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