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 **/
parse_timing_property(const struct device_node * np,const char * name,struct timing_entry * result)26 static 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 **/
of_parse_display_timing(const struct device_node * np,struct display_timing * dt)59 static 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 **/
of_get_display_timing(struct device_node * np,const char * name,struct display_timing * dt)113 int 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 }
130 EXPORT_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 **/
of_get_display_timings(struct device_node * np)136 struct 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 kfree(dt);
214 goto timingfail;
215 }
216
217 if (native_mode == entry)
218 disp->native_mode = disp->num_timings;
219
220 disp->timings[disp->num_timings] = dt;
221 disp->num_timings++;
222 }
223 of_node_put(timings_np);
224 /*
225 * native_mode points to the device_node returned by of_parse_phandle
226 * therefore call of_node_put on it
227 */
228 of_node_put(native_mode);
229
230 pr_debug("%s: got %d timings. Using timing #%d as default\n",
231 of_node_full_name(np), disp->num_timings,
232 disp->native_mode + 1);
233
234 return disp;
235
236 timingfail:
237 of_node_put(native_mode);
238 display_timings_release(disp);
239 disp = NULL;
240 entryfail:
241 kfree(disp);
242 dispfail:
243 of_node_put(timings_np);
244 return NULL;
245 }
246 EXPORT_SYMBOL_GPL(of_get_display_timings);
247
248 /**
249 * of_display_timings_exist - check if a display-timings node is provided
250 * @np: device_node with the timing
251 **/
of_display_timings_exist(struct device_node * np)252 int of_display_timings_exist(struct device_node *np)
253 {
254 struct device_node *timings_np;
255
256 if (!np)
257 return -EINVAL;
258
259 timings_np = of_parse_phandle(np, "display-timings", 0);
260 if (!timings_np)
261 return -EINVAL;
262
263 of_node_put(timings_np);
264 return 1;
265 }
266 EXPORT_SYMBOL_GPL(of_display_timings_exist);
267