On Mon, 20 Apr 2020 15:08:10 -0400 William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > On Mon, Apr 20, 2020 at 11:54:16AM -0700, Gwendal Grignou wrote: > > On Tue, Apr 14, 2020 at 1:48 PM William Breathitt Gray > > <vilhelm.gray@xxxxxxxxx> wrote: > > > > > > On Mon, Apr 13, 2020 at 12:55:14PM -0700, Gwendal Grignou wrote: > > > > When the camera vsync pin is connected to the embedded controller (EC) of > > > > a chromebook, the EC reports a sensor with a counter that increases > > > > at each GPIO rising edge. > > > > > > > > The sensor is presented using the counter subsystem. > > > > In addition, it is also presented via the IIO subsystem with a timestamp, > > > > allowing synchronisation with sensors connected to the same EC, for > > > > image stabilisation or augmented reality applications. > > > > > > Hi Gwendal, > > > > > > Sorry for the delay. I have some changes requested below. > > > > > > > To enable the counter: > > > > via counter ABI: > > > > echo "rising edge" > counterX/count0/signal_action > > > > via iio ABI > > > > echo 1 > iio:deviceY/en > > > > > > > > To disable the counter: > > > > via counter ABI: > > > > echo "none" > counterX/count0/signal_action > > > > via iio ABI > > > > echo 0 > iio:deviceY/en > > > > > > Although in theory a user could manually disable the actions for a > > > Signal, this is a very roundabout way of actually disabling the Count. > > > It's better to expose an "enable" attribute to allow the users to > > > perform this functionality; for example: > > > > > > echo 0 > counterX/count0/enable > > > echo 1 > counterX/count0/enable > > > > > > > > > > > To read the current counter value: > > > > via counter ABI: > > > > cat counterX/count0/count > > > > via iio ABI > > > > cat iio:deviceY/in_count_raw > > > > > > I know we discussed this in the last review but it's still the same as > > > before: IIO_COUNT interface is deprecated so new drivers won't be > > > allowed to use it. You'll have to remove the IIO_COUNT code in this > > > driver and replace it with Counter subsystem equivalents. > > I understand the need of a clean separation between counter and IIO subsystems. > > I will wait for counter to offer a way to gather timestamp'ed counts. > > Do you have a plan/proposed ABI you can share? > > > > Thanks, > > > > Gwendal. > > Hi Gwendal, > > I'm working on a reimplementation of the internals of the Counter > subsystem: https://gitlab.com/vilhelmgray/iio/-/tree/counter_chardev > > I'm hoping to submit it to the mailing list later this week if I don't > hit any delays; it'll include support as well for a character device > interface for userspace application. > > Once those changes are merged into IIO, I'll submit a patch to add > timestamp support -- hopefully within a week or two after. Right now I > haven't yet chosen any specific format for timestamps, but I will likely > match the format IIO subsystem currently has for its timestamp support > so that migration is easier for these drivers. > Don't copy our crazy clock choosing stuff. That's legacy rubbish for compatibility with a silly choice I made a long time ago. Pick a sensible clock type and stick to it. Jonathan > William Breathitt Gray
