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/*
* 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[];
/**
* 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
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