drivers/media/v4l2-core/v4l2-dv-timings.c

   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/videodev2.h>
  26 #include <linux/v4l2-dv-timings.h>
  27 #include <media/v4l2-dv-timings.h>
  28 #include <linux/math64.h>
  29
  30 MODULE_AUTHOR("Hans Verkuil");
  31 MODULE_DESCRIPTION("V4L2 DV Timings Helper Functions");
  32 MODULE_LICENSE("GPL");
  33
  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,
 146         { }
 147 };
 148 EXPORT_SYMBOL_GPL(v4l2_dv_timings_presets);
 149
 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,
 153                            void *fnc_handle)
 154 {
 155         const struct v4l2_bt_timings *bt = &t->bt;
 156         const struct v4l2_bt_timings_cap *cap = &dvcap->bt;
 157         u32 caps = cap->capabilities;
 158
 159         if (t->type != V4L2_DV_BT_656_1120)
 160                 return false;
 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)))
 172                 return false;
 173         return fnc == NULL || fnc(t, fnc_handle);
 174 }
 175 EXPORT_SYMBOL_GPL(v4l2_valid_dv_timings);
 176
 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,
 180                              void *fnc_handle)
 181 {
 182         u32 i, idx;
 183
 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,
 187                                           fnc, fnc_handle) &&
 188                     idx++ == t->index) {
 189                         t->timings = v4l2_dv_timings_presets[i];
 190                         return 0;
 191                 }
 192         }
 193         return -EINVAL;
 194 }
 195 EXPORT_SYMBOL_GPL(v4l2_enum_dv_timings_cap);
 196
 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,
 201                               void *fnc_handle)
 202 {
 203         int i;
 204
 205         if (!v4l2_valid_dv_timings(t, cap, fnc, fnc_handle))
 206                 return false;
 207
 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,
 210                                           fnc, fnc_handle) &&
 211                     v4l2_match_dv_timings(t, v4l2_dv_timings_presets + i,
 212                                           pclock_delta)) {
 213                         *t = v4l2_dv_timings_presets[i];
 214                         return true;
 215                 }
 216         }
 217         return false;
 218 }
 219 EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cap);
 220
 221 /**
 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.
 226  *
 227  * Compare t1 with t2 with a given margin of error for the pixelclock.
 228  */
 229 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *t1,
 230                            const struct v4l2_dv_timings *t2,
 231                            unsigned pclock_delta)
 232 {
 233         if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120)
 234                 return false;
 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)))
 249                 return true;
 250         return false;
 251 }
 252 EXPORT_SYMBOL_GPL(v4l2_match_dv_timings);
 253
 254 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix,
 255                            const struct v4l2_dv_timings *t, bool detailed)
 256 {
 257         const struct v4l2_bt_timings *bt = &t->bt;
 258         u32 htot, vtot;
 259
 260         if (t->type != V4L2_DV_BT_656_1120)
 261                 return;
 262
 263         htot = V4L2_DV_BT_FRAME_WIDTH(bt);
 264         vtot = V4L2_DV_BT_FRAME_HEIGHT(bt);
 265
 266         if (prefix == NULL)
 267                 prefix = "";
 268
 269         pr_info("%s: %s%ux%u%s%u (%ux%u)\n", dev_prefix, prefix,
 270                 bt->width, bt->height, bt->interlaced ? "i" : "p",
 271                 (htot * vtot) > 0 ? ((u32)bt->pixelclock / (htot * vtot)) : 0,
 272                 htot, vtot);
 273
 274         if (!detailed)
 275                 return;
 276
 277         pr_info("%s: horizontal: fp = %u, %ssync = %u, bp = %u\n",
 278                         dev_prefix, bt->hfrontporch,
 279                         (bt->polarities & V4L2_DV_HSYNC_POS_POL) ? "+" : "-",
 280                         bt->hsync, bt->hbackporch);
 281         pr_info("%s: vertical: fp = %u, %ssync = %u, bp = %u\n",
 282                         dev_prefix, bt->vfrontporch,
 283                         (bt->polarities & V4L2_DV_VSYNC_POS_POL) ? "+" : "-",
 284                         bt->vsync, bt->vbackporch);
 285         pr_info("%s: pixelclock: %llu\n", dev_prefix, bt->pixelclock);
 286         pr_info("%s: flags (0x%x):%s%s%s%s%s\n", dev_prefix, bt->flags,
 287                         (bt->flags & V4L2_DV_FL_REDUCED_BLANKING) ?
 288                         " REDUCED_BLANKING" : "",
 289                         (bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS) ?
 290                         " CAN_REDUCE_FPS" : "",
 291                         (bt->flags & V4L2_DV_FL_REDUCED_FPS) ?
 292                         " REDUCED_FPS" : "",
 293                         (bt->flags & V4L2_DV_FL_HALF_LINE) ?
 294                         " HALF_LINE" : "",
 295                         (bt->flags & V4L2_DV_FL_IS_CE_VIDEO) ?
 296                         " CE_VIDEO" : "");
 297         pr_info("%s: standards (0x%x):%s%s%s%s\n", dev_prefix, bt->standards,
 298                         (bt->standards & V4L2_DV_BT_STD_CEA861) ?  " CEA" : "",
 299                         (bt->standards & V4L2_DV_BT_STD_DMT) ?  " DMT" : "",
 300                         (bt->standards & V4L2_DV_BT_STD_CVT) ?  " CVT" : "",
 301                         (bt->standards & V4L2_DV_BT_STD_GTF) ?  " GTF" : "");
 302 }
 303 EXPORT_SYMBOL_GPL(v4l2_print_dv_timings);
 304
 305 /*
 306  * CVT defines
 307  * Based on Coordinated Video Timings Standard
 308  * version 1.1 September 10, 2003
 309  */
 310
 311 #define CVT_PXL_CLK_GRAN        250000  /* pixel clock granularity */
 312
 313 /* Normal blanking */
 314 #define CVT_MIN_V_BPORCH        7       /* lines */
 315 #define CVT_MIN_V_PORCH_RND     3       /* lines */
 316 #define CVT_MIN_VSYNC_BP        550     /* min time of vsync + back porch (us) */
 317 #define CVT_HSYNC_PERCENT       8       /* nominal hsync as percentage of line */
 318
 319 /* Normal blanking for CVT uses GTF to calculate horizontal blanking */
 320 #define CVT_CELL_GRAN           8       /* character cell granularity */
 321 #define CVT_M                   600     /* blanking formula gradient */
 322 #define CVT_C                   40      /* blanking formula offset */
 323 #define CVT_K                   128     /* blanking formula scaling factor */
 324 #define CVT_J                   20      /* blanking formula scaling factor */
 325 #define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
 326 #define CVT_M_PRIME (CVT_K * CVT_M / 256)
 327
 328 /* Reduced Blanking */
 329 #define CVT_RB_MIN_V_BPORCH    7       /* lines  */
 330 #define CVT_RB_V_FPORCH        3       /* lines  */
 331 #define CVT_RB_MIN_V_BLANK   460     /* us     */
 332 #define CVT_RB_H_SYNC         32       /* pixels */
 333 #define CVT_RB_H_BPORCH       80       /* pixels */
 334 #define CVT_RB_H_BLANK       160       /* pixels */
 335
 336 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
 337  * @frame_height - the total height of the frame (including blanking) in lines.
 338  * @hfreq - the horizontal frequency in Hz.
 339  * @vsync - the height of the vertical sync in lines.
 340  * @polarities - the horizontal and vertical polarities (same as struct
 341  *              v4l2_bt_timings polarities).
 342  * @fmt - the resulting timings.
 343  *
 344  * This function will attempt to detect if the given values correspond to a
 345  * valid CVT format. If so, then it will return true, and fmt will be filled
 346  * in with the found CVT timings.
 347  *
 348  * TODO: VESA defined a new version 2 of their reduced blanking
 349  * formula. Support for that is currently missing in this CVT
 350  * detection function.
 351  */
 352 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
 353                 u32 polarities, struct v4l2_dv_timings *fmt)
 354 {
 355         int  v_fp, v_bp, h_fp, h_bp, hsync;
 356         int  frame_width, image_height, image_width;
 357         bool reduced_blanking;
 358         unsigned pix_clk;
 359
 360         if (vsync < 4 || vsync > 7)
 361                 return false;
 362
 363         if (polarities == V4L2_DV_VSYNC_POS_POL)
 364                 reduced_blanking = false;
 365         else if (polarities == V4L2_DV_HSYNC_POS_POL)
 366                 reduced_blanking = true;
 367         else
 368                 return false;
 369
 370         if (hfreq == 0)
 371                 return false;
 372
 373         /* Vertical */
 374         if (reduced_blanking) {
 375                 v_fp = CVT_RB_V_FPORCH;
 376                 v_bp = (CVT_RB_MIN_V_BLANK * hfreq) / 1000000 + 1;
 377                 v_bp -= vsync + v_fp;
 378
 379                 if (v_bp < CVT_RB_MIN_V_BPORCH)
 380                         v_bp = CVT_RB_MIN_V_BPORCH;
 381         } else {
 382                 v_fp = CVT_MIN_V_PORCH_RND;
 383                 v_bp = (CVT_MIN_VSYNC_BP * hfreq) / 1000000 + 1 - vsync;
 384
 385                 if (v_bp < CVT_MIN_V_BPORCH)
 386                         v_bp = CVT_MIN_V_BPORCH;
 387         }
 388         image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
 389
 390         if (image_height < 0)
 391                 return false;
 392
 393         /* Aspect ratio based on vsync */
 394         switch (vsync) {
 395         case 4:
 396                 image_width = (image_height * 4) / 3;
 397                 break;
 398         case 5:
 399                 image_width = (image_height * 16) / 9;
 400                 break;
 401         case 6:
 402                 image_width = (image_height * 16) / 10;
 403                 break;
 404         case 7:
 405                 /* special case */
 406                 if (image_height == 1024)
 407                         image_width = (image_height * 5) / 4;
 408                 else if (image_height == 768)
 409                         image_width = (image_height * 15) / 9;
 410                 else
 411                         return false;
 412                 break;
 413         default:
 414                 return false;
 415         }
 416
 417         image_width = image_width & ~7;
 418
 419         /* Horizontal */
 420         if (reduced_blanking) {
 421                 pix_clk = (image_width + CVT_RB_H_BLANK) * hfreq;
 422                 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
 423
 424                 h_bp = CVT_RB_H_BPORCH;
 425                 hsync = CVT_RB_H_SYNC;
 426                 h_fp = CVT_RB_H_BLANK - h_bp - hsync;
 427
 428                 frame_width = image_width + CVT_RB_H_BLANK;
 429         } else {
 430                 unsigned ideal_duty_cycle_per_myriad =
 431                         100 * CVT_C_PRIME - (CVT_M_PRIME * 100000) / hfreq;
 432                 int h_blank;
 433
 434                 if (ideal_duty_cycle_per_myriad < 2000)
 435                         ideal_duty_cycle_per_myriad = 2000;
 436
 437                 h_blank = image_width * ideal_duty_cycle_per_myriad /
 438                                         (10000 - ideal_duty_cycle_per_myriad);
 439                 h_blank = (h_blank / (2 * CVT_CELL_GRAN)) * 2 * CVT_CELL_GRAN;
 440
 441                 pix_clk = (image_width + h_blank) * hfreq;
 442                 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
 443
 444                 h_bp = h_blank / 2;
 445                 frame_width = image_width + h_blank;
 446
 447                 hsync = frame_width * CVT_HSYNC_PERCENT / 100;
 448                 hsync = (hsync / CVT_CELL_GRAN) * CVT_CELL_GRAN;
 449                 h_fp = h_blank - hsync - h_bp;
 450         }
 451
 452         fmt->type = V4L2_DV_BT_656_1120;
 453         fmt->bt.polarities = polarities;
 454         fmt->bt.width = image_width;
 455         fmt->bt.height = image_height;
 456         fmt->bt.hfrontporch = h_fp;
 457         fmt->bt.vfrontporch = v_fp;
 458         fmt->bt.hsync = hsync;
 459         fmt->bt.vsync = vsync;
 460         fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
 461         fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
 462         fmt->bt.pixelclock = pix_clk;
 463         fmt->bt.standards = V4L2_DV_BT_STD_CVT;
 464         if (reduced_blanking)
 465                 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
 466         return true;
 467 }
 468 EXPORT_SYMBOL_GPL(v4l2_detect_cvt);
 469
 470 /*
 471  * GTF defines
 472  * Based on Generalized Timing Formula Standard
 473  * Version 1.1 September 2, 1999
 474  */
 475
 476 #define GTF_PXL_CLK_GRAN        250000  /* pixel clock granularity */
 477
 478 #define GTF_MIN_VSYNC_BP        550     /* min time of vsync + back porch (us) */
 479 #define GTF_V_FP                1       /* vertical front porch (lines) */
 480 #define GTF_CELL_GRAN           8       /* character cell granularity */
 481
 482 /* Default */
 483 #define GTF_D_M                 600     /* blanking formula gradient */
 484 #define GTF_D_C                 40      /* blanking formula offset */
 485 #define GTF_D_K                 128     /* blanking formula scaling factor */
 486 #define GTF_D_J                 20      /* blanking formula scaling factor */
 487 #define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
 488 #define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)
 489
 490 /* Secondary */
 491 #define GTF_S_M                 3600    /* blanking formula gradient */
 492 #define GTF_S_C                 40      /* blanking formula offset */
 493 #define GTF_S_K                 128     /* blanking formula scaling factor */
 494 #define GTF_S_J                 35      /* blanking formula scaling factor */
 495 #define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
 496 #define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)
 497
 498 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
 499  * @frame_height - the total height of the frame (including blanking) in lines.
 500  * @hfreq - the horizontal frequency in Hz.
 501  * @vsync - the height of the vertical sync in lines.
 502  * @polarities - the horizontal and vertical polarities (same as struct
 503  *              v4l2_bt_timings polarities).
 504  * @aspect - preferred aspect ratio. GTF has no method of determining the
 505  *              aspect ratio in order to derive the image width from the
 506  *              image height, so it has to be passed explicitly. Usually
 507  *              the native screen aspect ratio is used for this. If it
 508  *              is not filled in correctly, then 16:9 will be assumed.
 509  * @fmt - the resulting timings.
 510  *
 511  * This function will attempt to detect if the given values correspond to a
 512  * valid GTF format. If so, then it will return true, and fmt will be filled
 513  * in with the found GTF timings.
 514  */
 515 bool v4l2_detect_gtf(unsigned frame_height,
 516                 unsigned hfreq,
 517                 unsigned vsync,
 518                 u32 polarities,
 519                 struct v4l2_fract aspect,
 520                 struct v4l2_dv_timings *fmt)
 521 {
 522         int pix_clk;
 523         int  v_fp, v_bp, h_fp, hsync;
 524         int frame_width, image_height, image_width;
 525         bool default_gtf;
 526         int h_blank;
 527
 528         if (vsync != 3)
 529                 return false;
 530
 531         if (polarities == V4L2_DV_VSYNC_POS_POL)
 532                 default_gtf = true;
 533         else if (polarities == V4L2_DV_HSYNC_POS_POL)
 534                 default_gtf = false;
 535         else
 536                 return false;
 537
 538         if (hfreq == 0)
 539                 return false;
 540
 541         /* Vertical */
 542         v_fp = GTF_V_FP;
 543
 544         v_bp = (GTF_MIN_VSYNC_BP * hfreq + 500000) / 1000000 - vsync;
 545         image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
 546
 547         if (image_height < 0)
 548                 return false;
 549
 550         if (aspect.numerator == 0 || aspect.denominator == 0) {
 551                 aspect.numerator = 16;
 552                 aspect.denominator = 9;
 553         }
 554         image_width = ((image_height * aspect.numerator) / aspect.denominator);
 555         image_width = (image_width + GTF_CELL_GRAN/2) & ~(GTF_CELL_GRAN - 1);
 556
 557         /* Horizontal */
 558         if (default_gtf) {
 559                 u64 num;
 560                 u32 den;
 561
 562                 num = ((image_width * GTF_D_C_PRIME * (u64)hfreq) -
 563                       ((u64)image_width * GTF_D_M_PRIME * 1000));
 564                 den = hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000;
 565                 h_blank = div_u64((num + (den >> 1)), den);
 566         } else {
 567                 u64 num;
 568                 u32 den;
 569
 570                 num = ((image_width * GTF_S_C_PRIME * (u64)hfreq) -
 571                       ((u64)image_width * GTF_S_M_PRIME * 1000));
 572                 den = hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000;
 573                 h_blank = div_u64((num + (den >> 1)), den);
 574         }
 575
 576         h_blank = ((h_blank + GTF_CELL_GRAN) / (2 * GTF_CELL_GRAN)) *
 577                   (2 * GTF_CELL_GRAN);
 578         frame_width = image_width + h_blank;
 579
 580         pix_clk = (image_width + h_blank) * hfreq;
 581         pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;
 582
 583         hsync = (frame_width * 8 + 50) / 100;
 584         hsync = ((hsync + GTF_CELL_GRAN / 2) / GTF_CELL_GRAN) * GTF_CELL_GRAN;
 585
 586         h_fp = h_blank / 2 - hsync;
 587
 588         fmt->type = V4L2_DV_BT_656_1120;
 589         fmt->bt.polarities = polarities;
 590         fmt->bt.width = image_width;
 591         fmt->bt.height = image_height;
 592         fmt->bt.hfrontporch = h_fp;
 593         fmt->bt.vfrontporch = v_fp;
 594         fmt->bt.hsync = hsync;
 595         fmt->bt.vsync = vsync;
 596         fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
 597         fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
 598         fmt->bt.pixelclock = pix_clk;
 599         fmt->bt.standards = V4L2_DV_BT_STD_GTF;
 600         if (!default_gtf)
 601                 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
 602         return true;
 603 }
 604 EXPORT_SYMBOL_GPL(v4l2_detect_gtf);
 605
 606 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
 607  *      0x15 and 0x16 from the EDID.
 608  * @hor_landscape - byte 0x15 from the EDID.
 609  * @vert_portrait - byte 0x16 from the EDID.
 610  *
 611  * Determines the aspect ratio from the EDID.
 612  * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
 613  * "Horizontal and Vertical Screen Size or Aspect Ratio"
 614  */
 615 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait)
 616 {
 617         struct v4l2_fract aspect = { 16, 9 };
 618         u32 tmp;
 619         u8 ratio;
 620
 621         /* Nothing filled in, fallback to 16:9 */
 622         if (!hor_landscape && !vert_portrait)
 623                 return aspect;
 624         /* Both filled in, so they are interpreted as the screen size in cm */
 625         if (hor_landscape && vert_portrait) {
 626                 aspect.numerator = hor_landscape;
 627                 aspect.denominator = vert_portrait;
 628                 return aspect;
 629         }
 630         /* Only one is filled in, so interpret them as a ratio:
 631            (val + 99) / 100 */
 632         ratio = hor_landscape | vert_portrait;
 633         /* Change some rounded values into the exact aspect ratio */
 634         if (ratio == 79) {
 635                 aspect.numerator = 16;
 636                 aspect.denominator = 9;
 637         } else if (ratio == 34) {
 638                 aspect.numerator = 4;
 639                 aspect.denominator = 3;
 640         } else if (ratio == 68) {
 641                 aspect.numerator = 15;
 642                 aspect.denominator = 9;
 643         } else {
 644                 aspect.numerator = hor_landscape + 99;
 645                 aspect.denominator = 100;
 646         }
 647         if (hor_landscape)
 648                 return aspect;
 649         /* The aspect ratio is for portrait, so swap numerator and denominator */
 650         tmp = aspect.denominator;
 651         aspect.denominator = aspect.numerator;
 652         aspect.numerator = tmp;
 653         return aspect;
 654 }
 655 EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio);