_free_endpoint() when no longer needed.
 *
 * Return: Pointer to v4l2_of_endpoint if successful, on error a
 * negative error code.
 */
struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
	const struct device_node *node)
{
	struct v4l2_of_endpoint *endpoint;
	int len;
	int rval;

	endpoint = kzalloc(sizeof(*endpoint), GFP_KERNEL);
	if (!endpoint)
		return ERR_PTR(-ENOMEM);

	rval = v4l2_of_parse_endpoint(node, endpoint);
	if (rval < 0)
		goto out_err;

	if (of_get_property(node, "link-frequencies", &len)) {
		endpoint->link_frequencies = kmalloc(len, GFP_KERNEL);
		if (!endpoint->link_frequencies) {
			rval = -ENOMEM;
			goto out_err;
		}

		endpoint->nr_of_link_frequencies =
			len / sizeof(*endpoint->link_frequencies);

		rval = of_property_read_u64_array(
			node, "link-frequencies", endpoint->link_frequencies,
			endpoint->nr_of_link_frequencies);
		if (rval < 0)
			goto out_err;
	}

	return endpoint;

out_err:
	v4l2_of_free_endpoint(endpoint);
	return ERR_PTR(rval);
}
EXPORT_SYMBOL(v4l2_of_alloc_parse_endpoint);

/**
 * v4l2_of_parse_link() - parse a link between two endpoints
 * @node: pointer to the endpoint at the local end of the link
 * @link: pointer to the V4L2 OF link data structure
 *
 * Fill the link structure with the local and remote nodes and port numbers.
 * The local_node and remote_node fields are set to point to the local and
 * remote port's parent nodes respectively (the port parent node being the
 * parent node of the port node if that node isn't a 'ports' node, or the
 * grand-parent node of the port node otherwise).
 *
 * A reference is taken to both the local and remote nodes, the caller must use
 * v4l2_of_put_link() to drop the references when done with the link.
 *
 * Return: 0 on success, or -ENOLINK if the remote endpoint can't be found.
 */
int v4l2_of_parse_link(const struct device_node *node,
		       struct v4l2_of_link *link)
{
	struct device_node *np;

	memset(link, 0, sizeof(*link));

	np = of_get_parent(node);
	of_property_read_u32(np, "reg", &link->local_port);
	np = of_get_next_parent(np);
	if (of_node_cmp(np->name, "ports") == 0)
		np = of_get_next_parent(np);
	link->local_node = np;

	np = of_parse_phandle(node, "remote-endpoint", 0);
	if (!np) {
		of_node_put(link->local_node);
		return -ENOLINK;
	}

	np = of_get_parent(np);
	of_property_read_u32(np, "reg", &link->remote_port);
	np = of_get_next_parent(np);
	if (of_node_cmp(np->name, "ports") == 0)
		np = of_get_next_parent(np);
	link->remote_node = np;

	return 0;
}
EXPORT_SYMBOL(v4l2_of_parse_link);

/**
 * v4l2_of_put_link() - drop references to nodes in a link
 * @link: pointer to the V4L2 OF link data structure
 *
 * Drop references to the local and remote nodes in the link. This function must
 * be called on every link parsed with v4l2_of_parse_link().
 */
void v4l2_of_put_link(struct v4l2_of_link *link)
{
	of_node_put(link->local_node);
	of_node_put(link->remote_node);
}
EXPORT_SYMBOL(v4l2_of_put_link);