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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * OF helpers for parsing display timings4 *5 * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix6 *7 * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de>8 */9#include <linux/export.h>10#include <linux/of.h>11#include <linux/slab.h>12#include <video/display_timing.h>13#include <video/of_display_timing.h>14 15/**16 * parse_timing_property - parse timing_entry from device_node17 * @np: device_node with the property18 * @name: name of the property19 * @result: will be set to the return value20 *21 * DESCRIPTION:22 * Every display_timing can be specified with either just the typical value or23 * a range consisting of min/typ/max. This function helps handling this24 **/25static int parse_timing_property(const struct device_node *np, const char *name,26 struct timing_entry *result)27{28 struct property *prop;29 int length, cells, ret;30 31 prop = of_find_property(np, name, &length);32 if (!prop) {33 pr_err("%pOF: could not find property %s\n", np, name);34 return -EINVAL;35 }36 37 cells = length / sizeof(u32);38 if (cells == 1) {39 ret = of_property_read_u32(np, name, &result->typ);40 result->min = result->typ;41 result->max = result->typ;42 } else if (cells == 3) {43 ret = of_property_read_u32_array(np, name, &result->min, cells);44 } else {45 pr_err("%pOF: illegal timing specification in %s\n", np, name);46 return -EINVAL;47 }48 49 return ret;50}51 52/**53 * of_parse_display_timing - parse display_timing entry from device_node54 * @np: device_node with the properties55 * @dt: display_timing that contains the result. I may be partially written in case of errors56 **/57static 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 entry115 * @np: device_node with the timing subnode116 * @name: name of the timing node117 * @dt: display_timing struct to fill118 **/119int 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 int ret;124 125 if (!np)126 return -EINVAL;127 128 timing_np = of_get_child_by_name(np, name);129 if (!timing_np)130 return -ENOENT;131 132 ret = of_parse_display_timing(timing_np, dt);133 134 of_node_put(timing_np);135 136 return ret;137}138EXPORT_SYMBOL_GPL(of_get_display_timing);139 140/**141 * of_get_display_timings - parse all display_timing entries from a device_node142 * @np: device_node with the subnodes143 **/144struct display_timings *of_get_display_timings(const struct device_node *np)145{146 struct device_node *timings_np;147 struct device_node *entry;148 struct device_node *native_mode;149 struct display_timings *disp;150 151 if (!np)152 return NULL;153 154 timings_np = of_get_child_by_name(np, "display-timings");155 if (!timings_np) {156 pr_err("%pOF: could not find display-timings node\n", np);157 return NULL;158 }159 160 disp = kzalloc(sizeof(*disp), GFP_KERNEL);161 if (!disp) {162 pr_err("%pOF: could not allocate struct disp'\n", np);163 goto dispfail;164 }165 166 entry = of_parse_phandle(timings_np, "native-mode", 0);167 /* assume first child as native mode if none provided */168 if (!entry)169 entry = of_get_next_child(timings_np, NULL);170 /* if there is no child, it is useless to go on */171 if (!entry) {172 pr_err("%pOF: no timing specifications given\n", np);173 goto entryfail;174 }175 176 pr_debug("%pOF: using %pOFn as default timing\n", np, entry);177 178 native_mode = entry;179 180 disp->num_timings = of_get_child_count(timings_np);181 if (disp->num_timings == 0) {182 /* should never happen, as entry was already found above */183 pr_err("%pOF: no timings specified\n", np);184 goto entryfail;185 }186 187 disp->timings = kcalloc(disp->num_timings,188 sizeof(struct display_timing *),189 GFP_KERNEL);190 if (!disp->timings) {191 pr_err("%pOF: could not allocate timings array\n", np);192 goto entryfail;193 }194 195 disp->num_timings = 0;196 disp->native_mode = 0;197 198 for_each_child_of_node(timings_np, entry) {199 struct display_timing *dt;200 int r;201 202 dt = kmalloc(sizeof(*dt), GFP_KERNEL);203 if (!dt) {204 pr_err("%pOF: could not allocate display_timing struct\n",205 np);206 goto timingfail;207 }208 209 r = of_parse_display_timing(entry, dt);210 if (r) {211 /*212 * to not encourage wrong devicetrees, fail in case of213 * an error214 */215 pr_err("%pOF: error in timing %d\n",216 np, disp->num_timings + 1);217 kfree(dt);218 goto timingfail;219 }220 221 if (native_mode == entry)222 disp->native_mode = disp->num_timings;223 224 disp->timings[disp->num_timings] = dt;225 disp->num_timings++;226 }227 of_node_put(timings_np);228 /*229 * native_mode points to the device_node returned by of_parse_phandle230 * therefore call of_node_put on it231 */232 of_node_put(native_mode);233 234 pr_debug("%pOF: got %d timings. Using timing #%d as default\n",235 np, disp->num_timings,236 disp->native_mode + 1);237 238 return disp;239 240timingfail:241 of_node_put(native_mode);242 display_timings_release(disp);243 disp = NULL;244entryfail:245 kfree(disp);246dispfail:247 of_node_put(timings_np);248 return NULL;249}250EXPORT_SYMBOL_GPL(of_get_display_timings);251