Re: [PATCH 4/8] docs: counter: add unit timer sysfs attributes

From: William Breathitt Gray
Date: Thu Oct 28 2021 - 03:59:20 EST


On Wed, Oct 27, 2021 at 10:30:36AM -0500, David Lechner wrote:
> On 10/27/21 1:46 AM, William Breathitt Gray wrote:
> > On Sat, Oct 16, 2021 at 08:33:39PM -0500, David Lechner wrote:
> >> This documents new unit timer sysfs attributes for the counter
> >> subsystem.
> >>
> >> Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
> >
> > Hello David,
> >
> > The unit timer is effectively a Count in its own right, so instead of
> > introducing new sysfs attributes you can just implement it as another
> > Count in the driver. Count 0 is "QPOSCNT", so set the name of this new
> > Count 1 as "Unit Timer" (or the datasheet naming if more apt) to
> > differentiate the Counts. You can then provide the "unit_timer_enable",
> > "unit_timer_period", and "unit_timer_time" functionalities as respective
> > Count 1 extensions ("enable" and "period") and Count 1 "count".

Actually if the counter function here is COUNTER_FUNCTION_DECREASE, then
instead of introducing a new "period" extension, define this as a
"ceiling" extension; that's what ceiling represents in the Counter
interface: "the upper limit for the respective counter", which is the
period of a timer counting down to a timeout.

William Breathitt Gray

> >
> > If you believe it appropriate, you can provide the raw timer ticks via
> > the Count 1 "count" while a nanoseconds interface is provided via a
> > Count 1 extension "timeout" (or something similar).
> >
>
> Sounds reasonable.
>

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