[PATCH 1/2] mfd: max8925: request resource region

[Haojian Zhuang]

On Mon, May 7, 2012 at 6:14 PM, Arnd Bergmann <arnd at arndb.de> wrote:
> On Monday 07 May 2012, Mark Brown wrote:
>> > What if you have two devices both claiming IO regions at 0?  Hint: it
>> > fails.
>>
>> Don't think I've got any examples with regions beginning at 0 but other
>> regions seem to not run into any problems with overlap.  Note that all
>> these drivers do with the regions is use them to look up the base
>> register.
>
> ISA devices start at 0. Using a definition for IORESOURCE_IO of "PCI
> port number for relatively large values, but either ISA or PCMCIA or
> an arbitrary MFD for relatively small values" is absolutely crazy.
>
> FWIW, there are resources you define in include/linux/mfd/wm831x/core.h
> that have values between 0x4000 and 0x8000, which is exactly the
> range occupied by PCI devices on my thinkpad. It's only a matter of
> time until someone puts conflicting devices into one machine.
>
>        Arnd

Even we append a new IORESOURCE type. We still meet similar issue. So
it means that we can't use any IORESOURCE for this kind of i2c usage. Is
it right?

Regards
Haojian