drivers/video/of_display_timing.c

   1 /*
   2  * OF helpers for parsing display timings
   3  *
   4  * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix
   5  *
   6  * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de>
   7  *
   8  * This file is released under the GPLv2
   9  */
  10 #include <linux/export.h>
  11 #include <linux/of.h>
  12 #include <linux/slab.h>
  13 #include <video/display_timing.h>
  14 #include <video/of_display_timing.h>
  15
  16 /**
  17  * parse_timing_property - parse timing_entry from device_node
  18  * @np: device_node with the property
  19  * @name: name of the property
  20  * @result: will be set to the return value
  21  *
  22  * DESCRIPTION:
  23  * Every display_timing can be specified with either just the typical value or
  24  * a range consisting of min/typ/max. This function helps handling this
  25  **/
  26 static int parse_timing_property(const struct device_node *np, const char *name,
  27                           struct timing_entry *result)
  28 {
  29         struct property *prop;
  30         int length, cells, ret;
  31
  32         prop = of_find_property(np, name, &length);
  33         if (!prop) {
  34                 pr_err("%s: could not find property %s\n",
  35                         of_node_full_name(np), name);
  36                 return -EINVAL;
  37         }
  38
  39         cells = length / sizeof(u32);
  40         if (cells == 1) {
  41                 ret = of_property_read_u32(np, name, &result->typ);
  42                 result->min = result->typ;
  43                 result->max = result->typ;
  44         } else if (cells == 3) {
  45                 ret = of_property_read_u32_array(np, name, &result->min, cells);
  46         } else {
  47                 pr_err("%s: illegal timing specification in %s\n",
  48                         of_node_full_name(np), name);
  49                 return -EINVAL;
  50         }
  51
  52         return ret;
  53 }
  54
  55 /**
  56  * of_parse_display_timing - parse display_timing entry from device_node
  57  * @np: device_node with the properties
  58  **/
  59 static int of_parse_display_timing(const struct device_node *np,
  60                 struct display_timing *dt)
  61 {
  62         u32 val = 0;
  63         int ret = 0;
  64
  65         memset(dt, 0, sizeof(*dt));
  66
  67         ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch);
  68         ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch);
  69         ret |= parse_timing_property(np, "hactive", &dt->hactive);
  70         ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len);
  71         ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch);
  72         ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch);
  73         ret |= parse_timing_property(np, "vactive", &dt->vactive);
  74         ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len);
  75         ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock);
  76
  77         dt->flags = 0;
  78         if (!of_property_read_u32(np, "vsync-active", &val))
  79                 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
  80                                 DISPLAY_FLAGS_VSYNC_LOW;
  81         if (!of_property_read_u32(np, "hsync-active", &val))
  82                 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
  83                                 DISPLAY_FLAGS_HSYNC_LOW;
  84         if (!of_property_read_u32(np, "de-active", &val))
  85                 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
  86                                 DISPLAY_FLAGS_DE_LOW;
  87         if (!of_property_read_u32(np, "pixelclk-active", &val))
  88                 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
  89                                 DISPLAY_FLAGS_PIXDATA_NEGEDGE;
  90
  91         if (of_property_read_bool(np, "interlaced"))
  92                 dt->flags |= DISPLAY_FLAGS_INTERLACED;
  93         if (of_property_read_bool(np, "doublescan"))
  94                 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
  95         if (of_property_read_bool(np, "doubleclk"))
  96                 dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
  97
  98         if (ret) {
  99                 pr_err("%s: error reading timing properties\n",
 100                         of_node_full_name(np));
 101                 return -EINVAL;
 102         }
 103
 104         return 0;
 105 }
 106
 107 /**
 108  * of_get_display_timing - parse a display_timing entry
 109  * @np: device_node with the timing subnode
 110  * @name: name of the timing node
 111  * @dt: display_timing struct to fill
 112  **/
 113 int of_get_display_timing(struct device_node *np, const char *name,
 114                 struct display_timing *dt)
 115 {
 116         struct device_node *timing_np;
 117
 118         if (!np) {
 119                 pr_err("%s: no devicenode given\n", of_node_full_name(np));
 120                 return -EINVAL;
 121         }
 122
 123         timing_np = of_get_child_by_name(np, name);
 124         if (!timing_np) {
 125                 pr_err("%s: could not find node '%s'\n",
 126                         of_node_full_name(np), name);
 127                 return -ENOENT;
 128         }
 129
 130         return of_parse_display_timing(timing_np, dt);
 131 }
 132 EXPORT_SYMBOL_GPL(of_get_display_timing);
 133
 134 /**
 135  * of_get_display_timings - parse all display_timing entries from a device_node
 136  * @np: device_node with the subnodes
 137  **/
 138 struct display_timings *of_get_display_timings(struct device_node *np)
 139 {
 140         struct device_node *timings_np;
 141         struct device_node *entry;
 142         struct device_node *native_mode;
 143         struct display_timings *disp;
 144
 145         if (!np) {
 146                 pr_err("%s: no device node given\n", of_node_full_name(np));
 147                 return NULL;
 148         }
 149
 150         timings_np = of_get_child_by_name(np, "display-timings");
 151         if (!timings_np) {
 152                 pr_err("%s: could not find display-timings node\n",
 153                         of_node_full_name(np));
 154                 return NULL;
 155         }
 156
 157         disp = kzalloc(sizeof(*disp), GFP_KERNEL);
 158         if (!disp) {
 159                 pr_err("%s: could not allocate struct disp'\n",
 160                         of_node_full_name(np));
 161                 goto dispfail;
 162         }
 163
 164         entry = of_parse_phandle(timings_np, "native-mode", 0);
 165         /* assume first child as native mode if none provided */
 166         if (!entry)
 167                 entry = of_get_next_child(np, NULL);
 168         /* if there is no child, it is useless to go on */
 169         if (!entry) {
 170                 pr_err("%s: no timing specifications given\n",
 171                         of_node_full_name(np));
 172                 goto entryfail;
 173         }
 174
 175         pr_debug("%s: using %s as default timing\n",
 176                 of_node_full_name(np), entry->name);
 177
 178         native_mode = entry;
 179
 180         disp->num_timings = of_get_child_count(timings_np);
 181         if (disp->num_timings == 0) {
 182                 /* should never happen, as entry was already found above */
 183                 pr_err("%s: no timings specified\n", of_node_full_name(np));
 184                 goto entryfail;
 185         }
 186
 187         disp->timings = kzalloc(sizeof(struct display_timing *) *
 188                                 disp->num_timings, GFP_KERNEL);
 189         if (!disp->timings) {
 190                 pr_err("%s: could not allocate timings array\n",
 191                         of_node_full_name(np));
 192                 goto entryfail;
 193         }
 194
 195         disp->num_timings = 0;
 196         disp->native_mode = 0;
 197
 198         for_each_child_of_node(timings_np, entry) {
 199                 struct display_timing *dt;
 200                 int r;
 201
 202                 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 203                 if (!dt) {
 204                         pr_err("%s: could not allocate display_timing struct\n",
 205                                         of_node_full_name(np));
 206                         goto timingfail;
 207                 }
 208
 209                 r = of_parse_display_timing(entry, dt);
 210                 if (r) {
 211                         /*
 212                          * to not encourage wrong devicetrees, fail in case of
 213                          * an error
 214                          */
 215                         pr_err("%s: error in timing %d\n",
 216                                 of_node_full_name(np), disp->num_timings + 1);
 217                         goto timingfail;
 218                 }
 219
 220                 if (native_mode == entry)
 221                         disp->native_mode = disp->num_timings;
 222
 223                 disp->timings[disp->num_timings] = dt;
 224                 disp->num_timings++;
 225         }
 226         of_node_put(timings_np);
 227         /*
 228          * native_mode points to the device_node returned by of_parse_phandle
 229          * therefore call of_node_put on it
 230          */
 231         of_node_put(native_mode);
 232
 233         pr_debug("%s: got %d timings. Using timing #%d as default\n",
 234                 of_node_full_name(np), disp->num_timings,
 235                 disp->native_mode + 1);
 236
 237         return disp;
 238
 239 timingfail:
 240         if (native_mode)
 241                 of_node_put(native_mode);
 242         display_timings_release(disp);
 243 entryfail:
 244         kfree(disp);
 245 dispfail:
 246         of_node_put(timings_np);
 247         return NULL;
 248 }
 249 EXPORT_SYMBOL_GPL(of_get_display_timings);
 250
 251 /**
 252  * of_display_timings_exist - check if a display-timings node is provided
 253  * @np: device_node with the timing
 254  **/
 255 int of_display_timings_exist(struct device_node *np)
 256 {
 257         struct device_node *timings_np;
 258
 259         if (!np)
 260                 return -EINVAL;
 261
 262         timings_np = of_parse_phandle(np, "display-timings", 0);
 263         if (!timings_np)
 264                 return -EINVAL;
 265
 266         of_node_put(timings_np);
 267         return 1;
 268 }
 269 EXPORT_SYMBOL_GPL(of_display_timings_exist);