All of lore.kernel.org
 help / color / mirror / Atom feed
From: Mark Brown <broonie@kernel.org>
To: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>,
	Radu Pirea <radu.pirea@microchip.com>,
	robh+dt@kernel.org, mark.rutland@arm.com,
	linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org
Subject: Re: [PATCH 2/3] dt-bindings: add binding for at91-usart in spi mode
Date: Tue, 17 Apr 2018 12:03:58 +0100	[thread overview]
Message-ID: <20180417110358.GD8973@sirena.org.uk> (raw)
In-Reply-To: <20180413181251.GG22187@piout.net>

[-- Attachment #1: Type: text/plain, Size: 860 bytes --]

On Fri, Apr 13, 2018 at 08:12:51PM +0200, Alexandre Belloni wrote:
> On 13/04/2018 19:12:54+0200, Nicolas Ferre wrote:

> > This layout of the hardware is completely different from the USART one and
> > it seems to makes sense to address it with a different hardware description
> > and so a different compatible string.

> But then, you can end up with two drivers trying to use the same IP
> because nothing prevents you from writing a DT with both a usart and an
> spi node enabled for the same IP. request_mem_region() will not help
> here because then the working driver will depend on the probing order.

We don't really have too much in the way of better ideas for how to
handle this though.  Take a look at how the PXA SSP stuff handles this,
though that's not really doing too much different it at least layers a
mechanism on top to avoid collisions.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

WARNING: multiple messages have this Message-ID (diff)
From: broonie@kernel.org (Mark Brown)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/3] dt-bindings: add binding for at91-usart in spi mode
Date: Tue, 17 Apr 2018 12:03:58 +0100	[thread overview]
Message-ID: <20180417110358.GD8973@sirena.org.uk> (raw)
In-Reply-To: <20180413181251.GG22187@piout.net>

On Fri, Apr 13, 2018 at 08:12:51PM +0200, Alexandre Belloni wrote:
> On 13/04/2018 19:12:54+0200, Nicolas Ferre wrote:

> > This layout of the hardware is completely different from the USART one and
> > it seems to makes sense to address it with a different hardware description
> > and so a different compatible string.

> But then, you can end up with two drivers trying to use the same IP
> because nothing prevents you from writing a DT with both a usart and an
> spi node enabled for the same IP. request_mem_region() will not help
> here because then the working driver will depend on the probing order.

We don't really have too much in the way of better ideas for how to
handle this though.  Take a look at how the PXA SSP stuff handles this,
though that's not really doing too much different it at least layers a
mechanism on top to avoid collisions.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: not available
URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20180417/26668ad7/attachment.sig>

  reply	other threads:[~2018-04-17 11:04 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-13 16:11 [PATCH 0/3] Driver for AT91 USART in SPI mode Radu Pirea
2018-04-13 16:11 ` Radu Pirea
2018-04-13 16:11 ` Radu Pirea
2018-04-13 16:11 ` [PATCH 1/3] MAINTAINERS: add usart spi driver Radu Pirea
2018-04-13 16:11   ` Radu Pirea
2018-04-13 16:11   ` Radu Pirea
2018-04-13 16:11 ` [PATCH 2/3] dt-bindings: add binding for at91-usart in spi mode Radu Pirea
2018-04-13 16:11   ` Radu Pirea
2018-04-13 16:11   ` Radu Pirea
2018-04-13 16:23   ` Alexandre Belloni
2018-04-13 16:23     ` Alexandre Belloni
2018-04-13 17:12     ` Nicolas Ferre
2018-04-13 17:12       ` Nicolas Ferre
2018-04-13 17:12       ` Nicolas Ferre
2018-04-13 18:12       ` Alexandre Belloni
2018-04-13 18:12         ` Alexandre Belloni
2018-04-17 11:03         ` Mark Brown [this message]
2018-04-17 11:03           ` Mark Brown
2018-04-19 10:04           ` Radu Pirea
2018-04-19 10:04             ` Radu Pirea
2018-04-19 10:04             ` Radu Pirea
2018-04-19 14:55             ` Mark Brown
2018-04-19 14:55               ` Mark Brown
2018-04-19 13:32           ` Alexandre Belloni
2018-04-19 13:32             ` Alexandre Belloni
2018-04-19 14:07             ` Mark Brown
2018-04-19 14:07               ` Mark Brown
2018-04-13 16:11 ` [PATCH 3/3] spi: at91-usart: add driver for at91-usart as spi Radu Pirea
2018-04-13 16:11   ` Radu Pirea
2018-04-13 16:11   ` Radu Pirea

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=20180417110358.GD8973@sirena.org.uk \
    --to=broonie@kernel.org \
    --cc=alexandre.belloni@bootlin.com \
    --cc=devicetree@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-spi@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=nicolas.ferre@microchip.com \
    --cc=radu.pirea@microchip.com \
    --cc=robh+dt@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.