Re: [RFC RFT PATCH 0/4] gpiolib: speed up GPIO array processing

Janusz Krzysztofik
2018-08-29T18:15:14Z

Hi Linus,

On Wednesday, August 29, 2018 11:06:21 AM CEST Linus Walleij wrote:
> On Tue, Aug 21, 2018 at 1:42 AM Janusz Krzysztofik <jmkrzyszt@gmail.com>
wrote:
>
> > This series is a follow up of the former "mtd: rawnand: ams-delta: Use
> > gpio-omap accessors for data I/O" which already contained some changes
> > to gpiolib. Those previous attempts were commented by Borris Brezillon
> > who suggested using GPIO API modified to accept bitmaps, and by Linus
> > Walleij who suggested still more great ideas for further immprovement
> > of the proposed API changes - thanks!
> >
> > The goal is to boost performans of get/set array functions while
> > processing GPIO arrays which represent pins of a signle chip in
> > hardware order. If resulting performance is close to PIO, GPIO API
> > can be used for data I/O without much loss of speed.
>
> Hands down, this is a very pretty patch set. I'm a big fan already.
>
> This is mainly because it fulfills the requirement for libraries
> to be narrow and deep, which is what we want.
> This refers to John Ousterhouts software design philosophy,
> here is a great lecture if you haven't seen it already:
> https://www.youtube.com/watch?v=bmSAYlu0NcY
>
> Let's get this into v1 and get some testing and merge it for v4.20
> ASAP

Please hold on for a while, I'm going to resubmit soon, with the comment from
Peter Rosin on i2c-mux-gpio addressed and the error discovered by Miguel Ojeda
in hd44780 fixed.

Thanks,
Janusz

> so we get some proper testing before the v4.20 merge
> window. It would be excellent if some of the current users of
> the array API could provide tested-by's or at least ACKs.
>
> For example ts-nbus.c must be a big benefactor.
>
> Yours,
> Linus Walleij
>