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 /* 27 * v4l2_dv_timings_presets: list of all dv_timings presets. 28 */ 29 extern const struct v4l2_dv_timings v4l2_dv_timings_presets[]; 30 31 /** 32 * typedef v4l2_check_dv_timings_fnc - timings check callback 33 * 34 * @t: the v4l2_dv_timings struct. 35 * @handle: a handle from the driver. 36 * 37 * Returns true if the given timings are valid. 38 */ 39 typedef bool v4l2_check_dv_timings_fnc(const struct v4l2_dv_timings *t, void *handle); 40 41 /** 42 * v4l2_valid_dv_timings() - are these timings valid? 43 * 44 * @t: the v4l2_dv_timings struct. 45 * @cap: the v4l2_dv_timings_cap capabilities. 46 * @fnc: callback to check if this timing is OK. May be NULL. 47 * @fnc_handle: a handle that is passed on to @fnc. 48 * 49 * Returns true if the given dv_timings struct is supported by the 50 * hardware capabilities and the callback function (if non-NULL), returns 51 * false otherwise. 52 */ 53 bool v4l2_valid_dv_timings(const struct v4l2_dv_timings *t, 54 const struct v4l2_dv_timings_cap *cap, 55 v4l2_check_dv_timings_fnc fnc, 56 void *fnc_handle); 57 58 /** 59 * v4l2_enum_dv_timings_cap() - Helper function to enumerate possible DV 60 * timings based on capabilities 61 * 62 * @t: the v4l2_enum_dv_timings struct. 63 * @cap: the v4l2_dv_timings_cap capabilities. 64 * @fnc: callback to check if this timing is OK. May be NULL. 65 * @fnc_handle: a handle that is passed on to @fnc. 66 * 67 * This enumerates dv_timings using the full list of possible CEA-861 and DMT 68 * timings, filtering out any timings that are not supported based on the 69 * hardware capabilities and the callback function (if non-NULL). 70 * 71 * If a valid timing for the given index is found, it will fill in @t and 72 * return 0, otherwise it returns -EINVAL. 73 */ 74 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t, 75 const struct v4l2_dv_timings_cap *cap, 76 v4l2_check_dv_timings_fnc fnc, 77 void *fnc_handle); 78 79 /** 80 * v4l2_find_dv_timings_cap() - Find the closest timings struct 81 * 82 * @t: the v4l2_enum_dv_timings struct. 83 * @cap: the v4l2_dv_timings_cap capabilities. 84 * @pclock_delta: maximum delta between t->pixelclock and the timing struct 85 * under consideration. 86 * @fnc: callback to check if a given timings struct is OK. May be NULL. 87 * @fnc_handle: a handle that is passed on to @fnc. 88 * 89 * This function tries to map the given timings to an entry in the 90 * full list of possible CEA-861 and DMT timings, filtering out any timings 91 * that are not supported based on the hardware capabilities and the callback 92 * function (if non-NULL). 93 * 94 * On success it will fill in @t with the found timings and it returns true. 95 * On failure it will return false. 96 */ 97 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t, 98 const struct v4l2_dv_timings_cap *cap, 99 unsigned pclock_delta, 100 v4l2_check_dv_timings_fnc fnc, 101 void *fnc_handle); 102 103 /** 104 * v4l2_find_dv_timings_cea861_vic() - find timings based on CEA-861 VIC 105 * @t: the timings data. 106 * @vic: CEA-861 VIC code 107 * 108 * On success it will fill in @t with the found timings and it returns true. 109 * On failure it will return false. 110 */ 111 bool v4l2_find_dv_timings_cea861_vic(struct v4l2_dv_timings *t, u8 vic); 112 113 /** 114 * v4l2_match_dv_timings() - do two timings match? 115 * 116 * @measured: the measured timings data. 117 * @standard: the timings according to the standard. 118 * @pclock_delta: maximum delta in Hz between standard->pixelclock and 119 * the measured timings. 120 * @match_reduced_fps: if true, then fail if V4L2_DV_FL_REDUCED_FPS does not 121 * match. 122 * 123 * Returns true if the two timings match, returns false otherwise. 124 */ 125 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *measured, 126 const struct v4l2_dv_timings *standard, 127 unsigned pclock_delta, bool match_reduced_fps); 128 129 /** 130 * v4l2_print_dv_timings() - log the contents of a dv_timings struct 131 * @dev_prefix:device prefix for each log line. 132 * @prefix: additional prefix for each log line, may be NULL. 133 * @t: the timings data. 134 * @detailed: if true, give a detailed log. 135 */ 136 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix, 137 const struct v4l2_dv_timings *t, bool detailed); 138 139 /** 140 * v4l2_detect_cvt - detect if the given timings follow the CVT standard 141 * 142 * @frame_height: the total height of the frame (including blanking) in lines. 143 * @hfreq: the horizontal frequency in Hz. 144 * @vsync: the height of the vertical sync in lines. 145 * @active_width: active width of image (does not include blanking). This 146 * information is needed only in case of version 2 of reduced blanking. 147 * In other cases, this parameter does not have any effect on timings. 148 * @polarities: the horizontal and vertical polarities (same as struct 149 * v4l2_bt_timings polarities). 150 * @interlaced: if this flag is true, it indicates interlaced format 151 * @fmt: the resulting timings. 152 * 153 * This function will attempt to detect if the given values correspond to a 154 * valid CVT format. If so, then it will return true, and fmt will be filled 155 * in with the found CVT timings. 156 */ 157 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync, 158 unsigned active_width, u32 polarities, bool interlaced, 159 struct v4l2_dv_timings *fmt); 160 161 /** 162 * v4l2_detect_gtf - detect if the given timings follow the GTF standard 163 * 164 * @frame_height: the total height of the frame (including blanking) in lines. 165 * @hfreq: the horizontal frequency in Hz. 166 * @vsync: the height of the vertical sync in lines. 167 * @polarities: the horizontal and vertical polarities (same as struct 168 * v4l2_bt_timings polarities). 169 * @interlaced: if this flag is true, it indicates interlaced format 170 * @aspect: preferred aspect ratio. GTF has no method of determining the 171 * aspect ratio in order to derive the image width from the 172 * image height, so it has to be passed explicitly. Usually 173 * the native screen aspect ratio is used for this. If it 174 * is not filled in correctly, then 16:9 will be assumed. 175 * @fmt: the resulting timings. 176 * 177 * This function will attempt to detect if the given values correspond to a 178 * valid GTF format. If so, then it will return true, and fmt will be filled 179 * in with the found GTF timings. 180 */ 181 bool v4l2_detect_gtf(unsigned frame_height, unsigned hfreq, unsigned vsync, 182 u32 polarities, bool interlaced, struct v4l2_fract aspect, 183 struct v4l2_dv_timings *fmt); 184 185 /** 186 * v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes 187 * 0x15 and 0x16 from the EDID. 188 * 189 * @hor_landscape: byte 0x15 from the EDID. 190 * @vert_portrait: byte 0x16 from the EDID. 191 * 192 * Determines the aspect ratio from the EDID. 193 * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2: 194 * "Horizontal and Vertical Screen Size or Aspect Ratio" 195 */ 196 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait); 197 198 /** 199 * v4l2_dv_timings_aspect_ratio - calculate the aspect ratio based on the 200 * v4l2_dv_timings information. 201 * 202 * @t: the timings data. 203 */ 204 struct v4l2_fract v4l2_dv_timings_aspect_ratio(const struct v4l2_dv_timings *t); 205 206 /* 207 * reduce_fps - check if conditions for reduced fps are true. 208 * bt - v4l2 timing structure 209 * For different timings reduced fps is allowed if following conditions 210 * are met - 211 * For CVT timings: if reduced blanking v2 (vsync == 8) is true. 212 * For CEA861 timings: if V4L2_DV_FL_CAN_REDUCE_FPS flag is true. 213 */ 214 static inline bool can_reduce_fps(struct v4l2_bt_timings *bt) 215 { 216 if ((bt->standards & V4L2_DV_BT_STD_CVT) && (bt->vsync == 8)) 217 return true; 218 219 if ((bt->standards & V4L2_DV_BT_STD_CEA861) && 220 (bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS)) 221 return true; 222 223 return false; 224 } 225 226 227 #endif 228