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(const 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(const struct device_node
62 struct display_timing
*dt
;
66 dt
= kzalloc(sizeof(*dt
), GFP_KERNEL
);
68 pr_err("%s: could not allocate display_timing struct\n",
69 of_node_full_name(np
));
73 ret
|= parse_timing_property(np
, "hback-porch", &dt
->hback_porch
);
74 ret
|= parse_timing_property(np
, "hfront-porch", &dt
->hfront_porch
);
75 ret
|= parse_timing_property(np
, "hactive", &dt
->hactive
);
76 ret
|= parse_timing_property(np
, "hsync-len", &dt
->hsync_len
);
77 ret
|= parse_timing_property(np
, "vback-porch", &dt
->vback_porch
);
78 ret
|= parse_timing_property(np
, "vfront-porch", &dt
->vfront_porch
);
79 ret
|= parse_timing_property(np
, "vactive", &dt
->vactive
);
80 ret
|= parse_timing_property(np
, "vsync-len", &dt
->vsync_len
);
81 ret
|= parse_timing_property(np
, "clock-frequency", &dt
->pixelclock
);
84 if (!of_property_read_u32(np
, "vsync-active", &val
))
85 dt
->flags
|= val
? DISPLAY_FLAGS_VSYNC_HIGH
:
86 DISPLAY_FLAGS_VSYNC_LOW
;
87 if (!of_property_read_u32(np
, "hsync-active", &val
))
88 dt
->flags
|= val
? DISPLAY_FLAGS_HSYNC_HIGH
:
89 DISPLAY_FLAGS_HSYNC_LOW
;
90 if (!of_property_read_u32(np
, "de-active", &val
))
91 dt
->flags
|= val
? DISPLAY_FLAGS_DE_HIGH
:
93 if (!of_property_read_u32(np
, "pixelclk-active", &val
))
94 dt
->flags
|= val
? DISPLAY_FLAGS_PIXDATA_POSEDGE
:
95 DISPLAY_FLAGS_PIXDATA_NEGEDGE
;
97 if (of_property_read_bool(np
, "interlaced"))
98 dt
->flags
|= DISPLAY_FLAGS_INTERLACED
;
99 if (of_property_read_bool(np
, "doublescan"))
100 dt
->flags
|= DISPLAY_FLAGS_DOUBLESCAN
;
103 pr_err("%s: error reading timing properties\n",
104 of_node_full_name(np
));
113 * of_get_display_timings - parse all display_timing entries from a device_node
114 * @np: device_node with the subnodes
116 struct display_timings
*of_get_display_timings(struct device_node
*np
)
118 struct device_node
*timings_np
;
119 struct device_node
*entry
;
120 struct device_node
*native_mode
;
121 struct display_timings
*disp
;
124 pr_err("%s: no devicenode given\n", of_node_full_name(np
));
128 timings_np
= of_find_node_by_name(np
, "display-timings");
130 pr_err("%s: could not find display-timings node\n",
131 of_node_full_name(np
));
135 disp
= kzalloc(sizeof(*disp
), GFP_KERNEL
);
137 pr_err("%s: could not allocate struct disp'\n",
138 of_node_full_name(np
));
142 entry
= of_parse_phandle(timings_np
, "native-mode", 0);
143 /* assume first child as native mode if none provided */
145 entry
= of_get_next_child(np
, NULL
);
146 /* if there is no child, it is useless to go on */
148 pr_err("%s: no timing specifications given\n",
149 of_node_full_name(np
));
153 pr_debug("%s: using %s as default timing\n",
154 of_node_full_name(np
), entry
->name
);
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
));
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
));
173 disp
->num_timings
= 0;
174 disp
->native_mode
= 0;
176 for_each_child_of_node(timings_np
, entry
) {
177 struct display_timing
*dt
;
179 dt
= of_get_display_timing(entry
);
182 * to not encourage wrong devicetrees, fail in case of
185 pr_err("%s: error in timing %d\n",
186 of_node_full_name(np
), disp
->num_timings
+ 1);
190 if (native_mode
== entry
)
191 disp
->native_mode
= disp
->num_timings
;
193 disp
->timings
[disp
->num_timings
] = dt
;
196 of_node_put(timings_np
);
198 * native_mode points to the device_node returned by of_parse_phandle
199 * therefore call of_node_put on it
201 of_node_put(native_mode
);
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);
211 of_node_put(native_mode
);
212 display_timings_release(disp
);
216 of_node_put(timings_np
);
219 EXPORT_SYMBOL_GPL(of_get_display_timings
);
222 * of_display_timings_exist - check if a display-timings node is provided
223 * @np: device_node with the timing
225 int of_display_timings_exist(struct device_node
*np
)
227 struct device_node
*timings_np
;
232 timings_np
= of_parse_phandle(np
, "display-timings", 0);
236 of_node_put(timings_np
);
239 EXPORT_SYMBOL_GPL(of_display_timings_exist
);