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Message-ID: <2165137.iTHcPHRtIn@z50>
Date: Fri, 20 Jul 2018 20:38:15 +0200
From: Janusz Krzysztofik <jmkrzyszt@...il.com>
To: Boris Brezillon <boris.brezillon@...tlin.com>
Cc: Miquel Raynal <miquel.raynal@...tlin.com>,
Tony Lindgren <tony@...mide.com>,
Aaro Koskinen <aaro.koskinen@....fi>,
Grygorii Strashko <grygorii.strashko@...com>,
Santosh Shilimkar <ssantosh@...nel.org>,
Kevin Hilman <khilman@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Richard Weinberger <richard@....at>,
David Woodhouse <dwmw2@...radead.org>,
Brian Norris <computersforpeace@...il.com>,
Marek Vasut <marek.vasut@...il.com>,
linux-mtd@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject: Re: [RFC PATCH 8/8] mtd: rawnand: ams-delta: Use GPIO callbacks for data I/O
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@...il.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
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