bindings: iio: adc: Add documentation for ADS131E0x ADC driver

Add a device tree binding documentation for Texas Instruments
ADS131E0x ADC family driver.
Signed-off-by: Tomislav Denis <tomislav.denis@avl.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20210202084107.3260-3-tomislav.denis@avl.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml

+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/ti,ads131e08.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments ADS131E0x 4-, 6- and 8-Channel ADCs
+
+maintainers:
+  - Tomislav Denis <tomislav.denis@avl.com>
+
+description: |
+  The ADS131E0x are a family of multichannel, simultaneous sampling,
+  24-bit, delta-sigma, analog-to-digital converters (ADCs) with a
+  built-in programmable gain amplifier (PGA), internal reference
+  and an onboard oscillator.
+  The communication with ADC chip is via the SPI bus (mode 1).
+
+  https://www.ti.com/lit/ds/symlink/ads131e08.pdf
+
+properties:
+  compatible:
+    enum:
+      - ti,ads131e04
+      - ti,ads131e06
+      - ti,ads131e08
+
+  reg:
+    maxItems: 1
+
+  spi-max-frequency: true
+
+  spi-cpha: true
+
+  clocks:
+    description: |
+      Device tree identifier to the clock source (2.048 MHz).
+      Note: clock source is selected using CLKSEL pin.
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: adc-clk
+
+  interrupts:
+    description: |
+      IRQ line for the ADC data ready.
+    maxItems: 1
+
+  vref-supply:
+    description: |
+      Optional external voltage reference. If not supplied, internal voltage
+      reference is used.
+
+  ti,vref-internal:
+    description: |
+      Select the internal voltage reference value.
+      0: 2.4V
+      1: 4.0V
+      If this field is left empty, 2.4V is selected.
+      Note: internal voltage reference is used only if vref-supply is not supplied.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    default: 0
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+  - spi-cpha
+  - clocks
+  - clock-names
+  - interrupts
+
+patternProperties:
+  "^channel@([0-7])$":
+    $ref: "adc.yaml"
+    type: object
+    description: |
+      Represents the external channels which are connected to the ADC.
+
+    properties:
+      reg:
+        description: |
+          The channel number.
+          Up to 4 channels, numbered from 0 to 3 for ti,ads131e04.
+          Up to 6 channels, numbered from 0 to 5 for ti,ads131e06.
+          Up to 8 channels, numbered from 0 to 7 for ti,ads131e08.
+        items:
+          minimum: 0
+          maximum: 7
+
+      ti,gain:
+        description: |
+          The PGA gain value for the channel.
+          If this field is left empty, PGA gain 1 is used.
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [1, 2, 4, 8, 12]
+        default: 1
+
+      ti,mux:
+        description: |
+          Channel input selection(muliplexer).
+          0: Normal input.
+          1: Input shorted to (VREFP + VREFN) / 2 (for offset or noise measurements).
+          3: MVDD (for supply measurement)
+          4: Temperature sensor
+          If this field is left empty, normal input is selected.
+        $ref: /schemas/types.yaml#/definitions/uint32
+        enum: [0, 1, 3, 4]
+        default: 0
+
+    required:
+      - reg
+
+    additionalProperties: false
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      adc@0 {
+        compatible = "ti,ads131e08";
+        reg = <0>;
+        spi-max-frequency = <1000000>;
+        spi-cpha;
+        clocks = <&clk2048k>;
+        clock-names = "adc-clk";
+        interrupt-parent = <&gpio5>;
+        interrupts = <28 IRQ_TYPE_EDGE_FALLING>;
+        vref-supply = <&adc_vref>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        channel@0 {
+          reg = <0>;
+        };
+
+        channel@1 {
+          reg = <1>;
+        };
+
+        channel@2 {
+          reg = <2>;
+          ti,gain = <2>;
+        };
+
+        channel@3 {
+          reg = <3>;
+        };
+
+        channel@4 {
+          reg = <4>;
+        };
+
+        channel@5 {
+          reg = <5>;
+        };
+
+        channel@6 {
+          reg = <6>;
+        };
+
+        channel@7 {
+          reg = <7>;
+          ti,mux = <4>;
+        };
+      };
+    };

MAINTAINERS

@@ -17830,6 +17830,7 @@ TI ADS131E0X ADC SERIES DRIVER
 M:	Tomislav Denis <tomislav.denis@avl.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
+F:	Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml
 F:	drivers/iio/adc/ti-ads131e08.c
 
 TI AM437X VPFE DRIVER