From: Mark Brown <broonie@kernel.org>
To: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: fix cs_change for last transfer
Date: Mon, 16 Mar 2020 12:17:50 +0000 [thread overview]
Message-ID: <20200316121750.GD5010@sirena.org.uk> (raw)
In-Reply-To: <45912ba25c34a63b8098f471c3c8ebf8857a4716.1584292056.git.mirq-linux@rere.qmqm.pl>
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On Sun, Mar 15, 2020 at 06:08:53PM +0100, Michał Mirosław wrote:
> Generic spi_transfer_one_message() implementation introduced in
> commit b158935f70b9 has a bug in cs_change handling: it keeps CS
> asserted when cs_change is set. Fix it.
> struct spi_transfer *xfer;
> - bool keep_cs = false;
> + bool keep_cs = true;
> int ret = 0;
> struct spi_statistics *statm = &ctlr->statistics;
> struct spi_statistics *stats = &msg->spi->statistics;
> @@ -1268,7 +1268,7 @@ static int spi_transfer_one_message(struct spi_controller *ctlr,
> if (xfer->cs_change) {
> if (list_is_last(&xfer->transfer_list,
> &msg->transfers)) {
> - keep_cs = true;
> + keep_cs = false;
> } else {
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.
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next prev parent reply other threads:[~2020-03-16 12:17 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 [this message]
2020-03-16 14:34 ` Michał Mirosław
2020-03-16 15:13 ` Mark Brown
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