linux-kernel - Re: [PATCH 01/10] spi: dw: Add support for polled operation via no IRQ specified in DT

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Message-ID: <20200514130407.guyk3r4ltjvszy5s@mobilestation>
Date:   Thu, 14 May 2020 16:04:07 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Mark Brown <broonie@...nel.org>
CC:     Serge Semin <fancer.lancer@...il.com>,
        Lars Povlsen <lars.povlsen@...rochip.com>,
        SoC Team <soc@...nel.org>,
        Microchip Linux Driver Support <UNGLinuxDriver@...rochip.com>,
        <linux-spi@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH 01/10] spi: dw: Add support for polled operation via no
 IRQ specified in DT

Hi Mark

On Wed, May 13, 2020 at 03:20:50PM +0100, Mark Brown wrote:
> On Wed, May 13, 2020 at 04:00:22PM +0200, Lars Povlsen wrote:
> > With this change a SPI controller can be added without having a IRQ
> > associated, and causing all transfers to be polled. For SPI controllers
> > without DMA, this can significantly improve performance by less
> > interrupt handling overhead.
> 
> This overlaps substantially with some work that Serge Semin (CCed) has
> in progress, please coordinate with him.

Thanks for copying me these mails. I haven't been Cc'ed in the series and
hasn't been subscribed to the SPI mailing list, so I would have definitely
missed that.

I would like to coordinate my efforts with Lars. I'll have the patchset reviewed
soon in addition providing my comments/suggestions of how to make it useful for
both mine and Lars solution.

One thing I can tell about the mem_ops he implemented, is that they aren't
mem_ops, but dirmap (as you remember it's also implemented in my code, but with
alignment specific), and the exec_mem_op partly consists of a code, which belong
to the supports_op() callback. The rest of my comments will be inlined in the
patches.

-Sergey