Re: [RFC PATCH v2 0/3] gpio: Add gpio-delay support

[Rob Herring <robh+dt@xxxxxxxxxx>]

On Thu, Dec 15, 2022 at 7:16 AM Linus Walleij <linus.walleij@xxxxxxxxxx> wrote:
>
> On Wed, Dec 14, 2022 at 10:53 AM Alexander Stein
> <alexander.stein@xxxxxxxxxxxxxxx> wrote:
>
> > thanks for the feedback I've received. This is the reworked RFC for
> > adressing a platform specific ramp-up/ramp-down delay on GPIO outputs.
> > Now the delays are neither specified as gpio-controller nor
> > consumer-specific properties.
> >
> > v2 is a different approach than v1 in that it adds a new driver which will
> > simply forward setting the GPIO output of specified GPIOs in OF node.
> > The ramp-up/ramp-down delay can now be actually defined on consumer side,
> > see Patch 1 or 3 for examples.
>
> I really like this approach, it looks better than I imagined.

It seems over-engineered to me. So far no comments on my 3 suggestions either...

One is to just use some GPIO flag bits. Say 4-bits of GPIO flags
encoded as power of 2 ramp delay. We have to pick the units. For
example, 100us*2^N, which gives you 200us-3.2s of delay. Anything less
is short enough to just hard code in a driver.

Rob