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