Re: [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero

From: Anton Vorontsov <avorontsov@ru.mvista.com>
To: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: linux-kernel@vger.kernel.org, David Vrabel <david.vrabel@csr.com>,
	Greg Kroah-Hartman <gregkh@suse.de>,
	David Brownell <dbrownell@users.sourceforge.net>,
	Grant Likely <grant.likely@secretlab.ca>,
	Kumar Gala <galak@kernel.crashing.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	spi-devel-general@lists.sourceforge.net,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 6/7] spi/mpc8xxx: don't check platform_get_irq's return value against zero
Date: Wed, 16 Dec 2009 22:37:45 +0300	[thread overview]
Message-ID: <20091216193745.GA20429@oksana.dev.rtsoft.ru> (raw)
In-Reply-To: <20091216191839.GA23614@pengutronix.de>

On Wed, Dec 16, 2009 at 08:18:39PM +0100, Uwe Kleine-König wrote:
[...]
> > > I'm a bit annoyed as this is the third time[1] this month this irq0
> > > discussion pops up for me.  I think people see that irq0 is involved
> > > somehow, start wailing and stop seeing the issues being fixed.
> > 
> > For this particular driver, there is NO issue whatsoever. It is
> > only used for PowerPC, which has VIRQ0 == invalid IRQ. And note
> > that there still could be HWIRQ0 on PowerPC, but it is *never*
> > mapped to VIRQ0.
> Yes, there is an issue.  If the platform device doesn't have a resource
> specifing the irq, platform_get_irq returns -ENXIO.  So in the driver
> (unsigned)(-ENXIO) is passed to mpc8xxx_spi_probe as (!(-ENXIO)) is
> false and so the error isn't catched.

If you look into how we create the platform device, you'll notice
that -ENXIO isn't possible.
It's in arch/powerpc/platforms/83xx/mpc832x_rdb.c:of_fsl_spi_probe(),
which is a legacy interface that I'd like to be removed anyway.

Though, if you want to fix the inconsistency in the platform device
API, then I'd suggest to fix the platform_get_irq(). The driver itself
is correct.

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2