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("%pOF: could not find property %s\n", np, name);
  35                 return -EINVAL;
  36         }
  37
  38         cells = length / sizeof(u32);
  39         if (cells == 1) {
  40                 ret = of_property_read_u32(np, name, &result->typ);
  41                 result->min = result->typ;
  42                 result->max = result->typ;
  43         } else if (cells == 3) {
  44                 ret = of_property_read_u32_array(np, name, &result->min, cells);
  45         } else {
  46                 pr_err("%pOF: illegal timing specification in %s\n", np, name);
  47                 return -EINVAL;
  48         }
  49
  50         return ret;
  51 }
  52
  53 /**
  54  * of_parse_display_timing - parse display_timing entry from device_node
  55  * @np: device_node with the properties
  56  **/
  57 static int of_parse_display_timing(const struct device_node *np,
  58                 struct display_timing *dt)
  59 {
  60         u32 val = 0;
  61         int ret = 0;
  62
  63         memset(dt, 0, sizeof(*dt));
  64
  65         ret |= parse_timing_property(np, "hback-porch", &dt->hback_porch);
  66         ret |= parse_timing_property(np, "hfront-porch", &dt->hfront_porch);
  67         ret |= parse_timing_property(np, "hactive", &dt->hactive);
  68         ret |= parse_timing_property(np, "hsync-len", &dt->hsync_len);
  69         ret |= parse_timing_property(np, "vback-porch", &dt->vback_porch);
  70         ret |= parse_timing_property(np, "vfront-porch", &dt->vfront_porch);
  71         ret |= parse_timing_property(np, "vactive", &dt->vactive);
  72         ret |= parse_timing_property(np, "vsync-len", &dt->vsync_len);
  73         ret |= parse_timing_property(np, "clock-frequency", &dt->pixelclock);
  74
  75         dt->flags = 0;
  76         if (!of_property_read_u32(np, "vsync-active", &val))
  77                 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
  78                                 DISPLAY_FLAGS_VSYNC_LOW;
  79         if (!of_property_read_u32(np, "hsync-active", &val))
  80                 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
  81                                 DISPLAY_FLAGS_HSYNC_LOW;
  82         if (!of_property_read_u32(np, "de-active", &val))
  83                 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
  84                                 DISPLAY_FLAGS_DE_LOW;
  85         if (!of_property_read_u32(np, "pixelclk-active", &val))
  86                 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
  87                                 DISPLAY_FLAGS_PIXDATA_NEGEDGE;
  88
  89         if (!of_property_read_u32(np, "syncclk-active", &val))
  90                 dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE :
  91                                 DISPLAY_FLAGS_SYNC_NEGEDGE;
  92         else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE |
  93                               DISPLAY_FLAGS_PIXDATA_NEGEDGE))
  94                 dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ?
  95                                 DISPLAY_FLAGS_SYNC_POSEDGE :
  96                                 DISPLAY_FLAGS_SYNC_NEGEDGE;
  97
  98         if (of_property_read_bool(np, "interlaced"))
  99                 dt->flags |= DISPLAY_FLAGS_INTERLACED;
 100         if (of_property_read_bool(np, "doublescan"))
 101                 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
 102         if (of_property_read_bool(np, "doubleclk"))
 103                 dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
 104
 105         if (ret) {
 106                 pr_err("%pOF: error reading timing properties\n", np);
 107                 return -EINVAL;
 108         }
 109
 110         return 0;
 111 }
 112
 113 /**
 114  * of_get_display_timing - parse a display_timing entry
 115  * @np: device_node with the timing subnode
 116  * @name: name of the timing node
 117  * @dt: display_timing struct to fill
 118  **/
 119 int of_get_display_timing(const struct device_node *np, const char *name,
 120                 struct display_timing *dt)
 121 {
 122         struct device_node *timing_np;
 123
 124         if (!np)
 125                 return -EINVAL;
 126
 127         timing_np = of_get_child_by_name(np, name);
 128         if (!timing_np) {
 129                 pr_err("%pOF: could not find node '%s'\n", np, name);
 130                 return -ENOENT;
 131         }
 132
 133         return of_parse_display_timing(timing_np, dt);
 134 }
 135 EXPORT_SYMBOL_GPL(of_get_display_timing);
 136
 137 /**
 138  * of_get_display_timings - parse all display_timing entries from a device_node
 139  * @np: device_node with the subnodes
 140  **/
 141 struct display_timings *of_get_display_timings(const struct device_node *np)
 142 {
 143         struct device_node *timings_np;
 144         struct device_node *entry;
 145         struct device_node *native_mode;
 146         struct display_timings *disp;
 147
 148         if (!np)
 149                 return NULL;
 150
 151         timings_np = of_get_child_by_name(np, "display-timings");
 152         if (!timings_np) {
 153                 pr_err("%pOF: could not find display-timings node\n", np);
 154                 return NULL;
 155         }
 156
 157         disp = kzalloc(sizeof(*disp), GFP_KERNEL);
 158         if (!disp) {
 159                 pr_err("%pOF: could not allocate struct disp'\n", np);
 160                 goto dispfail;
 161         }
 162
 163         entry = of_parse_phandle(timings_np, "native-mode", 0);
 164         /* assume first child as native mode if none provided */
 165         if (!entry)
 166                 entry = of_get_next_child(timings_np, NULL);
 167         /* if there is no child, it is useless to go on */
 168         if (!entry) {
 169                 pr_err("%pOF: no timing specifications given\n", np);
 170                 goto entryfail;
 171         }
 172
 173         pr_debug("%pOF: using %s as default timing\n", np, entry->name);
 174
 175         native_mode = entry;
 176
 177         disp->num_timings = of_get_child_count(timings_np);
 178         if (disp->num_timings == 0) {
 179                 /* should never happen, as entry was already found above */
 180                 pr_err("%pOF: no timings specified\n", np);
 181                 goto entryfail;
 182         }
 183
 184         disp->timings = kcalloc(disp->num_timings,
 185                                 sizeof(struct display_timing *),
 186                                 GFP_KERNEL);
 187         if (!disp->timings) {
 188                 pr_err("%pOF: could not allocate timings array\n", np);
 189                 goto entryfail;
 190         }
 191
 192         disp->num_timings = 0;
 193         disp->native_mode = 0;
 194
 195         for_each_child_of_node(timings_np, entry) {
 196                 struct display_timing *dt;
 197                 int r;
 198
 199                 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
 200                 if (!dt) {
 201                         pr_err("%pOF: could not allocate display_timing struct\n",
 202                                 np);
 203                         goto timingfail;
 204                 }
 205
 206                 r = of_parse_display_timing(entry, dt);
 207                 if (r) {
 208                         /*
 209                          * to not encourage wrong devicetrees, fail in case of
 210                          * an error
 211                          */
 212                         pr_err("%pOF: error in timing %d\n",
 213                                 np, disp->num_timings + 1);
 214                         kfree(dt);
 215                         goto timingfail;
 216                 }
 217
 218                 if (native_mode == entry)
 219                         disp->native_mode = disp->num_timings;
 220
 221                 disp->timings[disp->num_timings] = dt;
 222                 disp->num_timings++;
 223         }
 224         of_node_put(timings_np);
 225         /*
 226          * native_mode points to the device_node returned by of_parse_phandle
 227          * therefore call of_node_put on it
 228          */
 229         of_node_put(native_mode);
 230
 231         pr_debug("%pOF: got %d timings. Using timing #%d as default\n",
 232                 np, disp->num_timings,
 233                 disp->native_mode + 1);
 234
 235         return disp;
 236
 237 timingfail:
 238         of_node_put(native_mode);
 239         display_timings_release(disp);
 240         disp = NULL;
 241 entryfail:
 242         kfree(disp);
 243 dispfail:
 244         of_node_put(timings_np);
 245         return NULL;
 246 }
 247 EXPORT_SYMBOL_GPL(of_get_display_timings);