dt-bindings: spi: convert spi-brcm63xx.txt to YAML

Changes done during conversion:

* added a description, lifting and adapting the limitation sentence from
  brcm,bcm63xx-hsspi.yml
* added appropriate compatibles for all SoCs that are supported by
  bcm63xx/bmips

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Link: https://lore.kernel.org/r/20230727070806.12205-1-jonas.gorski@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: KanjiMonster

Documentation/devicetree/bindings/spi/brcm,bcm63xx-spi.yaml

@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/spi/brcm,bcm63xx-spi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom BCM6348/BCM6358 SPI controller
+
+maintainers:
+  - Jonas Gorski <jonas.gorski@gmail.com>
+
+description: |
+  Broadcom "Low Speed" SPI controller found in many older MIPS based Broadband
+  SoCs.
+
+  This controller has a limitation that can not keep the chip select line active
+  between the SPI transfers within the same SPI message. This can terminate the
+  transaction to some SPI devices prematurely. The issue can be worked around by
+  the controller's prepend mode.
+
+allOf:
+  - $ref: spi-controller.yaml#
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - enum:
+              - brcm,bcm6368-spi
+              - brcm,bcm6362-spi
+              - brcm,bcm63268-spi
+          - const: brcm,bcm6358-spi
+      - enum:
+          - brcm,bcm6348-spi
+          - brcm,bcm6358-spi
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: SPI master reference clock
+
+  clock-names:
+    items:
+      - const: spi
+
+  interrupts:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    spi@10000800 {
+        compatible = "brcm,bcm6368-spi", "brcm,bcm6358-spi";
+        reg = <0x10000800 0x70c>;
+        interrupts = <1>;
+        clocks = <&clkctl 9>;
+        clock-names = "spi";
+        num-cs = <5>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+    };

Documentation/devicetree/bindings/spi/spi-bcm63xx.txt

@@ -4127,7 +4127,7 @@ BROADCOM BCM6348/BCM6358 SPI controller DRIVER
 M:	Jonas Gorski <jonas.gorski@gmail.com>
 L:	linux-spi@vger.kernel.org
 S:	Odd Fixes
-F:	Documentation/devicetree/bindings/spi/spi-bcm63xx.txt
+F:	Documentation/devicetree/bindings/spi/brcm,bcm63xx-spi.yaml
 F:	drivers/spi/spi-bcm63xx.c
 
 BROADCOM ETHERNET PHY DRIVERS