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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jon Smirl <jonsmirl@gmail.com>
Cc: Jean Delvare <khali@linux-fr.org>,
	linuxppc-dev@ozlabs.org, i2c@lm-sensors.org,
	linux-kernel@vger.kernel.org
Subject: Re: [i2c] [PATCH 19 3/5] Clean up error returns
Date: Tue, 22 Jan 2008 10:06:41 +1100	[thread overview]
Message-ID: <1200956801.6807.16.camel@pasglop> (raw)
In-Reply-To: <9e4733910801200718q7304bc29q38e67580613189e4@mail.gmail.com>


On Sun, 2008-01-20 at 10:18 -0500, Jon Smirl wrote:
> > So it seems to me like the polling mode code is never actually used?
> > Unless some platforms include an "empty" IRQ in their device
> > definition. Which indeed seems to be the case... but then they set
> the
> > IRQ to 0, NOT to NO_IRQ, so I'm wondering if the change you propose
> is
> > really correct.
> 
> All of this is very confusing to me, There are physical IRQs and
> virtual IRQs. Apparently zero is a legal physical IRQ but it is not a
> legal virtual IRQ. We only get virtual IRQs in this code. We need to
> get BenH to give us the right answer on these two cases.

Testing against NO_IRQ for a linux IRQ number should always be correct.

Physical IRQ numbers are remapped and shouldn't be visible to drivers,
NO_IRQ is a value that never exist for a valid logical interrupt number,
that is 0 for arch/powerpc and -1 for arch/ppc.

Ben.

  parent reply	other threads:[~2008-01-21 23:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-12  2:47 [PATCH 19 0/5] Version 18, series to add device tree naming to i2c Jon Smirl
2008-01-12  2:47 ` [PATCH 19 1/5] Implement module aliasing for i2c to translate from device tree names Jon Smirl
2008-01-12  3:00   ` [i2c] " Jon Smirl
2008-01-12  3:47     ` Stephen Rothwell
2008-01-12  2:47 ` [PATCH 19 2/5] Modify several rtc drivers to use the alias names list property of i2c Jon Smirl
2008-01-12  2:47 ` [PATCH 19 3/5] Clean up error returns Jon Smirl
2008-01-20 11:07   ` [i2c] " Jean Delvare
2008-01-20 15:18     ` Jon Smirl
2008-01-20 15:39       ` Jon Smirl
2008-01-21 16:10         ` Jean Delvare
2008-01-21 23:04           ` Benjamin Herrenschmidt
2008-01-21 23:06       ` Benjamin Herrenschmidt [this message]
2008-01-12  2:47 ` [PATCH 19 4/5] Convert PowerPC MPC i2c to of_platform_driver from platform_driver Jon Smirl
2008-01-12  4:07   ` Stephen Rothwell
2008-01-12  2:47 ` [PATCH 19 5/5] Convert pfc8563 i2c driver from old style to new style Jon Smirl
2008-04-10  9:14   ` Laurent Pinchart

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