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Message-Id: <201209101413.12955.hverkuil@xs4all.nl>
Date: Mon, 10 Sep 2012 14:13:12 +0200
From: Hans Verkuil <hverkuil@...all.nl>
To: Prabhakar Lad <prabhakar.lad@...com>
Cc: LMML <linux-media@...r.kernel.org>,
dlos <davinci-linux-open-source@...ux.davincidsp.com>,
linux-kernel@...r.kernel.org,
Manjunath Hadli <manjunath.hadli@...com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
linux-doc@...r.kernel.org, Hans Verkuil <hans.verkuil@...co.com>,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
Sakari Ailus <sakari.ailus@....fi>,
Mauro Carvalho Chehab <mchehab@...radead.org>,
Hans de Goede <hdegoede@...hat.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Rob Landley <rob@...dley.net>
Subject: Re: [PATCH] media: v4l2-ctrl: add a helper fucntion to modify the menu
On Mon September 10 2012 13:57:36 Prabhakar Lad wrote:
> From: Lad, Prabhakar <prabhakar.lad@...com>
>
> Signed-off-by: Lad, Prabhakar <prabhakar.lad@...com>
> Signed-off-by: Manjunath Hadli <manjunath.hadli@...com>
> Cc: Hans Verkuil <hans.verkuil@...co.com>
> Cc: Sakari Ailus <sakari.ailus@....fi>
> Cc: Sylwester Nawrocki <s.nawrocki@...sung.com>
> Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Cc: Mauro Carvalho Chehab <mchehab@...radead.org>
> Cc: Hans de Goede <hdegoede@...hat.com>
> Cc: Kyungmin Park <kyungmin.park@...sung.com>
> Cc: Rob Landley <rob@...dley.net>
> ---
> Documentation/video4linux/v4l2-controls.txt | 26 +++++++++++++++++++++++++
> drivers/media/v4l2-core/v4l2-ctrls.c | 28 +++++++++++++++++++++++++++
> include/media/v4l2-ctrls.h | 14 +++++++++++++
> 3 files changed, 68 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/video4linux/v4l2-controls.txt b/Documentation/video4linux/v4l2-controls.txt
> index 43da22b..54a9539 100644
> --- a/Documentation/video4linux/v4l2-controls.txt
> +++ b/Documentation/video4linux/v4l2-controls.txt
> @@ -196,6 +196,32 @@ the error code at the end. Saves a lot of repetitive error checking.
> It is recommended to add controls in ascending control ID order: it will be
> a bit faster that way.
>
> +2.1) Changing the menu of a standard control:
> +There are suitations when the control is standard but the menu items may be
> +device specific, in such cases the framework provides the helper to do that.
The "Menu Controls" section in this file would be a better place to add this.
> +
> +struct v4l2_ctrl * v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
> + const char * const *qmenu, s32 min, s32 max,
> + u32 menu_skip_mask, s32 def);
> +
> +This helper, function is used to modify the menu, min, max, mask and
> +the default value to set.
> +Example for usage:
> + static const char * const test_pattern[] = {
> + "Disabled",
> + "Vertical Bars",
> + "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, 0, 5, 0x3, 0);
> +
> 3) Optionally force initial control setup:
>
> v4l2_ctrl_handler_setup(&foo->ctrl_handler);
> diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
> index d731422..ac0fb28 100644
> --- a/drivers/media/v4l2-core/v4l2-ctrls.c
> +++ b/drivers/media/v4l2-core/v4l2-ctrls.c
> @@ -2666,3 +2666,31 @@ unsigned int v4l2_ctrl_poll(struct file *file, struct poll_table_struct *wait)
> return 0;
> }
> EXPORT_SYMBOL(v4l2_ctrl_poll);
> +
> +/* Helper function for standard menu controls to modify the menu */
> +struct v4l2_ctrl *v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
> + const char * const *qmenu, s32 min,
The minimum is always 0 for menu controls, so this argument should be
removed. It's not part of v4l2_ctrl_new_std_menu either.
There is no need to return the pointer here, so just set the return to void.
> + s32 max, u32 menu_skip_mask, s32 def)
> +{
> + if (ctrl->type != V4L2_CTRL_TYPE_MENU)
> + return NULL;
> +
> + if (qmenu == NULL)
> + return NULL;
Change this to:
if (WARN_ON(ctrl->type != V4L2_CTRL_TYPE_MENU || qmenu == NULL))
return;
> +
> + /* Determine if it is standard menu control */
> + if (!v4l2_ctrl_get_menu(ctrl->id))
> + return NULL;
This test can be removed. Why should we prohibit calling this function for
non-standard controls?
> +
> + if ((def > max) || (max < min))
> + return NULL;
Also replace with if (WARN_ON(def < 0 || def > max)).
All these errors are driver errors and so should just report it in the kernel
log and then bail out.
> +
> + ctrl->qmenu = qmenu;
> + ctrl->minimum = min;
No need to set minimum. It's already 0.
> + ctrl->maximum = max;
> + ctrl->menu_skip_mask = menu_skip_mask;
> + ctrl->cur.val = ctrl->val = ctrl->default_value = def;
> +
> + return ctrl;
> +}
> +EXPORT_SYMBOL(v4l2_ctrl_modify_menu);
> diff --git a/include/media/v4l2-ctrls.h b/include/media/v4l2-ctrls.h
> index 776605f..5b0ea04 100644
> --- a/include/media/v4l2-ctrls.h
> +++ b/include/media/v4l2-ctrls.h
> @@ -488,6 +488,20 @@ static inline void v4l2_ctrl_unlock(struct v4l2_ctrl *ctrl)
> mutex_unlock(ctrl->handler->lock);
> }
>
> +/**
> + * v4l2_ctrl_modify_menu() - Modify the menu. This function is used when the
> + * control is standard but the menu is specific to device.
> + * @ctrl: The control to change the menu.
> + * @qmenu: The menu to which control will point to.
> + * @min: Minimum value of the control.
> + * @max: Maximum valur of the control.
> + * @menu_skip_mask: The control's skip mask for menu controls.
> + * @def: The default value for control.
> + */
> +struct v4l2_ctrl *v4l2_ctrl_modify_menu(struct v4l2_ctrl *ctrl,
> + const char * const *qmenu, s32 min,
> + s32 max, u32 menu_skip_mask, s32 def);
> +
> /** v4l2_ctrl_g_ctrl() - Helper function to get the control's value from within a driver.
> * @ctrl: The control.
> *
>
Regards,
Hans
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