[PATCH 6/6] dt-bindings: spi: Document Renesas SPIBSC bindings

[Chris Brandt <chris.brandt@xxxxxxxxxxx>]

Document the bindings used by the Renesas SPI bus space controller.

Signed-off-by: Chris Brandt <chris.brandt@xxxxxxxxxxx>
---
 .../bindings/spi/spi-renesas-spibsc.txt       | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/spi/spi-renesas-spibsc.txt

diff --git a/Documentation/devicetree/bindings/spi/spi-renesas-spibsc.txt b/Documentation/devicetree/bindings/spi/spi-renesas-spibsc.txt
new file mode 100644
index 000000000000..b5f7081d2d1e
--- /dev/null
+++ b/Documentation/devicetree/bindings/spi/spi-renesas-spibsc.txt
@@ -0,0 +1,48 @@
+Renesas SPI Bus Space Controller (SPIBSC) Device Tree Bindings
+
+Otherwise referred to as the "SPI Multi I/O Bus Controller" in SoC hardware
+manuals. This controller was designed specifically for accessing SPI flash
+devices.
+
+Required properties:
+- compatible: should be an SoC-specific compatible value, followed by
+		"renesas,spibsc" as a fallback.
+		supported SoC-specific values are:
+		"renesas,r7s72100-spibsc"	(RZ/A1)
+		"renesas,r7s9210-spibsc"	(RZ/A2)
+- reg: should contain three register areas:
+       first for the base address of SPIBSC registers,
+       second for the direct mapping read mode
+- clocks: should contain the clock phandle/specifier pair for the module clock.
+- power-domains: should contain the power domain phandle/specifier pair.
+- #address-cells: should be 1
+- #size-cells: should be 0
+- flash: should be represented by a subnode of the SPIBSC node,
+	 its "compatible" property contains "jedec,spi-nor" if SPI is used.
+
+Example:
+
+	spibsc: spi@1f800000 {
+		compatible = "renesas,r7s9210-spibsc", "renesas,spibsc";
+		reg = <0x1f800000 0x8c>, <0x20000000 0x10000000 >;
+		clocks = <&cpg CPG_MOD 83>;
+		power-domains = <&cpg>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		flash@0 {
+			compatible = "jedec,spi-nor";
+			reg = <0>;
+			spi-max-frequency = <40000000>;
+
+			partitions {
+				compatible = "fixed-partitions";
+				#address-cells = <1>;
+				#size-cells = <1>;
+
+				partition@0000000 {
+					label = "u-boot";
+					reg = <0x00000000 0x80000>;
+				};
+			};
+		};
-- 
2.23.0