From: Mark Brown <broonie@kernel.org>
To: Dan.Sneddon@microchip.com
Cc: linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Tudor.Ambarus@microchip.com,
Nicolas.Ferre@microchip.com, alexandre.belloni@bootlin.com,
Ludovic.Desroches@microchip.com
Subject: Re: [PATCH] spi: atmel: Fix CS and initialization bug
Date: Tue, 29 Jun 2021 18:07:41 +0100 [thread overview]
Message-ID: <20210629170741.GF4613@sirena.org.uk> (raw)
In-Reply-To: <c849eb7a-d019-b88e-583a-78e1eba7624c@microchip.com>
[-- Attachment #1: Type: text/plain, Size: 1145 bytes --]
On Tue, Jun 29, 2021 at 05:01:57PM +0000, Dan.Sneddon@microchip.com wrote:
> On 6/29/21 9:47 AM, Mark Brown wrote:
> >In what way does it do that? I can't tell what the patch is supposed >to
> >do.
> The SPI_MASTER_GPIO_SS flag has to be set so that the set_cs function
> gets called even when using gpio cs pins.
This all needs to be clear in the changelog.
> >> - enable =3D (!!(spi->mode & SPI_CS_HIGH) =3D=3D enable);
> >> =20
> >> - if (enable) {
> >> + if ((enable && (spi->mode & SPI_CS_HIGH))
> >> + || (!enable && !(spi->mode & SPI_CS_HIGH))) {
> >This looks especially suspicious.
> It's due to the fact that the spi core tells set_cs if the cs should be
> high or low, not active or disabled. This logic is to convert from
> high/low to active/disabled.
spi_set_cs() handles SPI_CS_HIGH... this looks like a separate existing
driver bug, it should just be ignoring SPI_CS_HIGH if it's providing a
set_cs() operation and letting the core implement SPI_CS_HIGH for it. I
only checked breifly but it looks like spi-atmel is trying to use the
core support for chipselect handling here.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2021-06-29 17:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-29 16:29 [PATCH] spi: atmel: Fix CS and initialization bug Dan Sneddon
2021-06-29 16:47 ` Mark Brown
2021-06-29 17:01 ` Dan.Sneddon
2021-06-29 17:07 ` Mark Brown [this message]
2021-06-29 17:50 ` Dan.Sneddon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210629170741.GF4613@sirena.org.uk \
--to=broonie@kernel.org \
--cc=Dan.Sneddon@microchip.com \
--cc=Ludovic.Desroches@microchip.com \
--cc=Nicolas.Ferre@microchip.com \
--cc=Tudor.Ambarus@microchip.com \
--cc=alexandre.belloni@bootlin.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-spi@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).