Re: [PATCH v4] media: v4l2-ctrl: add a helper function to add standard control with driver specific menu

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Hi Prabhakar,

I found some grammar issues, but also some (small) things that should be changed.


On Tue 18 September 2012 20:54:38 Prabhakar Lad wrote:
> From: Lad, Prabhakar <prabhakar.lad@xxxxxx>
> 
> Add helper function v4l2_ctrl_new_std_menu_items(), which adds
> a standard menu control, with driver specific menu.
> 
> Signed-off-by: Lad, Prabhakar <prabhakar.lad@xxxxxx>
> Signed-off-by: Manjunath Hadli <manjunath.hadli@xxxxxx>
> Cc: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> Cc: Sakari Ailus <sakari.ailus@xxxxxx>
> Cc: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
> Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxx>
> Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
> Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> Cc: Rob Landley <rob@xxxxxxxxxxx>
> ---
> Changes for v4:
> 1: Rather then adding a function to modify the menu, added a helper
>    function, that creates a new standard control with user specific
>    menu.
> 
> Changes for v3:
> 1: Fixed style/grammer issues as pointed by Hans.
>    Thanks Hans for providing the description.
> 
> Changes for v2:
> 1: Fixed review comments from Hans, to have return type as
>    void, add WARN_ON() for fail conditions, allow this fucntion
>    to modify the menu of custom controls.
> 
>  Documentation/video4linux/v4l2-controls.txt |   25 ++++++++++++++++++++++++
>  drivers/media/v4l2-core/v4l2-ctrls.c        |   28 +++++++++++++++++++++++++++
>  include/media/v4l2-ctrls.h                  |   23 ++++++++++++++++++++++
>  3 files changed, 76 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/video4linux/v4l2-controls.txt b/Documentation/video4linux/v4l2-controls.txt
> index 43da22b..ad8e172 100644
> --- a/Documentation/video4linux/v4l2-controls.txt
> +++ b/Documentation/video4linux/v4l2-controls.txt
> @@ -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 driver specific menu are added by calling

with driver -> with a driver

> +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_user);

I would recommend that qmenu_user is just renamed to qmenu.
The _user suffix suggests that this is a userspace-provided menu, which
is not the case.

> +
>  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 +202,14 @@ 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 funtion is very similar as

funtion -> function
similar as -> similar to

> +v4l2_ctrl_new_std_menu but takes a extra parameter qmenu_user, which is

a extra -> an extra

> +driver specific menu but yet a standard menu control.

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
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index d731422..9ac1b75 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -1649,6 +1649,34 @@ 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 user 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_user)
> +{
> +	const char * const *qmenu = v4l2_ctrl_get_menu(id);
> +	const char *name;
> +	enum v4l2_ctrl_type type;
> +	s32 min;
> +	s32 step;
> +	u32 flags;
> +
> +	if (!qmenu) {

This test should be inverted: if (qmenu)

Add a comment that v4l2_ctrl_new_std_menu_items() may only be called for
standard controls *without* a standard menu.

> +		handler_set_err(hdl, -EINVAL);
> +		return NULL;
> +	}
> +
> +	v4l2_ctrl_fill(id, &name, &type, &min, &max, &step, &def, &flags);
> +	if (type != V4L2_CTRL_TYPE_MENU) {
> +		handler_set_err(hdl, -EINVAL);
> +		return NULL;
> +	}
> +	return v4l2_ctrl_new(hdl, ops, id, name, type,
> +			     0, max, mask, def, flags, qmenu_user, 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,
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 776605f..e0dd392 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -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_user:The new menu.
> +  *
> +  * Same as v4l2_ctrl_new_std_menu().but @qmenu_user will be the menu to

.but -> , but

'will be the driver specific menu of this control.'

> +  * which the control will be pointing to.
> +  *
> +  */
> +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_user);
> +
>  /** v4l2_ctrl_new_int_menu() - Create a new standard V4L2 integer menu control.
>    * @hdl:	The control handler.
>    * @ops:	The control ops.
> 

Regards,

	Hans
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