[PATCH v4 1/2] dt-bindings: iio: adc: Add Nuvoton MA35D1 EADC

[Chi-Wen Weng <cwweng.linux@gmail.com>]

From: Chi-Wen Weng <cwweng@nuvoton.com>

Add a binding for the Enhanced Analog-to-Digital Converter found on
Nuvoton MA35D1 SoCs.

The controller has eight external analog inputs. They can be used as
single-ended inputs or as the four fixed differential pairs 0-4, 1-5,
2-6 and 3-7.

Use the common ADC channel properties to describe the physical input
independently of the logical channel index.

Signed-off-by: Chi-Wen Weng <cwweng@nuvoton.com>
---
 .../bindings/iio/adc/nuvoton,ma35d1-eadc.yaml | 163 ++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml b/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
new file mode 100644
index 000000000000..85b0feac0236
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/nuvoton,ma35d1-eadc.yaml
@@ -0,0 +1,163 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/nuvoton,ma35d1-eadc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton MA35D1 Enhanced Analog-to-Digital Converter
+
+maintainers:
+  - Chi-Wen Weng <cwweng@nuvoton.com>
+
+description: |
+  The Nuvoton MA35D1 Enhanced Analog-to-Digital Converter (EADC) is a
+  12-bit successive approximation converter with eight external analog
+  inputs and one internally connected VBAT input.
+
+  The external inputs can be used as eight single-ended channels or as
+  four fixed differential pairs: 0-4, 1-5, 2-6 and 3-7. The internally
+  connected VBAT input is not described by a channel child node.
+
+  The controller provides four interrupt outputs, ADINT0 through ADINT3.
+
+properties:
+  compatible:
+    const: nuvoton,ma35d1-eadc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    items:
+      - description: ADINT0
+      - description: ADINT1
+      - description: ADINT2
+      - description: ADINT3
+
+  clocks:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+  vref-supply:
+    description:
+      Optional external reference voltage connected to the VREF pin. If this
+      supply is absent, the controller uses its internal 1.6 V reference.
+
+  dmas:
+    maxItems: 1
+
+  dma-names:
+    const: rx
+
+  '#io-channel-cells':
+    const: 1
+    description:
+      The cell selects the logical EADC channel identified by the reg value
+      of the corresponding channel child node.
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  '^channel@[0-7]$':
+    type: object
+    $ref: /schemas/iio/adc/adc.yaml#
+    description: |
+      External EADC channel description. The reg property identifies the
+      logical IIO channel index.
+
+      A single-ended channel may use single-channel to select an external
+      analog input independently of reg. If single-channel and diff-channels
+      are both absent, the external analog input is selected by reg.
+
+      A differential channel uses diff-channels to select one of the fixed
+      hardware input pairs: 0-4, 1-5, 2-6 or 3-7. Each single-ended input
+      and each differential input pair may be described at most once.
+
+    properties:
+      reg:
+        maximum: 7
+
+      single-channel:
+        maximum: 7
+
+      diff-channels:
+        oneOf:
+          - items:
+              - const: 0
+              - const: 4
+          - items:
+              - const: 1
+              - const: 5
+          - items:
+              - const: 2
+              - const: 6
+          - items:
+              - const: 3
+              - const: 7
+
+    allOf:
+      - not:
+          required:
+            - single-channel
+            - diff-channels
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - '#io-channel-cells'
+  - '#address-cells'
+  - '#size-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/nuvoton,ma35d1-clk.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/reset/nuvoton,ma35d1-reset.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        adc@40430000 {
+            compatible = "nuvoton,ma35d1-eadc";
+            reg = <0x0 0x40430000 0x0 0x10000>;
+            interrupts = <GIC_SPI 65 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 66 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 67 IRQ_TYPE_LEVEL_HIGH>,
+                         <GIC_SPI 68 IRQ_TYPE_LEVEL_HIGH>;
+            clocks = <&clk EADC_GATE>;
+            resets = <&sys MA35D1_RESET_EADC0>;
+
+            #io-channel-cells = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            channel@0 {
+                reg = <0>;
+                single-channel = <2>;
+            };
+
+            channel@1 {
+                reg = <1>;
+                diff-channels = <0 4>;
+            };
+        };
+    };
+
+...
-- 
2.25.1