dt-bindings:iio:adc:amlogic,meson-saradc yaml conversion

This binding is non trivial due to the range of different parts
supported having several subtle quirks. Martin has helped
clarify some of them.

Note, I haven't restricted the amlogic,hhi-sysctrl to only
be present on the relevant parts if nvmem stuff also is, but
it would seem to be rather odd if it were otherwise.

Perhaps we look to make this binding more restrictive at a later date.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20200920135436.199003-2-jic23@kernel.org

Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.txt

-* Amlogic Meson SAR (Successive Approximation Register) A/D converter
-
-Required properties:
-- compatible:	depending on the SoC this should be one of:
-			- "amlogic,meson8-saradc" for Meson8
-			- "amlogic,meson8b-saradc" for Meson8b
-			- "amlogic,meson8m2-saradc" for Meson8m2
-			- "amlogic,meson-gxbb-saradc" for GXBB
-			- "amlogic,meson-gxl-saradc" for GXL
-			- "amlogic,meson-gxm-saradc" for GXM
-			- "amlogic,meson-axg-saradc" for AXG
-			- "amlogic,meson-g12a-saradc" for AXG
-		along with the generic "amlogic,meson-saradc"
-- reg:		the physical base address and length of the registers
-- interrupts:	the interrupt indicating end of sampling
-- clocks:	phandle and clock identifier (see clock-names)
-- clock-names:	mandatory clocks:
-			- "clkin" for the reference clock (typically XTAL)
-			- "core" for the SAR ADC core clock
-		optional clocks:
-			- "adc_clk" for the ADC (sampling) clock
-			- "adc_sel" for the ADC (sampling) clock mux
-- vref-supply:	the regulator supply for the ADC reference voltage
-- #io-channel-cells: must be 1, see ../iio-bindings.txt
-
-Optional properties:
-- amlogic,hhi-sysctrl:	phandle to the syscon which contains the 5th bit
-			of the TSC (temperature sensor coefficient) on
-			Meson8b and Meson8m2 (which used to calibrate the
-			temperature sensor)
-- nvmem-cells:		phandle to the temperature_calib eFuse cells
-- nvmem-cell-names:	if present (to enable the temperature sensor
-			calibration) this must contain "temperature_calib"
-
-
-Example:
-	saradc: adc@8680 {
-		compatible = "amlogic,meson-gxl-saradc", "amlogic,meson-saradc";
-		#io-channel-cells = <1>;
-		reg = <0x0 0x8680 0x0 0x34>;
-		interrupts = <GIC_SPI 73 IRQ_TYPE_EDGE_RISING>;
-		clocks = <&xtal>,
-			 <&clkc CLKID_SAR_ADC>,
-			 <&clkc CLKID_SANA>,
-			 <&clkc CLKID_SAR_ADC_CLK>,
-			 <&clkc CLKID_SAR_ADC_SEL>;
-		clock-names = "clkin", "core", "sana", "adc_clk", "adc_sel";
-	};

Documentation/devicetree/bindings/iio/adc/amlogic,meson-saradc.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/amlogic,meson-saradc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Amlogic Meson SAR (Successive Approximation Register) A/D converter
+
+maintainers:
+  - Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+
+description:
+  Binding covers a range of ADCs found on Amlogic Meson SoCs.
+
+properties:
+  compatible:
+    oneOf:
+      - const: amlogic,meson-saradc
+      - items:
+          - enum:
+              - amlogic,meson8-saradc
+              - amlogic,meson8b-saradc
+              - amlogic,meson8m2-saradc
+              - amlogic,meson-gxbb-saradc
+              - amlogic,meson-gxl-saradc
+              - amlogic,meson-gxm-saradc
+              - amlogic,meson-axg-saradc
+              - amlogic,meson-g12a-saradc
+          - const: amlogic,meson-saradc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    description: Interrupt indicates end of sampling.
+    maxItems: 1
+
+  clocks:
+    minItems: 2
+    maxItems: 4
+
+  clock-names:
+    minItems: 2
+    maxItems: 4
+    items:
+      - const: clkin
+      - const: core
+      - const: adc_clk
+      - const: adc_sel
+
+  vref-supply: true
+
+  "#io-channel-cells":
+    const: 1
+
+  amlogic,hhi-sysctrl:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Syscon which contains the 5th bit of the TSC (temperature sensor
+      coefficient) on Meson8b and Meson8m2 (which used to calibrate the
+      temperature sensor)
+
+  nvmem-cells:
+    description: phandle to the temperature_calib eFuse cells
+    maxItems: 1
+
+  nvmem-cell-names:
+    const: temperature_calib
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson8-saradc
+              - amlogic,meson8b-saradc
+              - amlogic,meson8m2-saradc
+    then:
+      properties:
+        clocks:
+          maxItems: 2
+        clock-names:
+          maxItems: 2
+    else:
+      properties:
+        nvmem-cells: false
+        mvmem-cel-names: false
+        clocks:
+          minItems: 4
+        clock-names:
+          minItems: 4
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - amlogic,meson8b-saradc
+              - amlogic,meson8m2-saradc
+    then:
+      properties:
+        amlogic,hhi-sysctrl: true
+    else:
+      properties:
+        amlogic,hhi-sysctrl: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - "#io-channel-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/clock/gxbb-clkc.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+        adc@8680 {
+            compatible = "amlogic,meson-gxl-saradc", "amlogic,meson-saradc";
+            #io-channel-cells = <1>;
+            reg = <0x0 0x8680 0x0 0x34>;
+            interrupts = <GIC_SPI 73 IRQ_TYPE_EDGE_RISING>;
+            clocks = <&xtal>,
+                <&clkc CLKID_SAR_ADC>,
+                <&clkc CLKID_SAR_ADC_CLK>,
+                <&clkc CLKID_SAR_ADC_SEL>;
+            clock-names = "clkin", "core", "adc_clk", "adc_sel";
+        };
+        adc@9680 {
+            compatible = "amlogic,meson8b-saradc", "amlogic,meson-saradc";
+            #io-channel-cells = <1>;
+            reg = <0x0 0x9680 0x0 0x34>;
+            interrupts = <GIC_SPI 73 IRQ_TYPE_EDGE_RISING>;
+            clocks = <&xtal>, <&clkc CLKID_SAR_ADC>;
+            clock-names = "clkin", "core";
+            nvmem-cells = <&tsens_caldata>;
+            nvmem-cell-names = "temperature_calib";
+            amlogic,hhi-sysctrl = <&hhi>;
+        };
+    };
+...