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0216dc2fe6
linux/drivers/media/v4l2-core/v4l2-dv-timings.c
Hans Verkuil 0216dc2fe6 [media] v4l2-dv-timings: add v4l2_print_dv_timings helper 
Drivers often have to log the contents of a dv_timings struct. Adding
this helper will make it easier for drivers to do so.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
2013-08-24 04:26:05 -03:00

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/*
* v4l2-dv-timings - 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.
*
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/videodev2.h>
#include <linux/v4l2-dv-timings.h>
#include <media/v4l2-dv-timings.h>
static const struct v4l2_dv_timings timings[] = {
V4L2_DV_BT_CEA_640X480P59_94,
V4L2_DV_BT_CEA_720X480I59_94,
V4L2_DV_BT_CEA_720X480P59_94,
V4L2_DV_BT_CEA_720X576I50,
V4L2_DV_BT_CEA_720X576P50,
V4L2_DV_BT_CEA_1280X720P24,
V4L2_DV_BT_CEA_1280X720P25,
V4L2_DV_BT_CEA_1280X720P30,
V4L2_DV_BT_CEA_1280X720P50,
V4L2_DV_BT_CEA_1280X720P60,
V4L2_DV_BT_CEA_1920X1080P24,
V4L2_DV_BT_CEA_1920X1080P25,
V4L2_DV_BT_CEA_1920X1080P30,
V4L2_DV_BT_CEA_1920X1080I50,
V4L2_DV_BT_CEA_1920X1080P50,
V4L2_DV_BT_CEA_1920X1080I60,
V4L2_DV_BT_CEA_1920X1080P60,
V4L2_DV_BT_DMT_640X350P85,
V4L2_DV_BT_DMT_640X400P85,
V4L2_DV_BT_DMT_720X400P85,
V4L2_DV_BT_DMT_640X480P72,
V4L2_DV_BT_DMT_640X480P75,
V4L2_DV_BT_DMT_640X480P85,
V4L2_DV_BT_DMT_800X600P56,
V4L2_DV_BT_DMT_800X600P60,
V4L2_DV_BT_DMT_800X600P72,
V4L2_DV_BT_DMT_800X600P75,
V4L2_DV_BT_DMT_800X600P85,
V4L2_DV_BT_DMT_800X600P120_RB,
V4L2_DV_BT_DMT_848X480P60,
V4L2_DV_BT_DMT_1024X768I43,
V4L2_DV_BT_DMT_1024X768P60,
V4L2_DV_BT_DMT_1024X768P70,
V4L2_DV_BT_DMT_1024X768P75,
V4L2_DV_BT_DMT_1024X768P85,
V4L2_DV_BT_DMT_1024X768P120_RB,
V4L2_DV_BT_DMT_1152X864P75,
V4L2_DV_BT_DMT_1280X768P60_RB,
V4L2_DV_BT_DMT_1280X768P60,
V4L2_DV_BT_DMT_1280X768P75,
V4L2_DV_BT_DMT_1280X768P85,
V4L2_DV_BT_DMT_1280X768P120_RB,
V4L2_DV_BT_DMT_1280X800P60_RB,
V4L2_DV_BT_DMT_1280X800P60,
V4L2_DV_BT_DMT_1280X800P75,
V4L2_DV_BT_DMT_1280X800P85,
V4L2_DV_BT_DMT_1280X800P120_RB,
V4L2_DV_BT_DMT_1280X960P60,
V4L2_DV_BT_DMT_1280X960P85,
V4L2_DV_BT_DMT_1280X960P120_RB,
V4L2_DV_BT_DMT_1280X1024P60,
V4L2_DV_BT_DMT_1280X1024P75,
V4L2_DV_BT_DMT_1280X1024P85,
V4L2_DV_BT_DMT_1280X1024P120_RB,
V4L2_DV_BT_DMT_1360X768P60,
V4L2_DV_BT_DMT_1360X768P120_RB,
V4L2_DV_BT_DMT_1366X768P60,
V4L2_DV_BT_DMT_1366X768P60_RB,
V4L2_DV_BT_DMT_1400X1050P60_RB,
V4L2_DV_BT_DMT_1400X1050P60,
V4L2_DV_BT_DMT_1400X1050P75,
V4L2_DV_BT_DMT_1400X1050P85,
V4L2_DV_BT_DMT_1400X1050P120_RB,
V4L2_DV_BT_DMT_1440X900P60_RB,
V4L2_DV_BT_DMT_1440X900P60,
V4L2_DV_BT_DMT_1440X900P75,
V4L2_DV_BT_DMT_1440X900P85,
V4L2_DV_BT_DMT_1440X900P120_RB,
V4L2_DV_BT_DMT_1600X900P60_RB,
V4L2_DV_BT_DMT_1600X1200P60,
V4L2_DV_BT_DMT_1600X1200P65,
V4L2_DV_BT_DMT_1600X1200P70,
V4L2_DV_BT_DMT_1600X1200P75,
V4L2_DV_BT_DMT_1600X1200P85,
V4L2_DV_BT_DMT_1600X1200P120_RB,
V4L2_DV_BT_DMT_1680X1050P60_RB,
V4L2_DV_BT_DMT_1680X1050P60,
V4L2_DV_BT_DMT_1680X1050P75,
V4L2_DV_BT_DMT_1680X1050P85,
V4L2_DV_BT_DMT_1680X1050P120_RB,
V4L2_DV_BT_DMT_1792X1344P60,
V4L2_DV_BT_DMT_1792X1344P75,
V4L2_DV_BT_DMT_1792X1344P120_RB,
V4L2_DV_BT_DMT_1856X1392P60,
V4L2_DV_BT_DMT_1856X1392P75,
V4L2_DV_BT_DMT_1856X1392P120_RB,
V4L2_DV_BT_DMT_1920X1200P60_RB,
V4L2_DV_BT_DMT_1920X1200P60,
V4L2_DV_BT_DMT_1920X1200P75,
V4L2_DV_BT_DMT_1920X1200P85,
V4L2_DV_BT_DMT_1920X1200P120_RB,
V4L2_DV_BT_DMT_1920X1440P60,
V4L2_DV_BT_DMT_1920X1440P75,
V4L2_DV_BT_DMT_1920X1440P120_RB,
V4L2_DV_BT_DMT_2048X1152P60_RB,
V4L2_DV_BT_DMT_2560X1600P60_RB,
V4L2_DV_BT_DMT_2560X1600P60,
V4L2_DV_BT_DMT_2560X1600P75,
V4L2_DV_BT_DMT_2560X1600P85,
V4L2_DV_BT_DMT_2560X1600P120_RB,
};
bool v4l2_dv_valid_timings(const struct v4l2_dv_timings *t,
const struct v4l2_dv_timings_cap *dvcap)
{
const struct v4l2_bt_timings *bt = &t->bt;
const struct v4l2_bt_timings_cap *cap = &dvcap->bt;
u32 caps = cap->capabilities;
if (t->type != V4L2_DV_BT_656_1120)
return false;
if (t->type != dvcap->type ||
bt->height < cap->min_height ||
bt->height > cap->max_height ||
bt->width < cap->min_width ||
bt->width > cap->max_width ||
bt->pixelclock < cap->min_pixelclock ||
bt->pixelclock > cap->max_pixelclock ||
(cap->standards && !(bt->standards & cap->standards)) ||
(bt->interlaced && !(caps & V4L2_DV_BT_CAP_INTERLACED)) ||
(!bt->interlaced && !(caps & V4L2_DV_BT_CAP_PROGRESSIVE)))
return false;
return true;
}
EXPORT_SYMBOL_GPL(v4l2_dv_valid_timings);
int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,
const struct v4l2_dv_timings_cap *cap)
{
u32 i, idx;
memset(t->reserved, 0, sizeof(t->reserved));
for (i = idx = 0; i < ARRAY_SIZE(timings); i++) {
if (v4l2_dv_valid_timings(timings + i, cap) &&
idx++ == t->index) {
t->timings = timings[i];
return 0;
}
}
return -EINVAL;
}
EXPORT_SYMBOL_GPL(v4l2_enum_dv_timings_cap);
bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
const struct v4l2_dv_timings_cap *cap,
unsigned pclock_delta)
{
int i;
if (!v4l2_dv_valid_timings(t, cap))
return false;
for (i = 0; i < ARRAY_SIZE(timings); i++) {
if (v4l2_dv_valid_timings(timings + i, cap) &&
v4l_match_dv_timings(t, timings + i, pclock_delta)) {
*t = timings[i];
return true;
}
}
return false;
}
EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cap);
/**
* v4l_match_dv_timings - check if two timings match
* @t1 - compare this v4l2_dv_timings struct...
* @t2 - with this struct.
* @pclock_delta - the allowed pixelclock deviation.
*
* Compare t1 with t2 with a given margin of error for the pixelclock.
*/
bool v4l_match_dv_timings(const struct v4l2_dv_timings *t1,
const struct v4l2_dv_timings *t2,
unsigned pclock_delta)
{
if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120)
return false;
if (t1->bt.width == t2->bt.width &&
t1->bt.height == t2->bt.height &&
t1->bt.interlaced == t2->bt.interlaced &&
t1->bt.polarities == t2->bt.polarities &&
t1->bt.pixelclock >= t2->bt.pixelclock - pclock_delta &&
t1->bt.pixelclock <= t2->bt.pixelclock + pclock_delta &&
t1->bt.hfrontporch == t2->bt.hfrontporch &&
t1->bt.vfrontporch == t2->bt.vfrontporch &&
t1->bt.vsync == t2->bt.vsync &&
t1->bt.vbackporch == t2->bt.vbackporch &&
(!t1->bt.interlaced ||
(t1->bt.il_vfrontporch == t2->bt.il_vfrontporch &&
t1->bt.il_vsync == t2->bt.il_vsync &&
t1->bt.il_vbackporch == t2->bt.il_vbackporch)))
return true;
return false;
}
EXPORT_SYMBOL_GPL(v4l_match_dv_timings);
void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
const struct v4l2_dv_timings *t, bool detailed)
{
const struct v4l2_bt_timings *bt = &t->bt;
u32 htot, vtot;
if (t->type != V4L2_DV_BT_656_1120)
return;
htot = V4L2_DV_BT_FRAME_WIDTH(bt);
vtot = V4L2_DV_BT_FRAME_HEIGHT(bt);
if (prefix == NULL)
prefix = "";
pr_info("%s: %s%ux%u%s%u (%ux%u)\n", dev_prefix, prefix,
bt->width, bt->height, bt->interlaced ? "i" : "p",
(htot * vtot) > 0 ? ((u32)bt->pixelclock / (htot * vtot)) : 0,
htot, vtot);
if (!detailed)
return;
pr_info("%s: horizontal: fp = %u, %ssync = %u, bp = %u\n",
dev_prefix, bt->hfrontporch,
(bt->polarities & V4L2_DV_HSYNC_POS_POL) ? "+" : "-",
bt->hsync, bt->hbackporch);
pr_info("%s: vertical: fp = %u, %ssync = %u, bp = %u\n",
dev_prefix, bt->vfrontporch,
(bt->polarities & V4L2_DV_VSYNC_POS_POL) ? "+" : "-",
bt->vsync, bt->vbackporch);
pr_info("%s: pixelclock: %llu\n", dev_prefix, bt->pixelclock);
pr_info("%s: flags (0x%x):%s%s%s%s\n", dev_prefix, bt->flags,
(bt->flags & V4L2_DV_FL_REDUCED_BLANKING) ?
" REDUCED_BLANKING" : "",
(bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS) ?
" CAN_REDUCE_FPS" : "",
(bt->flags & V4L2_DV_FL_REDUCED_FPS) ?
" REDUCED_FPS" : "",
(bt->flags & V4L2_DV_FL_HALF_LINE) ?
" HALF_LINE" : "");
pr_info("%s: standards (0x%x):%s%s%s%s\n", dev_prefix, bt->standards,
(bt->standards & V4L2_DV_BT_STD_CEA861) ? " CEA" : "",
(bt->standards & V4L2_DV_BT_STD_DMT) ? " DMT" : "",
(bt->standards & V4L2_DV_BT_STD_CVT) ? " CVT" : "",
(bt->standards & V4L2_DV_BT_STD_GTF) ? " GTF" : "");
}
EXPORT_SYMBOL_GPL(v4l2_print_dv_timings);
/*
* CVT defines
* Based on Coordinated Video Timings Standard
* version 1.1 September 10, 2003
*/
#define CVT_PXL_CLK_GRAN 250000 /* pixel clock granularity */
/* Normal blanking */
#define CVT_MIN_V_BPORCH 7 /* lines */
#define CVT_MIN_V_PORCH_RND 3 /* lines */
#define CVT_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
/* Normal blanking for CVT uses GTF to calculate horizontal blanking */
#define CVT_CELL_GRAN 8 /* character cell granularity */
#define CVT_M 600 /* blanking formula gradient */
#define CVT_C 40 /* blanking formula offset */
#define CVT_K 128 /* blanking formula scaling factor */
#define CVT_J 20 /* blanking formula scaling factor */
#define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
#define CVT_M_PRIME (CVT_K * CVT_M / 256)
/* Reduced Blanking */
#define CVT_RB_MIN_V_BPORCH 7 /* lines */
#define CVT_RB_V_FPORCH 3 /* lines */
#define CVT_RB_MIN_V_BLANK 460 /* us */
#define CVT_RB_H_SYNC 32 /* pixels */
#define CVT_RB_H_BPORCH 80 /* pixels */
#define CVT_RB_H_BLANK 160 /* pixels */
/** 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.
* @polarities - the horizontal and vertical polarities (same as struct
* v4l2_bt_timings polarities).
* @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,
u32 polarities, struct v4l2_dv_timings *fmt)
{
int v_fp, v_bp, h_fp, h_bp, hsync;
int frame_width, image_height, image_width;
bool reduced_blanking;
unsigned pix_clk;
if (vsync < 4 || vsync > 7)
return false;
if (polarities == V4L2_DV_VSYNC_POS_POL)
reduced_blanking = false;
else if (polarities == V4L2_DV_HSYNC_POS_POL)
reduced_blanking = true;
else
return false;
/* Vertical */
if (reduced_blanking) {
v_fp = CVT_RB_V_FPORCH;
v_bp = (CVT_RB_MIN_V_BLANK * hfreq + 1999999) / 1000000;
v_bp -= vsync + v_fp;
if (v_bp < CVT_RB_MIN_V_BPORCH)
v_bp = CVT_RB_MIN_V_BPORCH;
} else {
v_fp = CVT_MIN_V_PORCH_RND;
v_bp = (CVT_MIN_VSYNC_BP * hfreq + 1999999) / 1000000 - vsync;
if (v_bp < CVT_MIN_V_BPORCH)
v_bp = CVT_MIN_V_BPORCH;
}
image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
/* Aspect ratio based on vsync */
switch (vsync) {
case 4:
image_width = (image_height * 4) / 3;
break;
case 5:
image_width = (image_height * 16) / 9;
break;
case 6:
image_width = (image_height * 16) / 10;
break;
case 7:
/* special case */
if (image_height == 1024)
image_width = (image_height * 5) / 4;
else if (image_height == 768)
image_width = (image_height * 15) / 9;
else
return false;
break;
default:
return false;
}
image_width = image_width & ~7;
/* Horizontal */
if (reduced_blanking) {
pix_clk = (image_width + CVT_RB_H_BLANK) * hfreq;
pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
h_bp = CVT_RB_H_BPORCH;
hsync = CVT_RB_H_SYNC;
h_fp = CVT_RB_H_BLANK - h_bp - hsync;
frame_width = image_width + CVT_RB_H_BLANK;
} else {
unsigned ideal_duty_cycle_per_myriad =
100 * CVT_C_PRIME - (CVT_M_PRIME * 100000) / hfreq;
int h_blank;
if (ideal_duty_cycle_per_myriad < 2000)
ideal_duty_cycle_per_myriad = 2000;
h_blank = image_width * ideal_duty_cycle_per_myriad /
(10000 - ideal_duty_cycle_per_myriad);
h_blank = (h_blank / (2 * CVT_CELL_GRAN)) * 2 * CVT_CELL_GRAN;
pix_clk = (image_width + h_blank) * hfreq;
pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
h_bp = h_blank / 2;
frame_width = image_width + h_blank;
hsync = (frame_width * 8 + 50) / 100;
hsync = hsync - hsync % CVT_CELL_GRAN;
h_fp = h_blank - hsync - h_bp;
}
fmt->bt.polarities = polarities;
fmt->bt.width = image_width;
fmt->bt.height = image_height;
fmt->bt.hfrontporch = h_fp;
fmt->bt.vfrontporch = v_fp;
fmt->bt.hsync = hsync;
fmt->bt.vsync = vsync;
fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
fmt->bt.pixelclock = pix_clk;
fmt->bt.standards = V4L2_DV_BT_STD_CVT;
if (reduced_blanking)
fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
return true;
}
EXPORT_SYMBOL_GPL(v4l2_detect_cvt);
/*
* GTF defines
* Based on Generalized Timing Formula Standard
* Version 1.1 September 2, 1999
*/
#define GTF_PXL_CLK_GRAN 250000 /* pixel clock granularity */
#define GTF_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
#define GTF_V_FP 1 /* vertical front porch (lines) */
#define GTF_CELL_GRAN 8 /* character cell granularity */
/* Default */
#define GTF_D_M 600 /* blanking formula gradient */
#define GTF_D_C 40 /* blanking formula offset */
#define GTF_D_K 128 /* blanking formula scaling factor */
#define GTF_D_J 20 /* blanking formula scaling factor */
#define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
#define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)
/* Secondary */
#define GTF_S_M 3600 /* blanking formula gradient */
#define GTF_S_C 40 /* blanking formula offset */
#define GTF_S_K 128 /* blanking formula scaling factor */
#define GTF_S_J 35 /* blanking formula scaling factor */
#define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
#define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)
/** 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).
* @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,
struct v4l2_fract aspect,
struct v4l2_dv_timings *fmt)
{
int pix_clk;
int v_fp, v_bp, h_fp, hsync;
int frame_width, image_height, image_width;
bool default_gtf;
int h_blank;
if (vsync != 3)
return false;
if (polarities == V4L2_DV_VSYNC_POS_POL)
default_gtf = true;
else if (polarities == V4L2_DV_HSYNC_POS_POL)
default_gtf = false;
else
return false;
/* Vertical */
v_fp = GTF_V_FP;
v_bp = (GTF_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync;
image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
if (aspect.numerator == 0 || aspect.denominator == 0) {
aspect.numerator = 16;
aspect.denominator = 9;
}
image_width = ((image_height * aspect.numerator) / aspect.denominator);
/* Horizontal */
if (default_gtf)
h_blank = ((image_width * GTF_D_C_PRIME * hfreq) -
(image_width * GTF_D_M_PRIME * 1000) +
(hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) / 2) /
(hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000);
else
h_blank = ((image_width * GTF_S_C_PRIME * hfreq) -
(image_width * GTF_S_M_PRIME * 1000) +
(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) / 2) /
(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000);
h_blank = h_blank - h_blank % (2 * GTF_CELL_GRAN);
frame_width = image_width + h_blank;
pix_clk = (image_width + h_blank) * hfreq;
pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;
hsync = (frame_width * 8 + 50) / 100;
hsync = hsync - hsync % GTF_CELL_GRAN;
h_fp = h_blank / 2 - hsync;
fmt->bt.polarities = polarities;
fmt->bt.width = image_width;
fmt->bt.height = image_height;
fmt->bt.hfrontporch = h_fp;
fmt->bt.vfrontporch = v_fp;
fmt->bt.hsync = hsync;
fmt->bt.vsync = vsync;
fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
fmt->bt.pixelclock = pix_clk;
fmt->bt.standards = V4L2_DV_BT_STD_GTF;
if (!default_gtf)
fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
return true;
}
EXPORT_SYMBOL_GPL(v4l2_detect_gtf);
/** 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)
{
struct v4l2_fract aspect = { 16, 9 };
u32 tmp;
u8 ratio;
/* Nothing filled in, fallback to 16:9 */
if (!hor_landscape && !vert_portrait)
return aspect;
/* Both filled in, so they are interpreted as the screen size in cm */
if (hor_landscape && vert_portrait) {
aspect.numerator = hor_landscape;
aspect.denominator = vert_portrait;
return aspect;
}
/* Only one is filled in, so interpret them as a ratio:
(val + 99) / 100 */
ratio = hor_landscape | vert_portrait;
/* Change some rounded values into the exact aspect ratio */
if (ratio == 79) {
aspect.numerator = 16;
aspect.denominator = 9;
} else if (ratio == 34) {
aspect.numerator = 4;
aspect.numerator = 3;
} else if (ratio == 68) {
aspect.numerator = 15;
aspect.numerator = 9;
} else {
aspect.numerator = hor_landscape + 99;
aspect.denominator = 100;
}
if (hor_landscape)
return aspect;
/* The aspect ratio is for portrait, so swap numerator and denominator */
tmp = aspect.denominator;
aspect.denominator = aspect.numerator;
aspect.numerator = tmp;
return aspect;
}
EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio);
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