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Date: Wed, 19 Sep 2012 14:34:01 +0530
From: Prabhakar Lad <prabhakar.csengg@...il.com>
To: Hans Verkuil <hverkuil@...all.nl>
Cc: LMML <linux-media@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>,
DLOS <davinci-linux-open-source@...ux.davincidsp.com>,
Mauro Carvalho Chehab <mchehab@...radead.org>,
linux-doc@...r.kernel.org, "Lad, Prabhakar" <prabhakar.lad@...com>,
Manjunath Hadli <manjunath.hadli@...com>,
Hans Verkuil <hans.verkuil@...co.com>,
Sakari Ailus <sakari.ailus@....fi>,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Hans de Goede <hdegoede@...hat.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Guennadi Liakhovetski <g.liakhovetski@....de>,
Rob Landley <rob@...dley.net>
Subject: Re: [PATCH v4] media: v4l2-ctrl: add a helper function to add
standard control with driver specific menu
Hi Hans,
Thanks for the review.
On Wed, Sep 19, 2012 at 1:23 PM, Hans Verkuil <hverkuil@...all.nl> wrote:
> 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@...com>
>>
>> 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@...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: Guennadi Liakhovetski <g.liakhovetski@....de>
>> Cc: Rob Landley <rob@...dley.net>
>> ---
>> 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
>
Ok.
>> +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.
>
Ok.
>> +
>> 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
>
Ok.
>> +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.
>
Ok.
>> +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)
>
This check is if it really belongs standard menu control, here
qmenu is filled by v4l2_ctrl_get_menu(), If it returns null its a error case.
> Add a comment that v4l2_ctrl_new_std_menu_items() may only be called for
> standard controls *without* a standard menu.
>
Ok.
>> + 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.'
>
Ok.
Regards,
--Prabhakar
>> + * 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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