1 /*
2  * v4l2-dv-timings - dv-timings helper functions
3  *
4  * Copyright 2013 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
5  *
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.
9  *
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
17  * SOFTWARE.
18  *
19  */
20 
21 #include <linux/module.h>
22 #include <linux/types.h>
23 #include <linux/kernel.h>
24 #include <linux/errno.h>
25 #include <linux/rational.h>
26 #include <linux/videodev2.h>
27 #include <linux/v4l2-dv-timings.h>
28 #include <media/v4l2-dv-timings.h>
29 #include <linux/math64.h>
30 
31 MODULE_AUTHOR("Hans Verkuil");
32 MODULE_DESCRIPTION("V4L2 DV Timings Helper Functions");
33 MODULE_LICENSE("GPL");
34 
35 const struct v4l2_dv_timings v4l2_dv_timings_presets[] = {
36 	V4L2_DV_BT_CEA_640X480P59_94,
37 	V4L2_DV_BT_CEA_720X480I59_94,
38 	V4L2_DV_BT_CEA_720X480P59_94,
39 	V4L2_DV_BT_CEA_720X576I50,
40 	V4L2_DV_BT_CEA_720X576P50,
41 	V4L2_DV_BT_CEA_1280X720P24,
42 	V4L2_DV_BT_CEA_1280X720P25,
43 	V4L2_DV_BT_CEA_1280X720P30,
44 	V4L2_DV_BT_CEA_1280X720P50,
45 	V4L2_DV_BT_CEA_1280X720P60,
46 	V4L2_DV_BT_CEA_1920X1080P24,
47 	V4L2_DV_BT_CEA_1920X1080P25,
48 	V4L2_DV_BT_CEA_1920X1080P30,
49 	V4L2_DV_BT_CEA_1920X1080I50,
50 	V4L2_DV_BT_CEA_1920X1080P50,
51 	V4L2_DV_BT_CEA_1920X1080I60,
52 	V4L2_DV_BT_CEA_1920X1080P60,
53 	V4L2_DV_BT_DMT_640X350P85,
54 	V4L2_DV_BT_DMT_640X400P85,
55 	V4L2_DV_BT_DMT_720X400P85,
56 	V4L2_DV_BT_DMT_640X480P72,
57 	V4L2_DV_BT_DMT_640X480P75,
58 	V4L2_DV_BT_DMT_640X480P85,
59 	V4L2_DV_BT_DMT_800X600P56,
60 	V4L2_DV_BT_DMT_800X600P60,
61 	V4L2_DV_BT_DMT_800X600P72,
62 	V4L2_DV_BT_DMT_800X600P75,
63 	V4L2_DV_BT_DMT_800X600P85,
64 	V4L2_DV_BT_DMT_800X600P120_RB,
65 	V4L2_DV_BT_DMT_848X480P60,
66 	V4L2_DV_BT_DMT_1024X768I43,
67 	V4L2_DV_BT_DMT_1024X768P60,
68 	V4L2_DV_BT_DMT_1024X768P70,
69 	V4L2_DV_BT_DMT_1024X768P75,
70 	V4L2_DV_BT_DMT_1024X768P85,
71 	V4L2_DV_BT_DMT_1024X768P120_RB,
72 	V4L2_DV_BT_DMT_1152X864P75,
73 	V4L2_DV_BT_DMT_1280X768P60_RB,
74 	V4L2_DV_BT_DMT_1280X768P60,
75 	V4L2_DV_BT_DMT_1280X768P75,
76 	V4L2_DV_BT_DMT_1280X768P85,
77 	V4L2_DV_BT_DMT_1280X768P120_RB,
78 	V4L2_DV_BT_DMT_1280X800P60_RB,
79 	V4L2_DV_BT_DMT_1280X800P60,
80 	V4L2_DV_BT_DMT_1280X800P75,
81 	V4L2_DV_BT_DMT_1280X800P85,
82 	V4L2_DV_BT_DMT_1280X800P120_RB,
83 	V4L2_DV_BT_DMT_1280X960P60,
84 	V4L2_DV_BT_DMT_1280X960P85,
85 	V4L2_DV_BT_DMT_1280X960P120_RB,
86 	V4L2_DV_BT_DMT_1280X1024P60,
87 	V4L2_DV_BT_DMT_1280X1024P75,
88 	V4L2_DV_BT_DMT_1280X1024P85,
89 	V4L2_DV_BT_DMT_1280X1024P120_RB,
90 	V4L2_DV_BT_DMT_1360X768P60,
91 	V4L2_DV_BT_DMT_1360X768P120_RB,
92 	V4L2_DV_BT_DMT_1366X768P60,
93 	V4L2_DV_BT_DMT_1366X768P60_RB,
94 	V4L2_DV_BT_DMT_1400X1050P60_RB,
95 	V4L2_DV_BT_DMT_1400X1050P60,
96 	V4L2_DV_BT_DMT_1400X1050P75,
97 	V4L2_DV_BT_DMT_1400X1050P85,
98 	V4L2_DV_BT_DMT_1400X1050P120_RB,
99 	V4L2_DV_BT_DMT_1440X900P60_RB,
100 	V4L2_DV_BT_DMT_1440X900P60,
101 	V4L2_DV_BT_DMT_1440X900P75,
102 	V4L2_DV_BT_DMT_1440X900P85,
103 	V4L2_DV_BT_DMT_1440X900P120_RB,
104 	V4L2_DV_BT_DMT_1600X900P60_RB,
105 	V4L2_DV_BT_DMT_1600X1200P60,
106 	V4L2_DV_BT_DMT_1600X1200P65,
107 	V4L2_DV_BT_DMT_1600X1200P70,
108 	V4L2_DV_BT_DMT_1600X1200P75,
109 	V4L2_DV_BT_DMT_1600X1200P85,
110 	V4L2_DV_BT_DMT_1600X1200P120_RB,
111 	V4L2_DV_BT_DMT_1680X1050P60_RB,
112 	V4L2_DV_BT_DMT_1680X1050P60,
113 	V4L2_DV_BT_DMT_1680X1050P75,
114 	V4L2_DV_BT_DMT_1680X1050P85,
115 	V4L2_DV_BT_DMT_1680X1050P120_RB,
116 	V4L2_DV_BT_DMT_1792X1344P60,
117 	V4L2_DV_BT_DMT_1792X1344P75,
118 	V4L2_DV_BT_DMT_1792X1344P120_RB,
119 	V4L2_DV_BT_DMT_1856X1392P60,
120 	V4L2_DV_BT_DMT_1856X1392P75,
121 	V4L2_DV_BT_DMT_1856X1392P120_RB,
122 	V4L2_DV_BT_DMT_1920X1200P60_RB,
123 	V4L2_DV_BT_DMT_1920X1200P60,
124 	V4L2_DV_BT_DMT_1920X1200P75,
125 	V4L2_DV_BT_DMT_1920X1200P85,
126 	V4L2_DV_BT_DMT_1920X1200P120_RB,
127 	V4L2_DV_BT_DMT_1920X1440P60,
128 	V4L2_DV_BT_DMT_1920X1440P75,
129 	V4L2_DV_BT_DMT_1920X1440P120_RB,
130 	V4L2_DV_BT_DMT_2048X1152P60_RB,
131 	V4L2_DV_BT_DMT_2560X1600P60_RB,
132 	V4L2_DV_BT_DMT_2560X1600P60,
133 	V4L2_DV_BT_DMT_2560X1600P75,
134 	V4L2_DV_BT_DMT_2560X1600P85,
135 	V4L2_DV_BT_DMT_2560X1600P120_RB,
136 	V4L2_DV_BT_CEA_3840X2160P24,
137 	V4L2_DV_BT_CEA_3840X2160P25,
138 	V4L2_DV_BT_CEA_3840X2160P30,
139 	V4L2_DV_BT_CEA_3840X2160P50,
140 	V4L2_DV_BT_CEA_3840X2160P60,
141 	V4L2_DV_BT_CEA_4096X2160P24,
142 	V4L2_DV_BT_CEA_4096X2160P25,
143 	V4L2_DV_BT_CEA_4096X2160P30,
144 	V4L2_DV_BT_CEA_4096X2160P50,
145 	V4L2_DV_BT_DMT_4096X2160P59_94_RB,
146 	V4L2_DV_BT_CEA_4096X2160P60,
147 	{ }
148 };
149 EXPORT_SYMBOL_GPL(v4l2_dv_timings_presets);
150 
151 bool v4l2_valid_dv_timings(const struct v4l2_dv_timings *t,
152 			   const struct v4l2_dv_timings_cap *dvcap,
153 			   v4l2_check_dv_timings_fnc fnc,
154 			   void *fnc_handle)
155 {
156 	const struct v4l2_bt_timings *bt = &t->bt;
157 	const struct v4l2_bt_timings_cap *cap = &dvcap->bt;
158 	u32 caps = cap->capabilities;
159 
160 	if (t->type != V4L2_DV_BT_656_1120)
161 		return false;
162 	if (t->type != dvcap->type ||
163 	    bt->height < cap->min_height ||
164 	    bt->height > cap->max_height ||
165 	    bt->width < cap->min_width ||
166 	    bt->width > cap->max_width ||
167 	    bt->pixelclock < cap->min_pixelclock ||
168 	    bt->pixelclock > cap->max_pixelclock ||
169 	    (!(caps & V4L2_DV_BT_CAP_CUSTOM) &&
170 	     cap->standards && bt->standards &&
171 	     !(bt->standards & cap->standards)) ||
172 	    (bt->interlaced && !(caps & V4L2_DV_BT_CAP_INTERLACED)) ||
173 	    (!bt->interlaced && !(caps & V4L2_DV_BT_CAP_PROGRESSIVE)))
174 		return false;
175 	return fnc == NULL || fnc(t, fnc_handle);
176 }
177 EXPORT_SYMBOL_GPL(v4l2_valid_dv_timings);
178 
179 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t,
180 			     const struct v4l2_dv_timings_cap *cap,
181 			     v4l2_check_dv_timings_fnc fnc,
182 			     void *fnc_handle)
183 {
184 	u32 i, idx;
185 
186 	memset(t->reserved, 0, sizeof(t->reserved));
187 	for (i = idx = 0; v4l2_dv_timings_presets[i].bt.width; i++) {
188 		if (v4l2_valid_dv_timings(v4l2_dv_timings_presets + i, cap,
189 					  fnc, fnc_handle) &&
190 		    idx++ == t->index) {
191 			t->timings = v4l2_dv_timings_presets[i];
192 			return 0;
193 		}
194 	}
195 	return -EINVAL;
196 }
197 EXPORT_SYMBOL_GPL(v4l2_enum_dv_timings_cap);
198 
199 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t,
200 			      const struct v4l2_dv_timings_cap *cap,
201 			      unsigned pclock_delta,
202 			      v4l2_check_dv_timings_fnc fnc,
203 			      void *fnc_handle)
204 {
205 	int i;
206 
207 	if (!v4l2_valid_dv_timings(t, cap, fnc, fnc_handle))
208 		return false;
209 
210 	for (i = 0; i < v4l2_dv_timings_presets[i].bt.width; i++) {
211 		if (v4l2_valid_dv_timings(v4l2_dv_timings_presets + i, cap,
212 					  fnc, fnc_handle) &&
213 		    v4l2_match_dv_timings(t, v4l2_dv_timings_presets + i,
214 					  pclock_delta, false)) {
215 			u32 flags = t->bt.flags & V4L2_DV_FL_REDUCED_FPS;
216 
217 			*t = v4l2_dv_timings_presets[i];
218 			if (can_reduce_fps(&t->bt))
219 				t->bt.flags |= flags;
220 
221 			return true;
222 		}
223 	}
224 	return false;
225 }
226 EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cap);
227 
228 bool v4l2_find_dv_timings_cea861_vic(struct v4l2_dv_timings *t, u8 vic)
229 {
230 	unsigned int i;
231 
232 	for (i = 0; i < v4l2_dv_timings_presets[i].bt.width; i++) {
233 		const struct v4l2_bt_timings *bt =
234 			&v4l2_dv_timings_presets[i].bt;
235 
236 		if ((bt->flags & V4L2_DV_FL_HAS_CEA861_VIC) &&
237 		    bt->cea861_vic == vic) {
238 			*t = v4l2_dv_timings_presets[i];
239 			return true;
240 		}
241 	}
242 	return false;
243 }
244 EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cea861_vic);
245 
246 /**
247  * v4l2_match_dv_timings - check if two timings match
248  * @t1 - compare this v4l2_dv_timings struct...
249  * @t2 - with this struct.
250  * @pclock_delta - the allowed pixelclock deviation.
251  * @match_reduced_fps - if true, then fail if V4L2_DV_FL_REDUCED_FPS does not
252  * match.
253  *
254  * Compare t1 with t2 with a given margin of error for the pixelclock.
255  */
256 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *t1,
257 			   const struct v4l2_dv_timings *t2,
258 			   unsigned pclock_delta, bool match_reduced_fps)
259 {
260 	if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120)
261 		return false;
262 	if (t1->bt.width == t2->bt.width &&
263 	    t1->bt.height == t2->bt.height &&
264 	    t1->bt.interlaced == t2->bt.interlaced &&
265 	    t1->bt.polarities == t2->bt.polarities &&
266 	    t1->bt.pixelclock >= t2->bt.pixelclock - pclock_delta &&
267 	    t1->bt.pixelclock <= t2->bt.pixelclock + pclock_delta &&
268 	    t1->bt.hfrontporch == t2->bt.hfrontporch &&
269 	    t1->bt.hsync == t2->bt.hsync &&
270 	    t1->bt.hbackporch == t2->bt.hbackporch &&
271 	    t1->bt.vfrontporch == t2->bt.vfrontporch &&
272 	    t1->bt.vsync == t2->bt.vsync &&
273 	    t1->bt.vbackporch == t2->bt.vbackporch &&
274 	    (!match_reduced_fps ||
275 	     (t1->bt.flags & V4L2_DV_FL_REDUCED_FPS) ==
276 		(t2->bt.flags & V4L2_DV_FL_REDUCED_FPS)) &&
277 	    (!t1->bt.interlaced ||
278 		(t1->bt.il_vfrontporch == t2->bt.il_vfrontporch &&
279 		 t1->bt.il_vsync == t2->bt.il_vsync &&
280 		 t1->bt.il_vbackporch == t2->bt.il_vbackporch)))
281 		return true;
282 	return false;
283 }
284 EXPORT_SYMBOL_GPL(v4l2_match_dv_timings);
285 
286 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
287 			   const struct v4l2_dv_timings *t, bool detailed)
288 {
289 	const struct v4l2_bt_timings *bt = &t->bt;
290 	u32 htot, vtot;
291 	u32 fps;
292 
293 	if (t->type != V4L2_DV_BT_656_1120)
294 		return;
295 
296 	htot = V4L2_DV_BT_FRAME_WIDTH(bt);
297 	vtot = V4L2_DV_BT_FRAME_HEIGHT(bt);
298 	if (bt->interlaced)
299 		vtot /= 2;
300 
301 	fps = (htot * vtot) > 0 ? div_u64((100 * (u64)bt->pixelclock),
302 				  (htot * vtot)) : 0;
303 
304 	if (prefix == NULL)
305 		prefix = "";
306 
307 	pr_info("%s: %s%ux%u%s%u.%u (%ux%u)\n", dev_prefix, prefix,
308 		bt->width, bt->height, bt->interlaced ? "i" : "p",
309 		fps / 100, fps % 100, htot, vtot);
310 
311 	if (!detailed)
312 		return;
313 
314 	pr_info("%s: horizontal: fp = %u, %ssync = %u, bp = %u\n",
315 			dev_prefix, bt->hfrontporch,
316 			(bt->polarities & V4L2_DV_HSYNC_POS_POL) ? "+" : "-",
317 			bt->hsync, bt->hbackporch);
318 	pr_info("%s: vertical: fp = %u, %ssync = %u, bp = %u\n",
319 			dev_prefix, bt->vfrontporch,
320 			(bt->polarities & V4L2_DV_VSYNC_POS_POL) ? "+" : "-",
321 			bt->vsync, bt->vbackporch);
322 	if (bt->interlaced)
323 		pr_info("%s: vertical bottom field: fp = %u, %ssync = %u, bp = %u\n",
324 			dev_prefix, bt->il_vfrontporch,
325 			(bt->polarities & V4L2_DV_VSYNC_POS_POL) ? "+" : "-",
326 			bt->il_vsync, bt->il_vbackporch);
327 	pr_info("%s: pixelclock: %llu\n", dev_prefix, bt->pixelclock);
328 	pr_info("%s: flags (0x%x):%s%s%s%s%s%s%s%s%s%s\n",
329 			dev_prefix, bt->flags,
330 			(bt->flags & V4L2_DV_FL_REDUCED_BLANKING) ?
331 			" REDUCED_BLANKING" : "",
332 			((bt->flags & V4L2_DV_FL_REDUCED_BLANKING) &&
333 			 bt->vsync == 8) ? " (V2)" : "",
334 			(bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS) ?
335 			" CAN_REDUCE_FPS" : "",
336 			(bt->flags & V4L2_DV_FL_REDUCED_FPS) ?
337 			" REDUCED_FPS" : "",
338 			(bt->flags & V4L2_DV_FL_HALF_LINE) ?
339 			" HALF_LINE" : "",
340 			(bt->flags & V4L2_DV_FL_IS_CE_VIDEO) ?
341 			" CE_VIDEO" : "",
342 			(bt->flags & V4L2_DV_FL_FIRST_FIELD_EXTRA_LINE) ?
343 			" FIRST_FIELD_EXTRA_LINE" : "",
344 			(bt->flags & V4L2_DV_FL_HAS_PICTURE_ASPECT) ?
345 			" HAS_PICTURE_ASPECT" : "",
346 			(bt->flags & V4L2_DV_FL_HAS_CEA861_VIC) ?
347 			" HAS_CEA861_VIC" : "",
348 			(bt->flags & V4L2_DV_FL_HAS_HDMI_VIC) ?
349 			" HAS_HDMI_VIC" : "");
350 	pr_info("%s: standards (0x%x):%s%s%s%s%s\n", dev_prefix, bt->standards,
351 			(bt->standards & V4L2_DV_BT_STD_CEA861) ?  " CEA" : "",
352 			(bt->standards & V4L2_DV_BT_STD_DMT) ?  " DMT" : "",
353 			(bt->standards & V4L2_DV_BT_STD_CVT) ?  " CVT" : "",
354 			(bt->standards & V4L2_DV_BT_STD_GTF) ?  " GTF" : "",
355 			(bt->standards & V4L2_DV_BT_STD_SDI) ?  " SDI" : "");
356 	if (bt->flags & V4L2_DV_FL_HAS_PICTURE_ASPECT)
357 		pr_info("%s: picture aspect (hor:vert): %u:%u\n", dev_prefix,
358 			bt->picture_aspect.numerator,
359 			bt->picture_aspect.denominator);
360 	if (bt->flags & V4L2_DV_FL_HAS_CEA861_VIC)
361 		pr_info("%s: CEA-861 VIC: %u\n", dev_prefix, bt->cea861_vic);
362 	if (bt->flags & V4L2_DV_FL_HAS_HDMI_VIC)
363 		pr_info("%s: HDMI VIC: %u\n", dev_prefix, bt->hdmi_vic);
364 }
365 EXPORT_SYMBOL_GPL(v4l2_print_dv_timings);
366 
367 struct v4l2_fract v4l2_dv_timings_aspect_ratio(const struct v4l2_dv_timings *t)
368 {
369 	struct v4l2_fract ratio = { 1, 1 };
370 	unsigned long n, d;
371 
372 	if (t->type != V4L2_DV_BT_656_1120)
373 		return ratio;
374 	if (!(t->bt.flags & V4L2_DV_FL_HAS_PICTURE_ASPECT))
375 		return ratio;
376 
377 	ratio.numerator = t->bt.width * t->bt.picture_aspect.denominator;
378 	ratio.denominator = t->bt.height * t->bt.picture_aspect.numerator;
379 
380 	rational_best_approximation(ratio.numerator, ratio.denominator,
381 				    ratio.numerator, ratio.denominator, &n, &d);
382 	ratio.numerator = n;
383 	ratio.denominator = d;
384 	return ratio;
385 }
386 EXPORT_SYMBOL_GPL(v4l2_dv_timings_aspect_ratio);
387 
388 /*
389  * CVT defines
390  * Based on Coordinated Video Timings Standard
391  * version 1.1 September 10, 2003
392  */
393 
394 #define CVT_PXL_CLK_GRAN	250000	/* pixel clock granularity */
395 #define CVT_PXL_CLK_GRAN_RB_V2 1000	/* granularity for reduced blanking v2*/
396 
397 /* Normal blanking */
398 #define CVT_MIN_V_BPORCH	7	/* lines */
399 #define CVT_MIN_V_PORCH_RND	3	/* lines */
400 #define CVT_MIN_VSYNC_BP	550	/* min time of vsync + back porch (us) */
401 #define CVT_HSYNC_PERCENT       8       /* nominal hsync as percentage of line */
402 
403 /* Normal blanking for CVT uses GTF to calculate horizontal blanking */
404 #define CVT_CELL_GRAN		8	/* character cell granularity */
405 #define CVT_M			600	/* blanking formula gradient */
406 #define CVT_C			40	/* blanking formula offset */
407 #define CVT_K			128	/* blanking formula scaling factor */
408 #define CVT_J			20	/* blanking formula scaling factor */
409 #define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
410 #define CVT_M_PRIME (CVT_K * CVT_M / 256)
411 
412 /* Reduced Blanking */
413 #define CVT_RB_MIN_V_BPORCH    7       /* lines  */
414 #define CVT_RB_V_FPORCH        3       /* lines  */
415 #define CVT_RB_MIN_V_BLANK   460       /* us     */
416 #define CVT_RB_H_SYNC         32       /* pixels */
417 #define CVT_RB_H_BLANK       160       /* pixels */
418 /* Reduce blanking Version 2 */
419 #define CVT_RB_V2_H_BLANK     80       /* pixels */
420 #define CVT_RB_MIN_V_FPORCH    3       /* lines  */
421 #define CVT_RB_V2_MIN_V_FPORCH 1       /* lines  */
422 #define CVT_RB_V_BPORCH        6       /* lines  */
423 
424 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
425  * @frame_height - the total height of the frame (including blanking) in lines.
426  * @hfreq - the horizontal frequency in Hz.
427  * @vsync - the height of the vertical sync in lines.
428  * @active_width - active width of image (does not include blanking). This
429  * information is needed only in case of version 2 of reduced blanking.
430  * In other cases, this parameter does not have any effect on timings.
431  * @polarities - the horizontal and vertical polarities (same as struct
432  *		v4l2_bt_timings polarities).
433  * @interlaced - if this flag is true, it indicates interlaced format
434  * @fmt - the resulting timings.
435  *
436  * This function will attempt to detect if the given values correspond to a
437  * valid CVT format. If so, then it will return true, and fmt will be filled
438  * in with the found CVT timings.
439  */
440 bool v4l2_detect_cvt(unsigned frame_height,
441 		     unsigned hfreq,
442 		     unsigned vsync,
443 		     unsigned active_width,
444 		     u32 polarities,
445 		     bool interlaced,
446 		     struct v4l2_dv_timings *fmt)
447 {
448 	int  v_fp, v_bp, h_fp, h_bp, hsync;
449 	int  frame_width, image_height, image_width;
450 	bool reduced_blanking;
451 	bool rb_v2 = false;
452 	unsigned pix_clk;
453 
454 	if (vsync < 4 || vsync > 8)
455 		return false;
456 
457 	if (polarities == V4L2_DV_VSYNC_POS_POL)
458 		reduced_blanking = false;
459 	else if (polarities == V4L2_DV_HSYNC_POS_POL)
460 		reduced_blanking = true;
461 	else
462 		return false;
463 
464 	if (reduced_blanking && vsync == 8)
465 		rb_v2 = true;
466 
467 	if (rb_v2 && active_width == 0)
468 		return false;
469 
470 	if (!rb_v2 && vsync > 7)
471 		return false;
472 
473 	if (hfreq == 0)
474 		return false;
475 
476 	/* Vertical */
477 	if (reduced_blanking) {
478 		if (rb_v2) {
479 			v_bp = CVT_RB_V_BPORCH;
480 			v_fp = (CVT_RB_MIN_V_BLANK * hfreq) / 1000000 + 1;
481 			v_fp -= vsync + v_bp;
482 
483 			if (v_fp < CVT_RB_V2_MIN_V_FPORCH)
484 				v_fp = CVT_RB_V2_MIN_V_FPORCH;
485 		} else {
486 			v_fp = CVT_RB_V_FPORCH;
487 			v_bp = (CVT_RB_MIN_V_BLANK * hfreq) / 1000000 + 1;
488 			v_bp -= vsync + v_fp;
489 
490 			if (v_bp < CVT_RB_MIN_V_BPORCH)
491 				v_bp = CVT_RB_MIN_V_BPORCH;
492 		}
493 	} else {
494 		v_fp = CVT_MIN_V_PORCH_RND;
495 		v_bp = (CVT_MIN_VSYNC_BP * hfreq) / 1000000 + 1 - vsync;
496 
497 		if (v_bp < CVT_MIN_V_BPORCH)
498 			v_bp = CVT_MIN_V_BPORCH;
499 	}
500 
501 	if (interlaced)
502 		image_height = (frame_height - 2 * v_fp - 2 * vsync - 2 * v_bp) & ~0x1;
503 	else
504 		image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
505 
506 	if (image_height < 0)
507 		return false;
508 
509 	/* Aspect ratio based on vsync */
510 	switch (vsync) {
511 	case 4:
512 		image_width = (image_height * 4) / 3;
513 		break;
514 	case 5:
515 		image_width = (image_height * 16) / 9;
516 		break;
517 	case 6:
518 		image_width = (image_height * 16) / 10;
519 		break;
520 	case 7:
521 		/* special case */
522 		if (image_height == 1024)
523 			image_width = (image_height * 5) / 4;
524 		else if (image_height == 768)
525 			image_width = (image_height * 15) / 9;
526 		else
527 			return false;
528 		break;
529 	case 8:
530 		image_width = active_width;
531 		break;
532 	default:
533 		return false;
534 	}
535 
536 	if (!rb_v2)
537 		image_width = image_width & ~7;
538 
539 	/* Horizontal */
540 	if (reduced_blanking) {
541 		int h_blank;
542 		int clk_gran;
543 
544 		h_blank = rb_v2 ? CVT_RB_V2_H_BLANK : CVT_RB_H_BLANK;
545 		clk_gran = rb_v2 ? CVT_PXL_CLK_GRAN_RB_V2 : CVT_PXL_CLK_GRAN;
546 
547 		pix_clk = (image_width + h_blank) * hfreq;
548 		pix_clk = (pix_clk / clk_gran) * clk_gran;
549 
550 		h_bp  = h_blank / 2;
551 		hsync = CVT_RB_H_SYNC;
552 		h_fp  = h_blank - h_bp - hsync;
553 
554 		frame_width = image_width + h_blank;
555 	} else {
556 		unsigned ideal_duty_cycle_per_myriad =
557 			100 * CVT_C_PRIME - (CVT_M_PRIME * 100000) / hfreq;
558 		int h_blank;
559 
560 		if (ideal_duty_cycle_per_myriad < 2000)
561 			ideal_duty_cycle_per_myriad = 2000;
562 
563 		h_blank = image_width * ideal_duty_cycle_per_myriad /
564 					(10000 - ideal_duty_cycle_per_myriad);
565 		h_blank = (h_blank / (2 * CVT_CELL_GRAN)) * 2 * CVT_CELL_GRAN;
566 
567 		pix_clk = (image_width + h_blank) * hfreq;
568 		pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
569 
570 		h_bp = h_blank / 2;
571 		frame_width = image_width + h_blank;
572 
573 		hsync = frame_width * CVT_HSYNC_PERCENT / 100;
574 		hsync = (hsync / CVT_CELL_GRAN) * CVT_CELL_GRAN;
575 		h_fp = h_blank - hsync - h_bp;
576 	}
577 
578 	fmt->type = V4L2_DV_BT_656_1120;
579 	fmt->bt.polarities = polarities;
580 	fmt->bt.width = image_width;
581 	fmt->bt.height = image_height;
582 	fmt->bt.hfrontporch = h_fp;
583 	fmt->bt.vfrontporch = v_fp;
584 	fmt->bt.hsync = hsync;
585 	fmt->bt.vsync = vsync;
586 	fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
587 
588 	if (!interlaced) {
589 		fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
590 		fmt->bt.interlaced = V4L2_DV_PROGRESSIVE;
591 	} else {
592 		fmt->bt.vbackporch = (frame_height - image_height - 2 * v_fp -
593 				      2 * vsync) / 2;
594 		fmt->bt.il_vbackporch = frame_height - image_height - 2 * v_fp -
595 					2 * vsync - fmt->bt.vbackporch;
596 		fmt->bt.il_vfrontporch = v_fp;
597 		fmt->bt.il_vsync = vsync;
598 		fmt->bt.flags |= V4L2_DV_FL_HALF_LINE;
599 		fmt->bt.interlaced = V4L2_DV_INTERLACED;
600 	}
601 
602 	fmt->bt.pixelclock = pix_clk;
603 	fmt->bt.standards = V4L2_DV_BT_STD_CVT;
604 
605 	if (reduced_blanking)
606 		fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
607 
608 	return true;
609 }
610 EXPORT_SYMBOL_GPL(v4l2_detect_cvt);
611 
612 /*
613  * GTF defines
614  * Based on Generalized Timing Formula Standard
615  * Version 1.1 September 2, 1999
616  */
617 
618 #define GTF_PXL_CLK_GRAN	250000	/* pixel clock granularity */
619 
620 #define GTF_MIN_VSYNC_BP	550	/* min time of vsync + back porch (us) */
621 #define GTF_V_FP		1	/* vertical front porch (lines) */
622 #define GTF_CELL_GRAN		8	/* character cell granularity */
623 
624 /* Default */
625 #define GTF_D_M			600	/* blanking formula gradient */
626 #define GTF_D_C			40	/* blanking formula offset */
627 #define GTF_D_K			128	/* blanking formula scaling factor */
628 #define GTF_D_J			20	/* blanking formula scaling factor */
629 #define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
630 #define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)
631 
632 /* Secondary */
633 #define GTF_S_M			3600	/* blanking formula gradient */
634 #define GTF_S_C			40	/* blanking formula offset */
635 #define GTF_S_K			128	/* blanking formula scaling factor */
636 #define GTF_S_J			35	/* blanking formula scaling factor */
637 #define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
638 #define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)
639 
640 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
641  * @frame_height - the total height of the frame (including blanking) in lines.
642  * @hfreq - the horizontal frequency in Hz.
643  * @vsync - the height of the vertical sync in lines.
644  * @polarities - the horizontal and vertical polarities (same as struct
645  *		v4l2_bt_timings polarities).
646  * @interlaced - if this flag is true, it indicates interlaced format
647  * @aspect - preferred aspect ratio. GTF has no method of determining the
648  *		aspect ratio in order to derive the image width from the
649  *		image height, so it has to be passed explicitly. Usually
650  *		the native screen aspect ratio is used for this. If it
651  *		is not filled in correctly, then 16:9 will be assumed.
652  * @fmt - the resulting timings.
653  *
654  * This function will attempt to detect if the given values correspond to a
655  * valid GTF format. If so, then it will return true, and fmt will be filled
656  * in with the found GTF timings.
657  */
658 bool v4l2_detect_gtf(unsigned frame_height,
659 		unsigned hfreq,
660 		unsigned vsync,
661 		u32 polarities,
662 		bool interlaced,
663 		struct v4l2_fract aspect,
664 		struct v4l2_dv_timings *fmt)
665 {
666 	int pix_clk;
667 	int  v_fp, v_bp, h_fp, hsync;
668 	int frame_width, image_height, image_width;
669 	bool default_gtf;
670 	int h_blank;
671 
672 	if (vsync != 3)
673 		return false;
674 
675 	if (polarities == V4L2_DV_VSYNC_POS_POL)
676 		default_gtf = true;
677 	else if (polarities == V4L2_DV_HSYNC_POS_POL)
678 		default_gtf = false;
679 	else
680 		return false;
681 
682 	if (hfreq == 0)
683 		return false;
684 
685 	/* Vertical */
686 	v_fp = GTF_V_FP;
687 	v_bp = (GTF_MIN_VSYNC_BP * hfreq + 500000) / 1000000 - vsync;
688 	if (interlaced)
689 		image_height = (frame_height - 2 * v_fp - 2 * vsync - 2 * v_bp) & ~0x1;
690 	else
691 		image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
692 
693 	if (image_height < 0)
694 		return false;
695 
696 	if (aspect.numerator == 0 || aspect.denominator == 0) {
697 		aspect.numerator = 16;
698 		aspect.denominator = 9;
699 	}
700 	image_width = ((image_height * aspect.numerator) / aspect.denominator);
701 	image_width = (image_width + GTF_CELL_GRAN/2) & ~(GTF_CELL_GRAN - 1);
702 
703 	/* Horizontal */
704 	if (default_gtf) {
705 		u64 num;
706 		u32 den;
707 
708 		num = ((image_width * GTF_D_C_PRIME * (u64)hfreq) -
709 		      ((u64)image_width * GTF_D_M_PRIME * 1000));
710 		den = (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) *
711 		      (2 * GTF_CELL_GRAN);
712 		h_blank = div_u64((num + (den >> 1)), den);
713 		h_blank *= (2 * GTF_CELL_GRAN);
714 	} else {
715 		u64 num;
716 		u32 den;
717 
718 		num = ((image_width * GTF_S_C_PRIME * (u64)hfreq) -
719 		      ((u64)image_width * GTF_S_M_PRIME * 1000));
720 		den = (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) *
721 		      (2 * GTF_CELL_GRAN);
722 		h_blank = div_u64((num + (den >> 1)), den);
723 		h_blank *= (2 * GTF_CELL_GRAN);
724 	}
725 
726 	frame_width = image_width + h_blank;
727 
728 	pix_clk = (image_width + h_blank) * hfreq;
729 	pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;
730 
731 	hsync = (frame_width * 8 + 50) / 100;
732 	hsync = ((hsync + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN) * GTF_CELL_GRAN;
733 
734 	h_fp = h_blank / 2 - hsync;
735 
736 	fmt->type = V4L2_DV_BT_656_1120;
737 	fmt->bt.polarities = polarities;
738 	fmt->bt.width = image_width;
739 	fmt->bt.height = image_height;
740 	fmt->bt.hfrontporch = h_fp;
741 	fmt->bt.vfrontporch = v_fp;
742 	fmt->bt.hsync = hsync;
743 	fmt->bt.vsync = vsync;
744 	fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
745 
746 	if (!interlaced) {
747 		fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
748 		fmt->bt.interlaced = V4L2_DV_PROGRESSIVE;
749 	} else {
750 		fmt->bt.vbackporch = (frame_height - image_height - 2 * v_fp -
751 				      2 * vsync) / 2;
752 		fmt->bt.il_vbackporch = frame_height - image_height - 2 * v_fp -
753 					2 * vsync - fmt->bt.vbackporch;
754 		fmt->bt.il_vfrontporch = v_fp;
755 		fmt->bt.il_vsync = vsync;
756 		fmt->bt.flags |= V4L2_DV_FL_HALF_LINE;
757 		fmt->bt.interlaced = V4L2_DV_INTERLACED;
758 	}
759 
760 	fmt->bt.pixelclock = pix_clk;
761 	fmt->bt.standards = V4L2_DV_BT_STD_GTF;
762 
763 	if (!default_gtf)
764 		fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
765 
766 	return true;
767 }
768 EXPORT_SYMBOL_GPL(v4l2_detect_gtf);
769 
770 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
771  *	0x15 and 0x16 from the EDID.
772  * @hor_landscape - byte 0x15 from the EDID.
773  * @vert_portrait - byte 0x16 from the EDID.
774  *
775  * Determines the aspect ratio from the EDID.
776  * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
777  * "Horizontal and Vertical Screen Size or Aspect Ratio"
778  */
779 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait)
780 {
781 	struct v4l2_fract aspect = { 16, 9 };
782 	u8 ratio;
783 
784 	/* Nothing filled in, fallback to 16:9 */
785 	if (!hor_landscape && !vert_portrait)
786 		return aspect;
787 	/* Both filled in, so they are interpreted as the screen size in cm */
788 	if (hor_landscape && vert_portrait) {
789 		aspect.numerator = hor_landscape;
790 		aspect.denominator = vert_portrait;
791 		return aspect;
792 	}
793 	/* Only one is filled in, so interpret them as a ratio:
794 	   (val + 99) / 100 */
795 	ratio = hor_landscape | vert_portrait;
796 	/* Change some rounded values into the exact aspect ratio */
797 	if (ratio == 79) {
798 		aspect.numerator = 16;
799 		aspect.denominator = 9;
800 	} else if (ratio == 34) {
801 		aspect.numerator = 4;
802 		aspect.denominator = 3;
803 	} else if (ratio == 68) {
804 		aspect.numerator = 15;
805 		aspect.denominator = 9;
806 	} else {
807 		aspect.numerator = hor_landscape + 99;
808 		aspect.denominator = 100;
809 	}
810 	if (hor_landscape)
811 		return aspect;
812 	/* The aspect ratio is for portrait, so swap numerator and denominator */
813 	swap(aspect.denominator, aspect.numerator);
814 	return aspect;
815 }
816 EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio);
817