On Sat, Jun 03, 2017 at 09:46:36PM -0700, Steve Longerbeam wrote:

On 06/03/2017 02:57 PM, Sakari Ailus wrote:

quoted

On Sat, Jun 03, 2017 at 09:51:39PM +0200, Pavel Machek wrote:

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Hi!

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+	/* Auto/manual exposure */
+	ctrls->auto_exp = v4l2_ctrl_new_std_menu(hdl, ops,
+						 V4L2_CID_EXPOSURE_AUTO,
+						 V4L2_EXPOSURE_MANUAL, 0,
+						 V4L2_EXPOSURE_AUTO);
+	ctrls->exposure = v4l2_ctrl_new_std(hdl, ops,
+					    V4L2_CID_EXPOSURE_ABSOLUTE,
+					    0, 65535, 1, 0);

Is exposure_absolute supposed to be in microseconds...?

Yes.

According to the docs V4L2_CID_EXPOSURE_ABSOLUTE is in 100 usec units.

 OTOH V4L2_CID_EXPOSURE has no defined unit, so it's a better fit IMO.

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Way more drivers appear to be using EXPOSURE than EXPOSURE_ABSOLUTE, too.

Done, switched to V4L2_CID_EXPOSURE. It's true, this control is not
taking 100 usec units, so unit-less is better.

Thanks. If you know the units, it would be of course better to use
right units...

Steve: what's the unit in this case? Is it lines or something else?

Yes, the register interface for exposure takes lines*16.

Maybe converting from seconds to lines is as simple as
framerate * height * seconds. But I'm not sure about that.

The smiapp and a few other drivers are using lines. One option could be to
use lines as the unit and have step as 16.

Then the hblank + vblank controls will be needed, too, to enable the user to
at least figure out the conversion to Si units.

-- 
Sakari Ailus
e-mail: sakari.ailus-X3B1VOXEql0@public.gmane.org	XMPP: sailus-PCDdDYkjdNMDXYZnReoRVg@public.gmane.org
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