/*
   * 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)
  ",
  				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;
  	struct property *prop;
  	const __be32 *cur;
  	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;
  
  	if (endpoint->bus_type == V4L2_MBUS_BT656) {
  
  		if (of_find_property(node, "pixel-mux", NULL))
  			bus->pixmux = 1;
  		else
  			bus->pixmux = 0;
  
  		bus->num_channels = 0;
  		of_property_for_each_u32(node, "channels", prop, cur, v) {
  			bus->channels[bus->num_channels] = v;
  			bus->num_channels++;
  			if (bus->num_channels == ARRAY_SIZE(bus->channels))
  				break;
  		}
  	}
  
  	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.
   */
  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);