[media] v4l: move v4l2 core into a separate directory

Currently, the v4l2 core is mixed together with other non-core drivers.
Move them into a separate directory.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 623 insertions, 0 deletions

diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c
new file mode 100644
index 00000000000..105f88cdb9d
--- /dev/null
+++ b/drivers/media/v4l2-core/v4l2-common.c
@@ -0,0 +1,623 @@
+/*
+ *	Video for Linux Two
+ *
+ *	A generic video device interface for the LINUX operating system
+ *	using a set of device structures/vectors for low level operations.
+ *
+ *	This file replaces the videodev.c file that comes with the
+ *	regular kernel distribution.
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License
+ *	as published by the Free Software Foundation; either version
+ *	2 of the License, or (at your option) any later version.
+ *
+ * Author:	Bill Dirks <bill@thedirks.org>
+ *		based on code by Alan Cox, <alan@cymru.net>
+ *
+ */
+
+/*
+ * Video capture interface for Linux
+ *
+ *	A generic video device interface for the LINUX operating system
+ *	using a set of device structures/vectors for low level operations.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Author:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
+ *
+ * Fixes:
+ */
+
+/*
+ * Video4linux 1/2 integration by Justin Schoeman
+ * <justin@suntiger.ee.up.ac.za>
+ * 2.4 PROCFS support ported from 2.4 kernels by
+ *  Iñaki García Etxebarria <garetxe@euskalnet.net>
+ * Makefile fix by "W. Michael Petullo" <mike@flyn.org>
+ * 2.4 devfs support ported from 2.4 kernels by
+ *  Dan Merillat <dan@merillat.org>
+ * Added Gerd Knorrs v4l1 enhancements (Justin Schoeman)
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#if defined(CONFIG_SPI)
+#include <linux/spi/spi.h>
+#endif
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+#include <asm/div64.h>
+#include <media/v4l2-common.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ctrls.h>
+#include <media/v4l2-chip-ident.h>
+
+#include <linux/videodev2.h>
+
+MODULE_AUTHOR("Bill Dirks, Justin Schoeman, Gerd Knorr");
+MODULE_DESCRIPTION("misc helper functions for v4l2 device drivers");
+MODULE_LICENSE("GPL");
+
+/*
+ *
+ *	V 4 L 2   D R I V E R   H E L P E R   A P I
+ *
+ */
+
+/*
+ *  Video Standard Operations (contributed by Michael Schimek)
+ */
+
+/* Helper functions for control handling			     */
+
+/* Check for correctness of the ctrl's value based on the data from
+   struct v4l2_queryctrl and the available menu items. Note that
+   menu_items may be NULL, in that case it is ignored. */
+int v4l2_ctrl_check(struct v4l2_ext_control *ctrl, struct v4l2_queryctrl *qctrl,
+		const char * const *menu_items)
+{
+	if (qctrl->flags & V4L2_CTRL_FLAG_DISABLED)
+		return -EINVAL;
+	if (qctrl->flags & V4L2_CTRL_FLAG_GRABBED)
+		return -EBUSY;
+	if (qctrl->type == V4L2_CTRL_TYPE_STRING)
+		return 0;
+	if (qctrl->type == V4L2_CTRL_TYPE_BUTTON ||
+	    qctrl->type == V4L2_CTRL_TYPE_INTEGER64 ||
+	    qctrl->type == V4L2_CTRL_TYPE_CTRL_CLASS)
+		return 0;
+	if (ctrl->value < qctrl->minimum || ctrl->value > qctrl->maximum)
+		return -ERANGE;
+	if (qctrl->type == V4L2_CTRL_TYPE_MENU && menu_items != NULL) {
+		if (menu_items[ctrl->value] == NULL ||
+		    menu_items[ctrl->value][0] == '\0')
+			return -EINVAL;
+	}
+	if (qctrl->type == V4L2_CTRL_TYPE_BITMASK &&
+			(ctrl->value & ~qctrl->maximum))
+		return -ERANGE;
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_ctrl_check);
+
+/* Fill in a struct v4l2_queryctrl */
+int v4l2_ctrl_query_fill(struct v4l2_queryctrl *qctrl, s32 min, s32 max, s32 step, s32 def)
+{
+	const char *name;
+
+	v4l2_ctrl_fill(qctrl->id, &name, &qctrl->type,
+		       &min, &max, &step, &def, &qctrl->flags);
+
+	if (name == NULL)
+		return -EINVAL;
+
+	qctrl->minimum = min;
+	qctrl->maximum = max;
+	qctrl->step = step;
+	qctrl->default_value = def;
+	qctrl->reserved[0] = qctrl->reserved[1] = 0;
+	strlcpy(qctrl->name, name, sizeof(qctrl->name));
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_ctrl_query_fill);
+
+/* Fill in a struct v4l2_querymenu based on the struct v4l2_queryctrl and
+   the menu. The qctrl pointer may be NULL, in which case it is ignored.
+   If menu_items is NULL, then the menu items are retrieved using
+   v4l2_ctrl_get_menu. */
+int v4l2_ctrl_query_menu(struct v4l2_querymenu *qmenu, struct v4l2_queryctrl *qctrl,
+	       const char * const *menu_items)
+{
+	int i;
+
+	qmenu->reserved = 0;
+	if (menu_items == NULL)
+		menu_items = v4l2_ctrl_get_menu(qmenu->id);
+	if (menu_items == NULL ||
+	    (qctrl && (qmenu->index < qctrl->minimum || qmenu->index > qctrl->maximum)))
+		return -EINVAL;
+	for (i = 0; i < qmenu->index && menu_items[i]; i++) ;
+	if (menu_items[i] == NULL || menu_items[i][0] == '\0')
+		return -EINVAL;
+	strlcpy(qmenu->name, menu_items[qmenu->index], sizeof(qmenu->name));
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_ctrl_query_menu);
+
+/* Fill in a struct v4l2_querymenu based on the specified array of valid
+   menu items (terminated by V4L2_CTRL_MENU_IDS_END).
+   Use this if there are 'holes' in the list of valid menu items. */
+int v4l2_ctrl_query_menu_valid_items(struct v4l2_querymenu *qmenu, const u32 *ids)
+{
+	const char * const *menu_items = v4l2_ctrl_get_menu(qmenu->id);
+
+	qmenu->reserved = 0;
+	if (menu_items == NULL || ids == NULL)
+		return -EINVAL;
+	while (*ids != V4L2_CTRL_MENU_IDS_END) {
+		if (*ids++ == qmenu->index) {
+			strlcpy(qmenu->name, menu_items[qmenu->index],
+					sizeof(qmenu->name));
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+EXPORT_SYMBOL(v4l2_ctrl_query_menu_valid_items);
+
+/* ctrl_classes points to an array of u32 pointers, the last element is
+   a NULL pointer. Each u32 array is a 0-terminated array of control IDs.
+   Each array must be sorted low to high and belong to the same control
+   class. The array of u32 pointers must also be sorted, from low class IDs
+   to high class IDs.
+
+   This function returns the first ID that follows after the given ID.
+   When no more controls are available 0 is returned. */
+u32 v4l2_ctrl_next(const u32 * const * ctrl_classes, u32 id)
+{
+	u32 ctrl_class = V4L2_CTRL_ID2CLASS(id);
+	const u32 *pctrl;
+
+	if (ctrl_classes == NULL)
+		return 0;
+
+	/* if no query is desired, then check if the ID is part of ctrl_classes */
+	if ((id & V4L2_CTRL_FLAG_NEXT_CTRL) == 0) {
+		/* find class */
+		while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) != ctrl_class)
+			ctrl_classes++;
+		if (*ctrl_classes == NULL)
+			return 0;
+		pctrl = *ctrl_classes;
+		/* find control ID */
+		while (*pctrl && *pctrl != id) pctrl++;
+		return *pctrl ? id : 0;
+	}
+	id &= V4L2_CTRL_ID_MASK;
+	id++;	/* select next control */
+	/* find first class that matches (or is greater than) the class of
+	   the ID */
+	while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) < ctrl_class)
+		ctrl_classes++;
+	/* no more classes */
+	if (*ctrl_classes == NULL)
+		return 0;
+	pctrl = *ctrl_classes;
+	/* find first ctrl within the class that is >= ID */
+	while (*pctrl && *pctrl < id) pctrl++;
+	if (*pctrl)
+		return *pctrl;
+	/* we are at the end of the controls of the current class. */
+	/* continue with next class if available */
+	ctrl_classes++;
+	if (*ctrl_classes == NULL)
+		return 0;
+	return **ctrl_classes;
+}
+EXPORT_SYMBOL(v4l2_ctrl_next);
+
+int v4l2_chip_match_host(const struct v4l2_dbg_match *match)
+{
+	switch (match->type) {
+	case V4L2_CHIP_MATCH_HOST:
+		return match->addr == 0;
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL(v4l2_chip_match_host);
+
+#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
+int v4l2_chip_match_i2c_client(struct i2c_client *c, const struct v4l2_dbg_match *match)
+{
+	int len;
+
+	if (c == NULL || match == NULL)
+		return 0;
+
+	switch (match->type) {
+	case V4L2_CHIP_MATCH_I2C_DRIVER:
+		if (c->driver == NULL || c->driver->driver.name == NULL)
+			return 0;
+		len = strlen(c->driver->driver.name);
+		/* legacy drivers have a ' suffix, don't try to match that */
+		if (len && c->driver->driver.name[len - 1] == '\'')
+			len--;
+		return len && !strncmp(c->driver->driver.name, match->name, len);
+	case V4L2_CHIP_MATCH_I2C_ADDR:
+		return c->addr == match->addr;
+	default:
+		return 0;
+	}
+}
+EXPORT_SYMBOL(v4l2_chip_match_i2c_client);
+
+int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_dbg_chip_ident *chip,
+		u32 ident, u32 revision)
+{
+	if (!v4l2_chip_match_i2c_client(c, &chip->match))
+		return 0;
+	if (chip->ident == V4L2_IDENT_NONE) {
+		chip->ident = ident;
+		chip->revision = revision;
+	}
+	else {
+		chip->ident = V4L2_IDENT_AMBIGUOUS;
+		chip->revision = 0;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);
+
+/* ----------------------------------------------------------------- */
+
+/* I2C Helper functions */
+
+
+void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
+		const struct v4l2_subdev_ops *ops)
+{
+	v4l2_subdev_init(sd, ops);
+	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
+	/* the owner is the same as the i2c_client's driver owner */
+	sd->owner = client->driver->driver.owner;
+	/* i2c_client and v4l2_subdev point to one another */
+	v4l2_set_subdevdata(sd, client);
+	i2c_set_clientdata(client, sd);
+	/* initialize name */
+	snprintf(sd->name, sizeof(sd->name), "%s %d-%04x",
+		client->driver->driver.name, i2c_adapter_id(client->adapter),
+		client->addr);
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);
+
+
+
+/* Load an i2c sub-device. */
+struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
+		struct i2c_adapter *adapter, struct i2c_board_info *info,
+		const unsigned short *probe_addrs)
+{
+	struct v4l2_subdev *sd = NULL;
+	struct i2c_client *client;
+
+	BUG_ON(!v4l2_dev);
+
+	request_module(I2C_MODULE_PREFIX "%s", info->type);
+
+	/* Create the i2c client */
+	if (info->addr == 0 && probe_addrs)
+		client = i2c_new_probed_device(adapter, info, probe_addrs,
+					       NULL);
+	else
+		client = i2c_new_device(adapter, info);
+
+	/* Note: by loading the module first we are certain that c->driver
+	   will be set if the driver was found. If the module was not loaded
+	   first, then the i2c core tries to delay-load the module for us,
+	   and then c->driver is still NULL until the module is finally
+	   loaded. This delay-load mechanism doesn't work if other drivers
+	   want to use the i2c device, so explicitly loading the module
+	   is the best alternative. */
+	if (client == NULL || client->driver == NULL)
+		goto error;
+
+	/* Lock the module so we can safely get the v4l2_subdev pointer */
+	if (!try_module_get(client->driver->driver.owner))
+		goto error;
+	sd = i2c_get_clientdata(client);
+
+	/* Register with the v4l2_device which increases the module's
+	   use count as well. */
+	if (v4l2_device_register_subdev(v4l2_dev, sd))
+		sd = NULL;
+	/* Decrease the module use count to match the first try_module_get. */
+	module_put(client->driver->driver.owner);
+
+error:
+	/* If we have a client but no subdev, then something went wrong and
+	   we must unregister the client. */
+	if (client && sd == NULL)
+		i2c_unregister_device(client);
+	return sd;
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);
+
+struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
+		struct i2c_adapter *adapter, const char *client_type,
+		u8 addr, const unsigned short *probe_addrs)
+{
+	struct i2c_board_info info;
+
+	/* Setup the i2c board info with the device type and
+	   the device address. */
+	memset(&info, 0, sizeof(info));
+	strlcpy(info.type, client_type, sizeof(info.type));
+	info.addr = addr;
+
+	return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info, probe_addrs);
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);
+
+/* Return i2c client address of v4l2_subdev. */
+unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
+{
+	struct i2c_client *client = v4l2_get_subdevdata(sd);
+
+	return client ? client->addr : I2C_CLIENT_END;
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);
+
+/* Return a list of I2C tuner addresses to probe. Use only if the tuner
+   addresses are unknown. */
+const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
+{
+	static const unsigned short radio_addrs[] = {
+#if defined(CONFIG_MEDIA_TUNER_TEA5761) || defined(CONFIG_MEDIA_TUNER_TEA5761_MODULE)
+		0x10,
+#endif
+		0x60,
+		I2C_CLIENT_END
+	};
+	static const unsigned short demod_addrs[] = {
+		0x42, 0x43, 0x4a, 0x4b,
+		I2C_CLIENT_END
+	};
+	static const unsigned short tv_addrs[] = {
+		0x42, 0x43, 0x4a, 0x4b,		/* tda8290 */
+		0x60, 0x61, 0x62, 0x63, 0x64,
+		I2C_CLIENT_END
+	};
+
+	switch (type) {
+	case ADDRS_RADIO:
+		return radio_addrs;
+	case ADDRS_DEMOD:
+		return demod_addrs;
+	case ADDRS_TV:
+		return tv_addrs;
+	case ADDRS_TV_WITH_DEMOD:
+		return tv_addrs + 4;
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);
+
+#endif /* defined(CONFIG_I2C) */
+
+#if defined(CONFIG_SPI)
+
+/* Load an spi sub-device. */
+
+void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
+		const struct v4l2_subdev_ops *ops)
+{
+	v4l2_subdev_init(sd, ops);
+	sd->flags |= V4L2_SUBDEV_FL_IS_SPI;
+	/* the owner is the same as the spi_device's driver owner */
+	sd->owner = spi->dev.driver->owner;
+	/* spi_device and v4l2_subdev point to one another */
+	v4l2_set_subdevdata(sd, spi);
+	spi_set_drvdata(spi, sd);
+	/* initialize name */
+	strlcpy(sd->name, spi->dev.driver->name, sizeof(sd->name));
+}
+EXPORT_SYMBOL_GPL(v4l2_spi_subdev_init);
+
+struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev,
+		struct spi_master *master, struct spi_board_info *info)
+{
+	struct v4l2_subdev *sd = NULL;
+	struct spi_device *spi = NULL;
+
+	BUG_ON(!v4l2_dev);
+
+	if (info->modalias)
+		request_module(info->modalias);
+
+	spi = spi_new_device(master, info);
+
+	if (spi == NULL || spi->dev.driver == NULL)
+		goto error;
+
+	if (!try_module_get(spi->dev.driver->owner))
+		goto error;
+
+	sd = spi_get_drvdata(spi);
+
+	/* Register with the v4l2_device which increases the module's
+	   use count as well. */
+	if (v4l2_device_register_subdev(v4l2_dev, sd))
+		sd = NULL;
+
+	/* Decrease the module use count to match the first try_module_get. */
+	module_put(spi->dev.driver->owner);
+
+error:
+	/* If we have a client but no subdev, then something went wrong and
+	   we must unregister the client. */
+	if (spi && sd == NULL)
+		spi_unregister_device(spi);
+
+	return sd;
+}
+EXPORT_SYMBOL_GPL(v4l2_spi_new_subdev);
+
+#endif /* defined(CONFIG_SPI) */
+
+/* Clamp x to be between min and max, aligned to a multiple of 2^align.  min
+ * and max don't have to be aligned, but there must be at least one valid
+ * value.  E.g., min=17,max=31,align=4 is not allowed as there are no multiples
+ * of 16 between 17 and 31.  */
+static unsigned int clamp_align(unsigned int x, unsigned int min,
+				unsigned int max, unsigned int align)
+{
+	/* Bits that must be zero to be aligned */
+	unsigned int mask = ~((1 << align) - 1);
+
+	/* Round to nearest aligned value */
+	if (align)
+		x = (x + (1 << (align - 1))) & mask;
+
+	/* Clamp to aligned value of min and max */
+	if (x < min)
+		x = (min + ~mask) & mask;
+	else if (x > max)
+		x = max & mask;
+
+	return x;
+}
+
+/* Bound an image to have a width between wmin and wmax, and height between
+ * hmin and hmax, inclusive.  Additionally, the width will be a multiple of
+ * 2^walign, the height will be a multiple of 2^halign, and the overall size
+ * (width*height) will be a multiple of 2^salign.  The image may be shrunk
+ * or enlarged to fit the alignment constraints.
+ *
+ * The width or height maximum must not be smaller than the corresponding
+ * minimum.  The alignments must not be so high there are no possible image
+ * sizes within the allowed bounds.  wmin and hmin must be at least 1
+ * (don't use 0).  If you don't care about a certain alignment, specify 0,
+ * as 2^0 is 1 and one byte alignment is equivalent to no alignment.  If
+ * you only want to adjust downward, specify a maximum that's the same as
+ * the initial value.
+ */
+void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
+			   unsigned int walign,
+			   u32 *h, unsigned int hmin, unsigned int hmax,
+			   unsigned int halign, unsigned int salign)
+{
+	*w = clamp_align(*w, wmin, wmax, walign);
+	*h = clamp_align(*h, hmin, hmax, halign);
+
+	/* Usually we don't need to align the size and are done now. */
+	if (!salign)
+		return;
+
+	/* How much alignment do we have? */
+	walign = __ffs(*w);
+	halign = __ffs(*h);
+	/* Enough to satisfy the image alignment? */
+	if (walign + halign < salign) {
+		/* Max walign where there is still a valid width */
+		unsigned int wmaxa = __fls(wmax ^ (wmin - 1));
+		/* Max halign where there is still a valid height */
+		unsigned int hmaxa = __fls(hmax ^ (hmin - 1));
+
+		/* up the smaller alignment until we have enough */
+		do {
+			if (halign >= hmaxa ||
+			    (walign <= halign && walign < wmaxa)) {
+				*w = clamp_align(*w, wmin, wmax, walign + 1);
+				walign = __ffs(*w);
+			} else {
+				*h = clamp_align(*h, hmin, hmax, halign + 1);
+				halign = __ffs(*h);
+			}
+		} while (halign + walign < salign);
+	}
+}
+EXPORT_SYMBOL_GPL(v4l_bound_align_image);
+
+/**
+ * v4l_fill_dv_preset_info - fill description of a digital video preset
+ * @preset - preset value
+ * @info - pointer to struct v4l2_dv_enum_preset
+ *
+ * drivers can use this helper function to fill description of dv preset
+ * in info.
+ */
+int v4l_fill_dv_preset_info(u32 preset, struct v4l2_dv_enum_preset *info)
+{
+	static const struct v4l2_dv_preset_info {
+		u16 width;
+		u16 height;
+		const char *name;
+	} dv_presets[] = {
+		{ 0, 0, "Invalid" },		/* V4L2_DV_INVALID */
+		{ 720,  480, "480p@59.94" },	/* V4L2_DV_480P59_94 */
+		{ 720,  576, "576p@50" },	/* V4L2_DV_576P50 */
+		{ 1280, 720, "720p@24" },	/* V4L2_DV_720P24 */
+		{ 1280, 720, "720p@25" },	/* V4L2_DV_720P25 */
+		{ 1280, 720, "720p@30" },	/* V4L2_DV_720P30 */
+		{ 1280, 720, "720p@50" },	/* V4L2_DV_720P50 */
+		{ 1280, 720, "720p@59.94" },	/* V4L2_DV_720P59_94 */
+		{ 1280, 720, "720p@60" },	/* V4L2_DV_720P60 */
+		{ 1920, 1080, "1080i@29.97" },	/* V4L2_DV_1080I29_97 */
+		{ 1920, 1080, "1080i@30" },	/* V4L2_DV_1080I30 */
+		{ 1920, 1080, "1080i@25" },	/* V4L2_DV_1080I25 */
+		{ 1920, 1080, "1080i@50" },	/* V4L2_DV_1080I50 */
+		{ 1920, 1080, "1080i@60" },	/* V4L2_DV_1080I60 */
+		{ 1920, 1080, "1080p@24" },	/* V4L2_DV_1080P24 */
+		{ 1920, 1080, "1080p@25" },	/* V4L2_DV_1080P25 */
+		{ 1920, 1080, "1080p@30" },	/* V4L2_DV_1080P30 */
+		{ 1920, 1080, "1080p@50" },	/* V4L2_DV_1080P50 */
+		{ 1920, 1080, "1080p@60" },	/* V4L2_DV_1080P60 */
+	};
+
+	if (info == NULL || preset >= ARRAY_SIZE(dv_presets))
+		return -EINVAL;
+
+	info->preset = preset;
+	info->width = dv_presets[preset].width;
+	info->height = dv_presets[preset].height;
+	strlcpy(info->name, dv_presets[preset].name, sizeof(info->name));
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l_fill_dv_preset_info);
+
+const struct v4l2_frmsize_discrete *v4l2_find_nearest_format(
+		const struct v4l2_discrete_probe *probe,
+		s32 width, s32 height)
+{
+	int i;
+	u32 error, min_error = UINT_MAX;
+	const struct v4l2_frmsize_discrete *size, *best = NULL;
+
+	if (!probe)
+		return best;
+
+	for (i = 0, size = probe->sizes; i < probe->num_sizes; i++, size++) {
+		error = abs(size->width - width) + abs(size->height - height);
+		if (error < min_error) {
+			min_error = error;
+			best = size;
+		}
+		if (!error)
+			break;
+	}
+
+	return best;
+}
+EXPORT_SYMBOL_GPL(v4l2_find_nearest_format);