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Steffen Trumtrarcc3f4142012-10-04 15:32:52 +02001/*
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 **/
26static int parse_timing_property(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_get_display_timing - parse display_timing entry from device_node
57 * @np: device_node with the properties
58 **/
59static struct display_timing *of_get_display_timing(struct device_node *np)
60{
61 struct display_timing *dt;
62 u32 val = 0;
63 int ret = 0;
64
65 dt = kzalloc(sizeof(*dt), GFP_KERNEL);
66 if (!dt) {
67 pr_err("%s: could not allocate display_timing struct\n",
68 of_node_full_name(np));
69 return NULL;
70 }
71
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);
81
Tomi Valkeinen06a33072013-03-12 10:26:45 +020082 dt->flags = 0;
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020083 if (!of_property_read_u32(np, "vsync-active", &val))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020084 dt->flags |= val ? DISPLAY_FLAGS_VSYNC_HIGH :
85 DISPLAY_FLAGS_VSYNC_LOW;
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020086 if (!of_property_read_u32(np, "hsync-active", &val))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020087 dt->flags |= val ? DISPLAY_FLAGS_HSYNC_HIGH :
88 DISPLAY_FLAGS_HSYNC_LOW;
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020089 if (!of_property_read_u32(np, "de-active", &val))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020090 dt->flags |= val ? DISPLAY_FLAGS_DE_HIGH :
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020091 DISPLAY_FLAGS_DE_LOW;
92 if (!of_property_read_u32(np, "pixelclk-active", &val))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020093 dt->flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE :
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020094 DISPLAY_FLAGS_PIXDATA_NEGEDGE;
95
96 if (of_property_read_bool(np, "interlaced"))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020097 dt->flags |= DISPLAY_FLAGS_INTERLACED;
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +020098 if (of_property_read_bool(np, "doublescan"))
Tomi Valkeinen06a33072013-03-12 10:26:45 +020099 dt->flags |= DISPLAY_FLAGS_DOUBLESCAN;
Steffen Trumtrarcc3f4142012-10-04 15:32:52 +0200100
101 if (ret) {
102 pr_err("%s: error reading timing properties\n",
103 of_node_full_name(np));
104 kfree(dt);
105 return NULL;
106 }
107
108 return dt;
109}
110
111/**
112 * of_get_display_timings - parse all display_timing entries from a device_node
113 * @np: device_node with the subnodes
114 **/
115struct display_timings *of_get_display_timings(struct device_node *np)
116{
117 struct device_node *timings_np;
118 struct device_node *entry;
119 struct device_node *native_mode;
120 struct display_timings *disp;
121
122 if (!np) {
123 pr_err("%s: no devicenode given\n", of_node_full_name(np));
124 return NULL;
125 }
126
127 timings_np = of_find_node_by_name(np, "display-timings");
128 if (!timings_np) {
129 pr_err("%s: could not find display-timings node\n",
130 of_node_full_name(np));
131 return NULL;
132 }
133
134 disp = kzalloc(sizeof(*disp), GFP_KERNEL);
135 if (!disp) {
136 pr_err("%s: could not allocate struct disp'\n",
137 of_node_full_name(np));
138 goto dispfail;
139 }
140
141 entry = of_parse_phandle(timings_np, "native-mode", 0);
142 /* assume first child as native mode if none provided */
143 if (!entry)
144 entry = of_get_next_child(np, NULL);
145 /* if there is no child, it is useless to go on */
146 if (!entry) {
147 pr_err("%s: no timing specifications given\n",
148 of_node_full_name(np));
149 goto entryfail;
150 }
151
152 pr_debug("%s: using %s as default timing\n",
153 of_node_full_name(np), entry->name);
154
155 native_mode = entry;
156
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));
161 goto entryfail;
162 }
163
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));
169 goto entryfail;
170 }
171
172 disp->num_timings = 0;
173 disp->native_mode = 0;
174
175 for_each_child_of_node(timings_np, entry) {
176 struct display_timing *dt;
177
178 dt = of_get_display_timing(entry);
179 if (!dt) {
180 /*
181 * to not encourage wrong devicetrees, fail in case of
182 * an error
183 */
184 pr_err("%s: error in timing %d\n",
185 of_node_full_name(np), disp->num_timings + 1);
186 goto timingfail;
187 }
188
189 if (native_mode == entry)
190 disp->native_mode = disp->num_timings;
191
192 disp->timings[disp->num_timings] = dt;
193 disp->num_timings++;
194 }
195 of_node_put(timings_np);
196 /*
197 * native_mode points to the device_node returned by of_parse_phandle
198 * therefore call of_node_put on it
199 */
200 of_node_put(native_mode);
201
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);
205
206 return disp;
207
208timingfail:
209 if (native_mode)
210 of_node_put(native_mode);
211 display_timings_release(disp);
212entryfail:
213 kfree(disp);
214dispfail:
215 of_node_put(timings_np);
216 return NULL;
217}
218EXPORT_SYMBOL_GPL(of_get_display_timings);
219
220/**
221 * of_display_timings_exist - check if a display-timings node is provided
222 * @np: device_node with the timing
223 **/
224int of_display_timings_exist(struct device_node *np)
225{
226 struct device_node *timings_np;
227
228 if (!np)
229 return -EINVAL;
230
231 timings_np = of_parse_phandle(np, "display-timings", 0);
232 if (!timings_np)
233 return -EINVAL;
234
235 of_node_put(timings_np);
236 return 1;
237}
238EXPORT_SYMBOL_GPL(of_display_timings_exist);