Thread (17 messages) 17 messages, 3 authors, 2019-10-02

Re: [PATCH v4 1/8] dt-bindings: timer: Convert Exynos MCT bindings to json-schema

From: Krzysztof Kozlowski <krzk@kernel.org>
Date: 2019-09-26 09:21:04
Also in: linux-arm-kernel, linux-samsung-soc, lkml

On Wed, Sep 25, 2019 at 03:40:52PM +0200, Marek Szyprowski wrote:
Hi Krzysztof,

On 23.09.2019 18:14, Krzysztof Kozlowski wrote:
quoted
Convert Samsung Exynos Soc Multi Core Timer bindings to DT schema format
using json-schema.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

---

Changes since v3:
1. Use interrupts-extended instead of interrupts-map.

Changes since v1:
1. Indent example with four spaces (more readable),
2. Rename nodes in example to timer,
3. Remove mct-map subnode.
---
  .../bindings/timer/samsung,exynos4210-mct.txt |  88 ------------
  .../timer/samsung,exynos4210-mct.yaml         | 125 ++++++++++++++++++
  2 files changed, 125 insertions(+), 88 deletions(-)
  delete mode 100644 Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
  create mode 100644 Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml
diff --git a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
deleted file mode 100644
index 8f78640ad64c..000000000000
--- a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.txt
+++ /dev/null
@@ -1,88 +0,0 @@
-Samsung's Multi Core Timer (MCT)
-
-The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
-global timer and CPU local timers. The global timer is a 64-bit free running
-up-counter and can generate 4 interrupts when the counter reaches one of the
-four preset counter values. The CPU local timers are 32-bit free running
-down-counters and generate an interrupt when the counter expires. There is
-one CPU local timer instantiated in MCT for every CPU in the system.
-
-Required properties:
-
-- compatible: should be "samsung,exynos4210-mct".
-  (a) "samsung,exynos4210-mct", for mct compatible with Exynos4210 mct.
-  (b) "samsung,exynos4412-mct", for mct compatible with Exynos4412 mct.
-
-- reg: base address of the mct controller and length of the address space
-  it occupies.
-
-- interrupts: the list of interrupts generated by the controller. The following
-  should be the order of the interrupts specified. The local timer interrupts
-  should be specified after the four global timer interrupts have been
-  specified.
-
-	0: Global Timer Interrupt 0
-	1: Global Timer Interrupt 1
-	2: Global Timer Interrupt 2
-	3: Global Timer Interrupt 3
-	4: Local Timer Interrupt 0
-	5: Local Timer Interrupt 1
-	6: ..
-	7: ..
-	i: Local Timer Interrupt n
-
-  For MCT block that uses a per-processor interrupt for local timers, such
-  as ones compatible with "samsung,exynos4412-mct", only one local timer
-  interrupt might be specified, meaning that all local timers use the same
-  per processor interrupt.
-
-Example 1: In this example, the IP contains two local timers, using separate
-	   interrupts, so two local timer interrupts have been specified,
-	   in addition to four global timer interrupts.
-
-	mct@10050000 {
-		compatible = "samsung,exynos4210-mct";
-		reg = <0x10050000 0x800>;
-		interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
-			     <0 42 0>, <0 48 0>;
-	};
-
-Example 2: In this example, the timer interrupts are connected to two separate
-	   interrupt controllers. Hence, an interrupt-map is created to map
-	   the interrupts to the respective interrupt controllers.
-
-	mct@101c0000 {
-		compatible = "samsung,exynos4210-mct";
-		reg = <0x101C0000 0x800>;
-		interrupt-parent = <&mct_map>;
-		interrupts = <0>, <1>, <2>, <3>, <4>, <5>;
-
-		mct_map: mct-map {
-			#interrupt-cells = <1>;
-			#address-cells = <0>;
-			#size-cells = <0>;
-			interrupt-map = <0 &gic 0 57 0>,
-					<1 &gic 0 69 0>,
-					<2 &combiner 12 6>,
-					<3 &combiner 12 7>,
-					<4 &gic 0 42 0>,
-					<5 &gic 0 48 0>;
-		};
-	};
-
-Example 3: In this example, the IP contains four local timers, but using
-	   a per-processor interrupt to handle them. Either all the local
-	   timer interrupts can be specified, with the same interrupt specifier
-	   value or just the first one.
-
-	mct@10050000 {
-		compatible = "samsung,exynos4412-mct";
-		reg = <0x10050000 0x800>;
-
-		/* Both ways are possible in this case. Either: */
-		interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
-			     <0 42 0>;
-		/* or: */
-		interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
-			     <0 42 0>, <0 42 0>, <0 42 0>, <0 42 0>;
-	};
diff --git a/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml
new file mode 100644
index 000000000000..bff3f54a398f
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/samsung,exynos4210-mct.yaml
@@ -0,0 +1,125 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/samsung,exynos4210-mct.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos SoC Multi Core Timer (MCT)
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |+
+  The Samsung's Multi Core Timer (MCT) module includes two main blocks, the
+  global timer and CPU local timers. The global timer is a 64-bit free running
+  up-counter and can generate 4 interrupts when the counter reaches one of the
+  four preset counter values. The CPU local timers are 32-bit free running
+  down-counters and generate an interrupt when the counter expires. There is
+  one CPU local timer instantiated in MCT for every CPU in the system.
+
+properties:
+  compatible:
+    enum:
+      - samsung,exynos4210-mct
+      - samsung,exynos4412-mct
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: |
+      Interrupts should be put in specific order. This is, the local timer
+      interrupts should be specified after the four global timer interrupts
+      have been specified:
+      0: Global Timer Interrupt 0
+      1: Global Timer Interrupt 1
+      2: Global Timer Interrupt 2
+      3: Global Timer Interrupt 3
+      4: Local Timer Interrupt 0
+      5: Local Timer Interrupt 1
+      6: ..
+      7: ..
+      i: Local Timer Interrupt n
+      For MCT block that uses a per-processor interrupt for local timers, such
+      as ones compatible with "samsung,exynos4412-mct", only one local timer
+      interrupt might be specified, meaning that all local timers use the same
+      per processor interrupt.
+    minItems: 5               # 4 Global + 1 local
+    maxItems: 20              # 4 Global + 16 local
+
+  interrupts-extended:
+    description: |
+      If interrupts are coming from different controllers, this property
+      can be used instead of regular "interrupts" property.
+      The format is exactly the same as with "interrupts".
+      Interrupts should be put in specific order. This is, the local timer
+    minItems: 5               # 4 Global + 1 local
+    maxItems: 20              # 4 Global + 16 local
+
+required:
+  - compatible
+  - interrupts
+  - reg
+
+allOf:
+  - if:
+      not:
+        required:
+          - interrupts
+    then:
+      required:
+        - interrupts-extended
+
+examples:
+  - |
+    // In this example, the IP contains two local timers, using separate
+    // interrupts, so two local timer interrupts have been specified,
+    // in addition to four global timer interrupts.
+
+    timer@10050000 {
+        compatible = "samsung,exynos4210-mct";
+        reg = <0x10050000 0x800>;
+        interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
+                     <0 42 0>, <0 48 0>;
+    };
+
+  - |
+    // In this example, the timer interrupts are connected to two separate
+    // interrupt controllers. Hence, an interrupts-extended is needed.
+
+    timer@101c0000 {
+        compatible = "samsung,exynos4210-mct";
+        reg = <0x101C0000 0x800>;
+        interrupts-extended = <&gic 0 57 0>,
+                              <&gic 0 69 0>,
+                              <&combiner 12 6>,
+                              <&combiner 12 7>,
+                              <&gic 0 42 0>,
+                              <&gic 0 48 0>;
+    };
+
+  - |
+    // In this example, the IP contains four local timers, but using
+    // a per-processor interrupt to handle them. Only one first local
+    // interrupt is specified.
+
+    timer@10050000 {
+        compatible = "samsung,exynos4412-mct";
+        reg = <0x10050000 0x800>;
+
+        interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
+                     <0 42 0>;
+    };
+
+  - |
+    // In this example, the IP contains four local timers, but using
+    // a per-processor interrupt to handle them. All the local timer
+    // interrupts are specified.
+
+    timer@10050000 {
+        compatible = "samsung,exynos4412-mct";
+        reg = <0x10050000 0x800>;
+
+        interrupts = <0 57 0>, <0 69 0>, <0 70 0>, <0 71 0>,
+                     <0 42 0>, <0 42 0>, <0 42 0>, <0 42 0>;
+    };
I would add "#include <dt-bindings/interrupt-controller/arm-gic.h>" and
replace zeros with proper defines like GIC_SPI and GIC_PPI. The last two
examples describes per-processor-interrupts, but have 0 in the specifier
cell 0. I would also use proper IRQ_TYPE_LEVEL_HIGH at cell 3 instead
of 0. I would also consider adding artificial 'interrupt-parent = &git'
property to the 1st, 3rd and 4th examples to make it clear that they
refer to ARM GIC bindings.
Makes sense, but how about doing this in separate patch? The example code
was like this amd this just converts the bindings so I think it is better
to reduce the amount of feature-like improvements.

Best regards,
Krzysztof
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