include/media/v4l2-dv-timings.h

   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_dv_valid_timings() - are these timings valid?
  31   * @t:   the v4l2_dv_timings struct.
  32   * @cap: the v4l2_dv_timings_cap capabilities.
  33   *
  34   * Returns true if the given dv_timings struct is supported by the
  35   * hardware capabilities, returns false otherwise.
  36   */
  37 bool v4l2_dv_valid_timings(const struct v4l2_dv_timings *t,
  38                            const struct v4l2_dv_timings_cap *cap);
  39
  40 /** v4l2_enum_dv_timings_cap() - Helper function to enumerate possible DV timings based on capabilities
  41   * @t:   the v4l2_enum_dv_timings struct.
  42   * @cap: the v4l2_dv_timings_cap capabilities.
  43   *
  44   * This enumerates dv_timings using the full list of possible CEA-861 and DMT
  45   * timings, filtering out any timings that are not supported based on the
  46   * hardware capabilities.
  47   *
  48   * If a valid timing for the given index is found, it will fill in @t and
  49   * return 0, otherwise it returns -EINVAL.
  50   */
  51 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,
  52                              const struct v4l2_dv_timings_cap *cap);
  53
  54 /** v4l2_find_dv_timings_cap() - Find the closest timings struct
  55   * @t:   the v4l2_enum_dv_timings struct.
  56   * @cap: the v4l2_dv_timings_cap capabilities.
  57   * @pclock_delta: maximum delta between t->pixelclock and the timing struct
  58   *             under consideration.
  59   *
  60   * This function tries to map the given timings to an entry in the
  61   * full list of possible CEA-861 and DMT timings, filtering out any timings
  62   * that are not supported based on the hardware capabilities.
  63   *
  64   * On success it will fill in @t with the found timings and it returns true.
  65   * On failure it will return false.
  66   */
  67 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
  68                               const struct v4l2_dv_timings_cap *cap,
  69                               unsigned pclock_delta);
  70
  71 /** v4l2_match_dv_timings() - do two timings match?
  72   * @measured:    the measured timings data.
  73   * @standard:    the timings according to the standard.
  74   * @pclock_delta: maximum delta in Hz between standard->pixelclock and
  75   *             the measured timings.
  76   *
  77   * Returns true if the two timings match, returns false otherwise.
  78   */
  79 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *measured,
  80                            const struct v4l2_dv_timings *standard,
  81                            unsigned pclock_delta);
  82
  83 /** v4l2_print_dv_timings() - log the contents of a dv_timings struct
  84   * @dev_prefix:device prefix for each log line.
  85   * @prefix:    additional prefix for each log line, may be NULL.
  86   * @t:         the timings data.
  87   * @detailed:  if true, give a detailed log.
  88   */
  89 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
  90                            const struct v4l2_dv_timings *t, bool detailed);
  91
  92 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
  93  * @frame_height - the total height of the frame (including blanking) in lines.
  94  * @hfreq - the horizontal frequency in Hz.
  95  * @vsync - the height of the vertical sync in lines.
  96  * @polarities - the horizontal and vertical polarities (same as struct
  97  *              v4l2_bt_timings polarities).
  98  * @fmt - the resulting timings.
  99  *
 100  * This function will attempt to detect if the given values correspond to a
 101  * valid CVT format. If so, then it will return true, and fmt will be filled
 102  * in with the found CVT timings.
 103  */
 104 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
 105                 u32 polarities, struct v4l2_dv_timings *fmt);
 106
 107 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
 108  * @frame_height - the total height of the frame (including blanking) in lines.
 109  * @hfreq - the horizontal frequency in Hz.
 110  * @vsync - the height of the vertical sync in lines.
 111  * @polarities - the horizontal and vertical polarities (same as struct
 112  *              v4l2_bt_timings polarities).
 113  * @aspect - preferred aspect ratio. GTF has no method of determining the
 114  *              aspect ratio in order to derive the image width from the
 115  *              image height, so it has to be passed explicitly. Usually
 116  *              the native screen aspect ratio is used for this. If it
 117  *              is not filled in correctly, then 16:9 will be assumed.
 118  * @fmt - the resulting timings.
 119  *
 120  * This function will attempt to detect if the given values correspond to a
 121  * valid GTF format. If so, then it will return true, and fmt will be filled
 122  * in with the found GTF timings.
 123  */
 124 bool v4l2_detect_gtf(unsigned frame_height, unsigned hfreq, unsigned vsync,
 125                 u32 polarities, struct v4l2_fract aspect,
 126                 struct v4l2_dv_timings *fmt);
 127
 128 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
 129  *      0x15 and 0x16 from the EDID.
 130  * @hor_landscape - byte 0x15 from the EDID.
 131  * @vert_portrait - byte 0x16 from the EDID.
 132  *
 133  * Determines the aspect ratio from the EDID.
 134  * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
 135  * "Horizontal and Vertical Screen Size or Aspect Ratio"
 136  */
 137 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait);
 138
 139 #endif