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_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