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Commit 76a59fe7 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

media: v4l2-common.h: document helper functions 



There are several helper functions that aren't documented.

Document them.

Acked-by: default avatarSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent 0545629e

drivers/media/v4l2-core/v4l2-common.c

+0 −14
Original line number Diff line number Diff line
@@ -320,20 +320,6 @@ static unsigned int clamp_align(unsigned int x, unsigned int min, 
	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,

include/media/v4l2-common.h

+96 −11
Original line number Diff line number Diff line
@@ -28,7 +28,7 @@ 


#include <media/v4l2-dev.h>



/* Common printk constucts for v4l-i2c drivers. These macros create a unique

/* Common printk constructs for v4l-i2c drivers. These macros create a unique

   prefix consisting of the driver name, the adapter number and the i2c

   address. */

#define v4l_printk(level, name, adapter, addr, fmt, arg...) \
@@ -174,17 +174,43 @@ void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client, 
 */

unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd);



/**

 * enum v4l2_i2c_tuner_type - specifies the range of tuner address that

 *	should be used when seeking for I2C devices.

 *

 * @ADDRS_RADIO:		Radio tuner addresses.

 *				Represent the following I2C addresses:

 *				0x10 (if compiled with tea5761 support)

 *				and 0x60.

 * @ADDRS_DEMOD:		Demod tuner addresses.

 *				Represent the following I2C addresses:

 *				0x42, 0x43, 0x4a and 0x4b.

 * @ADDRS_TV:			TV tuner addresses.

 *				Represent the following I2C addresses:

 *				0x42, 0x43, 0x4a, 0x4b, 0x60, 0x61, 0x62,

 *				0x63 and 0x64.

 * @ADDRS_TV_WITH_DEMOD:	TV tuner addresses if demod is present, this

 *				excludes addresses used by the demodulator

 *				from the list of candidates.

 *				Represent the following I2C addresses:

 *				0x60, 0x61, 0x62, 0x63 and 0x64.

 *

 * NOTE: All I2C addresses above use the 7-bit notation.

 */

enum v4l2_i2c_tuner_type {

	ADDRS_RADIO,	/* Radio tuner addresses */

	ADDRS_DEMOD,	/* Demod tuner addresses */

	ADDRS_TV,	/* TV tuner addresses */

	/* TV tuner addresses if demod is present, this excludes

	   addresses used by the demodulator from the list of

	   candidates. */

	ADDRS_RADIO,

	ADDRS_DEMOD,

	ADDRS_TV,

	ADDRS_TV_WITH_DEMOD,

};

/* Return a list of I2C tuner addresses to probe. Use only if the tuner

   addresses are unknown. */

/**

 * v4l2_i2c_tuner_addrs - Return a list of I2C tuner addresses to probe.

 *

 * @type: type of the tuner to seek, as defined by

 *	  &enum v4l2_i2c_tuner_type.

 *

 * NOTE: Use only if the tuner addresses are unknown.

 */

const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type);



/* ------------------------------------------------------------------------- */
@@ -228,6 +254,9 @@ void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi, 
 * FIXME: these remaining ioctls/structs should be removed as well, but they

 * are still used in tuner-simple.c (TUNER_SET_CONFIG) and cx18/ivtv (RESET).

 * To remove these ioctls some more cleanup is needed in those modules.

 *

 * It doesn't make much sense on documenting them, as what we really want is

 * to get rid of them.

 */



/* s_config */
@@ -243,17 +272,73 @@ struct v4l2_priv_tun_config { 


/* Miscellaneous helper functions */



void v4l_bound_align_image(unsigned int *w, unsigned int wmin,

/**

 * v4l_bound_align_image - adjust video dimensions according to

 *	a given constraints.

 *

 * @width:	pointer to width that will be adjusted if needed.

 * @wmin:	minimum width.

 * @wmax:	maximum width.

 * @walign:	least significant bit on width.

 * @height:	pointer to height that will be adjusted if needed.

 * @hmin:	minimum height.

 * @hmax:	maximum height.

 * @halign:	least significant bit on width.

 * @salign:	least significant bit for the image size (e. g.

 *		:math:`width * height`).

 *

 * Clip an image to have @width between @wmin and @wmax, and @height between

 * @hmin and @hmax, inclusive.

 *

 * Additionally, the @width will be a multiple of :math:`2^{walign}`,

 * the @height will be a multiple of :math:`2^{halign}`, and the overall

 * size :math:`width * height` will be a multiple of :math:`2^{salign}`.

 *

 * .. note::

 *

 *    #. The clipping rectangle may be shrunk or enlarged to fit the alignment

 *       constraints.

 *    #. @wmax must not be smaller than @wmin.

 *    #. @hmax must not be smaller than @hmin.

 *    #. 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).

 *    #. For @walign, @halign and @salign, if you don't care about a certain

 *       alignment, specify ``0``, as :math:`2^0 = 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(unsigned int *width, unsigned int wmin,

			   unsigned int wmax, unsigned int walign,

			   unsigned int *h, unsigned int hmin,

			   unsigned int *height, unsigned int hmin,

			   unsigned int hmax, unsigned int halign,

			   unsigned int salign);



/**

 * v4l2_find_nearest_format - find the nearest format size among a discrete

 *	set of resolutions.

 *

 * @sizes: array of &struct v4l2_frmsize_discrete image sizes.

 * @num_sizes: length of @sizes array.

 * @width: desired width.

 * @height: desired height.

 *

 * Finds the closest resolution to minimize the width and height differences

 * between what requested and the supported resolutions.

 */

const struct v4l2_frmsize_discrete *

v4l2_find_nearest_format(const struct v4l2_frmsize_discrete *sizes,

			  const size_t num_sizes,

			  s32 width, s32 height);



/**

 * v4l2_get_timestamp - helper routine to get a timestamp to be used when

 *	filling streaming metadata. Internally, it uses ktime_get_ts(),

 *	which is the recommended way to get it.

 *

 * @tv: pointer to &struct timeval to be filled.

 */

void v4l2_get_timestamp(struct timeval *tv);



#endif /* V4L2_COMMON_H_ */