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Message-ID: <504DDECB.9040508@ti.com>
Date: Mon, 10 Sep 2012 18:06:27 +0530
From: Manjunath Hadli <manjunath.hadli@...com>
To: Hans Verkuil <hverkuil@...all.nl>
CC: Prabhakar Lad <prabhakar.lad@...com>,
LMML <linux-media@...r.kernel.org>,
dlos <davinci-linux-open-source@...ux.davincidsp.com>,
<linux-kernel@...r.kernel.org>,
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
Hi Hans,
Thanks for the review.
On Monday 10 September 2012 05:43 PM, Hans Verkuil wrote:
> 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.
>
Ok.
>> +
>> +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.
>
Ok.
>> + 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;
>
Ok.
>> +
>> + /* 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?
>
Any how how if its custom control, the menu will be provided by user
itself, so why would he fell the necessity of this function ? But
providing an option wont harm I'll remove it.
>> +
>> + 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.
>
Ok.
>> +
>> + ctrl->qmenu = qmenu;
>> + ctrl->minimum = min;
>
> No need to set minimum. It's already 0.
>
Ok.
Regards,
--Prabhakar Lad
>> + 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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