4 * A generic video device interface for the LINUX operating system
5 * using a set of device structures/vectors for low level operations.
7 * This file replaces the videodev.c file that comes with the
8 * regular kernel distribution.
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License
12 * as published by the Free Software Foundation; either version
13 * 2 of the License, or (at your option) any later version.
15 * Author: Bill Dirks <bill@thedirks.org>
16 * based on code by Alan Cox, <alan@cymru.net>
21 * Video capture interface for Linux
23 * A generic video device interface for the LINUX operating system
24 * using a set of device structures/vectors for low level operations.
26 * This program is free software; you can redistribute it and/or
27 * modify it under the terms of the GNU General Public License
28 * as published by the Free Software Foundation; either version
29 * 2 of the License, or (at your option) any later version.
31 * Author: Alan Cox, <alan@lxorguk.ukuu.org.uk>
37 * Video4linux 1/2 integration by Justin Schoeman
38 * <justin@suntiger.ee.up.ac.za>
39 * 2.4 PROCFS support ported from 2.4 kernels by
40 * Iñaki García Etxebarria <garetxe@euskalnet.net>
41 * Makefile fix by "W. Michael Petullo" <mike@flyn.org>
42 * 2.4 devfs support ported from 2.4 kernels by
43 * Dan Merillat <dan@merillat.org>
44 * Added Gerd Knorrs v4l1 enhancements (Justin Schoeman)
47 #include <linux/module.h>
48 #include <linux/types.h>
49 #include <linux/kernel.h>
51 #include <linux/string.h>
52 #include <linux/errno.h>
53 #include <linux/i2c.h>
54 #if defined(CONFIG_SPI)
55 #include <linux/spi/spi.h>
57 #include <asm/uaccess.h>
58 #include <asm/pgtable.h>
60 #include <asm/div64.h>
61 #include <media/v4l2-common.h>
62 #include <media/v4l2-device.h>
63 #include <media/v4l2-ctrls.h>
64 #include <media/v4l2-chip-ident.h>
66 #include <linux/videodev2.h>
68 MODULE_AUTHOR("Bill Dirks, Justin Schoeman, Gerd Knorr");
69 MODULE_DESCRIPTION("misc helper functions for v4l2 device drivers");
70 MODULE_LICENSE("GPL");
74 * V 4 L 2 D R I V E R H E L P E R A P I
79 * Video Standard Operations (contributed by Michael Schimek)
82 /* Helper functions for control handling */
84 /* Check for correctness of the ctrl's value based on the data from
85 struct v4l2_queryctrl and the available menu items. Note that
86 menu_items may be NULL, in that case it is ignored. */
87 int v4l2_ctrl_check(struct v4l2_ext_control *ctrl, struct v4l2_queryctrl *qctrl,
88 const char * const *menu_items)
90 if (qctrl->flags & V4L2_CTRL_FLAG_DISABLED)
92 if (qctrl->flags & V4L2_CTRL_FLAG_GRABBED)
94 if (qctrl->type == V4L2_CTRL_TYPE_STRING)
96 if (qctrl->type == V4L2_CTRL_TYPE_BUTTON ||
97 qctrl->type == V4L2_CTRL_TYPE_INTEGER64 ||
98 qctrl->type == V4L2_CTRL_TYPE_CTRL_CLASS)
100 if (ctrl->value < qctrl->minimum || ctrl->value > qctrl->maximum)
102 if (qctrl->type == V4L2_CTRL_TYPE_MENU && menu_items != NULL) {
103 if (menu_items[ctrl->value] == NULL ||
104 menu_items[ctrl->value][0] == '\0')
107 if (qctrl->type == V4L2_CTRL_TYPE_BITMASK &&
108 (ctrl->value & ~qctrl->maximum))
112 EXPORT_SYMBOL(v4l2_ctrl_check);
114 /* Fill in a struct v4l2_queryctrl */
115 int v4l2_ctrl_query_fill(struct v4l2_queryctrl *qctrl, s32 min, s32 max, s32 step, s32 def)
119 v4l2_ctrl_fill(qctrl->id, &name, &qctrl->type,
120 &min, &max, &step, &def, &qctrl->flags);
125 qctrl->minimum = min;
126 qctrl->maximum = max;
128 qctrl->default_value = def;
129 qctrl->reserved[0] = qctrl->reserved[1] = 0;
130 strlcpy(qctrl->name, name, sizeof(qctrl->name));
133 EXPORT_SYMBOL(v4l2_ctrl_query_fill);
135 /* Fill in a struct v4l2_querymenu based on the struct v4l2_queryctrl and
136 the menu. The qctrl pointer may be NULL, in which case it is ignored.
137 If menu_items is NULL, then the menu items are retrieved using
138 v4l2_ctrl_get_menu. */
139 int v4l2_ctrl_query_menu(struct v4l2_querymenu *qmenu, struct v4l2_queryctrl *qctrl,
140 const char * const *menu_items)
145 if (menu_items == NULL)
146 menu_items = v4l2_ctrl_get_menu(qmenu->id);
147 if (menu_items == NULL ||
148 (qctrl && (qmenu->index < qctrl->minimum || qmenu->index > qctrl->maximum)))
150 for (i = 0; i < qmenu->index && menu_items[i]; i++) ;
151 if (menu_items[i] == NULL || menu_items[i][0] == '\0')
153 strlcpy(qmenu->name, menu_items[qmenu->index], sizeof(qmenu->name));
156 EXPORT_SYMBOL(v4l2_ctrl_query_menu);
158 /* Fill in a struct v4l2_querymenu based on the specified array of valid
159 menu items (terminated by V4L2_CTRL_MENU_IDS_END).
160 Use this if there are 'holes' in the list of valid menu items. */
161 int v4l2_ctrl_query_menu_valid_items(struct v4l2_querymenu *qmenu, const u32 *ids)
163 const char * const *menu_items = v4l2_ctrl_get_menu(qmenu->id);
166 if (menu_items == NULL || ids == NULL)
168 while (*ids != V4L2_CTRL_MENU_IDS_END) {
169 if (*ids++ == qmenu->index) {
170 strlcpy(qmenu->name, menu_items[qmenu->index],
171 sizeof(qmenu->name));
177 EXPORT_SYMBOL(v4l2_ctrl_query_menu_valid_items);
179 /* ctrl_classes points to an array of u32 pointers, the last element is
180 a NULL pointer. Each u32 array is a 0-terminated array of control IDs.
181 Each array must be sorted low to high and belong to the same control
182 class. The array of u32 pointers must also be sorted, from low class IDs
185 This function returns the first ID that follows after the given ID.
186 When no more controls are available 0 is returned. */
187 u32 v4l2_ctrl_next(const u32 * const * ctrl_classes, u32 id)
189 u32 ctrl_class = V4L2_CTRL_ID2CLASS(id);
192 if (ctrl_classes == NULL)
195 /* if no query is desired, then check if the ID is part of ctrl_classes */
196 if ((id & V4L2_CTRL_FLAG_NEXT_CTRL) == 0) {
198 while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) != ctrl_class)
200 if (*ctrl_classes == NULL)
202 pctrl = *ctrl_classes;
203 /* find control ID */
204 while (*pctrl && *pctrl != id) pctrl++;
205 return *pctrl ? id : 0;
207 id &= V4L2_CTRL_ID_MASK;
208 id++; /* select next control */
209 /* find first class that matches (or is greater than) the class of
211 while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) < ctrl_class)
213 /* no more classes */
214 if (*ctrl_classes == NULL)
216 pctrl = *ctrl_classes;
217 /* find first ctrl within the class that is >= ID */
218 while (*pctrl && *pctrl < id) pctrl++;
221 /* we are at the end of the controls of the current class. */
222 /* continue with next class if available */
224 if (*ctrl_classes == NULL)
226 return **ctrl_classes;
228 EXPORT_SYMBOL(v4l2_ctrl_next);
230 int v4l2_chip_match_host(const struct v4l2_dbg_match *match)
232 switch (match->type) {
233 case V4L2_CHIP_MATCH_BRIDGE:
234 return match->addr == 0;
239 EXPORT_SYMBOL(v4l2_chip_match_host);
241 #if IS_ENABLED(CONFIG_I2C)
242 int v4l2_chip_match_i2c_client(struct i2c_client *c, const struct v4l2_dbg_match *match)
246 if (c == NULL || match == NULL)
249 switch (match->type) {
250 case V4L2_CHIP_MATCH_I2C_DRIVER:
251 if (c->driver == NULL || c->driver->driver.name == NULL)
253 len = strlen(c->driver->driver.name);
254 return len && !strncmp(c->driver->driver.name, match->name, len);
255 case V4L2_CHIP_MATCH_I2C_ADDR:
256 return c->addr == match->addr;
257 case V4L2_CHIP_MATCH_SUBDEV:
263 EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
265 int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_dbg_chip_ident *chip,
266 u32 ident, u32 revision)
268 if (!v4l2_chip_match_i2c_client(c, &chip->match))
270 if (chip->ident == V4L2_IDENT_NONE) {
272 chip->revision = revision;
275 chip->ident = V4L2_IDENT_AMBIGUOUS;
280 EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
282 /* ----------------------------------------------------------------- */
284 /* I2C Helper functions */
287 void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
288 const struct v4l2_subdev_ops *ops)
290 v4l2_subdev_init(sd, ops);
291 sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
292 /* the owner is the same as the i2c_client's driver owner */
293 sd->owner = client->driver->driver.owner;
294 /* i2c_client and v4l2_subdev point to one another */
295 v4l2_set_subdevdata(sd, client);
296 i2c_set_clientdata(client, sd);
297 /* initialize name */
298 snprintf(sd->name, sizeof(sd->name), "%s %d-%04x",
299 client->driver->driver.name, i2c_adapter_id(client->adapter),
302 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
306 /* Load an i2c sub-device. */
307 struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
308 struct i2c_adapter *adapter, struct i2c_board_info *info,
309 const unsigned short *probe_addrs)
311 struct v4l2_subdev *sd = NULL;
312 struct i2c_client *client;
316 request_module(I2C_MODULE_PREFIX "%s", info->type);
318 /* Create the i2c client */
319 if (info->addr == 0 && probe_addrs)
320 client = i2c_new_probed_device(adapter, info, probe_addrs,
323 client = i2c_new_device(adapter, info);
325 /* Note: by loading the module first we are certain that c->driver
326 will be set if the driver was found. If the module was not loaded
327 first, then the i2c core tries to delay-load the module for us,
328 and then c->driver is still NULL until the module is finally
329 loaded. This delay-load mechanism doesn't work if other drivers
330 want to use the i2c device, so explicitly loading the module
331 is the best alternative. */
332 if (client == NULL || client->driver == NULL)
335 /* Lock the module so we can safely get the v4l2_subdev pointer */
336 if (!try_module_get(client->driver->driver.owner))
338 sd = i2c_get_clientdata(client);
340 /* Register with the v4l2_device which increases the module's
341 use count as well. */
342 if (v4l2_device_register_subdev(v4l2_dev, sd))
344 /* Decrease the module use count to match the first try_module_get. */
345 module_put(client->driver->driver.owner);
348 /* If we have a client but no subdev, then something went wrong and
349 we must unregister the client. */
350 if (client && sd == NULL)
351 i2c_unregister_device(client);
354 EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);
356 struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
357 struct i2c_adapter *adapter, const char *client_type,
358 u8 addr, const unsigned short *probe_addrs)
360 struct i2c_board_info info;
362 /* Setup the i2c board info with the device type and
363 the device address. */
364 memset(&info, 0, sizeof(info));
365 strlcpy(info.type, client_type, sizeof(info.type));
368 return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info, probe_addrs);
370 EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);
372 /* Return i2c client address of v4l2_subdev. */
373 unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
375 struct i2c_client *client = v4l2_get_subdevdata(sd);
377 return client ? client->addr : I2C_CLIENT_END;
379 EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);
381 /* Return a list of I2C tuner addresses to probe. Use only if the tuner
382 addresses are unknown. */
383 const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
385 static const unsigned short radio_addrs[] = {
386 #if IS_ENABLED(CONFIG_MEDIA_TUNER_TEA5761)
392 static const unsigned short demod_addrs[] = {
393 0x42, 0x43, 0x4a, 0x4b,
396 static const unsigned short tv_addrs[] = {
397 0x42, 0x43, 0x4a, 0x4b, /* tda8290 */
398 0x60, 0x61, 0x62, 0x63, 0x64,
409 case ADDRS_TV_WITH_DEMOD:
414 EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);
416 #endif /* defined(CONFIG_I2C) */
418 #if defined(CONFIG_SPI)
420 /* Load an spi sub-device. */
422 void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
423 const struct v4l2_subdev_ops *ops)
425 v4l2_subdev_init(sd, ops);
426 sd->flags |= V4L2_SUBDEV_FL_IS_SPI;
427 /* the owner is the same as the spi_device's driver owner */
428 sd->owner = spi->dev.driver->owner;
429 /* spi_device and v4l2_subdev point to one another */
430 v4l2_set_subdevdata(sd, spi);
431 spi_set_drvdata(spi, sd);
432 /* initialize name */
433 strlcpy(sd->name, spi->dev.driver->name, sizeof(sd->name));
435 EXPORT_SYMBOL_GPL(v4l2_spi_subdev_init);
437 struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev,
438 struct spi_master *master, struct spi_board_info *info)
440 struct v4l2_subdev *sd = NULL;
441 struct spi_device *spi = NULL;
445 if (info->modalias[0])
446 request_module(info->modalias);
448 spi = spi_new_device(master, info);
450 if (spi == NULL || spi->dev.driver == NULL)
453 if (!try_module_get(spi->dev.driver->owner))
456 sd = spi_get_drvdata(spi);
458 /* Register with the v4l2_device which increases the module's
459 use count as well. */
460 if (v4l2_device_register_subdev(v4l2_dev, sd))
463 /* Decrease the module use count to match the first try_module_get. */
464 module_put(spi->dev.driver->owner);
467 /* If we have a client but no subdev, then something went wrong and
468 we must unregister the client. */
469 if (spi && sd == NULL)
470 spi_unregister_device(spi);
474 EXPORT_SYMBOL_GPL(v4l2_spi_new_subdev);
476 #endif /* defined(CONFIG_SPI) */
478 /* Clamp x to be between min and max, aligned to a multiple of 2^align. min
479 * and max don't have to be aligned, but there must be at least one valid
480 * value. E.g., min=17,max=31,align=4 is not allowed as there are no multiples
481 * of 16 between 17 and 31. */
482 static unsigned int clamp_align(unsigned int x, unsigned int min,
483 unsigned int max, unsigned int align)
485 /* Bits that must be zero to be aligned */
486 unsigned int mask = ~((1 << align) - 1);
488 /* Round to nearest aligned value */
490 x = (x + (1 << (align - 1))) & mask;
492 /* Clamp to aligned value of min and max */
494 x = (min + ~mask) & mask;
501 /* Bound an image to have a width between wmin and wmax, and height between
502 * hmin and hmax, inclusive. Additionally, the width will be a multiple of
503 * 2^walign, the height will be a multiple of 2^halign, and the overall size
504 * (width*height) will be a multiple of 2^salign. The image may be shrunk
505 * or enlarged to fit the alignment constraints.
507 * The width or height maximum must not be smaller than the corresponding
508 * minimum. The alignments must not be so high there are no possible image
509 * sizes within the allowed bounds. wmin and hmin must be at least 1
510 * (don't use 0). If you don't care about a certain alignment, specify 0,
511 * as 2^0 is 1 and one byte alignment is equivalent to no alignment. If
512 * you only want to adjust downward, specify a maximum that's the same as
515 void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
517 u32 *h, unsigned int hmin, unsigned int hmax,
518 unsigned int halign, unsigned int salign)
520 *w = clamp_align(*w, wmin, wmax, walign);
521 *h = clamp_align(*h, hmin, hmax, halign);
523 /* Usually we don't need to align the size and are done now. */
527 /* How much alignment do we have? */
530 /* Enough to satisfy the image alignment? */
531 if (walign + halign < salign) {
532 /* Max walign where there is still a valid width */
533 unsigned int wmaxa = __fls(wmax ^ (wmin - 1));
534 /* Max halign where there is still a valid height */
535 unsigned int hmaxa = __fls(hmax ^ (hmin - 1));
537 /* up the smaller alignment until we have enough */
539 if (halign >= hmaxa ||
540 (walign <= halign && walign < wmaxa)) {
541 *w = clamp_align(*w, wmin, wmax, walign + 1);
544 *h = clamp_align(*h, hmin, hmax, halign + 1);
547 } while (halign + walign < salign);
550 EXPORT_SYMBOL_GPL(v4l_bound_align_image);
553 * v4l_match_dv_timings - check if two timings match
554 * @t1 - compare this v4l2_dv_timings struct...
555 * @t2 - with this struct.
556 * @pclock_delta - the allowed pixelclock deviation.
558 * Compare t1 with t2 with a given margin of error for the pixelclock.
560 bool v4l_match_dv_timings(const struct v4l2_dv_timings *t1,
561 const struct v4l2_dv_timings *t2,
562 unsigned pclock_delta)
564 if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120)
566 if (t1->bt.width == t2->bt.width &&
567 t1->bt.height == t2->bt.height &&
568 t1->bt.interlaced == t2->bt.interlaced &&
569 t1->bt.polarities == t2->bt.polarities &&
570 t1->bt.pixelclock >= t2->bt.pixelclock - pclock_delta &&
571 t1->bt.pixelclock <= t2->bt.pixelclock + pclock_delta &&
572 t1->bt.hfrontporch == t2->bt.hfrontporch &&
573 t1->bt.vfrontporch == t2->bt.vfrontporch &&
574 t1->bt.vsync == t2->bt.vsync &&
575 t1->bt.vbackporch == t2->bt.vbackporch &&
576 (!t1->bt.interlaced ||
577 (t1->bt.il_vfrontporch == t2->bt.il_vfrontporch &&
578 t1->bt.il_vsync == t2->bt.il_vsync &&
579 t1->bt.il_vbackporch == t2->bt.il_vbackporch)))
583 EXPORT_SYMBOL_GPL(v4l_match_dv_timings);
587 * Based on Coordinated Video Timings Standard
588 * version 1.1 September 10, 2003
591 #define CVT_PXL_CLK_GRAN 250000 /* pixel clock granularity */
593 /* Normal blanking */
594 #define CVT_MIN_V_BPORCH 7 /* lines */
595 #define CVT_MIN_V_PORCH_RND 3 /* lines */
596 #define CVT_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
598 /* Normal blanking for CVT uses GTF to calculate horizontal blanking */
599 #define CVT_CELL_GRAN 8 /* character cell granularity */
600 #define CVT_M 600 /* blanking formula gradient */
601 #define CVT_C 40 /* blanking formula offset */
602 #define CVT_K 128 /* blanking formula scaling factor */
603 #define CVT_J 20 /* blanking formula scaling factor */
604 #define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
605 #define CVT_M_PRIME (CVT_K * CVT_M / 256)
607 /* Reduced Blanking */
608 #define CVT_RB_MIN_V_BPORCH 7 /* lines */
609 #define CVT_RB_V_FPORCH 3 /* lines */
610 #define CVT_RB_MIN_V_BLANK 460 /* us */
611 #define CVT_RB_H_SYNC 32 /* pixels */
612 #define CVT_RB_H_BPORCH 80 /* pixels */
613 #define CVT_RB_H_BLANK 160 /* pixels */
615 /** v4l2_detect_cvt - detect if the given timings follow the CVT standard
616 * @frame_height - the total height of the frame (including blanking) in lines.
617 * @hfreq - the horizontal frequency in Hz.
618 * @vsync - the height of the vertical sync in lines.
619 * @polarities - the horizontal and vertical polarities (same as struct
620 * v4l2_bt_timings polarities).
621 * @fmt - the resulting timings.
623 * This function will attempt to detect if the given values correspond to a
624 * valid CVT format. If so, then it will return true, and fmt will be filled
625 * in with the found CVT timings.
627 bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
628 u32 polarities, struct v4l2_dv_timings *fmt)
630 int v_fp, v_bp, h_fp, h_bp, hsync;
631 int frame_width, image_height, image_width;
632 bool reduced_blanking;
635 if (vsync < 4 || vsync > 7)
638 if (polarities == V4L2_DV_VSYNC_POS_POL)
639 reduced_blanking = false;
640 else if (polarities == V4L2_DV_HSYNC_POS_POL)
641 reduced_blanking = true;
646 if (reduced_blanking) {
647 v_fp = CVT_RB_V_FPORCH;
648 v_bp = (CVT_RB_MIN_V_BLANK * hfreq + 999999) / 1000000;
649 v_bp -= vsync + v_fp;
651 if (v_bp < CVT_RB_MIN_V_BPORCH)
652 v_bp = CVT_RB_MIN_V_BPORCH;
654 v_fp = CVT_MIN_V_PORCH_RND;
655 v_bp = (CVT_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync;
657 if (v_bp < CVT_MIN_V_BPORCH)
658 v_bp = CVT_MIN_V_BPORCH;
660 image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
662 /* Aspect ratio based on vsync */
665 image_width = (image_height * 4) / 3;
668 image_width = (image_height * 16) / 9;
671 image_width = (image_height * 16) / 10;
675 if (image_height == 1024)
676 image_width = (image_height * 5) / 4;
677 else if (image_height == 768)
678 image_width = (image_height * 15) / 9;
686 image_width = image_width & ~7;
689 if (reduced_blanking) {
690 pix_clk = (image_width + CVT_RB_H_BLANK) * hfreq;
691 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
693 h_bp = CVT_RB_H_BPORCH;
694 hsync = CVT_RB_H_SYNC;
695 h_fp = CVT_RB_H_BLANK - h_bp - hsync;
697 frame_width = image_width + CVT_RB_H_BLANK;
700 unsigned ideal_duty_cycle = CVT_C_PRIME - (CVT_M_PRIME * 1000) / hfreq;
702 h_blank = (image_width * ideal_duty_cycle + (100 - ideal_duty_cycle) / 2) /
703 (100 - ideal_duty_cycle);
704 h_blank = h_blank - h_blank % (2 * CVT_CELL_GRAN);
706 if (h_blank * 100 / image_width < 20) {
707 h_blank = image_width / 5;
708 h_blank = (h_blank + 0x7) & ~0x7;
711 pix_clk = (image_width + h_blank) * hfreq;
712 pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;
715 frame_width = image_width + h_blank;
717 hsync = (frame_width * 8 + 50) / 100;
718 hsync = hsync - hsync % CVT_CELL_GRAN;
719 h_fp = h_blank - hsync - h_bp;
722 fmt->bt.polarities = polarities;
723 fmt->bt.width = image_width;
724 fmt->bt.height = image_height;
725 fmt->bt.hfrontporch = h_fp;
726 fmt->bt.vfrontporch = v_fp;
727 fmt->bt.hsync = hsync;
728 fmt->bt.vsync = vsync;
729 fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
730 fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
731 fmt->bt.pixelclock = pix_clk;
732 fmt->bt.standards = V4L2_DV_BT_STD_CVT;
733 if (reduced_blanking)
734 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
737 EXPORT_SYMBOL_GPL(v4l2_detect_cvt);
741 * Based on Generalized Timing Formula Standard
742 * Version 1.1 September 2, 1999
745 #define GTF_PXL_CLK_GRAN 250000 /* pixel clock granularity */
747 #define GTF_MIN_VSYNC_BP 550 /* min time of vsync + back porch (us) */
748 #define GTF_V_FP 1 /* vertical front porch (lines) */
749 #define GTF_CELL_GRAN 8 /* character cell granularity */
752 #define GTF_D_M 600 /* blanking formula gradient */
753 #define GTF_D_C 40 /* blanking formula offset */
754 #define GTF_D_K 128 /* blanking formula scaling factor */
755 #define GTF_D_J 20 /* blanking formula scaling factor */
756 #define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
757 #define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)
760 #define GTF_S_M 3600 /* blanking formula gradient */
761 #define GTF_S_C 40 /* blanking formula offset */
762 #define GTF_S_K 128 /* blanking formula scaling factor */
763 #define GTF_S_J 35 /* blanking formula scaling factor */
764 #define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
765 #define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)
767 /** v4l2_detect_gtf - detect if the given timings follow the GTF standard
768 * @frame_height - the total height of the frame (including blanking) in lines.
769 * @hfreq - the horizontal frequency in Hz.
770 * @vsync - the height of the vertical sync in lines.
771 * @polarities - the horizontal and vertical polarities (same as struct
772 * v4l2_bt_timings polarities).
773 * @aspect - preferred aspect ratio. GTF has no method of determining the
774 * aspect ratio in order to derive the image width from the
775 * image height, so it has to be passed explicitly. Usually
776 * the native screen aspect ratio is used for this. If it
777 * is not filled in correctly, then 16:9 will be assumed.
778 * @fmt - the resulting timings.
780 * This function will attempt to detect if the given values correspond to a
781 * valid GTF format. If so, then it will return true, and fmt will be filled
782 * in with the found GTF timings.
784 bool v4l2_detect_gtf(unsigned frame_height,
788 struct v4l2_fract aspect,
789 struct v4l2_dv_timings *fmt)
792 int v_fp, v_bp, h_fp, hsync;
793 int frame_width, image_height, image_width;
800 if (polarities == V4L2_DV_VSYNC_POS_POL)
802 else if (polarities == V4L2_DV_HSYNC_POS_POL)
809 v_bp = (GTF_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync;
810 image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;
812 if (aspect.numerator == 0 || aspect.denominator == 0) {
813 aspect.numerator = 16;
814 aspect.denominator = 9;
816 image_width = ((image_height * aspect.numerator) / aspect.denominator);
820 h_blank = ((image_width * GTF_D_C_PRIME * hfreq) -
821 (image_width * GTF_D_M_PRIME * 1000) +
822 (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) / 2) /
823 (hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000);
825 h_blank = ((image_width * GTF_S_C_PRIME * hfreq) -
826 (image_width * GTF_S_M_PRIME * 1000) +
827 (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) / 2) /
828 (hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000);
830 h_blank = h_blank - h_blank % (2 * GTF_CELL_GRAN);
831 frame_width = image_width + h_blank;
833 pix_clk = (image_width + h_blank) * hfreq;
834 pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;
836 hsync = (frame_width * 8 + 50) / 100;
837 hsync = hsync - hsync % GTF_CELL_GRAN;
839 h_fp = h_blank / 2 - hsync;
841 fmt->bt.polarities = polarities;
842 fmt->bt.width = image_width;
843 fmt->bt.height = image_height;
844 fmt->bt.hfrontporch = h_fp;
845 fmt->bt.vfrontporch = v_fp;
846 fmt->bt.hsync = hsync;
847 fmt->bt.vsync = vsync;
848 fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
849 fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
850 fmt->bt.pixelclock = pix_clk;
851 fmt->bt.standards = V4L2_DV_BT_STD_GTF;
853 fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
856 EXPORT_SYMBOL_GPL(v4l2_detect_gtf);
858 /** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
859 * 0x15 and 0x16 from the EDID.
860 * @hor_landscape - byte 0x15 from the EDID.
861 * @vert_portrait - byte 0x16 from the EDID.
863 * Determines the aspect ratio from the EDID.
864 * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
865 * "Horizontal and Vertical Screen Size or Aspect Ratio"
867 struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait)
869 struct v4l2_fract aspect = { 16, 9 };
873 /* Nothing filled in, fallback to 16:9 */
874 if (!hor_landscape && !vert_portrait)
876 /* Both filled in, so they are interpreted as the screen size in cm */
877 if (hor_landscape && vert_portrait) {
878 aspect.numerator = hor_landscape;
879 aspect.denominator = vert_portrait;
882 /* Only one is filled in, so interpret them as a ratio:
884 ratio = hor_landscape | vert_portrait;
885 /* Change some rounded values into the exact aspect ratio */
887 aspect.numerator = 16;
888 aspect.denominator = 9;
889 } else if (ratio == 34) {
890 aspect.numerator = 4;
891 aspect.numerator = 3;
892 } else if (ratio == 68) {
893 aspect.numerator = 15;
894 aspect.numerator = 9;
896 aspect.numerator = hor_landscape + 99;
897 aspect.denominator = 100;
901 /* The aspect ratio is for portrait, so swap numerator and denominator */
902 tmp = aspect.denominator;
903 aspect.denominator = aspect.numerator;
904 aspect.numerator = tmp;
907 EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio);
909 const struct v4l2_frmsize_discrete *v4l2_find_nearest_format(
910 const struct v4l2_discrete_probe *probe,
911 s32 width, s32 height)
914 u32 error, min_error = UINT_MAX;
915 const struct v4l2_frmsize_discrete *size, *best = NULL;
920 for (i = 0, size = probe->sizes; i < probe->num_sizes; i++, size++) {
921 error = abs(size->width - width) + abs(size->height - height);
922 if (error < min_error) {
932 EXPORT_SYMBOL_GPL(v4l2_find_nearest_format);
934 void v4l2_get_timestamp(struct timeval *tv)
939 tv->tv_sec = ts.tv_sec;
940 tv->tv_usec = ts.tv_nsec / NSEC_PER_USEC;
942 EXPORT_SYMBOL_GPL(v4l2_get_timestamp);