Re: [PATCH v2 2/2] dt-bindings: iio: adc: Add DT docs for AD7292

Hi Rob

Thanks for the review.

I'm having some trouble with the DTC.
I installed the DT tool from https://github.com/robherring/dt-schema.
Running make -k dt_binding_check goes through all the checks (CHKDT), producing
the .example.dts files but then gives errors like:

  DTC     Documentation/devicetree/bindings/arm/calxeda.example.dt.yaml
FATAL ERROR: Unknown output format "yaml"
make[1]: *** [scripts/Makefile.lib:314: Documentation/devicetree/bindings/arm/calxeda.example.dt.yaml] Error 1
make[1]: *** Deleting file 'Documentation/devicetree/bindings/arm/calxeda.example.dt.yaml'

My pip3 installation has:
jsonschema jsonschema-3.1.2.dev6+g0d827f3
rfc3987 1.3.8

$HOME/.local/bin is listed in my shell's PATH variable.

I was trying to follow the documentation at:
Documentation/devicetree/writing-schema.rst

Are there any other DTC dependencies that I am missing?

On 10/17, Rob Herring wrote:

On Tue, Oct 15, 2019 at 11:52:23PM -0300, Marcelo Schmitt wrote:

quoted

Add a device tree binding doc for AD7292 monitor and control system.

Signed-off-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
---
 .../bindings/iio/adc/adi,ad7292.yaml          | 107 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 108 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7292.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7292.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7292.yaml
new file mode 100644
index 000000000000..40028332d9e2
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7292.yaml

@@ -0,0 +1,107 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7292.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7292 10-Bit Monitor and Control System
+
+maintainers:
+  - Marcelo Schmitt <marcelo.schmitt1@gmail.com>
+
+description: |
+  Analog Devices AD7292 10-Bit Monitor and Control System with ADC, DACs,
+  Temperature Sensor, and GPIOs
+
+  Specifications about the part can be found at:
+    https://www.analog.com/media/en/technical-documentation/data-sheets/ad7292.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7292
+
+  reg:
+    maxItems: 1
+
+  vref-supply:
+    description: |
+      The regulator supply for ADC and DAC reference voltage.
+    maxItems: 1

Not necessary, regulator supplies are always 1 item, so drop maxItems.

quoted

+
+  spi-cpha:
+    description: |
+      See Documentation/devicetree/bindings/spi/spi-controller.yaml
+    maxItems: 1

This is just wrong because spi-cpha is a boolean. Just 'spi-cpha: true' 
is sufficient. If this device needs this property, then it should 
probably be required.

quoted

+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+required:
+  - compatible
+  - reg
+
+patternProperties:
+  "^channel@[0-7]$":
+    type: object
+    description: |
+      Represents the external channels which are connected to the ADC.
+      See Documentation/devicetree/bindings/iio/adc/adc.txt.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can have up to 8 channels numbered from 0 to 7.
+        maxItems: 1
+
+      diff-channels:
+        description: see Documentation/devicetree/bindings/iio/adc/adc.txt
+        maxItems: 1
+
+    required:
+      - reg
+
+examples:
+  - |
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      ad7292: ad7292@0 {

adc@0

quoted

+        compatible = "adi,ad7292";
+        reg = <0>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        spi-max-frequency = <25000000>;
+        vref-supply = <&adc_vref>;
+        spi-cpha;
+
+        channel@0 {
+          reg = <0>;
+          diff-channels = <0 1>;
+        };
+        channel@2 {
+          reg = <2>;
+        };
+        channel@3 {
+          reg = <3>;
+        };
+        channel@4 {
+          reg = <4>;
+        };
+        channel@5 {
+          reg = <5>;
+        };
+        channel@6 {
+          reg = <6>;
+        };
+        channel@7 {
+          reg = <7>;
+        };
+      };
+    }

Missing ';'. Make sure this builds with 'make -k dt_binding_check'. The 
'-k' is due to some other breakage ATM.

Rob