dt-bindings:iio:adc:atmel, sama9260-adc: conversion to yaml from at91_adc.txt

There are a few things we would do differently in an ADC binding if we
were starting from scratch but we are stuck with what we have (which
made sense back when this was written!)

We may be able to tighten up some elements of this binding in the future
by careful checking of what values properties can actually take.

Note the unusual sign off chain is representative of the path this patch
took.

Jonathan wrote the patch, which was then included in a series by
Alexandre and ultimately applied by Jonathan.

[Alexandre Belloni: add sama5d3, remove atmel,adc-res and atmel,adc-res-names]

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Link: https://lore.kernel.org/r/20201128222818.1910764-5-alexandre.belloni@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

2 files changed, 167 insertions, 78 deletions

diff --git a/Documentation/devicetree/bindings/iio/adc/at91_adc.txt b/Documentation/devicetree/bindings/iio/adc/at91_adc.txt
deleted file mode 100644
index da393ac5c05f..000000000000
--- a/Documentation/devicetree/bindings/iio/adc/at91_adc.txt
+++ /dev/null
@@ -1,78 +0,0 @@
-* AT91's Analog to Digital Converter (ADC)
-
-Required properties:
-  - compatible: Should be "atmel,<chip>-adc"
-    <chip> can be "at91sam9260", "at91sam9g45", "at91sam9x5" or "sama5d3"
-  - reg: Should contain ADC registers location and length
-  - interrupts: Should contain the IRQ line for the ADC
-  - clock-names: tuple listing input clock names.
-	Required elements: "adc_clk", "adc_op_clk".
-  - clocks: phandles to input clocks.
-  - atmel,adc-channels-used: Bitmask of the channels muxed and enabled for this
-    device
-  - atmel,adc-startup-time: Startup Time of the ADC in microseconds as
-    defined in the datasheet
-  - atmel,adc-vref: Reference voltage in millivolts for the conversions
-
-Optional properties:
-  - atmel,adc-use-external-triggers: Boolean to enable the external triggers
-  - atmel,adc-use-res: String selecting the resolution, can be "lowres" or
-		       "highres". If not specified, the highest resolution will
-		       be used.
-  - atmel,adc-sleep-mode: Boolean to enable sleep mode when no conversion
-  - atmel,adc-sample-hold-time: Sample and Hold Time in microseconds
-  - atmel,adc-ts-wires: Number of touchscreen wires. Should be 4 or 5. If this
-                        value is set, then the adc driver will enable touchscreen
-                        support.
-    NOTE: when adc touchscreen is enabled, the adc hardware trigger will be
-          disabled. Since touchscreen will occupy the trigger register.
-  - atmel,adc-ts-pressure-threshold: a pressure threshold for touchscreen. It
-                                     makes touch detection more precise.
-
-Optional trigger Nodes:
-  - Required properties:
-    * trigger-name: Name of the trigger exposed to the user
-    * trigger-value: Value to put in the Trigger register
-      to activate this trigger
-  - Optional properties:
-    * trigger-external: Is the trigger an external trigger?
-
-Examples:
-adc0: adc@fffb0000 {
-	#address-cells = <1>;
-	#size-cells = <0>;
-	compatible = "atmel,at91sam9260-adc";
-	reg = <0xfffb0000 0x100>;
-	interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0>;
-	clocks = <&adc_clk>, <&adc_op_clk>;
-	clock-names = "adc_clk", "adc_op_clk";
-	atmel,adc-channels-used = <0xff>;
-	atmel,adc-startup-time = <40>;
-	atmel,adc-use-external-triggers;
-	atmel,adc-vref = <3300>;
-	atmel,adc-res = <8 10>;
-	atmel,adc-res-names = "lowres", "highres";
-	atmel,adc-use-res = "lowres";
-
-	trigger0 {
-		trigger-name = "external-rising";
-		trigger-value = <0x1>;
-		trigger-external;
-	};
-	trigger1 {
-		trigger-name = "external-falling";
-		trigger-value = <0x2>;
-		trigger-external;
-	};
-
-	trigger2 {
-		trigger-name = "external-any";
-		trigger-value = <0x3>;
-		trigger-external;
-	};
-
-	trigger3 {
-		trigger-name = "continuous";
-		trigger-value = <0x6>;
-	};
-};
diff --git a/Documentation/devicetree/bindings/iio/adc/atmel,sama9260-adc.yaml b/Documentation/devicetree/bindings/iio/adc/atmel,sama9260-adc.yaml
new file mode 100644
index 000000000000..9b0ff59e75de
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/atmel,sama9260-adc.yaml
@@ -0,0 +1,167 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/atmel,sama9260-adc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: AT91 sama9260 and similar Analog to Digital Converter (ADC)
+
+maintainers:
+  - Alexandre Belloni <alexandre.belloni@bootlin.com>
+
+properties:
+  compatible:
+    enum:
+      - atmel,at91sam9260-adc
+      - atmel,at91sam9rl-adc
+      - atmel,at91sam9g45-adc
+      - atmel,at91sam9x5-adc
+      - atmel,at91sama5d3-adc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    minItems: 2
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: adc_clk
+      - const: adc_op_clk
+
+  atmel,adc-channels-used:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Bitmask of the channels muxed and enabled for this device
+
+  atmel,adc-startup-time:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Startup Time of the ADC in microseconds as defined in the datasheet
+
+  atmel,adc-vref:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Reference voltage in millivolts for the conversions
+
+  atmel,adc-use-external-triggers:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: Enable the external triggers
+
+  atmel,adc-use-res:
+    $ref: /schemas/types.yaml#/definitions/string
+    description:
+      String corresponding to an identifier from atmel,adc-res-names property.
+      If not specified, the highest resolution will be used.
+    enum:
+      - "lowres"
+      - "highres"
+
+  atmel,adc-sleep-mode:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: Enable sleep mode when no conversion
+
+  atmel,adc-sample-hold-time:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Sample and Hold Time in microseconds
+
+  atmel,adc-ts-wires:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Number of touchscreen wires. Must be set to enable touchscreen.
+      NOTE: when adc touchscreen is enabled, the adc hardware trigger will be
+      disabled. Since touchscreen will occupy the trigger register.
+    enum:
+      - 4
+      - 5
+
+  atmel,adc-ts-pressure-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Pressure threshold for touchscreen.
+
+  "#io-channel-cells":
+    const: 1
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - atmel,adc-channels-used
+  - atmel,adc-startup-time
+  - atmel,adc-vref
+
+patternProperties:
+  "^(trigger)[0-9]$":
+    type: object
+    description: Child node to describe a trigger exposed to the user.
+    properties:
+      trigger-name:
+        $ref: /schemas/types.yaml#/definitions/string
+        description: Identifying name.
+
+      trigger-value:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Value to put in the Trigger register to activate this trigger
+
+      trigger-external:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description: This trigger is provided from an external pin.
+
+    additionalProperties: false
+    required:
+      - trigger-name
+      - trigger-value
+
+examples:
+  - |
+    #include <dt-bindings/dma/at91.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+    soc {
+        #address-cells = <1>;
+        #size-cells = <1>;
+
+        adc@fffb0000 {
+            compatible = "atmel,at91sam9260-adc";
+            reg = <0xfffb0000 0x100>;
+            interrupts = <20 IRQ_TYPE_LEVEL_HIGH 0>;
+            clocks = <&adc_clk>, <&adc_op_clk>;
+            clock-names = "adc_clk", "adc_op_clk";
+            atmel,adc-channels-used = <0xff>;
+            atmel,adc-startup-time = <40>;
+            atmel,adc-use-external-triggers;
+            atmel,adc-vref = <3300>;
+            atmel,adc-use-res = "lowres";
+
+            trigger0 {
+                trigger-name = "external-rising";
+                trigger-value = <0x1>;
+                trigger-external;
+            };
+
+            trigger1 {
+                trigger-name = "external-falling";
+                trigger-value = <0x2>;
+                trigger-external;
+            };
+
+            trigger2 {
+                trigger-name = "external-any";
+                trigger-value = <0x3>;
+                trigger-external;
+            };
+
+            trigger3 {
+                trigger-name = "continuous";
+                trigger-value = <0x6>;
+            };
+        };
+    };
+...