Re: [RFC PATCH 8/8] mtd: rawnand: ams-delta: Use GPIO callbacks for data I/O

Janusz Krzysztofik
2018-07-20T18:37:38Z

On Thursday, July 19, 2018 8:47:49 AM CEST Boris Brezillon wrote:
> On Thu, 19 Jul 2018 01:57:10 +0200
> Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:
>
> > Don't readw()/writew() data directly from/to GPIO port which is under
> > control of gpio-omap driver, use GPIO chip callbacks instead.
> >
> > Thanks to utilization of get/set_multiple() callbacks, performance
> > degrade is minor for typical data transfers.
>
> Same comment here, don't use the gpio_chip hooks directly, use the
> consumer API instead.

I tired but performance was not acceptable.

I see your point but please understand, what I'm trying to do here is not to
develop a shiny general purpose fully GPIO based NAND driver, I'm trying to
resolve issues with NAND driver for Amstrad Delta I like to play with, without
loosing much performance.

I'm going to reconsider all possible options, not only doing data I/O over
GPIO inside the driver, to have the task completed. Once done, I can get
back to the GPIO based code I developed so far and create a new generic driver
as my free time permits, or anyone can do that if needed, the code is open
source after all.

Thanks,
Janusz