Re: [PATCH] spi: add driver for BCM2835

From: Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
To: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>
Cc: Grant Likely
	<grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>,
	spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	Chris Boot <bootc-1Slo4GeK4H1eoWH0uzbU5w@public.gmane.org>,
	linux-rpi-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH] spi: add driver for BCM2835
Date: Wed, 6 Mar 2013 12:33:43 +0800	[thread overview]
Message-ID: <20130306043333.GB4896@opensource.wolfsonmicro.com> (raw)
In-Reply-To: <5136C5AB.7020301-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>

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On Tue, Mar 05, 2013 at 09:27:23PM -0700, Stephen Warren wrote:
> On 03/05/2013 09:05 PM, Mark Brown wrote:
> > On Tue, Mar 05, 2013 at 07:49:02PM -0700, Stephen Warren wrote:

> >> +Optional properties: +- brcm,realtime: Boolean. Indicates the
> >> driver should operate with realtime +  priority to minimise the
> >> transfer latency on the bus.

> > This isn't obviously something that ought to be in DT, it'll depend
> > on the OS, kernel version and so on.  Indeed I don't think this is

> If that somehow accidentally snuck in, I can happily remove this feature.

Dunno, my call would be to remove it.

> >> wait_for_completion_timeout(&bs->done, +
> >> msecs_to_jiffies(BCM2835_SPI_TIMEOUT_MS)); +		if (!timeout) { +
> >> err = -ETIMEDOUT; +			goto out; +		}

> > But I wanted to transfer 10G in a single message at 1kHz!  :P

> I'm not sure what the solution is here; calculated timeout value, or
> no timeout?

Either that or just make sure that the timeout that's picked is very
high I guess.

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