[PATCH 1/2] dt-bindings: i2c: convert i2c-mux-reg to DT schema

[Abdurrahman Hussain]

Convert Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt to
the YAML schema so the i2c-mux-reg binding is validated by
dt_binding_check.

Also document a new optional "base-bus-num" property: when
present, child adapter N is registered as Linux i2c bus number
(base-bus-num + reg), so static references such as sensors.conf
stanzas remain stable across boots. The matching driver support is
added in the following patch.

Signed-off-by: Abdurrahman Hussain <abdurrahman@xxxxxxxxxx>
---
 .../devicetree/bindings/i2c/i2c-mux-reg.txt        |  74 --------------
 .../devicetree/bindings/i2c/i2c-mux-reg.yaml       | 110 +++++++++++++++++++++
 2 files changed, 110 insertions(+), 74 deletions(-)

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
deleted file mode 100644
index b9d9755e4172..000000000000
--- a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.txt
+++ /dev/null
@@ -1,74 +0,0 @@
-Register-based I2C Bus Mux
-
-This binding describes an I2C bus multiplexer that uses a single register
-to route the I2C signals.
-
-Required properties:
-- compatible: i2c-mux-reg
-- i2c-parent: The phandle of the I2C bus that this multiplexer's master-side
-  port is connected to.
-* Standard I2C mux properties. See i2c-mux.yaml in this directory.
-* I2C child bus nodes. See i2c-mux.yaml in this directory.
-
-Optional properties:
-- reg: this pair of <offset size> specifies the register to control the mux.
-  The <offset size> depends on its parent node. It can be any memory-mapped
-  address. The size must be either 1, 2, or 4 bytes. If reg is omitted, the
-  resource of this device will be used.
-- little-endian: The existence indicates the register is in little endian.
-- big-endian: The existence indicates the register is in big endian.
-  If both little-endian and big-endian are omitted, the endianness of the
-  CPU will be used.
-- write-only: The existence indicates the register is write-only.
-- idle-state: value to set the muxer to when idle. When no value is
-  given, it defaults to the last value used.
-
-Whenever an access is made to a device on a child bus, the value set
-in the relevant node's reg property will be output to the register.
-
-If an idle state is defined, using the idle-state (optional) property,
-whenever an access is not being made to a device on a child bus, the
-register will be set according to the idle value.
-
-If an idle state is not defined, the most recently used value will be
-left programmed into the register.
-
-Example of a mux on PCIe card, the host is a powerpc SoC (big endian):
-
-	i2c-mux {
-		/* the <offset size> depends on the address translation
-		 * of the parent device. If omitted, device resource
-		 * will be used instead. The size is to determine
-		 * whether iowrite32, iowrite16, or iowrite8 will be used.
-		 */
-		reg = <0x6028 0x4>;
-		little-endian;		/* little endian register on PCIe */
-		compatible = "i2c-mux-reg";
-		#address-cells = <1>;
-		#size-cells = <0>;
-		i2c-parent = <&i2c1>;
-		i2c@0 {
-			reg = <0>;
-			#address-cells = <1>;
-			#size-cells = <0>;
-
-			si5338: clock-generator@70 {
-				compatible = "silabs,si5338";
-				reg = <0x70>;
-				/* other stuff */
-			};
-		};
-
-		i2c@1 {
-			/* data is written using iowrite32 */
-			reg = <1>;
-			#address-cells = <1>;
-			#size-cells = <0>;
-
-			si5338: clock-generator@70 {
-				compatible = "silabs,si5338";
-				reg = <0x70>;
-				/* other stuff */
-			};
-		};
-	};
diff --git a/Documentation/devicetree/bindings/i2c/i2c-mux-reg.yaml b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.yaml
new file mode 100644
index 000000000000..7fadedabde70
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-mux-reg.yaml
@@ -0,0 +1,110 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/i2c/i2c-mux-reg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Register-based I2C Bus Mux
+
+maintainers:
+  - Peter Rosin <peda@xxxxxxxxxx>
+
+description: |
+  This binding describes an I2C bus multiplexer that uses a single
+  memory-mapped register to route the I2C signals.
+
+  Whenever an access is made to a device on a child bus, the value
+  set in the relevant node's reg property is output to the register.
+
+  If an idle state is defined via the idle-state property, the
+  register is set to that value whenever no access is being made.
+  Otherwise the most recently used value is left programmed.
+
+allOf:
+  - $ref: /schemas/i2c/i2c-mux.yaml#
+
+properties:
+  compatible:
+    const: i2c-mux-reg
+
+  reg:
+    maxItems: 1
+    description: |
+      Offset and size of the register that selects the active child
+      bus, relative to the parent node's address space. The size
+      determines the access width and must be 1, 2, or 4 bytes. If
+      omitted, the platform device's own memory resource is used
+      instead.
+
+  i2c-parent:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle of the I2C bus that this multiplexer's master-side port
+      is connected to.
+
+  little-endian:
+    type: boolean
+    description: Register is accessed in little-endian byte order.
+
+  big-endian:
+    type: boolean
+    description: Register is accessed in big-endian byte order.
+
+  write-only:
+    type: boolean
+    description:
+      Register is write-only; the driver must not read back the
+      current selection.
+
+  idle-state:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Value to write to the register when no child bus is selected.
+
+  base-bus-num:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Base Linux i2c-adapter number for the child buses. Child N is
+      registered as bus (base-bus-num + reg). When unset, child
+      adapters are allocated dynamically by the i2c core.
+
+required:
+  - compatible
+  - i2c-parent
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    i2c-mux@6028 {
+        compatible = "i2c-mux-reg";
+        reg = <0x6028 0x4>;
+        little-endian;
+        #address-cells = <1>;
+        #size-cells = <0>;
+        i2c-parent = <&i2c1>;
+        base-bus-num = <16>;
+
+        i2c@0 {
+            reg = <0>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            clock-generator@70 {
+                compatible = "silabs,si5338";
+                reg = <0x70>;
+            };
+        };
+
+        i2c@1 {
+            reg = <1>;
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            clock-generator@70 {
+                compatible = "silabs,si5338";
+                reg = <0x70>;
+            };
+        };
+    };
+...

-- 
2.54.0