LXR linux/drivers/video/of_display

   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 **/
  26static 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 **/
  59static 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 **/
 113int 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}
 130EXPORT_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 **/
 136struct 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                        goto timingfail;
 214                }
 215
 216                if (native_mode == entry)
 217                        disp->native_mode = disp->num_timings;
 218
 219                disp->timings[disp->num_timings] = dt;
 220                disp->num_timings++;
 221        }
 222        of_node_put(timings_np);
 223        /*
 224         * native_mode points to the device_node returned by of_parse_phandle
 225         * therefore call of_node_put on it
 226         */
 227        of_node_put(native_mode);
 228
 229        pr_debug("%s: got %d timings. Using timing #%d as default\n",
 230                of_node_full_name(np), disp->num_timings,
 231                disp->native_mode + 1);
 232
 233        return disp;
 234
 235timingfail:
 236        if (native_mode)
 237                of_node_put(native_mode);
 238        display_timings_release(disp);
 239entryfail:
 240        kfree(disp);
 241dispfail:
 242        of_node_put(timings_np);
 243        return NULL;
 244}
 245EXPORT_SYMBOL_GPL(of_get_display_timings);
 246
 247/**
 248 * of_display_timings_exist - check if a display-timings node is provided
 249 * @np: device_node with the timing
 250 **/
 251int of_display_timings_exist(struct device_node *np)
 252{
 253        struct device_node *timings_np;
 254
 255        if (!np)
 256                return -EINVAL;
 257
 258        timings_np = of_parse_phandle(np, "display-timings", 0);
 259        if (!timings_np)
 260                return -EINVAL;
 261
 262        of_node_put(timings_np);
 263        return 1;
 264}
 265EXPORT_SYMBOL_GPL(of_display_timings_exist);
 266