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_u32(np, "syncclk-active", &val))
  92                 dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE :
  93                                 DISPLAY_FLAGS_SYNC_NEGEDGE;
  94         else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE |
  95                               DISPLAY_FLAGS_PIXDATA_NEGEDGE))
  96                 dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ?
  97                                 DISPLAY_FLAGS_SYNC_POSEDGE :
  98                                 DISPLAY_FLAGS_SYNC_NEGEDGE;
  99
 100         if (of_property_read_bool(np, "interlaced"))
 101                 dt->flags |= DISPLAY_FLAGS_INTERLACED;
 102         if (of_property_read_bool(np, "doublescan"))
 103                 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
 104         if (of_property_read_bool(np, "doubleclk"))
 105                 dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
 106
 107         if (ret) {
 108                 pr_err("%s: error reading timing properties\n",
 109                         of_node_full_name(np));
 110                 return -EINVAL;
 111         }
 112
 113         return 0;
 114 }
 115
 116 /**
 117  * of_get_display_timing - parse a display_timing entry
 118  * @np: device_node with the timing subnode
 119  * @name: name of the timing node
 120  * @dt: display_timing struct to fill
 121  **/
 122 int of_get_display_timing(const struct device_node *np, const char *name,
 123                 struct display_timing *dt)
 124 {
 125         struct device_node *timing_np;
 126
 127         if (!np)
 128                 return -EINVAL;
 129
 130         timing_np = of_get_child_by_name(np, name);
 131         if (!timing_np) {
 132                 pr_err("%s: could not find node '%s'\n",
 133                         of_node_full_name(np), name);
 134                 return -ENOENT;
 135         }
 136
 137         return of_parse_display_timing(timing_np, dt);
 138 }
 139 EXPORT_SYMBOL_GPL(of_get_display_timing);
 140
 141 /**
 142  * of_get_display_timings - parse all display_timing entries from a device_node
 143  * @np: device_node with the subnodes
 144  **/
 145 struct display_timings *of_get_display_timings(const struct device_node *np)
 146 {
 147         struct device_node *timings_np;
 148         struct device_node *entry;
 149         struct device_node *native_mode;
 150         struct display_timings *disp;
 151
 152         if (!np)
 153                 return NULL;
 154
 155         timings_np = of_get_child_by_name(np, "display-timings");
 156         if (!timings_np) {
 157                 pr_err("%s: could not find display-timings node\n",
 158                         of_node_full_name(np));
 159                 return NULL;
 160         }
 161
 162         disp = kzalloc(sizeof(*disp), GFP_KERNEL);
 163         if (!disp) {
 164                 pr_err("%s: could not allocate struct disp'\n",
 165                         of_node_full_name(np));
 166                 goto dispfail;
 167         }
 168
 169         entry = of_parse_phandle(timings_np, "native-mode", 0);
 170         /* assume first child as native mode if none provided */
 171         if (!entry)
 172                 entry = of_get_next_child(timings_np, NULL);
 173         /* if there is no child, it is useless to go on */
 174         if (!entry) {
 175                 pr_err("%s: no timing specifications given\n",
 176                         of_node_full_name(np));
 177                 goto entryfail;
 178         }
 179
 180         pr_debug("%s: using %s as default timing\n",
 181                 of_node_full_name(np), entry->name);
 182
 183         native_mode = entry;
 184
 185         disp->num_timings = of_get_child_count(timings_np);
 186         if (disp->num_timings == 0) {
 187                 /* should never happen, as entry was already found above */
 188                 pr_err("%s: no timings specified\n", of_node_full_name(np));
 189                 goto entryfail;
 190         }
 191
 192         disp->timings = kzalloc(sizeof(struct display_timing *) *
 193                                 disp->num_timings, GFP_KERNEL);
 194         if (!disp->timings) {
 195                 pr_err("%s: could not allocate timings array\n",
 196                         of_node_full_name(np));
 197                 goto entryfail;
 198         }
 199
 200         disp->num_timings = 0;
 201         disp->native_mode = 0;
 202
 203         for_each_child_of_node(timings_np, entry) {
 204                 struct display_timing *dt;
 205                 int r;
 206
 207                 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 208                 if (!dt) {
 209                         pr_err("%s: could not allocate display_timing struct\n",
 210                                         of_node_full_name(np));
 211                         goto timingfail;
 212                 }
 213
 214                 r = of_parse_display_timing(entry, dt);
 215                 if (r) {
 216                         /*
 217                          * to not encourage wrong devicetrees, fail in case of
 218                          * an error
 219                          */
 220                         pr_err("%s: error in timing %d\n",
 221                                 of_node_full_name(np), disp->num_timings + 1);
 222                         kfree(dt);
 223                         goto timingfail;
 224                 }
 225
 226                 if (native_mode == entry)
 227                         disp->native_mode = disp->num_timings;
 228
 229                 disp->timings[disp->num_timings] = dt;
 230                 disp->num_timings++;
 231         }
 232         of_node_put(timings_np);
 233         /*
 234          * native_mode points to the device_node returned by of_parse_phandle
 235          * therefore call of_node_put on it
 236          */
 237         of_node_put(native_mode);
 238
 239         pr_debug("%s: got %d timings. Using timing #%d as default\n",
 240                 of_node_full_name(np), disp->num_timings,
 241                 disp->native_mode + 1);
 242
 243         return disp;
 244
 245 timingfail:
 246         of_node_put(native_mode);
 247         display_timings_release(disp);
 248         disp = NULL;
 249 entryfail:
 250         kfree(disp);
 251 dispfail:
 252         of_node_put(timings_np);
 253         return NULL;
 254 }
 255 EXPORT_SYMBOL_GPL(of_get_display_timings);
 256
 257 /**
 258  * of_display_timings_exist - check if a display-timings node is provided
 259  * @np: device_node with the timing
 260  **/
 261 int of_display_timings_exist(const struct device_node *np)
 262 {
 263         struct device_node *timings_np;
 264
 265         if (!np)
 266                 return -EINVAL;
 267
 268         timings_np = of_parse_phandle(np, "display-timings", 0);
 269         if (!timings_np)
 270                 return -EINVAL;
 271
 272         of_node_put(timings_np);
 273         return 1;
 274 }
 275 EXPORT_SYMBOL_GPL(of_display_timings_exist);