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Date:   Wed, 8 Aug 2018 19:42:42 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Janusz Krzysztofik <jmkrzyszt@gmail.com>
Cc:     Boris Brezillon <boris.brezillon@bootlin.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        linux-omap@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
        Tony Lindgren <tony@atomide.com>,
        Richard Weinberger <richard@nod.at>,
        linux-gpio@vger.kernel.org, Aaro Koskinen <aaro.koskinen@iki.fi>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        Marek Vasut <marek.vasut@gmail.com>,
        linux-mtd@lists.infradead.org,
        Brian Norris <computersforpeace@gmail.com>,
        David Woodhouse <dwmw2@infradead.org>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH v2 07/12] mtd: rawnand: ams-delta: Set port
 direction once per transfer
Message-ID: <20180808194242.7540ce12@xps13>
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        <20180806222918.12644-8-jmkrzyszt@gmail.com>
        <20180807205752.32cd3e53@bbrezillon>
        <3260564.acbQT1CZaz@z50>
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Hi Janusz,

Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote on Wed, 08 Aug 2018
18:55:35 +0200:

> Hi Boris,
> 
> On Tuesday, August 7, 2018 8:57:52 PM CEST Boris Brezillon wrote:
> > On Tue,  7 Aug 2018 00:29:13 +0200
> > Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:
> >   
> > > In its current shape, the driver sets data port direction before each
> > > byte read/write operation, even during multi-byte transfers.  Since
> > > performance of the driver is completely not acceptable on Amstrad Delta
> > > after it has been converted to GPIO bitbang, try to improve things a
> > > bit by setting the port direction only on first byte of each transfer.  
> > ...
> > I'd suggest a slightly different approach where the data pins
> > direction state is stored in the the priv struct and only changed when
> > required. This way you just have to add a test in
> > ams_delta_read/write_byte().  
> 
> Good idea, I'm going to use it, thanks.
> 
> Once done, may I also move that one earlier in the series so that it can be 
> applied while our discussion on GPIO bitmap changes still continues?

I think I may answer on his behalf: yes! You can move the GPIO bitmap
changes at the end of the series, checking that you never break the
bisectability. Then I could apply the major changes and let us iterate
on the GPIO bitmap stuff only.

Thanks,
Miquèl