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Commit 578d0b6b authored by Andrzej Pietrasiewicz's avatar Andrzej Pietrasiewicz Committed by Felipe Balbi
Browse files

usb: gadget: uvc: comments for iterating over streaming hierarchy 



The purpose of the functions and their parametrs might not be obvious
to the reader, so explain it.

Signed-off-by: default avatarAndrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: default avatarFelipe Balbi <balbi@ti.com>
parent 72796835

drivers/usb/gadget/function/uvc_configfs.c

+34 −0
Original line number Diff line number Diff line
@@ -1918,6 +1918,25 @@ enum uvcg_strm_type { 
	UVCG_FRAME

};



/*

 * Iterate over a hierarchy of streaming descriptors' config items.

 * The items are created by the user with configfs.

 *

 * It "processes" the header pointed to by @priv1, then for each format

 * that follows the header "processes" the format itself and then for

 * each frame inside a format "processes" the frame.

 *

 * As a "processing" function the @fun is used.

 *

 * __uvcg_iter_strm_cls() is used in two context: first, to calculate

 * the amount of memory needed for an array of streaming descriptors

 * and second, to actually fill the array.

 *

 * @h: streaming header pointer

 * @priv2: an "inout" parameter (the caller might want to see the changes to it)

 * @priv3: an "inout" parameter (the caller might want to see the changes to it)

 * @fun: callback function for processing each level of the hierarchy

 */

static int __uvcg_iter_strm_cls(struct uvcg_streaming_header *h,

	void *priv2, void *priv3,

	int (*fun)(void *, void *, void *, int, enum uvcg_strm_type type))
@@ -1951,6 +1970,14 @@ static int __uvcg_iter_strm_cls(struct uvcg_streaming_header *h, 
	return ret;

}



/*

 * Count how many bytes are needed for an array of streaming descriptors.

 *

 * @priv1: pointer to a header, format or frame

 * @priv2: inout parameter, accumulated size of the array

 * @priv3: inout parameter, accumulated number of the array elements

 * @n: unused, this function's prototype must match @fun in __uvcg_iter_strm_cls

 */

static int __uvcg_cnt_strm(void *priv1, void *priv2, void *priv3, int n,

			   enum uvcg_strm_type type)

{
@@ -2000,6 +2027,13 @@ static int __uvcg_cnt_strm(void *priv1, void *priv2, void *priv3, int n, 
	return 0;

}



/*

 * Fill an array of streaming descriptors.

 *

 * @priv1: pointer to a header, format or frame

 * @priv2: inout parameter, pointer into a block of memory

 * @priv3: inout parameter, pointer to a 2-dimensional array

 */

static int __uvcg_fill_strm(void *priv1, void *priv2, void *priv3, int n,

			    enum uvcg_strm_type type)

{