On Fri, Jun 13, 2014 at 9:08 AM, Arnd Bergmann <[email protected]> wrote:
> On Friday 13 June 2014 09:05:14 [email protected] wrote:
>> I was adding the CPU revision ID to the top level compatible string,
>> nothing specific to the device. By knowing the CPU revision I know
>> which errata to apply.
>>
>> If you patch the device strings, then you have to maintain knowledge
>> of which devices are broken in two places -- the device driver and the
>> machine file where you are patching the strings.
>
> IMHO, the driver only has to know what device versions exist, it
> shouldn't need to know which soc has which version of the device.
>
> Can you describe which kind of quirk you are looking at in the driver,
> and how common it is?
Allwinner wired the volume control for their on-chip codec up
backwards on the A revsion of the the A10 chip. In later revisions is
it fixed to work in the right direction.
I was wanting to add code like this to the device driver...
if (of_machine_is_compatible("allwinner,sun7i-a20a")) {
fix bug
}
Another solution would be for me to detect the chip revision in the
init code of the driver and remember it.
--
Jon Smirl
[email protected]
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