1 /*
2  * v4l2-dv-timings - Internal header with dv-timings helper functions
3  *
4  * Copyright 2013 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
5  *
6  * This program is free software; you may redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; version 2 of the License.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
11  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
12  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
13  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
14  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
15  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
16  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
17  * SOFTWARE.
18  *
19  */
20 
21 #ifndef __V4L2_DV_TIMINGS_H
22 #define __V4L2_DV_TIMINGS_H
23 
24 #include <linux/videodev2.h>
25 
26 /** v4l2_dv_timings_presets: list of all dv_timings presets.
27  */
28 extern const struct v4l2_dv_timings v4l2_dv_timings_presets[];
29 
30 /** v4l2_check_dv_timings_fnc - timings check callback
31  * @t: the v4l2_dv_timings struct.
32  * @handle: a handle from the driver.
33  *
34  * Returns true if the given timings are valid.
35  */
36 typedef bool v4l2_check_dv_timings_fnc(const struct v4l2_dv_timings *t, void *handle);
37 
38 /** v4l2_valid_dv_timings() - are these timings valid?
39   * @t:	  the v4l2_dv_timings struct.
40   * @cap: the v4l2_dv_timings_cap capabilities.
41   * @fnc: callback to check if this timing is OK. May be NULL.
42   * @fnc_handle: a handle that is passed on to @fnc.
43   *
44   * Returns true if the given dv_timings struct is supported by the
45   * hardware capabilities and the callback function (if non-NULL), returns
46   * false otherwise.
47   */
48 bool v4l2_valid_dv_timings(const struct v4l2_dv_timings *t,
49 			   const struct v4l2_dv_timings_cap *cap,
50 			   v4l2_check_dv_timings_fnc fnc,
51 			   void *fnc_handle);
52 
53 /** v4l2_enum_dv_timings_cap() - Helper function to enumerate possible DV timings based on capabilities
54   * @t:	  the v4l2_enum_dv_timings struct.
55   * @cap: the v4l2_dv_timings_cap capabilities.
56   * @fnc: callback to check if this timing is OK. May be NULL.
57   * @fnc_handle: a handle that is passed on to @fnc.
58   *
59   * This enumerates dv_timings using the full list of possible CEA-861 and DMT
60   * timings, filtering out any timings that are not supported based on the
61   * hardware capabilities and the callback function (if non-NULL).
62   *
63   * If a valid timing for the given index is found, it will fill in @t and
64   * return 0, otherwise it returns -EINVAL.
65   */
66 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,
67 			     const struct v4l2_dv_timings_cap *cap,
68 			     v4l2_check_dv_timings_fnc fnc,
69 			     void *fnc_handle);
70 
71 /** v4l2_find_dv_timings_cap() - Find the closest timings struct
72   * @t:	  the v4l2_enum_dv_timings struct.
73   * @cap: the v4l2_dv_timings_cap capabilities.
74   * @pclock_delta: maximum delta between t->pixelclock and the timing struct
75   *		under consideration.
76   * @fnc: callback to check if a given timings struct is OK. May be NULL.
77   * @fnc_handle: a handle that is passed on to @fnc.
78   *
79   * This function tries to map the given timings to an entry in the
80   * full list of possible CEA-861 and DMT timings, filtering out any timings
81   * that are not supported based on the hardware capabilities and the callback
82   * function (if non-NULL).
83   *
84   * On success it will fill in @t with the found timings and it returns true.
85   * On failure it will return false.
86   */
87 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
88 			      const struct v4l2_dv_timings_cap *cap,
89 			      unsigned pclock_delta,
90 			      v4l2_check_dv_timings_fnc fnc,
91 			      void *fnc_handle);
92 
93 /** v4l2_match_dv_timings() - do two timings match?
94   * @measured:	  the measured timings data.
95   * @standard:	  the timings according to the standard.
96   * @pclock_delta: maximum delta in Hz between standard->pixelclock and
97   * 		the measured timings.
98   *
99   * Returns true if the two timings match, returns false otherwise.
100   */
101 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *measured,
102 			   const struct v4l2_dv_timings *standard,
103 			   unsigned pclock_delta);
104 
105 /** v4l2_print_dv_timings() - log the contents of a dv_timings struct
106   * @dev_prefix:device prefix for each log line.
107   * @prefix:	additional prefix for each log line, may be NULL.
108   * @t:		the timings data.
109   * @detailed:	if true, give a detailed log.
110   */
111 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
112 			   const struct v4l2_dv_timings *t, bool detailed);
113 
114 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
115  * @frame_height - the total height of the frame (including blanking) in lines.
116  * @hfreq - the horizontal frequency in Hz.
117  * @vsync - the height of the vertical sync in lines.
118  * @polarities - the horizontal and vertical polarities (same as struct
119  *		v4l2_bt_timings polarities).
120  * @fmt - the resulting timings.
121  *
122  * This function will attempt to detect if the given values correspond to a
123  * valid CVT format. If so, then it will return true, and fmt will be filled
124  * in with the found CVT timings.
125  */
126 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
127 		u32 polarities, struct v4l2_dv_timings *fmt);
128 
129 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
130  * @frame_height - the total height of the frame (including blanking) in lines.
131  * @hfreq - the horizontal frequency in Hz.
132  * @vsync - the height of the vertical sync in lines.
133  * @polarities - the horizontal and vertical polarities (same as struct
134  *		v4l2_bt_timings polarities).
135  * @aspect - preferred aspect ratio. GTF has no method of determining the
136  *		aspect ratio in order to derive the image width from the
137  *		image height, so it has to be passed explicitly. Usually
138  *		the native screen aspect ratio is used for this. If it
139  *		is not filled in correctly, then 16:9 will be assumed.
140  * @fmt - the resulting timings.
141  *
142  * This function will attempt to detect if the given values correspond to a
143  * valid GTF format. If so, then it will return true, and fmt will be filled
144  * in with the found GTF timings.
145  */
146 bool v4l2_detect_gtf(unsigned frame_height, unsigned hfreq, unsigned vsync,
147 		u32 polarities, struct v4l2_fract aspect,
148 		struct v4l2_dv_timings *fmt);
149 
150 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
151  *	0x15 and 0x16 from the EDID.
152  * @hor_landscape - byte 0x15 from the EDID.
153  * @vert_portrait - byte 0x16 from the EDID.
154  *
155  * Determines the aspect ratio from the EDID.
156  * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
157  * "Horizontal and Vertical Screen Size or Aspect Ratio"
158  */
159 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait);
160 
161 #endif
162