Hi! > On 02/15/17 00:47, Pavel Machek wrote: > > On Tue 2017-02-14 14:20:22, Sakari Ailus wrote: > >> Add a V4L2 control class for voice coil lens driver devices. These are > >> simple devices that are used to move a camera lens from its resting > >> position. > >> > >> Signed-off-by: Sakari Ailus > > > > Looks good to me. > > > > I wonder... should we somehow expose the range of diopters to > > userspace? I believe userland camera application will need that > > information. > > It'd certainly be useful to be able to provide more information. > > The question is: where to store it, and how? It depends on the voice > coil, the spring constant, the lens and the distance of the lens from > the sensor --- at least. Probably the sensor size as well. > > On voice coil lenses it is also somewhat inexact. I was thinking read-only attribute providing minimum and maximum diopters in case there's linear relationship as on N900. +#define V4L2_CID_VOICE_DIOPTERS_AT_REST (V4L2_CID_VOICE_COIL_CLASS_BASE + 2) +#define V4L2_CID_VOICE_DIOPTERS_AT_MAX (V4L2_CID_VOICE_COIL_CLASS_BASE + 3) ? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html