[i2c] [PATCH] of/i2c: don't pass -1 to irq_dispose_mapping, otherwise kernel will oops

[Jon Smirl]

On 7/12/08, Wolfram Sang <w.sang at pengutronix.de> wrote:
> On Fri, Jul 11, 2008 at 12:23:23PM -0600, Grant Likely wrote:
>
> > On Fri, Jul 11, 2008 at 09:48:59PM +0400, Anton Vorontsov wrote:
>  > > Firstly kernel warns at set_irq_chip, and then dies completely:
>  > >
>  > > Trying to install chip for IRQ-1
>  > >
>  > > diff --git a/drivers/of/of_i2c.c b/drivers/of/of_i2c.c
>  > > index b2ccdcb..95a24de 100644
>  > > --- a/drivers/of/of_i2c.c
>  > > +++ b/drivers/of/of_i2c.c
>  > > @@ -93,10 +93,8 @@ void of_register_i2c_devices(struct i2c_adapter *adap,
>  > >             if (info.irq == NO_IRQ)
>  > >                     info.irq = -1;
>  >
>  > What is the reason that info.irq is set to -1 in the first place?  This
>  > looks like another bug to me.  Does something in the i2c layer depend on
>  > the -1 value?
>  >
>
>
> You already acked a fix to this :) I wasn't sure if my patch would
>  make it on its own, as Jon Smirl was also working on fixes to of_i2c.c
>  and he seemed to pick up this issue, too.

I did another patch for the mpc-i2c driver changing all of the
comparisons to NO_IRQ. My understanding of this is the ppc has NO_IRQ
set to -1, and powerpc has NO_IRQ = 0. So to make all of this work
right you have to use the NO_IRQ symbol and you can't check against 0
or -1 directly. I also believe work is underway to get all platforms
to NO_IRQ = 0 but I don't know if it is completed yet.


>
>  (Original patch is here:
>  http://ozlabs.org/pipermail/linuxppc-dev/2008-June/058801.html
>  )
>
>  All the best,
>
>    Wolfram
>
>
>  --
>   Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
>   Pengutronix - Linux Solutions for Science and Industry
>
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-- 
Jon Smirl
jonsmirl at gmail.com