Change the documentation to reflect the new bindings used for Marvell
ICU. This involves describing each interrupt group as a subnode of the
ICU node. Each of them having their own compatible.

The DT binding documentation still documents the legacy binding, where
there was a single node with no subnode.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
---
 .../bindings/interrupt-controller/marvell,icu.txt  | 83 ++++++++++++++++++----
 1 file changed, 71 insertions(+), 12 deletions(-)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/marvell,icu.txt b/Documentation/devicetree/bindings/interrupt-controller/marvell,icu.txt
index 649b7ec9d9b1..83b4fbf8af65 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/marvell,icu.txt
+++ b/Documentation/devicetree/bindings/interrupt-controller/marvell,icu.txt

@@ -5,6 +5,8 @@ The Marvell ICU (Interrupt Consolidation Unit) controller is
 responsible for collecting all wired-interrupt sources in the CP and
 communicating them to the GIC in the AP, the unit translates interrupt
 requests on input wires to MSG memory mapped transactions to the GIC.
+These messages will access a different GIC memory area depending on
+their type (NSR, SR, SEI, REI, etc).
 
 Required properties:
 

@@ -12,20 +14,19 @@ Required properties:
 
 - reg: Should contain ICU registers location and length.
 
+Subnodes: Each group of interrupt is declared as a subnode of the ICU,
+with their own compatible.
+
+Required properties for the icu_nsr/icu_sei subnodes:
+
+- compatible: Should be "marvell,cp110-icu-nsr" or "marvell,cp110-icu-sei".
+