Re: [PATCH 0/2] i2c: Don't assume bus nr 0 if none was specified

From: Grant Likely
Date: Sat Mar 17 2012 - 11:17:43 EST


On Fri, 16 Mar 2012 13:27:27 +0100, Karol Lewandowski <k.lewandowsk@xxxxxxxxxxx> wrote:
> On 16.03.2012 13:19, Karol Lewandowski wrote:
>
> > Hi,
> >
> > i2c controller drivers used to assume bus number 0 when none (-1) was specified.
> >
> > This worked on non-device tree systems, where one could explicitly specify
> > bus number via platform data. On DT-enabled systems bus number is always -1.
> >
> > Some drivers assume bus number 0 when -1 is specified. This patchset kills
> > this logic and switches to dynamic bus allocation (default when -1 is provided[1]).
>
>
> [ I must have lost actual problem description while rewording
> message itself... ]
>
> Problem arises when multiple drivers (or multiple instances
> of one driver) try to assume the same fixed bus number (0).
>
> This causes simply causes i2c_add_numbered_bus() to fail.
> Leaving -1 works perfectly, as registration function switches
> to dynamic id registration.

Patch series looks good to me. You'll need acks from the affected users.

g.

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