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Commit 117a711a authored by Lad, Prabhakar's avatar Lad, Prabhakar Committed by Mauro Carvalho Chehab
Browse files

[media] media: v4l2-ctrl: add a helper function to add standard control with driver specific menu 



Add helper function v4l2_ctrl_new_std_menu_items(), which adds
a standard menu control, with driver specific menu.

Signed-off-by: default avatarLad, Prabhakar <prabhakar.lad@ti.com>
Signed-off-by: default avatarManjunath Hadli <manjunath.hadli@ti.com>
Acked-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Acked-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 5ebef0fb

Documentation/video4linux/v4l2-controls.txt

+24 −0
Original line number Diff line number Diff line
@@ -136,11 +136,25 @@ Or alternatively for integer menu controls, by calling v4l2_ctrl_new_int_menu: 
			const struct v4l2_ctrl_ops *ops,

			u32 id, s32 max, s32 def, const s64 *qmenu_int);



Standard menu controls with a driver specific menu are added by calling

v4l2_ctrl_new_std_menu_items:



	struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(

		struct v4l2_ctrl_handler *hdl,

		const struct v4l2_ctrl_ops *ops, u32 id, s32 max,

		s32 skip_mask, s32 def, const char * const *qmenu);



These functions are typically called right after the v4l2_ctrl_handler_init:



	static const s64 exp_bias_qmenu[] = {

	       -2, -1, 0, 1, 2

	};

	static const char * const test_pattern[] = {

		"Disabled",

		"Vertical Bars",

		"Solid Black",

		"Solid White",

	};



	v4l2_ctrl_handler_init(&foo->ctrl_handler, nr_of_controls);

	v4l2_ctrl_new_std(&foo->ctrl_handler, &foo_ctrl_ops,
@@ -156,6 +170,9 @@ These functions are typically called right after the v4l2_ctrl_handler_init: 
			ARRAY_SIZE(exp_bias_qmenu) - 1,

			ARRAY_SIZE(exp_bias_qmenu) / 2 - 1,

			exp_bias_qmenu);

	v4l2_ctrl_new_std_menu_items(&foo->ctrl_handler, &foo_ctrl_ops,

			V4L2_CID_TEST_PATTERN, ARRAY_SIZE(test_pattern) - 1, 0,

			0, test_pattern);

	...

	if (foo->ctrl_handler.error) {

		int err = foo->ctrl_handler.error;
@@ -185,6 +202,13 @@ v4l2_ctrl_new_std_menu in that it doesn't have the mask argument and takes 
as the last argument an array of signed 64-bit integers that form an exact

menu item list.



The v4l2_ctrl_new_std_menu_items function is very similar to

v4l2_ctrl_new_std_menu but takes an extra parameter qmenu, which is the driver

specific menu for an otherwise standard menu control. A good example for this

control is the test pattern control for capture/display/sensors devices that

have the capability to generate test patterns. These test patterns are hardware

specific, so the contents of the menu will vary from device to device.



Note that if something fails, the function will return NULL or an error and

set ctrl_handler->error to the error code. If ctrl_handler->error was already

set, then it will just return and do nothing. This is also true for

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

+30 −0
Original line number Diff line number Diff line
@@ -1650,6 +1650,36 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl, 
}

EXPORT_SYMBOL(v4l2_ctrl_new_std_menu);



/* Helper function for standard menu controls with driver defined menu */

struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,

			const struct v4l2_ctrl_ops *ops, u32 id, s32 max,

			s32 mask, s32 def, const char * const *qmenu)

{

	enum v4l2_ctrl_type type;

	const char *name;

	u32 flags;

	s32 step;

	s32 min;



	/* v4l2_ctrl_new_std_menu_items() should only be called for

	 * standard controls without a standard menu.

	 */

	if (v4l2_ctrl_get_menu(id)) {

		handler_set_err(hdl, -EINVAL);

		return NULL;

	}



	v4l2_ctrl_fill(id, &name, &type, &min, &max, &step, &def, &flags);

	if (type != V4L2_CTRL_TYPE_MENU || qmenu == NULL) {

		handler_set_err(hdl, -EINVAL);

		return NULL;

	}

	return v4l2_ctrl_new(hdl, ops, id, name, type, 0, max, mask, def,

			     flags, qmenu, NULL, NULL);



}

EXPORT_SYMBOL(v4l2_ctrl_new_std_menu_items);



/* Helper function for standard integer menu controls */

struct v4l2_ctrl *v4l2_ctrl_new_int_menu(struct v4l2_ctrl_handler *hdl,

			const struct v4l2_ctrl_ops *ops,

include/media/v4l2-ctrls.h

+23 −0
Original line number Diff line number Diff line
@@ -351,6 +351,29 @@ struct v4l2_ctrl *v4l2_ctrl_new_std_menu(struct v4l2_ctrl_handler *hdl, 
			const struct v4l2_ctrl_ops *ops,

			u32 id, s32 max, s32 mask, s32 def);



/** v4l2_ctrl_new_std_menu_items() - Create a new standard V4L2 menu control

  * with driver specific menu.

  * @hdl:	The control handler.

  * @ops:	The control ops.

  * @id:	The control ID.

  * @max:	The control's maximum value.

  * @mask:	The control's skip mask for menu controls. This makes it

  *		easy to skip menu items that are not valid. If bit X is set,

  *		then menu item X is skipped. Of course, this only works for

  *		menus with <= 32 menu items. There are no menus that come

  *		close to that number, so this is OK. Should we ever need more,

  *		then this will have to be extended to a u64 or a bit array.

  * @def:	The control's default value.

  * @qmenu:	The new menu.

  *

  * Same as v4l2_ctrl_new_std_menu(), but @qmenu will be the driver specific

  * menu of this control.

  *

  */

struct v4l2_ctrl *v4l2_ctrl_new_std_menu_items(struct v4l2_ctrl_handler *hdl,

			const struct v4l2_ctrl_ops *ops, u32 id, s32 max,

			s32 mask, s32 def, const char * const *qmenu);



/** v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.

  * @hdl:	The control handler.

  * @ops:	The control ops.