2 * OF helpers for parsing display timings
4 * Copyright (c) 2012 Steffen Trumtrar <s.trumtrar@pengutronix.de>, Pengutronix
6 * based on of_videomode.c by Sascha Hauer <s.hauer@pengutronix.de>
8 * This file is released under the GPLv2
10 #include <linux/export.h>
12 #include <linux/slab.h>
13 #include <video/display_timing.h>
14 #include <video/of_display_timing.h>
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
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
26 static int parse_timing_property(const struct device_node *np, const char *name,
27 struct timing_entry *result)
29 struct property *prop;
30 int length, cells, ret;
32 prop = of_find_property(np, name, &length);
34 pr_err("%s: could not find property %s\n",
35 of_node_full_name(np), name);
39 cells = length / sizeof(u32);
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);
47 pr_err("%s: illegal timing specification in %s\n",
48 of_node_full_name(np), name);
56 * of_parse_display_timing - parse display_timing entry from device_node
57 * @np: device_node with the properties
59 static int of_parse_display_timing(const struct device_node *np,
60 struct display_timing *dt)
65 memset(dt, 0, sizeof(*dt));
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);
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 :
87 if (!of_property_read_u32(np, "pixelclk-active", &val))
88 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
89 DISPLAY_FLAGS_PIXDATA_NEGEDGE;
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;
99 pr_err("%s: error reading timing properties\n",
100 of_node_full_name(np));
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
113 int of_get_display_timing(struct device_node *np, const char *name,
114 struct display_timing *dt)
116 struct device_node *timing_np;
121 timing_np = of_get_child_by_name(np, name);
123 pr_err("%s: could not find node '%s'\n",
124 of_node_full_name(np), name);
128 return of_parse_display_timing(timing_np, dt);
130 EXPORT_SYMBOL_GPL(of_get_display_timing);
133 * of_get_display_timings - parse all display_timing entries from a device_node
134 * @np: device_node with the subnodes
136 struct display_timings *of_get_display_timings(struct device_node *np)
138 struct device_node *timings_np;
139 struct device_node *entry;
140 struct device_node *native_mode;
141 struct display_timings *disp;
146 timings_np = of_get_child_by_name(np, "display-timings");
148 pr_err("%s: could not find display-timings node\n",
149 of_node_full_name(np));
153 disp = kzalloc(sizeof(*disp), GFP_KERNEL);
155 pr_err("%s: could not allocate struct disp'\n",
156 of_node_full_name(np));
160 entry = of_parse_phandle(timings_np, "native-mode", 0);
161 /* assume first child as native mode if none provided */
163 entry = of_get_next_child(timings_np, NULL);
164 /* if there is no child, it is useless to go on */
166 pr_err("%s: no timing specifications given\n",
167 of_node_full_name(np));
171 pr_debug("%s: using %s as default timing\n",
172 of_node_full_name(np), entry->name);
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));
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));
191 disp->num_timings = 0;
192 disp->native_mode = 0;
194 for_each_child_of_node(timings_np, entry) {
195 struct display_timing *dt;
198 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
200 pr_err("%s: could not allocate display_timing struct\n",
201 of_node_full_name(np));
205 r = of_parse_display_timing(entry, dt);
208 * to not encourage wrong devicetrees, fail in case of
211 pr_err("%s: error in timing %d\n",
212 of_node_full_name(np), disp->num_timings + 1);
216 if (native_mode == entry)
217 disp->native_mode = disp->num_timings;
219 disp->timings[disp->num_timings] = dt;
222 of_node_put(timings_np);
224 * native_mode points to the device_node returned by of_parse_phandle
225 * therefore call of_node_put on it
227 of_node_put(native_mode);
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);
237 of_node_put(native_mode);
238 display_timings_release(disp);
242 of_node_put(timings_np);
245 EXPORT_SYMBOL_GPL(of_get_display_timings);
248 * of_display_timings_exist - check if a display-timings node is provided
249 * @np: device_node with the timing
251 int of_display_timings_exist(struct device_node *np)
253 struct device_node *timings_np;
258 timings_np = of_parse_phandle(np, "display-timings", 0);
262 of_node_put(timings_np);
265 EXPORT_SYMBOL_GPL(of_display_timings_exist);