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

   1 /*
   2  * V4L2 OF binding parsing library
   3  *
   4  * Copyright (C) 2012 - 2013 Samsung Electronics Co., Ltd.
   5  * Author: Sylwester Nawrocki <s.nawrocki@samsung.com>
   6  *
   7  * Copyright (C) 2012 Renesas Electronics Corp.
   8  * Author: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of version 2 of the GNU General Public License as
  12  * published by the Free Software Foundation.
  13  */
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/slab.h>
  18 #include <linux/string.h>
  19 #include <linux/types.h>
  20
  21 #include <media/v4l2-of.h>
  22
  23 static int v4l2_of_parse_csi_bus(const struct device_node *node,
  24                                  struct v4l2_of_endpoint *endpoint)
  25 {
  26         struct v4l2_of_bus_mipi_csi2 *bus = &endpoint->bus.mipi_csi2;
  27         struct property *prop;
  28         bool have_clk_lane = false;
  29         unsigned int flags = 0;
  30         u32 v;
  31
  32         prop = of_find_property(node, "data-lanes", NULL);
  33         if (prop) {
  34                 const __be32 *lane = NULL;
  35                 unsigned int i;
  36
  37                 for (i = 0; i < ARRAY_SIZE(bus->data_lanes); i++) {
  38                         lane = of_prop_next_u32(prop, lane, &v);
  39                         if (!lane)
  40                                 break;
  41                         bus->data_lanes[i] = v;
  42                 }
  43                 bus->num_data_lanes = i;
  44         }
  45
  46         prop = of_find_property(node, "lane-polarities", NULL);
  47         if (prop) {
  48                 const __be32 *polarity = NULL;
  49                 unsigned int i;
  50
  51                 for (i = 0; i < ARRAY_SIZE(bus->lane_polarities); i++) {
  52                         polarity = of_prop_next_u32(prop, polarity, &v);
  53                         if (!polarity)
  54                                 break;
  55                         bus->lane_polarities[i] = v;
  56                 }
  57
  58                 if (i < 1 + bus->num_data_lanes /* clock + data */) {
  59                         pr_warn("%s: too few lane-polarities entries (need %u, got %u)\n",
  60                                 node->full_name, 1 + bus->num_data_lanes, i);
  61                         return -EINVAL;
  62                 }
  63         }
  64
  65         if (!of_property_read_u32(node, "clock-lanes", &v)) {
  66                 bus->clock_lane = v;
  67                 have_clk_lane = true;
  68         }
  69
  70         if (of_get_property(node, "clock-noncontinuous", &v))
  71                 flags |= V4L2_MBUS_CSI2_NONCONTINUOUS_CLOCK;
  72         else if (have_clk_lane || bus->num_data_lanes > 0)
  73                 flags |= V4L2_MBUS_CSI2_CONTINUOUS_CLOCK;
  74
  75         bus->flags = flags;
  76         endpoint->bus_type = V4L2_MBUS_CSI2;
  77
  78         return 0;
  79 }
  80
  81 static void v4l2_of_parse_parallel_bus(const struct device_node *node,
  82                                        struct v4l2_of_endpoint *endpoint)
  83 {
  84         struct v4l2_of_bus_parallel *bus = &endpoint->bus.parallel;
  85         unsigned int flags = 0;
  86         u32 v;
  87
  88         if (!of_property_read_u32(node, "hsync-active", &v))
  89                 flags |= v ? V4L2_MBUS_HSYNC_ACTIVE_HIGH :
  90                         V4L2_MBUS_HSYNC_ACTIVE_LOW;
  91
  92         if (!of_property_read_u32(node, "vsync-active", &v))
  93                 flags |= v ? V4L2_MBUS_VSYNC_ACTIVE_HIGH :
  94                         V4L2_MBUS_VSYNC_ACTIVE_LOW;
  95
  96         if (!of_property_read_u32(node, "field-even-active", &v))
  97                 flags |= v ? V4L2_MBUS_FIELD_EVEN_HIGH :
  98                         V4L2_MBUS_FIELD_EVEN_LOW;
  99         if (flags)
 100                 endpoint->bus_type = V4L2_MBUS_PARALLEL;
 101         else
 102                 endpoint->bus_type = V4L2_MBUS_BT656;
 103
 104         if (!of_property_read_u32(node, "pclk-sample", &v))
 105                 flags |= v ? V4L2_MBUS_PCLK_SAMPLE_RISING :
 106                         V4L2_MBUS_PCLK_SAMPLE_FALLING;
 107
 108         if (!of_property_read_u32(node, "data-active", &v))
 109                 flags |= v ? V4L2_MBUS_DATA_ACTIVE_HIGH :
 110                         V4L2_MBUS_DATA_ACTIVE_LOW;
 111
 112         if (of_get_property(node, "slave-mode", &v))
 113                 flags |= V4L2_MBUS_SLAVE;
 114         else
 115                 flags |= V4L2_MBUS_MASTER;
 116
 117         if (!of_property_read_u32(node, "bus-width", &v))
 118                 bus->bus_width = v;
 119
 120         if (!of_property_read_u32(node, "data-shift", &v))
 121                 bus->data_shift = v;
 122
 123         if (!of_property_read_u32(node, "sync-on-green-active", &v))
 124                 flags |= v ? V4L2_MBUS_VIDEO_SOG_ACTIVE_HIGH :
 125                         V4L2_MBUS_VIDEO_SOG_ACTIVE_LOW;
 126
 127         bus->flags = flags;
 128
 129 }
 130
 131 /**
 132  * v4l2_of_parse_endpoint() - parse all endpoint node properties
 133  * @node: pointer to endpoint device_node
 134  * @endpoint: pointer to the V4L2 OF endpoint data structure
 135  *
 136  * All properties are optional. If none are found, we don't set any flags.
 137  * This means the port has a static configuration and no properties have
 138  * to be specified explicitly.
 139  * If any properties that identify the bus as parallel are found and
 140  * slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if we recognise
 141  * the bus as serial CSI-2 and clock-noncontinuous isn't set, we set the
 142  * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
 143  * The caller should hold a reference to @node.
 144  *
 145  * NOTE: This function does not parse properties the size of which is
 146  * variable without a low fixed limit. Please use
 147  * v4l2_of_alloc_parse_endpoint() in new drivers instead.
 148  *
 149  * Return: 0.
 150  */
 151 int v4l2_of_parse_endpoint(const struct device_node *node,
 152                            struct v4l2_of_endpoint *endpoint)
 153 {
 154         int rval;
 155
 156         of_graph_parse_endpoint(node, &endpoint->base);
 157         /* Zero fields from bus_type to until the end */
 158         memset(&endpoint->bus_type, 0, sizeof(*endpoint) -
 159                offsetof(typeof(*endpoint), bus_type));
 160
 161         rval = v4l2_of_parse_csi_bus(node, endpoint);
 162         if (rval)
 163                 return rval;
 164         /*
 165          * Parse the parallel video bus properties only if none
 166          * of the MIPI CSI-2 specific properties were found.
 167          */
 168         if (endpoint->bus.mipi_csi2.flags == 0)
 169                 v4l2_of_parse_parallel_bus(node, endpoint);
 170
 171         return 0;
 172 }
 173 EXPORT_SYMBOL(v4l2_of_parse_endpoint);
 174
 175 /*
 176  * v4l2_of_free_endpoint() - free the endpoint acquired by
 177  * v4l2_of_alloc_parse_endpoint()
 178  * @endpoint - the endpoint the resources of which are to be released
 179  *
 180  * It is safe to call this function with NULL argument or on an
 181  * endpoint the parsing of which failed.
 182  */
 183 void v4l2_of_free_endpoint(struct v4l2_of_endpoint *endpoint)
 184 {
 185         if (IS_ERR_OR_NULL(endpoint))
 186                 return;
 187
 188         kfree(endpoint->link_frequencies);
 189         kfree(endpoint);
 190 }
 191 EXPORT_SYMBOL(v4l2_of_free_endpoint);
 192
 193 /**
 194  * v4l2_of_alloc_parse_endpoint() - parse all endpoint node properties
 195  * @node: pointer to endpoint device_node
 196  *
 197  * All properties are optional. If none are found, we don't set any flags.
 198  * This means the port has a static configuration and no properties have
 199  * to be specified explicitly.
 200  * If any properties that identify the bus as parallel are found and
 201  * slave-mode isn't set, we set V4L2_MBUS_MASTER. Similarly, if we recognise
 202  * the bus as serial CSI-2 and clock-noncontinuous isn't set, we set the
 203  * V4L2_MBUS_CSI2_CONTINUOUS_CLOCK flag.
 204  * The caller should hold a reference to @node.
 205  *
 206  * v4l2_of_alloc_parse_endpoint() has two important differences to
 207  * v4l2_of_parse_endpoint():
 208  *
 209  * 1. It also parses variable size data and
 210  *
 211  * 2. The memory it has allocated to store the variable size data must
 212  *    be freed using v4l2_of_free_endpoint() when no longer needed.
 213  *
 214  * Return: Pointer to v4l2_of_endpoint if successful, on error a
 215  * negative error code.
 216  */
 217 struct v4l2_of_endpoint *v4l2_of_alloc_parse_endpoint(
 218         const struct device_node *node)
 219 {
 220         struct v4l2_of_endpoint *endpoint;
 221         int len;
 222         int rval;
 223
 224         endpoint = kzalloc(sizeof(*endpoint), GFP_KERNEL);
 225         if (!endpoint)
 226                 return ERR_PTR(-ENOMEM);
 227
 228         rval = v4l2_of_parse_endpoint(node, endpoint);
 229         if (rval < 0)
 230                 goto out_err;
 231
 232         if (of_get_property(node, "link-frequencies", &len)) {
 233                 endpoint->link_frequencies = kmalloc(len, GFP_KERNEL);
 234                 if (!endpoint->link_frequencies) {
 235                         rval = -ENOMEM;
 236                         goto out_err;
 237                 }
 238
 239                 endpoint->nr_of_link_frequencies =
 240                         len / sizeof(*endpoint->link_frequencies);
 241
 242                 rval = of_property_read_u64_array(
 243                         node, "link-frequencies", endpoint->link_frequencies,
 244                         endpoint->nr_of_link_frequencies);
 245                 if (rval < 0)
 246                         goto out_err;
 247         }
 248
 249         return endpoint;
 250
 251 out_err:
 252         v4l2_of_free_endpoint(endpoint);
 253         return ERR_PTR(rval);
 254 }
 255 EXPORT_SYMBOL(v4l2_of_alloc_parse_endpoint);
 256
 257 /**
 258  * v4l2_of_parse_link() - parse a link between two endpoints
 259  * @node: pointer to the endpoint at the local end of the link
 260  * @link: pointer to the V4L2 OF link data structure
 261  *
 262  * Fill the link structure with the local and remote nodes and port numbers.
 263  * The local_node and remote_node fields are set to point to the local and
 264  * remote port's parent nodes respectively (the port parent node being the
 265  * parent node of the port node if that node isn't a 'ports' node, or the
 266  * grand-parent node of the port node otherwise).
 267  *
 268  * A reference is taken to both the local and remote nodes, the caller must use
 269  * v4l2_of_put_link() to drop the references when done with the link.
 270  *
 271  * Return: 0 on success, or -ENOLINK if the remote endpoint can't be found.
 272  */
 273 int v4l2_of_parse_link(const struct device_node *node,
 274                        struct v4l2_of_link *link)
 275 {
 276         struct device_node *np;
 277
 278         memset(link, 0, sizeof(*link));
 279
 280         np = of_get_parent(node);
 281         of_property_read_u32(np, "reg", &link->local_port);
 282         np = of_get_next_parent(np);
 283         if (of_node_cmp(np->name, "ports") == 0)
 284                 np = of_get_next_parent(np);
 285         link->local_node = np;
 286
 287         np = of_parse_phandle(node, "remote-endpoint", 0);
 288         if (!np) {
 289                 of_node_put(link->local_node);
 290                 return -ENOLINK;
 291         }
 292
 293         np = of_get_parent(np);
 294         of_property_read_u32(np, "reg", &link->remote_port);
 295         np = of_get_next_parent(np);
 296         if (of_node_cmp(np->name, "ports") == 0)
 297                 np = of_get_next_parent(np);
 298         link->remote_node = np;
 299
 300         return 0;
 301 }
 302 EXPORT_SYMBOL(v4l2_of_parse_link);
 303
 304 /**
 305  * v4l2_of_put_link() - drop references to nodes in a link
 306  * @link: pointer to the V4L2 OF link data structure
 307  *
 308  * Drop references to the local and remote nodes in the link. This function must
 309  * be called on every link parsed with v4l2_of_parse_link().
 310  */
 311 void v4l2_of_put_link(struct v4l2_of_link *link)
 312 {
 313         of_node_put(link->local_node);
 314         of_node_put(link->remote_node);
 315 }
 316 EXPORT_SYMBOL(v4l2_of_put_link);