Re: [PATCH v3] media: v4l2-ctrl: add a helper function to modify the menu

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Prabhakar,

Thanks for the patch.

On Tuesday 11 September 2012 19:53:38 Prabhakar Lad wrote:
> From: Lad, Prabhakar <prabhakar.lad@ti.com>
> 
> Add a helper function to modify the menu, max and default value
> to set.
> 
> Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
> Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com>
> Cc: Hans Verkuil <hans.verkuil@cisco.com>
> Cc: Sakari Ailus <sakari.ailus@iki.fi>
> Cc: Sylwester Nawrocki <s.nawrocki@samsung.com>
> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: Kyungmin Park <kyungmin.park@samsung.com>
> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> Cc: Rob Landley <rob@landley.net>
> ---
> 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 |   29 ++++++++++++++++++++++++
>  drivers/media/v4l2-core/v4l2-ctrls.c        |   17 +++++++++++++++
>  include/media/v4l2-ctrls.h                  |   11 ++++++++++
>  3 files changed, 57 insertions(+), 0 deletions(-)
> 
> diff --git a/Documentation/video4linux/v4l2-controls.txt
> b/Documentation/video4linux/v4l2-controls.txt index 43da22b..01d0a82 100644
> --- a/Documentation/video4linux/v4l2-controls.txt
> +++ b/Documentation/video4linux/v4l2-controls.txt
> @@ -367,6 +367,35 @@ it to 0 means that all menu items are supported.
>  You set this mask either through the v4l2_ctrl_config struct for a custom
>  control, or by calling v4l2_ctrl_new_std_menu().
> 
> +There are situations where menu items may be device specific. In such cases
> the
> +framework provides a helper function to change the menu:
> +
> +void v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl, const char * const
> *qmenu,
> +	s32 max, u32 menu_skip_mask, s32 def);

Sorry if this is a stupid question, but wouldn't it be better to add a 
function to create a custom menu instead of modifying it afterwards ?

> +
> +A good example 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.
> +
> +This helper function is used to modify the menu, max, mask and the default
> +value of the control.
> +
> +Example:
> +
> +	static const char * const test_pattern[] = {
> +		"Disabled",
> +		"Vertical Bars",
> +		"Solid Black",
> +		"Solid White",
> +		NULL,
> +	};
> +	struct v4l2_ctrl *test_pattern_ctrl =
> +		v4l2_ctrl_new_std_menu(&foo->ctrl_handler, &foo_ctrl_ops,
> +			V4L2_CID_TEST_PATTERN, V4L2_TEST_PATTERN_DISABLED, 0,
> +			V4L2_TEST_PATTERN_DISABLED);
> +
> +	v4l2_ctrl_modify_menu(test_pattern_ctrl, test_pattern, 3, 0,
> +		V4L2_TEST_PATTERN_DISABLED);
> 
>  Custom Controls
>  ===============

-- 
Regards,

Laurent Pinchart