Hi Sakari,
On Wednesday 06 April 2011 11:25:56 Sakari Ailus wrote:
> Nayden Kanchev wrote:
> > On 04/06/2011 11:10 AM, Sakari Ailus wrote:
> >> - Added an open question on a new control:
> >> V4L2_CID_FLASH_EXTERNAL_STROBE_WHENCE.
> >
> > <snip>
> >
> >> 2. External strobe edge / level
> >> -------------------------------
> >>
> >> No use is seen currently for this, but it may well appear, and the
> >> hardware supports this. Level based trigger should be used since it is
> >> more precise.
> >>
> >> V4L2_CID_FLASH_EXTERNAL_STROBE_WHENCE
> >>
> >> Whether the flash controller considers external strobe as edge, when the
> >> only limit of the strobe is the timeout on flash controller, or level,
> >> when the flash strobe will last as long as the strobe signal, or as long
> >> until the timeout expires.
> >>
> >> enum v4l2_flash_external_strobe_whence {
> >>
> >> V4L2_CID_FLASH_EXTERNAL_STROBE_LEVEL,
> >> V4L2_CID_FLASH_EXTERNAL_STROBE_EDGE,
> >>
> >> };
>
> Removed "CID_":
>
> enum v4l2_flash_external_strobe_whence {
> V4L2_FLASH_EXTERNAL_STROBE_LEVEL,
> V4L2_FLASH_EXTERNAL_STROBE_EDGE,
> };
>
> I guess this should be an rw menu control for LED flash?
>
> > I agree that control over the strobe usage (level/edge) is required.
> > Although we have some bad experience will lack of detailed information
> > how exactly the flash chip will use those signals.
> >
> > For example with AS3645A flash driver strobing by edge produced really
> > strange flash output - light intensity was changing during the process
> > and flash was stopped before the HW timeout.
> >
> > On the other hand strobing by level didn't cause problems.
> >
> > So even if HW supports some functionally we should prevent such
> > malfunctioning by adding some restrictions in the board code also.
>
> I agree.
>
> The control should be probably exposed to tell which kind of
> functionality does the flash chip provide, even if the menu has just one
> option in it.
>
> > I would also rename xxx_STROBE_WHENCE to xxx_STROBE_TYPE but it is just
> > a suggestion :)
>
> Sounds good to me.
>
> V4L2_CID_FLASH_STROBE_MODE should be renamed to
> V4L2_CID_FLASH_STROBE_WHENCE. That proper use of whence IMO. :-)
Does this really need to be exposed to userspace ? Shouldn't it just be static
information coming from platform data ?
--
Regards,
Laurent Pinchart
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