2 * v4l2-dv-timings - dv-timings helper functions
4 * Copyright 2013 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
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.
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
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/errno.h>
25 #include <linux/videodev2.h>
26 #include <linux/v4l2-dv-timings.h>
27 #include <media/v4l2-dv-timings.h>
28 #include <linux/math64.h>
30 MODULE_AUTHOR("Hans Verkuil");
31 MODULE_DESCRIPTION("V4L2 DV Timings Helper Functions");
32 MODULE_LICENSE("GPL");
34 const struct v4l2_dv_timings v4l2_dv_timings_presets
[] = {
35 V4L2_DV_BT_CEA_640X480P59_94
,
36 V4L2_DV_BT_CEA_720X480I59_94
,
37 V4L2_DV_BT_CEA_720X480P59_94
,
38 V4L2_DV_BT_CEA_720X576I50
,
39 V4L2_DV_BT_CEA_720X576P50
,
40 V4L2_DV_BT_CEA_1280X720P24
,
41 V4L2_DV_BT_CEA_1280X720P25
,
42 V4L2_DV_BT_CEA_1280X720P30
,
43 V4L2_DV_BT_CEA_1280X720P50
,
44 V4L2_DV_BT_CEA_1280X720P60
,
45 V4L2_DV_BT_CEA_1920X1080P24
,
46 V4L2_DV_BT_CEA_1920X1080P25
,
47 V4L2_DV_BT_CEA_1920X1080P30
,
48 V4L2_DV_BT_CEA_1920X1080I50
,
49 V4L2_DV_BT_CEA_1920X1080P50
,
50 V4L2_DV_BT_CEA_1920X1080I60
,
51 V4L2_DV_BT_CEA_1920X1080P60
,
52 V4L2_DV_BT_DMT_640X350P85
,
53 V4L2_DV_BT_DMT_640X400P85
,
54 V4L2_DV_BT_DMT_720X400P85
,
55 V4L2_DV_BT_DMT_640X480P72
,
56 V4L2_DV_BT_DMT_640X480P75
,
57 V4L2_DV_BT_DMT_640X480P85
,
58 V4L2_DV_BT_DMT_800X600P56
,
59 V4L2_DV_BT_DMT_800X600P60
,
60 V4L2_DV_BT_DMT_800X600P72
,
61 V4L2_DV_BT_DMT_800X600P75
,
62 V4L2_DV_BT_DMT_800X600P85
,
63 V4L2_DV_BT_DMT_800X600P120_RB
,
64 V4L2_DV_BT_DMT_848X480P60
,
65 V4L2_DV_BT_DMT_1024X768I43
,
66 V4L2_DV_BT_DMT_1024X768P60
,
67 V4L2_DV_BT_DMT_1024X768P70
,
68 V4L2_DV_BT_DMT_1024X768P75
,
69 V4L2_DV_BT_DMT_1024X768P85
,
70 V4L2_DV_BT_DMT_1024X768P120_RB
,
71 V4L2_DV_BT_DMT_1152X864P75
,
72 V4L2_DV_BT_DMT_1280X768P60_RB
,
73 V4L2_DV_BT_DMT_1280X768P60
,
74 V4L2_DV_BT_DMT_1280X768P75
,
75 V4L2_DV_BT_DMT_1280X768P85
,
76 V4L2_DV_BT_DMT_1280X768P120_RB
,
77 V4L2_DV_BT_DMT_1280X800P60_RB
,
78 V4L2_DV_BT_DMT_1280X800P60
,
79 V4L2_DV_BT_DMT_1280X800P75
,
80 V4L2_DV_BT_DMT_1280X800P85
,
81 V4L2_DV_BT_DMT_1280X800P120_RB
,
82 V4L2_DV_BT_DMT_1280X960P60
,
83 V4L2_DV_BT_DMT_1280X960P85
,
84 V4L2_DV_BT_DMT_1280X960P120_RB
,
85 V4L2_DV_BT_DMT_1280X1024P60
,
86 V4L2_DV_BT_DMT_1280X1024P75
,
87 V4L2_DV_BT_DMT_1280X1024P85
,
88 V4L2_DV_BT_DMT_1280X1024P120_RB
,
89 V4L2_DV_BT_DMT_1360X768P60
,
90 V4L2_DV_BT_DMT_1360X768P120_RB
,
91 V4L2_DV_BT_DMT_1366X768P60
,
92 V4L2_DV_BT_DMT_1366X768P60_RB
,
93 V4L2_DV_BT_DMT_1400X1050P60_RB
,
94 V4L2_DV_BT_DMT_1400X1050P60
,
95 V4L2_DV_BT_DMT_1400X1050P75
,
96 V4L2_DV_BT_DMT_1400X1050P85
,
97 V4L2_DV_BT_DMT_1400X1050P120_RB
,
98 V4L2_DV_BT_DMT_1440X900P60_RB
,
99 V4L2_DV_BT_DMT_1440X900P60
,
100 V4L2_DV_BT_DMT_1440X900P75
,
101 V4L2_DV_BT_DMT_1440X900P85
,
102 V4L2_DV_BT_DMT_1440X900P120_RB
,
103 V4L2_DV_BT_DMT_1600X900P60_RB
,
104 V4L2_DV_BT_DMT_1600X1200P60
,
105 V4L2_DV_BT_DMT_1600X1200P65
,
106 V4L2_DV_BT_DMT_1600X1200P70
,
107 V4L2_DV_BT_DMT_1600X1200P75
,
108 V4L2_DV_BT_DMT_1600X1200P85
,
109 V4L2_DV_BT_DMT_1600X1200P120_RB
,
110 V4L2_DV_BT_DMT_1680X1050P60_RB
,
111 V4L2_DV_BT_DMT_1680X1050P60
,
112 V4L2_DV_BT_DMT_1680X1050P75
,
113 V4L2_DV_BT_DMT_1680X1050P85
,
114 V4L2_DV_BT_DMT_1680X1050P120_RB
,
115 V4L2_DV_BT_DMT_1792X1344P60
,
116 V4L2_DV_BT_DMT_1792X1344P75
,
117 V4L2_DV_BT_DMT_1792X1344P120_RB
,
118 V4L2_DV_BT_DMT_1856X1392P60
,
119 V4L2_DV_BT_DMT_1856X1392P75
,
120 V4L2_DV_BT_DMT_1856X1392P120_RB
,
121 V4L2_DV_BT_DMT_1920X1200P60_RB
,
122 V4L2_DV_BT_DMT_1920X1200P60
,
123 V4L2_DV_BT_DMT_1920X1200P75
,
124 V4L2_DV_BT_DMT_1920X1200P85
,
125 V4L2_DV_BT_DMT_1920X1200P120_RB
,
126 V4L2_DV_BT_DMT_1920X1440P60
,
127 V4L2_DV_BT_DMT_1920X1440P75
,
128 V4L2_DV_BT_DMT_1920X1440P120_RB
,
129 V4L2_DV_BT_DMT_2048X1152P60_RB
,
130 V4L2_DV_BT_DMT_2560X1600P60_RB
,
131 V4L2_DV_BT_DMT_2560X1600P60
,
132 V4L2_DV_BT_DMT_2560X1600P75
,
133 V4L2_DV_BT_DMT_2560X1600P85
,
134 V4L2_DV_BT_DMT_2560X1600P120_RB
,
135 V4L2_DV_BT_CEA_3840X2160P24
,
136 V4L2_DV_BT_CEA_3840X2160P25
,
137 V4L2_DV_BT_CEA_3840X2160P30
,
138 V4L2_DV_BT_CEA_3840X2160P50
,
139 V4L2_DV_BT_CEA_3840X2160P60
,
140 V4L2_DV_BT_CEA_4096X2160P24
,
141 V4L2_DV_BT_CEA_4096X2160P25
,
142 V4L2_DV_BT_CEA_4096X2160P30
,
143 V4L2_DV_BT_CEA_4096X2160P50
,
144 V4L2_DV_BT_DMT_4096X2160P59_94_RB
,
145 V4L2_DV_BT_CEA_4096X2160P60
,
148 EXPORT_SYMBOL_GPL(v4l2_dv_timings_presets
);
150 bool v4l2_valid_dv_timings(const struct v4l2_dv_timings
*t
,
151 const struct v4l2_dv_timings_cap
*dvcap
,
152 v4l2_check_dv_timings_fnc fnc
,
155 const struct v4l2_bt_timings
*bt
= &t
->bt
;
156 const struct v4l2_bt_timings_cap
*cap
= &dvcap
->bt
;
157 u32 caps
= cap
->capabilities
;
159 if (t
->type
!= V4L2_DV_BT_656_1120
)
161 if (t
->type
!= dvcap
->type
||
162 bt
->height
< cap
->min_height
||
163 bt
->height
> cap
->max_height
||
164 bt
->width
< cap
->min_width
||
165 bt
->width
> cap
->max_width
||
166 bt
->pixelclock
< cap
->min_pixelclock
||
167 bt
->pixelclock
> cap
->max_pixelclock
||
168 (cap
->standards
&& bt
->standards
&&
169 !(bt
->standards
& cap
->standards
)) ||
170 (bt
->interlaced
&& !(caps
& V4L2_DV_BT_CAP_INTERLACED
)) ||
171 (!bt
->interlaced
&& !(caps
& V4L2_DV_BT_CAP_PROGRESSIVE
)))
173 return fnc
== NULL
|| fnc(t
, fnc_handle
);
175 EXPORT_SYMBOL_GPL(v4l2_valid_dv_timings
);
177 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings
*t
,
178 const struct v4l2_dv_timings_cap
*cap
,
179 v4l2_check_dv_timings_fnc fnc
,
184 memset(t
->reserved
, 0, sizeof(t
->reserved
));
185 for (i
= idx
= 0; v4l2_dv_timings_presets
[i
].bt
.width
; i
++) {
186 if (v4l2_valid_dv_timings(v4l2_dv_timings_presets
+ i
, cap
,
189 t
->timings
= v4l2_dv_timings_presets
[i
];
195 EXPORT_SYMBOL_GPL(v4l2_enum_dv_timings_cap
);
197 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings
*t
,
198 const struct v4l2_dv_timings_cap
*cap
,
199 unsigned pclock_delta
,
200 v4l2_check_dv_timings_fnc fnc
,
205 if (!v4l2_valid_dv_timings(t
, cap
, fnc
, fnc_handle
))
208 for (i
= 0; i
< v4l2_dv_timings_presets
[i
].bt
.width
; i
++) {
209 if (v4l2_valid_dv_timings(v4l2_dv_timings_presets
+ i
, cap
,
211 v4l2_match_dv_timings(t
, v4l2_dv_timings_presets
+ i
,
213 *t
= v4l2_dv_timings_presets
[i
];
219 EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cap
);
222 * v4l2_match_dv_timings - check if two timings match
223 * @t1 - compare this v4l2_dv_timings struct...
224 * @t2 - with this struct.
225 * @pclock_delta - the allowed pixelclock deviation.
227 * Compare t1 with t2 with a given margin of error for the pixelclock.
229 bool v4l2_match_dv_timings(const struct v4l2_dv_timings
*t1
,
230 const struct v4l2_dv_timings
*t2
,
231 unsigned pclock_delta
)
233 if (t1
->type
!= t2
->type
|| t1
->type
!= V4L2_DV_BT_656_1120
)
235 if (t1
->bt
.width
== t2
->bt
.width
&&
236 t1
->bt
.height
== t2
->bt
.height
&&
237 t1
->bt
.interlaced
== t2
->bt
.interlaced
&&
238 t1
->bt
.polarities
== t2
->bt
.polarities
&&
239 t1
->bt
.pixelclock
>= t2
->bt
.pixelclock
- pclock_delta
&&
240 t1
->bt
.pixelclock
<= t2
->bt
.pixelclock
+ pclock_delta
&&
241 t1
->bt
.hfrontporch
== t2
->bt
.hfrontporch
&&
242 t1
->bt
.vfrontporch
== t2
->bt
.vfrontporch
&&
243 t1
->bt
.vsync
== t2
->bt
.vsync
&&
244 t1
->bt
.vbackporch
== t2
->bt
.vbackporch
&&
245 (!t1
->bt
.interlaced
||
246 (t1
->bt
.il_vfrontporch
== t2
->bt
.il_vfrontporch
&&
247 t1
->bt
.il_vsync
== t2
->bt
.il_vsync
&&
248 t1
->bt
.il_vbackporch
== t2
->bt
.il_vbackporch
)))
252 EXPORT_SYMBOL_GPL(v4l2_match_dv_timings
);
254 void v4l2_print_dv_timings(const char *dev_prefix
, const char *prefix
,
255 const struct v4l2_dv_timings
*t
, bool detailed
)
257 const struct v4l2_bt_timings
*bt
= &t
->bt
;
260 if (t
->type
!= V4L2_DV_BT_656_1120
)
263 htot
= V4L2_DV_BT_FRAME_WIDTH(bt
);
264 vtot
= V4L2_DV_BT_FRAME_HEIGHT(bt
);
271 pr_info("%s: %s%ux%u%s%u (%ux%u)\n", dev_prefix
, prefix
,
272 bt
->width
, bt
->height
, bt
->interlaced
? "i" : "p",
273 (htot
* vtot
) > 0 ? ((u32
)bt
->pixelclock
/ (htot
* vtot
)) : 0,
279 pr_info("%s: horizontal: fp = %u, %ssync = %u, bp = %u\n",
280 dev_prefix
, bt
->hfrontporch
,
281 (bt
->polarities
& V4L2_DV_HSYNC_POS_POL
) ? "+" : "-",
282 bt
->hsync
, bt
->hbackporch
);
283 pr_info("%s: vertical: fp = %u, %ssync = %u, bp = %u\n",
284 dev_prefix
, bt
->vfrontporch
,
285 (bt
->polarities
& V4L2_DV_VSYNC_POS_POL
) ? "+" : "-",
286 bt
->vsync
, bt
->vbackporch
);
288 pr_info("%s: vertical bottom field: fp = %u, %ssync = %u, bp = %u\n",
289 dev_prefix
, bt
->il_vfrontporch
,
290 (bt
->polarities
& V4L2_DV_VSYNC_POS_POL
) ? "+" : "-",
291 bt
->il_vsync
, bt
->il_vbackporch
);
292 pr_info("%s: pixelclock: %llu\n", dev_prefix
, bt
->pixelclock
);
293 pr_info("%s: flags (0x%x):%s%s%s%s%s\n", dev_prefix
, bt
->flags
,
294 (bt
->flags
& V4L2_DV_FL_REDUCED_BLANKING
) ?
295 " REDUCED_BLANKING" : "",
296 (bt
->flags
& V4L2_DV_FL_CAN_REDUCE_FPS
) ?
297 " CAN_REDUCE_FPS" : "",
298 (bt
->flags
& V4L2_DV_FL_REDUCED_FPS
) ?
300 (bt
->flags
& V4L2_DV_FL_HALF_LINE
) ?
302 (bt
->flags
& V4L2_DV_FL_IS_CE_VIDEO
) ?
304 pr_info("%s: standards (0x%x):%s%s%s%s\n", dev_prefix
, bt
->standards
,
305 (bt
->standards
& V4L2_DV_BT_STD_CEA861
) ? " CEA" : "",
306 (bt
->standards
& V4L2_DV_BT_STD_DMT
) ? " DMT" : "",
307 (bt
->standards
& V4L2_DV_BT_STD_CVT
) ? " CVT" : "",
308 (bt
->standards
& V4L2_DV_BT_STD_GTF
) ? " GTF" : "");
310 EXPORT_SYMBOL_GPL(v4l2_print_dv_timings
);
314 * Based on Coordinated Video Timings Standard
315 * version 1.1 September 10, 2003
318 #define CVT_PXL_CLK_GRAN 250000 /* pixel clock granularity */
320 /* Normal blanking */
321 #define CVT_MIN_V_BPORCH 7 /* lines */
322 #define CVT_MIN_V_PORCH_RND 3 /* lines */
323 #define CVT_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
324 #define CVT_HSYNC_PERCENT 8 /* nominal hsync as percentage of line */
326 /* Normal blanking for CVT uses GTF to calculate horizontal blanking */
327 #define CVT_CELL_GRAN 8 /* character cell granularity */
328 #define CVT_M 600 /* blanking formula gradient */
329 #define CVT_C 40 /* blanking formula offset */
330 #define CVT_K 128 /* blanking formula scaling factor */
331 #define CVT_J 20 /* blanking formula scaling factor */
332 #define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
333 #define CVT_M_PRIME (CVT_K * CVT_M / 256)
335 /* Reduced Blanking */
336 #define CVT_RB_MIN_V_BPORCH 7 /* lines */
337 #define CVT_RB_V_FPORCH 3 /* lines */
338 #define CVT_RB_MIN_V_BLANK 460 /* us */
339 #define CVT_RB_H_SYNC 32 /* pixels */
340 #define CVT_RB_H_BPORCH 80 /* pixels */
341 #define CVT_RB_H_BLANK 160 /* pixels */
343 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
344 * @frame_height - the total height of the frame (including blanking) in lines.
345 * @hfreq - the horizontal frequency in Hz.
346 * @vsync - the height of the vertical sync in lines.
347 * @polarities - the horizontal and vertical polarities (same as struct
348 * v4l2_bt_timings polarities).
349 * @interlaced - if this flag is true, it indicates interlaced format
350 * @fmt - the resulting timings.
352 * This function will attempt to detect if the given values correspond to a
353 * valid CVT format. If so, then it will return true, and fmt will be filled
354 * in with the found CVT timings.
356 * TODO: VESA defined a new version 2 of their reduced blanking
357 * formula. Support for that is currently missing in this CVT
358 * detection function.
360 bool v4l2_detect_cvt(unsigned frame_height
, unsigned hfreq
, unsigned vsync
,
361 u32 polarities
, bool interlaced
, struct v4l2_dv_timings
*fmt
)
363 int v_fp
, v_bp
, h_fp
, h_bp
, hsync
;
364 int frame_width
, image_height
, image_width
;
365 bool reduced_blanking
;
368 if (vsync
< 4 || vsync
> 7)
371 if (polarities
== V4L2_DV_VSYNC_POS_POL
)
372 reduced_blanking
= false;
373 else if (polarities
== V4L2_DV_HSYNC_POS_POL
)
374 reduced_blanking
= true;
382 if (reduced_blanking
) {
383 v_fp
= CVT_RB_V_FPORCH
;
384 v_bp
= (CVT_RB_MIN_V_BLANK
* hfreq
) / 1000000 + 1;
385 v_bp
-= vsync
+ v_fp
;
387 if (v_bp
< CVT_RB_MIN_V_BPORCH
)
388 v_bp
= CVT_RB_MIN_V_BPORCH
;
390 v_fp
= CVT_MIN_V_PORCH_RND
;
391 v_bp
= (CVT_MIN_VSYNC_BP
* hfreq
) / 1000000 + 1 - vsync
;
393 if (v_bp
< CVT_MIN_V_BPORCH
)
394 v_bp
= CVT_MIN_V_BPORCH
;
398 image_height
= (frame_height
- 2 * v_fp
- 2 * vsync
- 2 * v_bp
) & ~0x1;
400 image_height
= (frame_height
- v_fp
- vsync
- v_bp
+ 1) & ~0x1;
402 if (image_height
< 0)
405 /* Aspect ratio based on vsync */
408 image_width
= (image_height
* 4) / 3;
411 image_width
= (image_height
* 16) / 9;
414 image_width
= (image_height
* 16) / 10;
418 if (image_height
== 1024)
419 image_width
= (image_height
* 5) / 4;
420 else if (image_height
== 768)
421 image_width
= (image_height
* 15) / 9;
429 image_width
= image_width
& ~7;
432 if (reduced_blanking
) {
433 pix_clk
= (image_width
+ CVT_RB_H_BLANK
) * hfreq
;
434 pix_clk
= (pix_clk
/ CVT_PXL_CLK_GRAN
) * CVT_PXL_CLK_GRAN
;
436 h_bp
= CVT_RB_H_BPORCH
;
437 hsync
= CVT_RB_H_SYNC
;
438 h_fp
= CVT_RB_H_BLANK
- h_bp
- hsync
;
440 frame_width
= image_width
+ CVT_RB_H_BLANK
;
442 unsigned ideal_duty_cycle_per_myriad
=
443 100 * CVT_C_PRIME
- (CVT_M_PRIME
* 100000) / hfreq
;
446 if (ideal_duty_cycle_per_myriad
< 2000)
447 ideal_duty_cycle_per_myriad
= 2000;
449 h_blank
= image_width
* ideal_duty_cycle_per_myriad
/
450 (10000 - ideal_duty_cycle_per_myriad
);
451 h_blank
= (h_blank
/ (2 * CVT_CELL_GRAN
)) * 2 * CVT_CELL_GRAN
;
453 pix_clk
= (image_width
+ h_blank
) * hfreq
;
454 pix_clk
= (pix_clk
/ CVT_PXL_CLK_GRAN
) * CVT_PXL_CLK_GRAN
;
457 frame_width
= image_width
+ h_blank
;
459 hsync
= frame_width
* CVT_HSYNC_PERCENT
/ 100;
460 hsync
= (hsync
/ CVT_CELL_GRAN
) * CVT_CELL_GRAN
;
461 h_fp
= h_blank
- hsync
- h_bp
;
464 fmt
->type
= V4L2_DV_BT_656_1120
;
465 fmt
->bt
.polarities
= polarities
;
466 fmt
->bt
.width
= image_width
;
467 fmt
->bt
.height
= image_height
;
468 fmt
->bt
.hfrontporch
= h_fp
;
469 fmt
->bt
.vfrontporch
= v_fp
;
470 fmt
->bt
.hsync
= hsync
;
471 fmt
->bt
.vsync
= vsync
;
472 fmt
->bt
.hbackporch
= frame_width
- image_width
- h_fp
- hsync
;
475 fmt
->bt
.vbackporch
= frame_height
- image_height
- v_fp
- vsync
;
476 fmt
->bt
.interlaced
= V4L2_DV_PROGRESSIVE
;
478 fmt
->bt
.vbackporch
= (frame_height
- image_height
- 2 * v_fp
-
480 fmt
->bt
.il_vbackporch
= frame_height
- image_height
- 2 * v_fp
-
481 2 * vsync
- fmt
->bt
.vbackporch
;
482 fmt
->bt
.il_vfrontporch
= v_fp
;
483 fmt
->bt
.il_vsync
= vsync
;
484 fmt
->bt
.flags
|= V4L2_DV_FL_HALF_LINE
;
485 fmt
->bt
.interlaced
= V4L2_DV_INTERLACED
;
488 fmt
->bt
.pixelclock
= pix_clk
;
489 fmt
->bt
.standards
= V4L2_DV_BT_STD_CVT
;
491 if (reduced_blanking
)
492 fmt
->bt
.flags
|= V4L2_DV_FL_REDUCED_BLANKING
;
496 EXPORT_SYMBOL_GPL(v4l2_detect_cvt
);
500 * Based on Generalized Timing Formula Standard
501 * Version 1.1 September 2, 1999
504 #define GTF_PXL_CLK_GRAN 250000 /* pixel clock granularity */
506 #define GTF_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
507 #define GTF_V_FP 1 /* vertical front porch (lines) */
508 #define GTF_CELL_GRAN 8 /* character cell granularity */
511 #define GTF_D_M 600 /* blanking formula gradient */
512 #define GTF_D_C 40 /* blanking formula offset */
513 #define GTF_D_K 128 /* blanking formula scaling factor */
514 #define GTF_D_J 20 /* blanking formula scaling factor */
515 #define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
516 #define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)
519 #define GTF_S_M 3600 /* blanking formula gradient */
520 #define GTF_S_C 40 /* blanking formula offset */
521 #define GTF_S_K 128 /* blanking formula scaling factor */
522 #define GTF_S_J 35 /* blanking formula scaling factor */
523 #define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
524 #define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)
526 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
527 * @frame_height - the total height of the frame (including blanking) in lines.
528 * @hfreq - the horizontal frequency in Hz.
529 * @vsync - the height of the vertical sync in lines.
530 * @polarities - the horizontal and vertical polarities (same as struct
531 * v4l2_bt_timings polarities).
532 * @interlaced - if this flag is true, it indicates interlaced format
533 * @aspect - preferred aspect ratio. GTF has no method of determining the
534 * aspect ratio in order to derive the image width from the
535 * image height, so it has to be passed explicitly. Usually
536 * the native screen aspect ratio is used for this. If it
537 * is not filled in correctly, then 16:9 will be assumed.
538 * @fmt - the resulting timings.
540 * This function will attempt to detect if the given values correspond to a
541 * valid GTF format. If so, then it will return true, and fmt will be filled
542 * in with the found GTF timings.
544 bool v4l2_detect_gtf(unsigned frame_height
,
549 struct v4l2_fract aspect
,
550 struct v4l2_dv_timings
*fmt
)
553 int v_fp
, v_bp
, h_fp
, hsync
;
554 int frame_width
, image_height
, image_width
;
561 if (polarities
== V4L2_DV_VSYNC_POS_POL
)
563 else if (polarities
== V4L2_DV_HSYNC_POS_POL
)
573 v_bp
= (GTF_MIN_VSYNC_BP
* hfreq
+ 500000) / 1000000 - vsync
;
575 image_height
= (frame_height
- 2 * v_fp
- 2 * vsync
- 2 * v_bp
) & ~0x1;
577 image_height
= (frame_height
- v_fp
- vsync
- v_bp
+ 1) & ~0x1;
579 if (image_height
< 0)
582 if (aspect
.numerator
== 0 || aspect
.denominator
== 0) {
583 aspect
.numerator
= 16;
584 aspect
.denominator
= 9;
586 image_width
= ((image_height
* aspect
.numerator
) / aspect
.denominator
);
587 image_width
= (image_width
+ GTF_CELL_GRAN
/2) & ~(GTF_CELL_GRAN
- 1);
594 num
= ((image_width
* GTF_D_C_PRIME
* (u64
)hfreq
) -
595 ((u64
)image_width
* GTF_D_M_PRIME
* 1000));
596 den
= (hfreq
* (100 - GTF_D_C_PRIME
) + GTF_D_M_PRIME
* 1000) *
598 h_blank
= div_u64((num
+ (den
>> 1)), den
);
599 h_blank
*= (2 * GTF_CELL_GRAN
);
604 num
= ((image_width
* GTF_S_C_PRIME
* (u64
)hfreq
) -
605 ((u64
)image_width
* GTF_S_M_PRIME
* 1000));
606 den
= (hfreq
* (100 - GTF_S_C_PRIME
) + GTF_S_M_PRIME
* 1000) *
608 h_blank
= div_u64((num
+ (den
>> 1)), den
);
609 h_blank
*= (2 * GTF_CELL_GRAN
);
612 frame_width
= image_width
+ h_blank
;
614 pix_clk
= (image_width
+ h_blank
) * hfreq
;
615 pix_clk
= pix_clk
/ GTF_PXL_CLK_GRAN
* GTF_PXL_CLK_GRAN
;
617 hsync
= (frame_width
* 8 + 50) / 100;
618 hsync
= ((hsync
+ GTF_CELL_GRAN
/ 2) / GTF_CELL_GRAN
) * GTF_CELL_GRAN
;
620 h_fp
= h_blank
/ 2 - hsync
;
622 fmt
->type
= V4L2_DV_BT_656_1120
;
623 fmt
->bt
.polarities
= polarities
;
624 fmt
->bt
.width
= image_width
;
625 fmt
->bt
.height
= image_height
;
626 fmt
->bt
.hfrontporch
= h_fp
;
627 fmt
->bt
.vfrontporch
= v_fp
;
628 fmt
->bt
.hsync
= hsync
;
629 fmt
->bt
.vsync
= vsync
;
630 fmt
->bt
.hbackporch
= frame_width
- image_width
- h_fp
- hsync
;
633 fmt
->bt
.vbackporch
= frame_height
- image_height
- v_fp
- vsync
;
634 fmt
->bt
.interlaced
= V4L2_DV_PROGRESSIVE
;
636 fmt
->bt
.vbackporch
= (frame_height
- image_height
- 2 * v_fp
-
638 fmt
->bt
.il_vbackporch
= frame_height
- image_height
- 2 * v_fp
-
639 2 * vsync
- fmt
->bt
.vbackporch
;
640 fmt
->bt
.il_vfrontporch
= v_fp
;
641 fmt
->bt
.il_vsync
= vsync
;
642 fmt
->bt
.flags
|= V4L2_DV_FL_HALF_LINE
;
643 fmt
->bt
.interlaced
= V4L2_DV_INTERLACED
;
646 fmt
->bt
.pixelclock
= pix_clk
;
647 fmt
->bt
.standards
= V4L2_DV_BT_STD_GTF
;
650 fmt
->bt
.flags
|= V4L2_DV_FL_REDUCED_BLANKING
;
654 EXPORT_SYMBOL_GPL(v4l2_detect_gtf
);
656 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
657 * 0x15 and 0x16 from the EDID.
658 * @hor_landscape - byte 0x15 from the EDID.
659 * @vert_portrait - byte 0x16 from the EDID.
661 * Determines the aspect ratio from the EDID.
662 * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
663 * "Horizontal and Vertical Screen Size or Aspect Ratio"
665 struct v4l2_fract
v4l2_calc_aspect_ratio(u8 hor_landscape
, u8 vert_portrait
)
667 struct v4l2_fract aspect
= { 16, 9 };
671 /* Nothing filled in, fallback to 16:9 */
672 if (!hor_landscape
&& !vert_portrait
)
674 /* Both filled in, so they are interpreted as the screen size in cm */
675 if (hor_landscape
&& vert_portrait
) {
676 aspect
.numerator
= hor_landscape
;
677 aspect
.denominator
= vert_portrait
;
680 /* Only one is filled in, so interpret them as a ratio:
682 ratio
= hor_landscape
| vert_portrait
;
683 /* Change some rounded values into the exact aspect ratio */
685 aspect
.numerator
= 16;
686 aspect
.denominator
= 9;
687 } else if (ratio
== 34) {
688 aspect
.numerator
= 4;
689 aspect
.denominator
= 3;
690 } else if (ratio
== 68) {
691 aspect
.numerator
= 15;
692 aspect
.denominator
= 9;
694 aspect
.numerator
= hor_landscape
+ 99;
695 aspect
.denominator
= 100;
699 /* The aspect ratio is for portrait, so swap numerator and denominator */
700 tmp
= aspect
.denominator
;
701 aspect
.denominator
= aspect
.numerator
;
702 aspect
.numerator
= tmp
;
705 EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio
);