linux-kernel - Re: [PATCH v2 04/15] spi: Replace open coded spi_controller_xfer

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Message-ID: <e3688ce5-616a-4399-a4e3-c410a09f6a45@sirena.org.uk>
Date:   Tue, 11 Jul 2023 14:05:18 +0100
From:   Mark Brown <broonie@...nel.org>
To:     AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Amit Kumar Mahapatra via Alsa-devel 
        <alsa-devel@...a-project.org>,
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        Tharun Kumar P <tharunkumar.pasumarthi@...rochip.com>,
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        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, linux-spi@...r.kernel.org,
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        Richard Cochran <richardcochran@...il.com>
Subject: Re: [PATCH v2 04/15] spi: Replace open coded
 spi_controller_xfer_timeout()

On Tue, Jul 11, 2023 at 10:28:13AM +0200, AngeloGioacchino Del Regno wrote:
> Il 10/07/23 17:49, Andy Shevchenko ha scritto:

> > +		ms = spi_controller_xfer_timeout(ctlr, xfer);

> I agree on using helpers, but the logic is slightly changing here: yes it is
> unlikely (and also probably useless) to get ms == UINT_MAX, but the helper is
> limiting the maximum timeout value to 500mS, which may not work for some slow
> controllers/devices.

The helper is limiting the *minimum* timeout value to 500ms - it's using
max() not min().  The idea is the other way around, that for a very fast
transfer we don't want to end up with such a short timeout that it false
triggers due to scheduling issues.

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