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From:   Sander Vanheule <sander@svanheule.net>
To:     Marc Zyngier <maz@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        devicetree@vger.kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Birger Koblitz <mail@birger-koblitz.de>,
        Bert Vermeulen <bert@biot.com>,
        John Crispin <john@phrozen.org>, linux-kernel@vger.kernel.org,
        Sander Vanheule <sander@svanheule.net>
Subject: [PATCH v4 1/3] dt-bindings: interrupt-controller: realtek,rtl-intc: require parents
Date:   Sun,  6 Feb 2022 17:41:51 +0100
Message-Id: <d1920b7b0b882512e628b4e4e93fa8fef1b5364a.1644165421.git.sander@svanheule.net>
In-Reply-To: <cover.1644165421.git.sander@svanheule.net>
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The interrupt router has 32 inputs, and up to 15 outputs connected to
the MIPS CPU's interrupts. The way these are mapped to each other is
runtime configurable. This controller can also mask individual interrupt
sources, and has a status register to indicate pending interrupts. This
means the controller is not transparent, and the use of "interrupt-map"
inappropriate. Instead, a list of parent interrupts should be specified.

Two-part compatibles are introduced to be able to require "interrupts"
for new devicetrees. The relevant descriptions are extended or added to
more clearly describe the functionality of this controller. The old
compatible, with "interrupt-map" and "#address-cells", is deprecated.
Interrupt specifiers for new compatibles will require two cells, to
indicate the output selection.

To prevent spurious changes to the binding when more SoCs are added,
"allOf" is used with one "if", and the compatible enum only has one
item.

The example is updated to provide a correct example for RTL8380 SoCs.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
---
Changes in v4:
- Indicate more clearly that the controller is not transparent.
---
 .../realtek,rtl-intc.yaml                     | 82 ++++++++++++++-----
 1 file changed, 62 insertions(+), 20 deletions(-)

diff --git a/Documentation/devicetree/bindings/interrupt-controller/realtek,rtl-intc.yaml b/Documentation/devicetree/bindings/interrupt-controller/realtek,rtl-intc.yaml
index 9e76fff20323..f212962afd62 100644
--- a/Documentation/devicetree/bindings/interrupt-controller/realtek,rtl-intc.yaml
+++ b/Documentation/devicetree/bindings/interrupt-controller/realtek,rtl-intc.yaml
@@ -6,6 +6,14 @@ $schema: http://devicetree.org/meta-schemas/core.yaml#
 
 title: Realtek RTL SoC interrupt controller devicetree bindings
 
+description:
+  Interrupt controller and router for Realtek MIPS SoCs, allowing each SoC
+  interrupt to be routed to one parent CPU (hardware) interrupt, or left
+  disconnected.
+  All connected input lines from SoC peripherals can be masked individually,
+  and an interrupt status register is present to indicate which interrupts are
+  pending.
+
 maintainers:
   - Birger Koblitz <mail@birger-koblitz.de>
   - Bert Vermeulen <bert@biot.com>
@@ -13,45 +21,79 @@ maintainers:
 
 properties:
   compatible:
-    const: realtek,rtl-intc
+    oneOf:
+      - items:
+          - enum:
+              - realtek,rtl8380-intc
+          - const: realtek,rtl-intc
+      - const: realtek,rtl-intc
+        deprecated: true
 
-  "#interrupt-cells":
-    const: 1
+  "#interrupt-cells": true
 
   reg:
     maxItems: 1
 
   interrupts:
-    maxItems: 1
+    minItems: 1
+    maxItems: 15
+    description:
+      List of parent interrupts, in the order that they are connected to this
+      interrupt router's outputs.
 
   interrupt-controller: true
 
-  "#address-cells":
-    const: 0
-
-  interrupt-map:
-    description: Describes mapping from SoC interrupts to CPU interrupts
-
 required:
   - compatible
   - reg
   - "#interrupt-cells"
   - interrupt-controller
-  - "#address-cells"
-  - interrupt-map
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          const: realtek,rtl-intc
+    then:
+      properties:
+        "#interrupt-cells":
+          const: 1
+
+        "#address-cells":
+          const: 0
+
+        interrupt-map: true
+      required:
+        - "#address-cells"
+        - interrupt-map
+    else:
+      properties:
+        "#interrupt-cells":
+          description:
+            Two cells to specify which line to connect to, and which output it should
+            be routed to. Both cells use a zero-based index.
+          const: 2
+      required:
+        - interrupts
 
 additionalProperties: false
 
 examples:
   - |
     intc: interrupt-controller@3000 {
-      compatible = "realtek,rtl-intc";
-      #interrupt-cells = <1>;
+      compatible = "realtek,rtl8380-intc", "realtek,rtl-intc";
+      #interrupt-cells = <2>;
       interrupt-controller;
-      reg = <0x3000 0x20>;
-      #address-cells = <0>;
-      interrupt-map =
-              <31 &cpuintc 2>,
-              <30 &cpuintc 1>,
-              <29 &cpuintc 5>;
+      reg = <0x3000 0x18>;
+
+      interrupt-parent = <&cpuintc>;
+      interrupts = <2>, <3>, <4>, <5>, <6>;
+    };
+
+    irq-consumer@0 {
+      reg = <0 4>;
+      interrupt-parent = <&intc>;
+      interrupts =
+        <19 3>, /* IRQ 19, routed to output 3 (cpuintc 5) */
+        <18 4>; /* IRQ 18, routed to output 4 (cpuintc 6) */
     };
-- 
2.34.1