From: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: "Michał Mirosław" <mirq-linux-CoA6ZxLDdyEEUmgCuDUIdw@public.gmane.org>
Cc: linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] spi: fix cs_change for last transfer
Date: Mon, 16 Mar 2020 15:13:20 +0000 [thread overview]
Message-ID: <20200316151320.GI5010@sirena.org.uk> (raw)
In-Reply-To: <20200316143455.GA19141-cHozx32mtrEEUmgCuDUIdw@public.gmane.org>
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On Mon, Mar 16, 2020 at 03:34:55PM +0100, Michał Mirosław wrote:
> On Mon, Mar 16, 2020 at 12:17:50PM +0000, Mark Brown wrote:
> > This is the opposite of the intended behaviour - we want to deassert
> > chip select at the end of the message unless cs_change is set on the
> > last transfer. If this were broken I would expect to see widespread
> > problems being reported.
> This is unfortunate naming I suppose. I reread the spi.h comments
> a few more times and it seems indeed, that .cs_change == 1 on last
> transfer means to a driver: "you may leave CS unchanged" - quite the
> reverse compared to non-last transfers.
cs_change also means that we should add an extra chip select transition
on transfers other than the last.
> Please drop this patch then.
OK.
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prev parent reply other threads:[~2020-03-16 15:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-15 17:08 [PATCH] spi: fix cs_change for last transfer Michał Mirosław
2020-03-16 12:17 ` Mark Brown
2020-03-16 14:34 ` Michał Mirosław
[not found] ` <20200316143455.GA19141-cHozx32mtrEEUmgCuDUIdw@public.gmane.org>
2020-03-16 15:13 ` Mark Brown [this message]
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