Hi,
On 12/28/2011 07:23 AM, HeungJun, Kim wrote:
> It adds the new CID for setting White Balance Preset. This CID is provided as
> menu type using the following items:
> 0 - V4L2_WHITE_BALANCE_INCANDESCENT,
> 1 - V4L2_WHITE_BALANCE_FLUORESCENT,
> 2 - V4L2_WHITE_BALANCE_DAYLIGHT,
> 3 - V4L2_WHITE_BALANCE_CLOUDY,
> 4 - V4L2_WHITE_BALANCE_SHADE,
I have been also investigating those white balance presets recently and noticed
they're also needed for the pwc driver. Looking at
drivers/media/video/pwc/pwc-v4l2.c there is something like:
const char * const pwc_auto_whitebal_qmenu[] = {
"Indoor (Incandescant Lighting) Mode",
"Outdoor (Sunlight) Mode",
"Indoor (Fluorescent Lighting) Mode",
"Manual Mode",
"Auto Mode",
NULL
};
static const struct v4l2_ctrl_config pwc_auto_white_balance_cfg = {
.ops = &pwc_ctrl_ops,
.id = V4L2_CID_AUTO_WHITE_BALANCE,
.type = V4L2_CTRL_TYPE_MENU,
.max = awb_auto,
.qmenu = pwc_auto_whitebal_qmenu,
};
...
cfg = pwc_auto_white_balance_cfg;
cfg.name = v4l2_ctrl_get_name(cfg.id);
cfg.def = def;
pdev->auto_white_balance = v4l2_ctrl_new_custom(hdl, &cfg, NULL);
So this driver re-defines V4L2_CID_AUTO_WHITE_BALANCE as a menu control
with custom entries. That's interesting... However it works in practice
and applications have access to what's provided by hardware.
Perhaps V4L2_CID_AUTO_WHITE_BALANCE_TEMPERATURE would be a better fit for
that :)
Nevertheless, redefining standard controls in particular drivers sounds
a little dubious. I wonder if this is a generally agreed approach ?
Then, how does your V4L2_CID_PRESET_WHITE_BALANCE control interact with
V4L2_CID_AUTO_WHITE_BALANCE control ? Does V4L2_CID_AUTO_WHITE_BALANCE need
to be set to false for V4L2_CID_PRESET_WHITE_BALANCE to be effective ?
> Signed-off-by: HeungJun, Kim <[email protected]>
> Signed-off-by: Kyungmin Park <[email protected]>
> ---
> Documentation/DocBook/media/v4l/controls.xml | 38
> ++++++++++++++++++++++++++
> drivers/media/video/v4l2-ctrls.c | 12 ++++++++
> include/linux/videodev2.h | 9 ++++++
> 3 files changed, 59 insertions(+), 0 deletions(-)
>
> diff --git a/Documentation/DocBook/media/v4l/controls.xml
> b/Documentation/DocBook/media/v4l/controls.xml
> index c0422c6..350c138 100644
> --- a/Documentation/DocBook/media/v4l/controls.xml
> +++ b/Documentation/DocBook/media/v4l/controls.xml
> @@ -2841,6 +2841,44 @@ it one step further. This is a write-only
> control.</entry>
> </row>
> <row><entry></entry></row>
>
> + <row id="v4l2-preset-white-balance">
> + <entry
> spanname="id"><constant>V4L2_CID_PRESET_WHITE_BALANCE</constant> </entry>
Wouldn't V4L2_CID_WHITE_BALANCE_PRESET be better ?
> + <entry>enum v4l2_preset_white_balance</entry>
> + </row><row><entry spanname="descr">This control sets
> + the camera's white balance by the presets. These preset is provided
> + by the type of the enum values which are generally provided
> + by several digital cameras. But, it dosen't mean that the specific
s/dosent'/doesn't
> + preset always can be counterposed with the unique white balance value.
> + This is a read/write control.</entry>
We probably only need such a remark if a control is read-only or write-only.
> + </row>
> + <row>
> + <entrytbl spanname="descr" cols="2">
> + <tbody valign="top">
> + <row>
> +
> <entry><constant>V4L2_WHITE_BALANCE_INCANDESCENT</constant> </entry>
> + <entry>White Balance Incandescent/Tungster preset.</entry>
s/Tungster/Tungsten
If we are to have these presets, then we need to be a little bit more verbose
about what they mean. To avoid situation similar to V4L2_CID_COLORFX control
where nobody knows exactly what's an exact meaning of the menu items.
> + </row>
> + <row>
> +
> <entry><constant>V4L2_WHITE_BALANCE_FLUORESCENT</constant> </entry>
> + <entry>White Balance Fluorescent preset.</entry>
> + </row>
> + <row>
> +
> <entry><constant>V4L2_WHITE_BALANCE_DAYLIGHT</constant> </entry>
> + <entry>White Balance Daylight preset.</entry>
> + </row>
> + <row>
> +
> <entry><constant>V4L2_WHITE_BALANCE_CLOUDY</constant> </entry>
> + <entry>White Balance Cloudy preset.</entry>
> + </row>
> + <row>
> +
> <entry><constant>V4L2_WHITE_BALANCE_SHADE</constant> </entry>
> + <entry>White Balance Share preset.</entry>
s/Share/Shade
> + </row>
> + </tbody>
> + </entrytbl>
> + </row>
> + <row><entry></entry></row>
> +
> <row>
> <entry
> spanname="id"><constant>V4L2_CID_PRIVACY</constant> </entry>
> <entry>boolean</entry>
> diff --git a/drivers/media/video/v4l2-ctrls.c
> b/drivers/media/video/v4l2-ctrls.c
> index 0f415da..f51b576 100644
> --- a/drivers/media/video/v4l2-ctrls.c
> +++ b/drivers/media/video/v4l2-ctrls.c
> @@ -234,6 +234,14 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
> "Vivid",
> NULL
> };
> + static const char * const preset_white_balance[] = {
> + "Incandescent",
> + "Fluorescent",
> + "Daylight",
> + "Cloudy",
> + "Shade",
> + NULL,
> + };
> static const char * const tune_preemphasis[] = {
> "No Preemphasis",
> "50 useconds",
> @@ -390,6 +398,8 @@ const char * const *v4l2_ctrl_get_menu(u32 id)
> return camera_exposure_auto;
> case V4L2_CID_COLORFX:
> return colorfx;
> + case V4L2_CID_PRESET_WHITE_BALANCE:
> + return preset_white_balance;
> case V4L2_CID_TUNE_PREEMPHASIS:
> return tune_preemphasis;
> case V4L2_CID_FLASH_LED_MODE:
> @@ -567,6 +577,7 @@ const char *v4l2_ctrl_get_name(u32 id)
> case V4L2_CID_PRIVACY: return "Privacy";
> case V4L2_CID_IRIS_ABSOLUTE: return "Iris, Absolute";
> case V4L2_CID_IRIS_RELATIVE: return "Iris, Relative";
> + case V4L2_CID_PRESET_WHITE_BALANCE: return "White Balance, Preset";
>
> /* FM Radio Modulator control */
> /* Keep the order of the 'case's the same as in videodev2.h! */
> @@ -680,6 +691,7 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum
> v4l2_ctrl_type *type,
> case V4L2_CID_MPEG_STREAM_VBI_FMT:
> case V4L2_CID_EXPOSURE_AUTO:
> case V4L2_CID_COLORFX:
> + case V4L2_CID_PRESET_WHITE_BALANCE:
> case V4L2_CID_TUNE_PREEMPHASIS:
> case V4L2_CID_FLASH_LED_MODE:
> case V4L2_CID_FLASH_STROBE_SOURCE:
> diff --git a/include/linux/videodev2.h b/include/linux/videodev2.h
> index 3d62631..a842de0 100644
> --- a/include/linux/videodev2.h
> +++ b/include/linux/videodev2.h
> @@ -1618,6 +1618,15 @@ enum v4l2_exposure_auto_type {
> #define V4L2_CID_IRIS_ABSOLUTE
> (V4L2_CID_CAMERA_CLASS_BASE+17)
> #define V4L2_CID_IRIS_RELATIVE
> (V4L2_CID_CAMERA_CLASS_BASE+18)
>
> +#define V4L2_CID_PRESET_WHITE_BALANCE
> (V4L2_CID_CAMERA_CLASS_BASE+19)
> +enum v4l2_preset_white_balance {
> + V4L2_WHITE_BALANCE_INCANDESCENT = 0,
> + V4L2_WHITE_BALANCE_FLUORESCENT = 1,
> + V4L2_WHITE_BALANCE_DAYLIGHT = 2,
> + V4L2_WHITE_BALANCE_CLOUDY = 3,
> + V4L2_WHITE_BALANCE_SHADE = 4,
> +};
> +
> /* FM Modulator class control IDs */
> #define V4L2_CID_FM_TX_CLASS_BASE (V4L2_CTRL_CLASS_FM_TX | 0x900)
> #define V4L2_CID_FM_TX_CLASS (V4L2_CTRL_CLASS_FM_TX | 1)
--
Thanks,
Sylwester
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