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From: Mark Brown <broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
To: Jassi Brar <jassisinghbrar-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: spi-devel-general-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	David Brownell
	<dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 1/2] spi/spi_s3c64xx: Make probe more robust against missing board config
Date: Mon, 23 Aug 2010 10:57:22 +0100	[thread overview]
Message-ID: <20100823095722.GA6061@rakim.wolfsonmicro.main> (raw)
In-Reply-To: <AANLkTikDj7YsOQXnFGjZCNRYuQQbLRtKiWw5Sm=vkCuq-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Sun, Aug 22, 2010 at 12:37:25PM +0900, Jassi Brar wrote:

> An immediate kernel crash ? :)
> I mean if the developer didn't even run-check the board init code, he ought
> to face a kernel crash.
> On a more lenient note, probably a check like yours or !sci->num_cs
> could be added.

I'd personally not actually be that upset with a BUG_ON(), my main
reason for changing the code was that it was non-obvious what the source
of the error was rather than the fact that things fell over.

> > It did occur to me that a nice way of dealing with this would be to have
> > the driver default to using the built in chip select (even if driven as
> > a GPIO for the sake of code simplicity) but leave the current method
> > there as an override.  That way if people are using the IP block in the
> > "natural" manner they'd have less to set up.

> I thought about it but decided against it, for that would complicate the
> driver by having to switch between two mechanism in runtime and there
> are some peculiarities in the controller about clocking and CS'ing.

Yeah, that's why I suggested driving it as a GPIO for simplicity - from
the user point of view it doesn't matter if that's what the controller
does so long as the driver figures out the chip select without external
help.

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      parent reply	other threads:[~2010-08-23  9:57 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-20 16:17 [PATCH 1/2] spi/spi_s3c64xx: Make probe more robust against missing board config Mark Brown
2010-08-20 16:17 ` [PATCH 2/2] spi/spi_s3c64xx: Staticise non-exported functions Mark Brown
     [not found]   ` <1282321028-32196-2-git-send-email-broonie-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
2010-08-21  1:52     ` Jassi Brar
2010-08-20 20:46 ` [PATCH 1/2] spi/spi_s3c64xx: Make probe more robust against missing board config Grant Likely
2010-08-21  1:45 ` [spi-devel-general] " Jassi Brar
2010-08-21 10:08   ` Mark Brown
     [not found]     ` <20100821100855.GA5545-yzvPICuk2AATkU/dhu1WVueM+bqZidxxQQ4Iyu8u01E@public.gmane.org>
2010-08-21 13:58       ` Jassi Brar
2010-08-21 19:30         ` [spi-devel-general] " Mark Brown
2010-08-22  3:37           ` Jassi Brar
     [not found]             ` <AANLkTikDj7YsOQXnFGjZCNRYuQQbLRtKiWw5Sm=vkCuq-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-08-23  9:57               ` Mark Brown [this message]

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