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_valid_timings() - are these timings valid?
  27   * @t:   the v4l2_dv_timings struct.
  28   * @cap: the v4l2_dv_timings_cap capabilities.
  29   *
  30   * Returns true if the given dv_timings struct is supported by the
  31   * hardware capabilities, returns false otherwise.
  32   */
  33 bool v4l2_dv_valid_timings(const struct v4l2_dv_timings *t,
  34                            const struct v4l2_dv_timings_cap *cap);
  35
  36 /** v4l2_enum_dv_timings_cap() - Helper function to enumerate possible DV timings based on capabilities
  37   * @t:   the v4l2_enum_dv_timings struct.
  38   * @cap: the v4l2_dv_timings_cap capabilities.
  39   *
  40   * This enumerates dv_timings using the full list of possible CEA-861 and DMT
  41   * timings, filtering out any timings that are not supported based on the
  42   * hardware capabilities.
  43   *
  44   * If a valid timing for the given index is found, it will fill in @t and
  45   * return 0, otherwise it returns -EINVAL.
  46   */
  47 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,
  48                              const struct v4l2_dv_timings_cap *cap);
  49
  50 /** v4l2_find_dv_timings_cap() - Find the closest timings struct
  51   * @t:   the v4l2_enum_dv_timings struct.
  52   * @cap: the v4l2_dv_timings_cap capabilities.
  53   * @pclock_delta: maximum delta between t->pixelclock and the timing struct
  54   *             under consideration.
  55   *
  56   * This function tries to map the given timings to an entry in the
  57   * full list of possible CEA-861 and DMT timings, filtering out any timings
  58   * that are not supported based on the hardware capabilities.
  59   *
  60   * On success it will fill in @t with the found timings and it returns true.
  61   * On failure it will return false.
  62   */
  63 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
  64                               const struct v4l2_dv_timings_cap *cap,
  65                               unsigned pclock_delta);
  66
  67 /** v4l_match_dv_timings() - do two timings match?
  68   * @measured:    the measured timings data.
  69   * @standard:    the timings according to the standard.
  70   * @pclock_delta: maximum delta in Hz between standard->pixelclock and
  71   *             the measured timings.
  72   *
  73   * Returns true if the two timings match, returns false otherwise.
  74   */
  75 bool v4l_match_dv_timings(const struct v4l2_dv_timings *measured,
  76                           const struct v4l2_dv_timings *standard,
  77                           unsigned pclock_delta);
  78
  79 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
  80  * @frame_height - the total height of the frame (including blanking) in lines.
  81  * @hfreq - the horizontal frequency in Hz.
  82  * @vsync - the height of the vertical sync in lines.
  83  * @polarities - the horizontal and vertical polarities (same as struct
  84  *              v4l2_bt_timings polarities).
  85  * @fmt - the resulting timings.
  86  *
  87  * This function will attempt to detect if the given values correspond to a
  88  * valid CVT format. If so, then it will return true, and fmt will be filled
  89  * in with the found CVT timings.
  90  */
  91 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
  92                 u32 polarities, struct v4l2_dv_timings *fmt);
  93
  94 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
  95  * @frame_height - the total height of the frame (including blanking) in lines.
  96  * @hfreq - the horizontal frequency in Hz.
  97  * @vsync - the height of the vertical sync in lines.
  98  * @polarities - the horizontal and vertical polarities (same as struct
  99  *              v4l2_bt_timings polarities).
 100  * @aspect - preferred aspect ratio. GTF has no method of determining the
 101  *              aspect ratio in order to derive the image width from the
 102  *              image height, so it has to be passed explicitly. Usually
 103  *              the native screen aspect ratio is used for this. If it
 104  *              is not filled in correctly, then 16:9 will be assumed.
 105  * @fmt - the resulting timings.
 106  *
 107  * This function will attempt to detect if the given values correspond to a
 108  * valid GTF format. If so, then it will return true, and fmt will be filled
 109  * in with the found GTF timings.
 110  */
 111 bool v4l2_detect_gtf(unsigned frame_height, unsigned hfreq, unsigned vsync,
 112                 u32 polarities, struct v4l2_fract aspect,
 113                 struct v4l2_dv_timings *fmt);
 114
 115 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
 116  *      0x15 and 0x16 from the EDID.
 117  * @hor_landscape - byte 0x15 from the EDID.
 118  * @vert_portrait - byte 0x16 from the EDID.
 119  *
 120  * Determines the aspect ratio from the EDID.
 121  * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
 122  * "Horizontal and Vertical Screen Size or Aspect Ratio"
 123  */
 124 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait);
 125
 126 #endif