From: Hector Martin <marcan@marcan.st>
To: Mark Brown <broonie@kernel.org>
Cc: Alexandru Ardelean <alexandru.ardelean@analog.com>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
Joey Gouly <joey.gouly@arm.com>
Subject: Re: [PATCH] spi: Fix incorrect cs_setup delay handling
Date: Sat, 11 Dec 2021 01:32:06 +0900 [thread overview]
Message-ID: <3c94fa29-6c21-9fbd-b1f5-eb6c846054bb@marcan.st> (raw)
In-Reply-To: <YbN+cBQlsLprirxW@sirena.org.uk>
On 11/12/2021 01.21, Mark Brown wrote:
> On Sat, Dec 11, 2021 at 12:36:34AM +0900, Hector Martin wrote:
>
>> We need to wait *after* asserting CS and before the transfer, not before
>> asserting CS which isn't very useful.
>
> This needs a better changelog, there's multiple delays being handled
> here and it's not clear from this which are affected here or what the
> problem is.
cs_setup is affected, I thought at least that was clear from the patch
summary :-)
From spi.h:
* @cs_setup: delay to be introduced by the controller after CS is asserted
So clearly that delay has to happen at the end of spi_set_cs, *after*
the assertion, not at the beginning before it.
If you prefer, I can resend it with a reference to the spi.h comment.
--
Hector Martin (marcan@marcan.st)
Public Key: https://mrcn.st/pub
next prev parent reply other threads:[~2021-12-10 16:32 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-10 15:36 Hector Martin
2021-12-10 16:21 ` Mark Brown
2021-12-10 16:32 ` Hector Martin [this message]
2021-12-10 16:39 ` Mark Brown
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