Subject: Re: [PATCH 2/2] uio: add an of_genirq driver

From: "Hans J. Koch" <[email-masked]>
Date: Mon, 15 Jun 2009 01:01:36 +0200

On Mon, Jun 15, 2009 at 12:00:22AM +0200, Wolfram Sang wrote:
> > > For x86 it's not defined at all. But as this code is for the PowerPC,
> > 
> > No, it isn't. What makes you say that? The Kconfig entry doesn't depend
> > on PowerPC. I compiled it on x86...
> 
> It depends on OF. You could compile on x86? Have to check that...

Ooops, forget it. It cannot be selected on x86. I was a bit distracted when
I wrote that, sorry.

> 
> > > where using NO_IRQ seems still to be OK.
> > 
> > No. uio_pdrv_genirq can be used on all platforms, and not all platforms have
> > NO_IRQ. NO_IRQ can be used in platform specific code only.
> 
> Well, the wrapper uses irq_of_parse_and_map(). So far, it returns NO_IRQ if an
> IRQ was not specified (or not found). I could check if there was an
> interrupt-property at all, so I can distinguish between 'not specified' and
> 'not found'. Then, UIO_IRQ_NONE would only be used, if there was none
> specified. Otherwise it will always be the result from irq_of_parse_and_map(),
> whatever that is (even NO_IRQ). Is this what you have in mind?

I would find it better if probe() failed if no irq is specified, printing a
message that tells the user to setup his data correctly before loading the
driver. A user _has_ to setup irq, if there is none, he still has to set
irq=UIO_IRQ_NONE. For that matter, 'not specified' and 'not found' is both
the same bad thing.

Thanks,
Hans

> 
> Regards,
> 
>    Wolfram
> 
> -- 
> Pengutronix e.K.                           | Wolfram Sang                |
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