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 29 MODULE_AUTHOR("Hans Verkuil"); 30 MODULE_DESCRIPTION("V4L2 DV Timings Helper Functions"); 31 MODULE_LICENSE("GPL"); 32 33 const struct v4l2_dv_timings v4l2_dv_timings_presets[] = { 34 V4L2_DV_BT_CEA_640X480P59_94, 35 V4L2_DV_BT_CEA_720X480I59_94, 36 V4L2_DV_BT_CEA_720X480P59_94, 37 V4L2_DV_BT_CEA_720X576I50, 38 V4L2_DV_BT_CEA_720X576P50, 39 V4L2_DV_BT_CEA_1280X720P24, 40 V4L2_DV_BT_CEA_1280X720P25, 41 V4L2_DV_BT_CEA_1280X720P30, 42 V4L2_DV_BT_CEA_1280X720P50, 43 V4L2_DV_BT_CEA_1280X720P60, 44 V4L2_DV_BT_CEA_1920X1080P24, 45 V4L2_DV_BT_CEA_1920X1080P25, 46 V4L2_DV_BT_CEA_1920X1080P30, 47 V4L2_DV_BT_CEA_1920X1080I50, 48 V4L2_DV_BT_CEA_1920X1080P50, 49 V4L2_DV_BT_CEA_1920X1080I60, 50 V4L2_DV_BT_CEA_1920X1080P60, 51 V4L2_DV_BT_DMT_640X350P85, 52 V4L2_DV_BT_DMT_640X400P85, 53 V4L2_DV_BT_DMT_720X400P85, 54 V4L2_DV_BT_DMT_640X480P72, 55 V4L2_DV_BT_DMT_640X480P75, 56 V4L2_DV_BT_DMT_640X480P85, 57 V4L2_DV_BT_DMT_800X600P56, 58 V4L2_DV_BT_DMT_800X600P60, 59 V4L2_DV_BT_DMT_800X600P72, 60 V4L2_DV_BT_DMT_800X600P75, 61 V4L2_DV_BT_DMT_800X600P85, 62 V4L2_DV_BT_DMT_800X600P120_RB, 63 V4L2_DV_BT_DMT_848X480P60, 64 V4L2_DV_BT_DMT_1024X768I43, 65 V4L2_DV_BT_DMT_1024X768P60, 66 V4L2_DV_BT_DMT_1024X768P70, 67 V4L2_DV_BT_DMT_1024X768P75, 68 V4L2_DV_BT_DMT_1024X768P85, 69 V4L2_DV_BT_DMT_1024X768P120_RB, 70 V4L2_DV_BT_DMT_1152X864P75, 71 V4L2_DV_BT_DMT_1280X768P60_RB, 72 V4L2_DV_BT_DMT_1280X768P60, 73 V4L2_DV_BT_DMT_1280X768P75, 74 V4L2_DV_BT_DMT_1280X768P85, 75 V4L2_DV_BT_DMT_1280X768P120_RB, 76 V4L2_DV_BT_DMT_1280X800P60_RB, 77 V4L2_DV_BT_DMT_1280X800P60, 78 V4L2_DV_BT_DMT_1280X800P75, 79 V4L2_DV_BT_DMT_1280X800P85, 80 V4L2_DV_BT_DMT_1280X800P120_RB, 81 V4L2_DV_BT_DMT_1280X960P60, 82 V4L2_DV_BT_DMT_1280X960P85, 83 V4L2_DV_BT_DMT_1280X960P120_RB, 84 V4L2_DV_BT_DMT_1280X1024P60, 85 V4L2_DV_BT_DMT_1280X1024P75, 86 V4L2_DV_BT_DMT_1280X1024P85, 87 V4L2_DV_BT_DMT_1280X1024P120_RB, 88 V4L2_DV_BT_DMT_1360X768P60, 89 V4L2_DV_BT_DMT_1360X768P120_RB, 90 V4L2_DV_BT_DMT_1366X768P60, 91 V4L2_DV_BT_DMT_1366X768P60_RB, 92 V4L2_DV_BT_DMT_1400X1050P60_RB, 93 V4L2_DV_BT_DMT_1400X1050P60, 94 V4L2_DV_BT_DMT_1400X1050P75, 95 V4L2_DV_BT_DMT_1400X1050P85, 96 V4L2_DV_BT_DMT_1400X1050P120_RB, 97 V4L2_DV_BT_DMT_1440X900P60_RB, 98 V4L2_DV_BT_DMT_1440X900P60, 99 V4L2_DV_BT_DMT_1440X900P75, 100 V4L2_DV_BT_DMT_1440X900P85, 101 V4L2_DV_BT_DMT_1440X900P120_RB, 102 V4L2_DV_BT_DMT_1600X900P60_RB, 103 V4L2_DV_BT_DMT_1600X1200P60, 104 V4L2_DV_BT_DMT_1600X1200P65, 105 V4L2_DV_BT_DMT_1600X1200P70, 106 V4L2_DV_BT_DMT_1600X1200P75, 107 V4L2_DV_BT_DMT_1600X1200P85, 108 V4L2_DV_BT_DMT_1600X1200P120_RB, 109 V4L2_DV_BT_DMT_1680X1050P60_RB, 110 V4L2_DV_BT_DMT_1680X1050P60, 111 V4L2_DV_BT_DMT_1680X1050P75, 112 V4L2_DV_BT_DMT_1680X1050P85, 113 V4L2_DV_BT_DMT_1680X1050P120_RB, 114 V4L2_DV_BT_DMT_1792X1344P60, 115 V4L2_DV_BT_DMT_1792X1344P75, 116 V4L2_DV_BT_DMT_1792X1344P120_RB, 117 V4L2_DV_BT_DMT_1856X1392P60, 118 V4L2_DV_BT_DMT_1856X1392P75, 119 V4L2_DV_BT_DMT_1856X1392P120_RB, 120 V4L2_DV_BT_DMT_1920X1200P60_RB, 121 V4L2_DV_BT_DMT_1920X1200P60, 122 V4L2_DV_BT_DMT_1920X1200P75, 123 V4L2_DV_BT_DMT_1920X1200P85, 124 V4L2_DV_BT_DMT_1920X1200P120_RB, 125 V4L2_DV_BT_DMT_1920X1440P60, 126 V4L2_DV_BT_DMT_1920X1440P75, 127 V4L2_DV_BT_DMT_1920X1440P120_RB, 128 V4L2_DV_BT_DMT_2048X1152P60_RB, 129 V4L2_DV_BT_DMT_2560X1600P60_RB, 130 V4L2_DV_BT_DMT_2560X1600P60, 131 V4L2_DV_BT_DMT_2560X1600P75, 132 V4L2_DV_BT_DMT_2560X1600P85, 133 V4L2_DV_BT_DMT_2560X1600P120_RB, 134 V4L2_DV_BT_CEA_3840X2160P24, 135 V4L2_DV_BT_CEA_3840X2160P25, 136 V4L2_DV_BT_CEA_3840X2160P30, 137 V4L2_DV_BT_CEA_3840X2160P50, 138 V4L2_DV_BT_CEA_3840X2160P60, 139 V4L2_DV_BT_CEA_4096X2160P24, 140 V4L2_DV_BT_CEA_4096X2160P25, 141 V4L2_DV_BT_CEA_4096X2160P30, 142 V4L2_DV_BT_CEA_4096X2160P50, 143 V4L2_DV_BT_DMT_4096X2160P59_94_RB, 144 V4L2_DV_BT_CEA_4096X2160P60, 145 { } 146 }; 147 EXPORT_SYMBOL_GPL(v4l2_dv_timings_presets); 148 149 bool v4l2_valid_dv_timings(const struct v4l2_dv_timings *t, 150 const struct v4l2_dv_timings_cap *dvcap, 151 v4l2_check_dv_timings_fnc fnc, 152 void *fnc_handle) 153 { 154 const struct v4l2_bt_timings *bt = &t->bt; 155 const struct v4l2_bt_timings_cap *cap = &dvcap->bt; 156 u32 caps = cap->capabilities; 157 158 if (t->type != V4L2_DV_BT_656_1120) 159 return false; 160 if (t->type != dvcap->type || 161 bt->height < cap->min_height || 162 bt->height > cap->max_height || 163 bt->width < cap->min_width || 164 bt->width > cap->max_width || 165 bt->pixelclock < cap->min_pixelclock || 166 bt->pixelclock > cap->max_pixelclock || 167 (cap->standards && bt->standards && 168 !(bt->standards & cap->standards)) || 169 (bt->interlaced && !(caps & V4L2_DV_BT_CAP_INTERLACED)) || 170 (!bt->interlaced && !(caps & V4L2_DV_BT_CAP_PROGRESSIVE))) 171 return false; 172 return fnc == NULL || fnc(t, fnc_handle); 173 } 174 EXPORT_SYMBOL_GPL(v4l2_valid_dv_timings); 175 176 int v4l2_enum_dv_timings_cap(struct v4l2_enum_dv_timings *t, 177 const struct v4l2_dv_timings_cap *cap, 178 v4l2_check_dv_timings_fnc fnc, 179 void *fnc_handle) 180 { 181 u32 i, idx; 182 183 memset(t->reserved, 0, sizeof(t->reserved)); 184 for (i = idx = 0; v4l2_dv_timings_presets[i].bt.width; i++) { 185 if (v4l2_valid_dv_timings(v4l2_dv_timings_presets + i, cap, 186 fnc, fnc_handle) && 187 idx++ == t->index) { 188 t->timings = v4l2_dv_timings_presets[i]; 189 return 0; 190 } 191 } 192 return -EINVAL; 193 } 194 EXPORT_SYMBOL_GPL(v4l2_enum_dv_timings_cap); 195 196 bool v4l2_find_dv_timings_cap(struct v4l2_dv_timings *t, 197 const struct v4l2_dv_timings_cap *cap, 198 unsigned pclock_delta, 199 v4l2_check_dv_timings_fnc fnc, 200 void *fnc_handle) 201 { 202 int i; 203 204 if (!v4l2_valid_dv_timings(t, cap, fnc, fnc_handle)) 205 return false; 206 207 for (i = 0; i < v4l2_dv_timings_presets[i].bt.width; i++) { 208 if (v4l2_valid_dv_timings(v4l2_dv_timings_presets + i, cap, 209 fnc, fnc_handle) && 210 v4l2_match_dv_timings(t, v4l2_dv_timings_presets + i, 211 pclock_delta)) { 212 *t = v4l2_dv_timings_presets[i]; 213 return true; 214 } 215 } 216 return false; 217 } 218 EXPORT_SYMBOL_GPL(v4l2_find_dv_timings_cap); 219 220 /** 221 * v4l2_match_dv_timings - check if two timings match 222 * @t1 - compare this v4l2_dv_timings struct... 223 * @t2 - with this struct. 224 * @pclock_delta - the allowed pixelclock deviation. 225 * 226 * Compare t1 with t2 with a given margin of error for the pixelclock. 227 */ 228 bool v4l2_match_dv_timings(const struct v4l2_dv_timings *t1, 229 const struct v4l2_dv_timings *t2, 230 unsigned pclock_delta) 231 { 232 if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120) 233 return false; 234 if (t1->bt.width == t2->bt.width && 235 t1->bt.height == t2->bt.height && 236 t1->bt.interlaced == t2->bt.interlaced && 237 t1->bt.polarities == t2->bt.polarities && 238 t1->bt.pixelclock >= t2->bt.pixelclock - pclock_delta && 239 t1->bt.pixelclock <= t2->bt.pixelclock + pclock_delta && 240 t1->bt.hfrontporch == t2->bt.hfrontporch && 241 t1->bt.vfrontporch == t2->bt.vfrontporch && 242 t1->bt.vsync == t2->bt.vsync && 243 t1->bt.vbackporch == t2->bt.vbackporch && 244 (!t1->bt.interlaced || 245 (t1->bt.il_vfrontporch == t2->bt.il_vfrontporch && 246 t1->bt.il_vsync == t2->bt.il_vsync && 247 t1->bt.il_vbackporch == t2->bt.il_vbackporch))) 248 return true; 249 return false; 250 } 251 EXPORT_SYMBOL_GPL(v4l2_match_dv_timings); 252 253 void v4l2_print_dv_timings(const char *dev_prefix, const char *prefix, 254 const struct v4l2_dv_timings *t, bool detailed) 255 { 256 const struct v4l2_bt_timings *bt = &t->bt; 257 u32 htot, vtot; 258 259 if (t->type != V4L2_DV_BT_656_1120) 260 return; 261 262 htot = V4L2_DV_BT_FRAME_WIDTH(bt); 263 vtot = V4L2_DV_BT_FRAME_HEIGHT(bt); 264 265 if (prefix == NULL) 266 prefix = ""; 267 268 pr_info("%s: %s%ux%u%s%u (%ux%u)\n", dev_prefix, prefix, 269 bt->width, bt->height, bt->interlaced ? "i" : "p", 270 (htot * vtot) > 0 ? ((u32)bt->pixelclock / (htot * vtot)) : 0, 271 htot, vtot); 272 273 if (!detailed) 274 return; 275 276 pr_info("%s: horizontal: fp = %u, %ssync = %u, bp = %u\n", 277 dev_prefix, bt->hfrontporch, 278 (bt->polarities & V4L2_DV_HSYNC_POS_POL) ? "+" : "-", 279 bt->hsync, bt->hbackporch); 280 pr_info("%s: vertical: fp = %u, %ssync = %u, bp = %u\n", 281 dev_prefix, bt->vfrontporch, 282 (bt->polarities & V4L2_DV_VSYNC_POS_POL) ? "+" : "-", 283 bt->vsync, bt->vbackporch); 284 pr_info("%s: pixelclock: %llu\n", dev_prefix, bt->pixelclock); 285 pr_info("%s: flags (0x%x):%s%s%s%s\n", dev_prefix, bt->flags, 286 (bt->flags & V4L2_DV_FL_REDUCED_BLANKING) ? 287 " REDUCED_BLANKING" : "", 288 (bt->flags & V4L2_DV_FL_CAN_REDUCE_FPS) ? 289 " CAN_REDUCE_FPS" : "", 290 (bt->flags & V4L2_DV_FL_REDUCED_FPS) ? 291 " REDUCED_FPS" : "", 292 (bt->flags & V4L2_DV_FL_HALF_LINE) ? 293 " HALF_LINE" : ""); 294 pr_info("%s: standards (0x%x):%s%s%s%s\n", dev_prefix, bt->standards, 295 (bt->standards & V4L2_DV_BT_STD_CEA861) ? " CEA" : "", 296 (bt->standards & V4L2_DV_BT_STD_DMT) ? " DMT" : "", 297 (bt->standards & V4L2_DV_BT_STD_CVT) ? " CVT" : "", 298 (bt->standards & V4L2_DV_BT_STD_GTF) ? " GTF" : ""); 299 } 300 EXPORT_SYMBOL_GPL(v4l2_print_dv_timings); 301 302 /* 303 * CVT defines 304 * Based on Coordinated Video Timings Standard 305 * version 1.1 September 10, 2003 306 */ 307 308 #define CVT_PXL_CLK_GRAN 250000 /* pixel clock granularity */ 309 310 /* Normal blanking */ 311 #define CVT_MIN_V_BPORCH 7 /* lines */ 312 #define CVT_MIN_V_PORCH_RND 3 /* lines */ 313 #define CVT_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */ 314 315 /* Normal blanking for CVT uses GTF to calculate horizontal blanking */ 316 #define CVT_CELL_GRAN 8 /* character cell granularity */ 317 #define CVT_M 600 /* blanking formula gradient */ 318 #define CVT_C 40 /* blanking formula offset */ 319 #define CVT_K 128 /* blanking formula scaling factor */ 320 #define CVT_J 20 /* blanking formula scaling factor */ 321 #define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J) 322 #define CVT_M_PRIME (CVT_K * CVT_M / 256) 323 324 /* Reduced Blanking */ 325 #define CVT_RB_MIN_V_BPORCH 7 /* lines */ 326 #define CVT_RB_V_FPORCH 3 /* lines */ 327 #define CVT_RB_MIN_V_BLANK 460 /* us */ 328 #define CVT_RB_H_SYNC 32 /* pixels */ 329 #define CVT_RB_H_BPORCH 80 /* pixels */ 330 #define CVT_RB_H_BLANK 160 /* pixels */ 331 332 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard 333 * @frame_height - the total height of the frame (including blanking) in lines. 334 * @hfreq - the horizontal frequency in Hz. 335 * @vsync - the height of the vertical sync in lines. 336 * @polarities - the horizontal and vertical polarities (same as struct 337 * v4l2_bt_timings polarities). 338 * @fmt - the resulting timings. 339 * 340 * This function will attempt to detect if the given values correspond to a 341 * valid CVT format. If so, then it will return true, and fmt will be filled 342 * in with the found CVT timings. 343 * 344 * TODO: VESA defined a new version 2 of their reduced blanking 345 * formula. Support for that is currently missing in this CVT 346 * detection function. 347 */ 348 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync, 349 u32 polarities, struct v4l2_dv_timings *fmt) 350 { 351 int v_fp, v_bp, h_fp, h_bp, hsync; 352 int frame_width, image_height, image_width; 353 bool reduced_blanking; 354 unsigned pix_clk; 355 356 if (vsync < 4 || vsync > 7) 357 return false; 358 359 if (polarities == V4L2_DV_VSYNC_POS_POL) 360 reduced_blanking = false; 361 else if (polarities == V4L2_DV_HSYNC_POS_POL) 362 reduced_blanking = true; 363 else 364 return false; 365 366 /* Vertical */ 367 if (reduced_blanking) { 368 v_fp = CVT_RB_V_FPORCH; 369 v_bp = (CVT_RB_MIN_V_BLANK * hfreq + 1999999) / 1000000; 370 v_bp -= vsync + v_fp; 371 372 if (v_bp < CVT_RB_MIN_V_BPORCH) 373 v_bp = CVT_RB_MIN_V_BPORCH; 374 } else { 375 v_fp = CVT_MIN_V_PORCH_RND; 376 v_bp = (CVT_MIN_VSYNC_BP * hfreq + 1999999) / 1000000 - vsync; 377 378 if (v_bp < CVT_MIN_V_BPORCH) 379 v_bp = CVT_MIN_V_BPORCH; 380 } 381 image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1; 382 383 /* Aspect ratio based on vsync */ 384 switch (vsync) { 385 case 4: 386 image_width = (image_height * 4) / 3; 387 break; 388 case 5: 389 image_width = (image_height * 16) / 9; 390 break; 391 case 6: 392 image_width = (image_height * 16) / 10; 393 break; 394 case 7: 395 /* special case */ 396 if (image_height == 1024) 397 image_width = (image_height * 5) / 4; 398 else if (image_height == 768) 399 image_width = (image_height * 15) / 9; 400 else 401 return false; 402 break; 403 default: 404 return false; 405 } 406 407 image_width = image_width & ~7; 408 409 /* Horizontal */ 410 if (reduced_blanking) { 411 pix_clk = (image_width + CVT_RB_H_BLANK) * hfreq; 412 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN; 413 414 h_bp = CVT_RB_H_BPORCH; 415 hsync = CVT_RB_H_SYNC; 416 h_fp = CVT_RB_H_BLANK - h_bp - hsync; 417 418 frame_width = image_width + CVT_RB_H_BLANK; 419 } else { 420 unsigned ideal_duty_cycle_per_myriad = 421 100 * CVT_C_PRIME - (CVT_M_PRIME * 100000) / hfreq; 422 int h_blank; 423 424 if (ideal_duty_cycle_per_myriad < 2000) 425 ideal_duty_cycle_per_myriad = 2000; 426 427 h_blank = image_width * ideal_duty_cycle_per_myriad / 428 (10000 - ideal_duty_cycle_per_myriad); 429 h_blank = (h_blank / (2 * CVT_CELL_GRAN)) * 2 * CVT_CELL_GRAN; 430 431 pix_clk = (image_width + h_blank) * hfreq; 432 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN; 433 434 h_bp = h_blank / 2; 435 frame_width = image_width + h_blank; 436 437 hsync = (frame_width * 8 + 50) / 100; 438 hsync = hsync - hsync % CVT_CELL_GRAN; 439 h_fp = h_blank - hsync - h_bp; 440 } 441 442 fmt->type = V4L2_DV_BT_656_1120; 443 fmt->bt.polarities = polarities; 444 fmt->bt.width = image_width; 445 fmt->bt.height = image_height; 446 fmt->bt.hfrontporch = h_fp; 447 fmt->bt.vfrontporch = v_fp; 448 fmt->bt.hsync = hsync; 449 fmt->bt.vsync = vsync; 450 fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync; 451 fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync; 452 fmt->bt.pixelclock = pix_clk; 453 fmt->bt.standards = V4L2_DV_BT_STD_CVT; 454 if (reduced_blanking) 455 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING; 456 return true; 457 } 458 EXPORT_SYMBOL_GPL(v4l2_detect_cvt); 459 460 /* 461 * GTF defines 462 * Based on Generalized Timing Formula Standard 463 * Version 1.1 September 2, 1999 464 */ 465 466 #define GTF_PXL_CLK_GRAN 250000 /* pixel clock granularity */ 467 468 #define GTF_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */ 469 #define GTF_V_FP 1 /* vertical front porch (lines) */ 470 #define GTF_CELL_GRAN 8 /* character cell granularity */ 471 472 /* Default */ 473 #define GTF_D_M 600 /* blanking formula gradient */ 474 #define GTF_D_C 40 /* blanking formula offset */ 475 #define GTF_D_K 128 /* blanking formula scaling factor */ 476 #define GTF_D_J 20 /* blanking formula scaling factor */ 477 #define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J) 478 #define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256) 479 480 /* Secondary */ 481 #define GTF_S_M 3600 /* blanking formula gradient */ 482 #define GTF_S_C 40 /* blanking formula offset */ 483 #define GTF_S_K 128 /* blanking formula scaling factor */ 484 #define GTF_S_J 35 /* blanking formula scaling factor */ 485 #define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J) 486 #define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256) 487 488 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard 489 * @frame_height - the total height of the frame (including blanking) in lines. 490 * @hfreq - the horizontal frequency in Hz. 491 * @vsync - the height of the vertical sync in lines. 492 * @polarities - the horizontal and vertical polarities (same as struct 493 * v4l2_bt_timings polarities). 494 * @aspect - preferred aspect ratio. GTF has no method of determining the 495 * aspect ratio in order to derive the image width from the 496 * image height, so it has to be passed explicitly. Usually 497 * the native screen aspect ratio is used for this. If it 498 * is not filled in correctly, then 16:9 will be assumed. 499 * @fmt - the resulting timings. 500 * 501 * This function will attempt to detect if the given values correspond to a 502 * valid GTF format. If so, then it will return true, and fmt will be filled 503 * in with the found GTF timings. 504 */ 505 bool v4l2_detect_gtf(unsigned frame_height, 506 unsigned hfreq, 507 unsigned vsync, 508 u32 polarities, 509 struct v4l2_fract aspect, 510 struct v4l2_dv_timings *fmt) 511 { 512 int pix_clk; 513 int v_fp, v_bp, h_fp, hsync; 514 int frame_width, image_height, image_width; 515 bool default_gtf; 516 int h_blank; 517 518 if (vsync != 3) 519 return false; 520 521 if (polarities == V4L2_DV_VSYNC_POS_POL) 522 default_gtf = true; 523 else if (polarities == V4L2_DV_HSYNC_POS_POL) 524 default_gtf = false; 525 else 526 return false; 527 528 /* Vertical */ 529 v_fp = GTF_V_FP; 530 v_bp = (GTF_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync; 531 image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1; 532 533 if (aspect.numerator == 0 || aspect.denominator == 0) { 534 aspect.numerator = 16; 535 aspect.denominator = 9; 536 } 537 image_width = ((image_height * aspect.numerator) / aspect.denominator); 538 image_width = (image_width + GTF_CELL_GRAN/2) & ~(GTF_CELL_GRAN - 1); 539 540 /* Horizontal */ 541 if (default_gtf) 542 h_blank = ((image_width * GTF_D_C_PRIME * hfreq) - 543 (image_width * GTF_D_M_PRIME * 1000) + 544 (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) / 2) / 545 (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000); 546 else 547 h_blank = ((image_width * GTF_S_C_PRIME * hfreq) - 548 (image_width * GTF_S_M_PRIME * 1000) + 549 (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) / 2) / 550 (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000); 551 552 h_blank = h_blank - h_blank % (2 * GTF_CELL_GRAN); 553 frame_width = image_width + h_blank; 554 555 pix_clk = (image_width + h_blank) * hfreq; 556 pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN; 557 558 hsync = (frame_width * 8 + 50) / 100; 559 hsync = hsync - hsync % GTF_CELL_GRAN; 560 561 h_fp = h_blank / 2 - hsync; 562 563 fmt->type = V4L2_DV_BT_656_1120; 564 fmt->bt.polarities = polarities; 565 fmt->bt.width = image_width; 566 fmt->bt.height = image_height; 567 fmt->bt.hfrontporch = h_fp; 568 fmt->bt.vfrontporch = v_fp; 569 fmt->bt.hsync = hsync; 570 fmt->bt.vsync = vsync; 571 fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync; 572 fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync; 573 fmt->bt.pixelclock = pix_clk; 574 fmt->bt.standards = V4L2_DV_BT_STD_GTF; 575 if (!default_gtf) 576 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING; 577 return true; 578 } 579 EXPORT_SYMBOL_GPL(v4l2_detect_gtf); 580 581 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes 582 * 0x15 and 0x16 from the EDID. 583 * @hor_landscape - byte 0x15 from the EDID. 584 * @vert_portrait - byte 0x16 from the EDID. 585 * 586 * Determines the aspect ratio from the EDID. 587 * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2: 588 * "Horizontal and Vertical Screen Size or Aspect Ratio" 589 */ 590 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait) 591 { 592 struct v4l2_fract aspect = { 16, 9 }; 593 u32 tmp; 594 u8 ratio; 595 596 /* Nothing filled in, fallback to 16:9 */ 597 if (!hor_landscape && !vert_portrait) 598 return aspect; 599 /* Both filled in, so they are interpreted as the screen size in cm */ 600 if (hor_landscape && vert_portrait) { 601 aspect.numerator = hor_landscape; 602 aspect.denominator = vert_portrait; 603 return aspect; 604 } 605 /* Only one is filled in, so interpret them as a ratio: 606 (val + 99) / 100 */ 607 ratio = hor_landscape | vert_portrait; 608 /* Change some rounded values into the exact aspect ratio */ 609 if (ratio == 79) { 610 aspect.numerator = 16; 611 aspect.denominator = 9; 612 } else if (ratio == 34) { 613 aspect.numerator = 4; 614 aspect.denominator = 3; 615 } else if (ratio == 68) { 616 aspect.numerator = 15; 617 aspect.denominator = 9; 618 } else { 619 aspect.numerator = hor_landscape + 99; 620 aspect.denominator = 100; 621 } 622 if (hor_landscape) 623 return aspect; 624 /* The aspect ratio is for portrait, so swap numerator and denominator */ 625 tmp = aspect.denominator; 626 aspect.denominator = aspect.numerator; 627 aspect.numerator = tmp; 628 return aspect; 629 } 630 EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio); 631