spi: Add YAML schemas for the generic SPI options

The SPI controllers have a bunch of generic options that are needed in a
device tree. Add a YAML schemas for those.

Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/spi-controller.yaml

@@ -0,0 +1,161 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/spi-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SPI Controller Generic Binding
+
+maintainers:
+  - Mark Brown <broonie@kernel.org>
+
+description: |
+  SPI busses can be described with a node for the SPI controller device
+  and a set of child nodes for each SPI slave on the bus. The system SPI
+  controller may be described for use in SPI master mode or in SPI slave mode,
+  but not for both at the same time.
+
+properties:
+  $nodename:
+    pattern: "^spi(@.*|-[0-9a-f])*$"
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  cs-gpios:
+    description: |
+      GPIOs used as chip selects.
+      If that property is used, the number of chip selects will be
+      increased automatically with max(cs-gpios, hardware chip selects).
+
+      So if, for example, the controller has 2 CS lines, and the
+      cs-gpios looks like this
+        cs-gpios = <&gpio1 0 0>, <0>, <&gpio1 1 0>, <&gpio1 2 0>;
+
+      Then it should be configured so that num_chipselect = 4, with
+      the following mapping
+        cs0 : &gpio1 0 0
+        cs1 : native
+        cs2 : &gpio1 1 0
+        cs3 : &gpio1 2 0
+
+  num-cs:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Total number of chip selects.
+
+  spi-slave:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      The SPI controller acts as a slave, instead of a master.
+
+patternProperties:
+  "^slave$":
+    type: object
+
+    properties:
+      compatible:
+        description:
+          Compatible of the SPI device.
+
+    required:
+      - compatible
+
+  "^.*@[0-9a-f]+$":
+    type: object
+
+    properties:
+      compatible:
+        description:
+          Compatible of the SPI device.
+
+      reg:
+        maxItems: 1
+        minimum: 0
+        maximum: 256
+        description:
+          Chip select used by the device.
+
+      spi-3wire:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description:
+          The device requires 3-wire mode.
+
+      spi-cpha:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description:
+          The device requires shifted clock phase (CPHA) mode.
+
+      spi-cpol:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description:
+          The device requires inverse clock polarity (CPOL) mode.
+
+      spi-cs-high:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description:
+          The device requires the chip select active high.
+
+      spi-lsb-first:
+        $ref: /schemas/types.yaml#/definitions/flag
+        description:
+          The device requires the LSB first mode.
+
+      spi-max-frequency:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          Maximum SPI clocking speed of the device in Hz.
+
+      spi-rx-bus-width:
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [ 1, 2, 4 ]
+          - default: 1
+        description:
+          Bus width to the SPI bus used for MISO.
+
+      spi-rx-delay-us:
+        description:
+          Delay, in microseconds, after a read transfer.
+
+      spi-tx-bus-width:
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [ 1, 2, 4 ]
+          - default: 1
+        description:
+          Bus width to the SPI bus used for MOSI.
+
+      spi-tx-delay-us:
+        description:
+          Delay, in microseconds, after a write transfer.
+
+    required:
+      - compatible
+      - reg
+
+examples:
+  - |
+    spi@f00 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        compatible = "fsl,mpc5200b-spi","fsl,mpc5200-spi";
+        reg = <0xf00 0x20>;
+        interrupts = <2 13 0 2 14 0>;
+        interrupt-parent = <&mpc5200_pic>;
+
+        ethernet-switch@0 {
+            compatible = "micrel,ks8995m";
+            spi-max-frequency = <1000000>;
+            reg = <0>;
+        };
+
+        codec@1 {
+            compatible = "ti,tlv320aic26";
+            spi-max-frequency = <100000>;
+            reg = <1>;
+        };
+    };