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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 **/
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 **/
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_u32(np, "syncclk-active", &val))
92 dt->flags |= val ? DISPLAY_FLAGS_SYNC_POSEDGE :
93 DISPLAY_FLAGS_SYNC_NEGEDGE;
94 else if (dt->flags & (DISPLAY_FLAGS_PIXDATA_POSEDGE |
95 DISPLAY_FLAGS_PIXDATA_NEGEDGE))
96 dt->flags |= dt->flags & DISPLAY_FLAGS_PIXDATA_POSEDGE ?
97 DISPLAY_FLAGS_SYNC_POSEDGE :
98 DISPLAY_FLAGS_SYNC_NEGEDGE;
99
100 if (of_property_read_bool(np, "interlaced"))
101 dt->flags |= DISPLAY_FLAGS_INTERLACED;
102 if (of_property_read_bool(np, "doublescan"))
103 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
104 if (of_property_read_bool(np, "doubleclk"))
105 dt->flags |= DISPLAY_FLAGS_DOUBLECLK;
106
107 if (ret) {
108 pr_err("%s: error reading timing properties\n",
109 of_node_full_name(np));
110 return -EINVAL;
111 }
112
113 return 0;
114 }
115
116 /**
117 * of_get_display_timing - parse a display_timing entry
118 * @np: device_node with the timing subnode
119 * @name: name of the timing node
120 * @dt: display_timing struct to fill
121 **/
122 int of_get_display_timing(const struct device_node *np, const char *name,
123 struct display_timing *dt)
124 {
125 struct device_node *timing_np;
126
127 if (!np)
128 return -EINVAL;
129
130 timing_np = of_get_child_by_name(np, name);
131 if (!timing_np) {
132 pr_err("%s: could not find node '%s'\n",
133 of_node_full_name(np), name);
134 return -ENOENT;
135 }
136
137 return of_parse_display_timing(timing_np, dt);
138 }
139 EXPORT_SYMBOL_GPL(of_get_display_timing);
140
141 /**
142 * of_get_display_timings - parse all display_timing entries from a device_node
143 * @np: device_node with the subnodes
144 **/
145 struct display_timings *of_get_display_timings(const struct device_node *np)
146 {
147 struct device_node *timings_np;
148 struct device_node *entry;
149 struct device_node *native_mode;
150 struct display_timings *disp;
151
152 if (!np)
153 return NULL;
154
155 timings_np = of_get_child_by_name(np, "display-timings");
156 if (!timings_np) {
157 pr_err("%s: could not find display-timings node\n",
158 of_node_full_name(np));
159 return NULL;
160 }
161
162 disp = kzalloc(sizeof(*disp), GFP_KERNEL);
163 if (!disp) {
164 pr_err("%s: could not allocate struct disp'\n",
165 of_node_full_name(np));
166 goto dispfail;
167 }
168
169 entry = of_parse_phandle(timings_np, "native-mode", 0);
170 /* assume first child as native mode if none provided */
171 if (!entry)
172 entry = of_get_next_child(timings_np, NULL);
173 /* if there is no child, it is useless to go on */
174 if (!entry) {
175 pr_err("%s: no timing specifications given\n",
176 of_node_full_name(np));
177 goto entryfail;
178 }
179
180 pr_debug("%s: using %s as default timing\n",
181 of_node_full_name(np), entry->name);
182
183 native_mode = entry;
184
185 disp->num_timings = of_get_child_count(timings_np);
186 if (disp->num_timings == 0) {
187 /* should never happen, as entry was already found above */
188 pr_err("%s: no timings specified\n", of_node_full_name(np));
189 goto entryfail;
190 }
191
192 disp->timings = kzalloc(sizeof(struct display_timing *) *
193 disp->num_timings, GFP_KERNEL);
194 if (!disp->timings) {
195 pr_err("%s: could not allocate timings array\n",
196 of_node_full_name(np));
197 goto entryfail;
198 }
199
200 disp->num_timings = 0;
201 disp->native_mode = 0;
202
203 for_each_child_of_node(timings_np, entry) {
204 struct display_timing *dt;
205 int r;
206
207 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
208 if (!dt) {
209 pr_err("%s: could not allocate display_timing struct\n",
210 of_node_full_name(np));
211 goto timingfail;
212 }
213
214 r = of_parse_display_timing(entry, dt);
215 if (r) {
216 /*
217 * to not encourage wrong devicetrees, fail in case of
218 * an error
219 */
220 pr_err("%s: error in timing %d\n",
221 of_node_full_name(np), disp->num_timings + 1);
222 kfree(dt);
223 goto timingfail;
224 }
225
226 if (native_mode == entry)
227 disp->native_mode = disp->num_timings;
228
229 disp->timings[disp->num_timings] = dt;
230 disp->num_timings++;
231 }
232 of_node_put(timings_np);
233 /*
234 * native_mode points to the device_node returned by of_parse_phandle
235 * therefore call of_node_put on it
236 */
237 of_node_put(native_mode);
238
239 pr_debug("%s: got %d timings. Using timing #%d as default\n",
240 of_node_full_name(np), disp->num_timings,
241 disp->native_mode + 1);
242
243 return disp;
244
245 timingfail:
246 of_node_put(native_mode);
247 display_timings_release(disp);
248 disp = NULL;
249 entryfail:
250 kfree(disp);
251 dispfail:
252 of_node_put(timings_np);
253 return NULL;
254 }
255 EXPORT_SYMBOL_GPL(of_get_display_timings);
256
257 /**
258 * of_display_timings_exist - check if a display-timings node is provided
259 * @np: device_node with the timing
260 **/
261 int of_display_timings_exist(const struct device_node *np)
262 {
263 struct device_node *timings_np;
264
265 if (!np)
266 return -EINVAL;
267
268 timings_np = of_parse_phandle(np, "display-timings", 0);
269 if (!timings_np)
270 return -EINVAL;
271
272 of_node_put(timings_np);
273 return 1;
274 }
275 EXPORT_SYMBOL_GPL(of_display_timings_exist);