[PATCH 6/9] ARM: dt: dove: add Dove PMU DT entry to dove.dtsi

On 03/17/2015 02:43 PM, Russell King - ARM Linux wrote:

On Mon, Mar 16, 2015 at 07:27:30PM +0100, Gregory CLEMENT wrote:

quoted

quoted

+			pmu: power-management at d0000 {
+				compatible = "marvell,dove-pmu";
+				reg = <0xd0000 0x8000>, <0xd8000 0x8000>;

Here you overlap some other nodes such as the thermal one (from 0xd001c
to 0xd0028), the clock gate one (from 0xd0038 to 0xd003c), the gpio one,
the pinctrl one ...

Yes, I'm well aware of that, but here's the thing...

I'm describing the hardware here.

The real problem is that Dove (etc) went down the path of breaking up
the PMU device into multiple smaller devices each specifying a sub-set
of the register range.  By doing that, Dove moved away from describing

Russell,

I totally agree that from today's point-of-view having a single pmu
node with sub-nodes would have been the better approach.

the hardware - instead, we've described the Linux _implementation_ with
its separate (sub-)devices - its the implementation's choice that we'd
break up the PMU into these separate devices, almost to the point of
specifying each individual register.

What could be done to work around this oversight is to mvoe these
devices beneath the PMU node, which IMHO makes complete sense as these
are sub-devices of the PMU/PMC rather than separate devices.

If we do this, we should have a look at syscon and potentially also
simple-mfd which will allow us to share the registers and register
platform_devices for the sub-nodes.

The current pmu power/reset/irq can still use the extra locking
and directly access MMIO registers - but for the others we should
really look into using regmaps.

The only thing here is that power domain descriptions are also encoded
as direct sub-nodes of the pmu node, right?

Sebastian