Root/
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(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 | **/ |
59 | static 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 | |
82 | dt->dmt_flags = 0; |
83 | dt->data_flags = 0; |
84 | if (!of_property_read_u32(np, "vsync-active", &val)) |
85 | dt->dmt_flags |= val ? VESA_DMT_VSYNC_HIGH : |
86 | VESA_DMT_VSYNC_LOW; |
87 | if (!of_property_read_u32(np, "hsync-active", &val)) |
88 | dt->dmt_flags |= val ? VESA_DMT_HSYNC_HIGH : |
89 | VESA_DMT_HSYNC_LOW; |
90 | if (!of_property_read_u32(np, "de-active", &val)) |
91 | dt->data_flags |= val ? DISPLAY_FLAGS_DE_HIGH : |
92 | DISPLAY_FLAGS_DE_LOW; |
93 | if (!of_property_read_u32(np, "pixelclk-active", &val)) |
94 | dt->data_flags |= val ? DISPLAY_FLAGS_PIXDATA_POSEDGE : |
95 | DISPLAY_FLAGS_PIXDATA_NEGEDGE; |
96 | |
97 | if (of_property_read_bool(np, "interlaced")) |
98 | dt->data_flags |= DISPLAY_FLAGS_INTERLACED; |
99 | if (of_property_read_bool(np, "doublescan")) |
100 | dt->data_flags |= DISPLAY_FLAGS_DOUBLESCAN; |
101 | |
102 | if (ret) { |
103 | pr_err("%s: error reading timing properties\n", |
104 | of_node_full_name(np)); |
105 | kfree(dt); |
106 | return NULL; |
107 | } |
108 | |
109 | return dt; |
110 | } |
111 | |
112 | /** |
113 | * of_get_display_timings - parse all display_timing entries from a device_node |
114 | * @np: device_node with the subnodes |
115 | **/ |
116 | struct display_timings *of_get_display_timings(struct device_node *np) |
117 | { |
118 | struct device_node *timings_np; |
119 | struct device_node *entry; |
120 | struct device_node *native_mode; |
121 | struct display_timings *disp; |
122 | |
123 | if (!np) { |
124 | pr_err("%s: no devicenode given\n", of_node_full_name(np)); |
125 | return NULL; |
126 | } |
127 | |
128 | timings_np = of_find_node_by_name(np, "display-timings"); |
129 | if (!timings_np) { |
130 | pr_err("%s: could not find display-timings node\n", |
131 | of_node_full_name(np)); |
132 | return NULL; |
133 | } |
134 | |
135 | disp = kzalloc(sizeof(*disp), GFP_KERNEL); |
136 | if (!disp) { |
137 | pr_err("%s: could not allocate struct disp'\n", |
138 | of_node_full_name(np)); |
139 | goto dispfail; |
140 | } |
141 | |
142 | entry = of_parse_phandle(timings_np, "native-mode", 0); |
143 | /* assume first child as native mode if none provided */ |
144 | if (!entry) |
145 | entry = of_get_next_child(np, NULL); |
146 | /* if there is no child, it is useless to go on */ |
147 | if (!entry) { |
148 | pr_err("%s: no timing specifications given\n", |
149 | of_node_full_name(np)); |
150 | goto entryfail; |
151 | } |
152 | |
153 | pr_debug("%s: using %s as default timing\n", |
154 | of_node_full_name(np), entry->name); |
155 | |
156 | native_mode = entry; |
157 | |
158 | disp->num_timings = of_get_child_count(timings_np); |
159 | if (disp->num_timings == 0) { |
160 | /* should never happen, as entry was already found above */ |
161 | pr_err("%s: no timings specified\n", of_node_full_name(np)); |
162 | goto entryfail; |
163 | } |
164 | |
165 | disp->timings = kzalloc(sizeof(struct display_timing *) * |
166 | disp->num_timings, GFP_KERNEL); |
167 | if (!disp->timings) { |
168 | pr_err("%s: could not allocate timings array\n", |
169 | of_node_full_name(np)); |
170 | goto entryfail; |
171 | } |
172 | |
173 | disp->num_timings = 0; |
174 | disp->native_mode = 0; |
175 | |
176 | for_each_child_of_node(timings_np, entry) { |
177 | struct display_timing *dt; |
178 | |
179 | dt = of_get_display_timing(entry); |
180 | if (!dt) { |
181 | /* |
182 | * to not encourage wrong devicetrees, fail in case of |
183 | * an error |
184 | */ |
185 | pr_err("%s: error in timing %d\n", |
186 | of_node_full_name(np), disp->num_timings + 1); |
187 | goto timingfail; |
188 | } |
189 | |
190 | if (native_mode == entry) |
191 | disp->native_mode = disp->num_timings; |
192 | |
193 | disp->timings[disp->num_timings] = dt; |
194 | disp->num_timings++; |
195 | } |
196 | of_node_put(timings_np); |
197 | /* |
198 | * native_mode points to the device_node returned by of_parse_phandle |
199 | * therefore call of_node_put on it |
200 | */ |
201 | of_node_put(native_mode); |
202 | |
203 | pr_debug("%s: got %d timings. Using timing #%d as default\n", |
204 | of_node_full_name(np), disp->num_timings, |
205 | disp->native_mode + 1); |
206 | |
207 | return disp; |
208 | |
209 | timingfail: |
210 | if (native_mode) |
211 | of_node_put(native_mode); |
212 | display_timings_release(disp); |
213 | entryfail: |
214 | kfree(disp); |
215 | dispfail: |
216 | of_node_put(timings_np); |
217 | return NULL; |
218 | } |
219 | EXPORT_SYMBOL_GPL(of_get_display_timings); |
220 | |
221 | /** |
222 | * of_display_timings_exist - check if a display-timings node is provided |
223 | * @np: device_node with the timing |
224 | **/ |
225 | int of_display_timings_exist(struct device_node *np) |
226 | { |
227 | struct device_node *timings_np; |
228 | |
229 | if (!np) |
230 | return -EINVAL; |
231 | |
232 | timings_np = of_parse_phandle(np, "display-timings", 0); |
233 | if (!timings_np) |
234 | return -EINVAL; |
235 | |
236 | of_node_put(timings_np); |
237 | return 1; |
238 | } |
239 | EXPORT_SYMBOL_GPL(of_display_timings_exist); |
240 |
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