[PATCH 1/4] ARM: tegra: pmc: convert PMC driver to support DT only

[Stephen Warren]

On 02/25/2013 07:28 AM, Peter De Schrijver wrote:
> On Sat, Feb 23, 2013 at 05:31:17AM +0100, Stephen Warren wrote:
...
>> Peter, can you confirm exactly which [PMC] HW versions, if any, are 100%
>> backwards-compatible?
>>
> 
> The major difference between the PMCs are the powerdomain IDs. The Tegra30 IDs
> are a strict superset of the Tegra20 IDs, but the Tegra114 IDs are not. There
> are differences in the CPU domains and 3D. The CPU domains aren't a problem I
> think because we won't powergate those domains directly using the PMC. We
> always program the flowcontroller to do the powergating on WFI. 3D is a
> different story however. We do powergate 3D under software control and the
> sequencing is different between Tegra30 and Tegra114. Also Tegra30 has 2
> domains for 3D while Tegra114 has only 1. Then of course Tegra114 lacks the
> SATA and PCIe domains because those features are missing compared to Tegra30.
> But the IDs haven't been reused. All in all I think it's best to explicitly
> require the driver to support the various SoCs.

That does sound like a good idea; a separate compatible value for each SoC.