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(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_get_display_timing - parse display_timing entry from device_node
57 * @np: device_node with the properties
59 static struct display_timing *of_get_display_timing(struct device_node *np)
61 struct display_timing *dt;
65 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
67 pr_err("%s: could not allocate display_timing struct\n",
68 of_node_full_name(np));
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);
83 if (!of_property_read_u32(np, "vsync-active", &val))
84 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
85 DISPLAY_FLAGS_VSYNC_LOW;
86 if (!of_property_read_u32(np, "hsync-active", &val))
87 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
88 DISPLAY_FLAGS_HSYNC_LOW;
89 if (!of_property_read_u32(np, "de-active", &val))
90 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
92 if (!of_property_read_u32(np, "pixelclk-active", &val))
93 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
94 DISPLAY_FLAGS_PIXDATA_NEGEDGE;
96 if (of_property_read_bool(np, "interlaced"))
97 dt->flags |= DISPLAY_FLAGS_INTERLACED;
98 if (of_property_read_bool(np, "doublescan"))
99 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
102 pr_err("%s: error reading timing properties\n",
103 of_node_full_name(np));
112 * of_get_display_timings - parse all display_timing entries from a device_node
113 * @np: device_node with the subnodes
115 struct display_timings *of_get_display_timings(struct device_node *np)
117 struct device_node *timings_np;
118 struct device_node *entry;
119 struct device_node *native_mode;
120 struct display_timings *disp;
123 pr_err("%s: no devicenode given\n", of_node_full_name(np));
127 timings_np = of_find_node_by_name(np, "display-timings");
129 pr_err("%s: could not find display-timings node\n",
130 of_node_full_name(np));
134 disp = kzalloc(sizeof(*disp), GFP_KERNEL);
136 pr_err("%s: could not allocate struct disp'\n",
137 of_node_full_name(np));
141 entry = of_parse_phandle(timings_np, "native-mode", 0);
142 /* assume first child as native mode if none provided */
144 entry = of_get_next_child(np, NULL);
145 /* if there is no child, it is useless to go on */
147 pr_err("%s: no timing specifications given\n",
148 of_node_full_name(np));
152 pr_debug("%s: using %s as default timing\n",
153 of_node_full_name(np), entry->name);
157 disp->num_timings = of_get_child_count(timings_np);
158 if (disp->num_timings == 0) {
159 /* should never happen, as entry was already found above */
160 pr_err("%s: no timings specified\n", of_node_full_name(np));
164 disp->timings = kzalloc(sizeof(struct display_timing *) *
165 disp->num_timings, GFP_KERNEL);
166 if (!disp->timings) {
167 pr_err("%s: could not allocate timings array\n",
168 of_node_full_name(np));
172 disp->num_timings = 0;
173 disp->native_mode = 0;
175 for_each_child_of_node(timings_np, entry) {
176 struct display_timing *dt;
178 dt = of_get_display_timing(entry);
181 * to not encourage wrong devicetrees, fail in case of
184 pr_err("%s: error in timing %d\n",
185 of_node_full_name(np), disp->num_timings + 1);
189 if (native_mode == entry)
190 disp->native_mode = disp->num_timings;
192 disp->timings[disp->num_timings] = dt;
195 of_node_put(timings_np);
197 * native_mode points to the device_node returned by of_parse_phandle
198 * therefore call of_node_put on it
200 of_node_put(native_mode);
202 pr_debug("%s: got %d timings. Using timing #%d as default\n",
203 of_node_full_name(np), disp->num_timings,
204 disp->native_mode + 1);
210 of_node_put(native_mode);
211 display_timings_release(disp);
215 of_node_put(timings_np);
218 EXPORT_SYMBOL_GPL(of_get_display_timings);
221 * of_display_timings_exist - check if a display-timings node is provided
222 * @np: device_node with the timing
224 int of_display_timings_exist(struct device_node *np)
226 struct device_node *timings_np;
231 timings_np = of_parse_phandle(np, "display-timings", 0);
235 of_node_put(timings_np);
238 EXPORT_SYMBOL_GPL(of_display_timings_exist);