[PATCH v2 2/2] irqchip: gic: Document optional Clock and Power Domain properties

[geert+renesas@glider.be (Geert Uytterhoeven)]

Depending on the GIC variant, the GIC module has one or more clock
inputs. Document the optional "clocks" and "clock-names" properties,
and their possible values, based on the Technical Reference Manuals.
optional.

Add the optional "power-domains" property.

This will allow to describe in DT the relationship between the GIC and
the Clock and/or Power Domain topology on SoCs where this is relevant
and needed for proper operation.

Note: As the current GIC driver doesn't support Runtime PM yet, PM
Domain constraints must be handled elsewhere in e.g. platform code.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
---
Note: v1 was Acked-by: Rob Herring <robh@kernel.org>, but I didn't add
      it, due to the addition of clock-names.

v2:
  - Add "clock-names",
  - Document clock inputs on various GIC variants.

Clock inputs are based on the following documentation:
  - "ARM11 MPCore Processor Technical Reference Manual" (r2p0),
  - "Cortex-A9 MPCore Technical Reference Manual" (r4p1, r2p0),
  - "Cortex-A15 Technical Reference Manual" (r4p0, r2p0),
  - "CoreLink GIC-400 Generic Interrupt Controller Technical Reference
    Manual" (r0p1, r0p0),
  - "PrimeCell Generic Interrupt Controller (PL390) Technical Reference
    Manual" (r0p0).

I could not find clock input information in:
  - "ARM1176JZF Development Chip Technical Reference Manual" (r0p0),
  - "Cortex-A7 MPCore processors" (r0p5, r0p3).

Other:
  - "brcm,brahma-b15-gic" seems to be always used together with
    "arm,cortex-a15-gic".

No access to datasheets:
  - "qcom,msm-8660-qgic",
  - "qcom,msm-qgic2".
---
 Documentation/devicetree/bindings/arm/gic.txt | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/gic.txt b/Documentation/devicetree/bindings/arm/gic.txt
index 24742853ba460223..cc56021eb60babea 100644
--- a/Documentation/devicetree/bindings/arm/gic.txt
+++ b/Documentation/devicetree/bindings/arm/gic.txt
@@ -59,6 +59,21 @@ Optional
   regions, used when the GIC doesn't have banked registers. The offset is
   cpu-offset * cpu-nr.
 
+- clocks        : List of phandle and clock-specific pairs, one for each entry
+  in clock-names.
+- clock-names   : List of names for the GIC clock input(s). Valid clock names
+  depend on the GIC variant:
+	"ic_clk" (for "arm,arm11mp-gic")
+	"PERIPHCLKEN" (for "arm,cortex-a15-gic")
+	"PERIPHCLK", "PERIPHCLKEN" (for "arm,cortex-a9-gic")
+	"clk" (for "arm,gic-400")
+	"gclk" (for "arm,pl390")
+
+- power-domains : A phandle and PM domain specifier as defined by bindings of
+		  the power controller specified by phandle, used when the GIC
+		  is part of a Power or Clock Domain.
+
+
 Example:
 
 	intc: interrupt-controller at fff11000 {
-- 
1.9.1