From: Mark Brown <broonie@kernel.org>
To: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Cc: Serge Semin <fancer.lancer@gmail.com>,
Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>,
Ramil Zaripov <Ramil.Zaripov@baikalelectronics.ru>,
Pavel Parkhomenko <Pavel.Parkhomenko@baikalelectronics.ru>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] spi: Take the SPI IO-mutex in the spi_setup() method
Date: Thu, 19 Nov 2020 18:43:40 +0000 [thread overview]
Message-ID: <20201119184340.GJ5554@sirena.org.uk> (raw)
In-Reply-To: <20201118162931.sdpofyw74yyr5n5z@mobilestation>
[-- Attachment #1: Type: text/plain, Size: 1179 bytes --]
On Wed, Nov 18, 2020 at 07:29:31PM +0300, Serge Semin wrote:
> On Wed, Nov 18, 2020 at 01:16:04PM +0000, Mark Brown wrote:
> > Yeah, problems with it are very common as the documentation has noted
> > since forever. IIRC there was some problem triggered by trying to force
> > it to be serialised but I can't remember what it was.
> Does it mean nack for this patch from you? So you suggest to fix the controller
> driver instead, right? If so the best solution would be to just lock the
> IO mutex in the set_cs callback of the DW APB SSI driver...
I'm not 100% clear what the original issue was, given that this is a
constant source of errors in drivers it seems like it should be better
to change the core but since I don't know why we have this the way it is
it's hard to tell what special cases we might have that could explode if
we try to do so. I *think* the main issue is things that don't actually
have separate per device registers trying to configure the single set of
controler registers shared by all devices in which case the locking is
fine and helps with this specific case where it's a read/modify/write
operation on per device stuff and this makes sense.
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
next prev parent reply other threads:[~2020-11-19 18:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-17 9:45 [RFC PATCH] spi: Take the SPI IO-mutex in the spi_setup() method Serge Semin
2020-11-17 10:56 ` Andy Shevchenko
2020-11-17 11:28 ` Serge Semin
2020-11-18 13:16 ` Mark Brown
2020-11-18 16:29 ` Serge Semin
2020-11-19 18:43 ` Mark Brown [this message]
2020-11-19 19:30 ` Geert Uytterhoeven
2020-11-20 17:17 ` Mark Brown
2020-11-20 17:26 ` Serge Semin
2020-11-20 21:35 ` Mark Brown
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=20201119184340.GJ5554@sirena.org.uk \
--to=broonie@kernel.org \
--cc=Alexey.Malahov@baikalelectronics.ru \
--cc=Pavel.Parkhomenko@baikalelectronics.ru \
--cc=Ramil.Zaripov@baikalelectronics.ru \
--cc=Sergey.Semin@baikalelectronics.ru \
--cc=fancer.lancer@gmail.com \
--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).