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From: wsa@the-dreams.de (Wolfram Sang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] i2c: s3c2410: Properly handle interrupts of number 0
Date: Fri, 2 Mar 2018 13:46:47 +0100	[thread overview]
Message-ID: <20180302124647.sfhnto77wgdh5sv6@katana> (raw)
In-Reply-To: <20180302111931.GX9418@n2100.armlinux.org.uk>


So, maybe some words why I accepted this patch.

On Fri, Mar 02, 2018 at 11:19:31AM +0000, Russell King - ARM Linux wrote:
> On Thu, Mar 01, 2018 at 09:34:44PM +0100, Krzysztof Kozlowski wrote:
> > Interrupt number 0 (returned by platform_get_irq()) might be a valid IRQ
> > so do not treat it as an error.  If interrupt 0 was configured, the driver
> > would exit the probe early, before finishing initialization, but with
> > 0-exit status.
> 
> The official position (as stated by Linus) is that interrupt zero is
> not a valid interrupt for peripheral drivers (it may be valid within
> architecture code for things like the x86 PIT, but nothing else.)

I am aware of that situation and I totally agree with the reasoning.

> You need to number your platform interrupts from one rather than zero.

Ack.

> Note that there have been patches proposed to make platform_get_irq()
> return an error rather than returning a value of zero, so changing
> the driver in this way is not a good idea.

I'd much agree to such an approach, yet I didn't see it coming along so
far for years(?) now.

The reason I applied this patch is consistency with the current
interface. The code is wrong with the way platform_get_irq right now
works. This is independent of platform_get_irq should work, I thought.
This needs to be fixed in a seperate series. This patch will not harm
that transition.

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  parent reply	other threads:[~2018-03-02 12:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-01 20:34 [PATCH] i2c: s3c2410: Properly handle interrupts of number 0 Krzysztof Kozlowski
2018-03-02 10:29 ` Wolfram Sang
2018-03-02 11:00   ` Dan Carpenter
2018-03-02 11:02     ` Dan Carpenter
2018-03-02 11:08     ` Wolfram Sang
2018-03-02 11:19 ` Russell King - ARM Linux
2018-03-02 11:49   ` Dan Carpenter
2018-03-02 12:19     ` Russell King - ARM Linux
2018-03-02 12:26       ` Dan Carpenter
2018-03-02 12:34         ` Russell King - ARM Linux
2018-03-02 12:46   ` Wolfram Sang [this message]
2018-03-02 12:59     ` Russell King - ARM Linux
2018-03-02 13:58       ` Wolfram Sang
2018-03-02 14:09         ` Dan Carpenter
2018-03-02 15:32           ` Russell King - ARM Linux
2018-03-02 16:28             ` Mark Rutland
2018-03-03 16:25               ` Andy Shevchenko
2018-03-03 18:36                 ` Russell King - ARM Linux

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