linux/include/media/v4l2-dv-timings.h
Prashant Laddha 5fea1bb703 [media] v4l2-dv-timings: add support for reduced blanking v2
Added support for reduced blanking version 2 (RB v2) in cvt timings.
Standard specifies a fixed vsync pulse of 8 lines to indicate RB v2
timings. Vertical back porch is fixed at 6 lines and vertical front
porch is remainder of vertical blanking time.

For RB v2, horizontal blanking is fixed at 80 pixels. Horizontal sync
is fixed at 32. All horizontal timing counts (active pixels, front,
back porches) can be specified upto a precision of 1.

RB v2 allows for non standard aspect ratios. In RB v2 vsync does not
indicate aspect ratio. In absence of aspect ratio v4l2_detect_cvt()
cannot calculate image width from image height. Hence extending the
v4l2_detect_cvt() to pass image width in case of RB v2.

Signed-off-by: Prashant Laddha <prladdha@cisco.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
2015-07-06 08:25:49 -03:00

168 lines
7.1 KiB
C

/*
* 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.
*
* 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);
/** 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);
#endif