/*
   * v4l2-dv-timings - Internal header with dv-timings helper functions
   *
   * Copyright 2013 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
   *
   * This program is free software; you may redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   *
   */
  
  #ifndef __V4L2_DV_TIMINGS_H
  #define __V4L2_DV_TIMINGS_H
  
  #include <linux/videodev2.h>

  /*

   * v4l2_dv_timings_presets: list of all dv_timings presets.

   */
  extern const struct v4l2_dv_timings v4l2_dv_timings_presets[];

  /**
   * typedef v4l2_check_dv_timings_fnc - timings check callback

   *

   * @t: the v4l2_dv_timings struct.
   * @handle: a handle from the driver.
   *
   * Returns true if the given timings are valid.
   */
  typedef bool v4l2_check_dv_timings_fnc(const struct v4l2_dv_timings *t, void *handle);

  /**
   * v4l2_valid_dv_timings() - are these timings valid?
   *
   * @t:	  the v4l2_dv_timings struct.
   * @cap: the v4l2_dv_timings_cap capabilities.
   * @fnc: callback to check if this timing is OK. May be NULL.
   * @fnc_handle: a handle that is passed on to @fnc.
   *
   * Returns true if the given dv_timings struct is supported by the
   * hardware capabilities and the callback function (if non-NULL), returns
   * false otherwise.
   */

  bool v4l2_valid_dv_timings(const struct v4l2_dv_timings *t,

  			   const struct v4l2_dv_timings_cap *cap,
  			   v4l2_check_dv_timings_fnc fnc,
  			   void *fnc_handle);

  /**
   * v4l2_enum_dv_timings_cap() - Helper function to enumerate possible DV
   *	 timings based on capabilities
   *
   * @t:	  the v4l2_enum_dv_timings struct.
   * @cap: the v4l2_dv_timings_cap capabilities.
   * @fnc: callback to check if this timing is OK. May be NULL.
   * @fnc_handle: a handle that is passed on to @fnc.
   *
   * This enumerates dv_timings using the full list of possible CEA-861 and DMT
   * timings, filtering out any timings that are not supported based on the
   * hardware capabilities and the callback function (if non-NULL).
   *
   * If a valid timing for the given index is found, it will fill in @t and
   * return 0, otherwise it returns -EINVAL.
   */

  int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,

  			     const struct v4l2_dv_timings_cap *cap,
  			     v4l2_check_dv_timings_fnc fnc,
  			     void *fnc_handle);

  /**
   * v4l2_find_dv_timings_cap() - Find the closest timings struct
   *
   * @t:	  the v4l2_enum_dv_timings struct.
   * @cap: the v4l2_dv_timings_cap capabilities.
   * @pclock_delta: maximum delta between t->pixelclock and the timing struct
   *		under consideration.
   * @fnc: callback to check if a given timings struct is OK. May be NULL.
   * @fnc_handle: a handle that is passed on to @fnc.
   *
   * This function tries to map the given timings to an entry in the
   * full list of possible CEA-861 and DMT timings, filtering out any timings
   * that are not supported based on the hardware capabilities and the callback
   * function (if non-NULL).
   *
   * On success it will fill in @t with the found timings and it returns true.
   * On failure it will return false.
   */

  bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
  			      const struct v4l2_dv_timings_cap *cap,

  			      unsigned pclock_delta,
  			      v4l2_check_dv_timings_fnc fnc,
  			      void *fnc_handle);

  /**
   * v4l2_match_dv_timings() - do two timings match?
   *
   * @measured:	  the measured timings data.
   * @standard:	  the timings according to the standard.
   * @pclock_delta: maximum delta in Hz between standard->pixelclock and
   * 		the measured timings.

   * @match_reduced_fps: if true, then fail if V4L2_DV_FL_REDUCED_FPS does not
   * match.

   *
   * Returns true if the two timings match, returns false otherwise.
   */

  bool v4l2_match_dv_timings(const struct v4l2_dv_timings *measured,
  			   const struct v4l2_dv_timings *standard,

  			   unsigned pclock_delta, bool match_reduced_fps);

  /**
   * v4l2_print_dv_timings() - log the contents of a dv_timings struct
   * @dev_prefix:device prefix for each log line.
   * @prefix:	additional prefix for each log line, may be NULL.
   * @t:		the timings data.
   * @detailed:	if true, give a detailed log.
   */

  void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
  			   const struct v4l2_dv_timings *t, bool detailed);

  /**
   * v4l2_detect_cvt - detect if the given timings follow the CVT standard
   *

   * @frame_height: the total height of the frame (including blanking) in lines.
   * @hfreq: the horizontal frequency in Hz.
   * @vsync: the height of the vertical sync in lines.
   * @active_width: active width of image (does not include blanking). This

   * information is needed only in case of version 2 of reduced blanking.
   * In other cases, this parameter does not have any effect on timings.

   * @polarities: the horizontal and vertical polarities (same as struct

   *		v4l2_bt_timings polarities).

   * @interlaced: if this flag is true, it indicates interlaced format
   * @fmt: the resulting timings.

   *
   * This function will attempt to detect if the given values correspond to a
   * valid CVT format. If so, then it will return true, and fmt will be filled
   * in with the found CVT timings.
   */
  bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,

  		unsigned active_width, u32 polarities, bool interlaced,
  		struct v4l2_dv_timings *fmt);

  /**
   * v4l2_detect_gtf - detect if the given timings follow the GTF standard
   *

   * @frame_height: the total height of the frame (including blanking) in lines.
   * @hfreq: the horizontal frequency in Hz.
   * @vsync: the height of the vertical sync in lines.
   * @polarities: the horizontal and vertical polarities (same as struct

   *		v4l2_bt_timings polarities).

   * @interlaced: if this flag is true, it indicates interlaced format
   * @aspect: preferred aspect ratio. GTF has no method of determining the

   *		aspect ratio in order to derive the image width from the
   *		image height, so it has to be passed explicitly. Usually
   *		the native screen aspect ratio is used for this. If it
   *		is not filled in correctly, then 16:9 will be assumed.

   * @fmt: the resulting timings.

   *
   * This function will attempt to detect if the given values correspond to a
   * valid GTF format. If so, then it will return true, and fmt will be filled
   * in with the found GTF timings.
   */
  bool v4l2_detect_gtf(unsigned frame_height, unsigned hfreq, unsigned vsync,

  		u32 polarities, bool interlaced, struct v4l2_fract aspect,

  		struct v4l2_dv_timings *fmt);

  /**
   * v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes

   *	0x15 and 0x16 from the EDID.

   *

   * @hor_landscape: byte 0x15 from the EDID.
   * @vert_portrait: byte 0x16 from the EDID.

   *
   * Determines the aspect ratio from the EDID.
   * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
   * "Horizontal and Vertical Screen Size or Aspect Ratio"
   */
  struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait);

  /*
   * reduce_fps - check if conditions for reduced fps are true.
   * bt - v4l2 timing structure
   * For different timings reduced fps is allowed if following conditions
   * are met -
   * For CVT timings: if reduced blanking v2 (vsync == 8) is true.
   * For CEA861 timings: if V4L2_DV_FL_CAN_REDUCE_FPS flag is true.
   */
  static inline  bool can_reduce_fps(struct v4l2_bt_timings *bt)
  {
  	if ((bt->standards & V4L2_DV_BT_STD_CVT) && (bt->vsync == 8))
  		return true;
  
  	if ((bt->standards & V4L2_DV_BT_STD_CEA861) &&
  	    (bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS))
  		return true;
  
  	return false;
  }

  #endif