dts: stm32: add SPI nodes and give example for /delete-node/

Most STM32F429 SoCs have 6 SPIs, but STM32F429Vx SoCs only have
4 SPIs. This is one of the rare conditions where device-tree
directive /delete-node/ should be used.

Add spi5 and spi6 node to stm32f429.dtsi. Create file
stm32f429vX.dtsi to delete those nodes and document usage of
/delete-node/ directive.

Signed-off-by: Daniel Wagenknecht <[email protected]>

Author: Daniel Wagenknecht

dts/arm/st/stm32f429.dtsi

@@ -35,5 +35,31 @@
 			status = "disabled";
 			label = "SPI_4";
 		};
+
+		/* spi5 is present on all STM32F429XX SoCs except
+		 * STM32F429vX SoCs. Delete node in stm32f429vX.dtsi.
+		 */
+		 spi5: spi@40015000 {
+			compatible = "st,stm32-spi";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <0x40015000 0x400>;
+			interrupts = <85 5>;
+			status = "disabled";
+			label = "SPI_5";
+		};
+
+		/* spi6 is present on all STM32F429XX SoCs except
+		 * STM32F429vX SoCs. Delete node in stm32f429vX.dtsi.
+		 */
+		spi6: spi@40015400 {
+			compatible = "st,stm32-spi";
+			#address-cells = <1>;
+			#size-cells = <0>;
+			reg = <0x40015400 0x400>;
+			interrupts = <86 5>;
+			status = "disabled";
+			label = "SPI_6";
+		};
 	};
 };

dts/arm/st/stm32f429vX.dtsi

@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2018 Daniel Wagenknecht
+ *
+ * Document the usage of /delete-node/ for device tree nodes
+ * that are missing on on only a small subset of SoCs of a given group
+ * of SoCs.
+ * Don't remove this file even if none of the SoCs currently
+ * implemented in zephyr use it.
+ *
+ * spi5 and spi6 are present on all STM32F429XX SoCs except
+ * STM32F429vX SoCs, so they are defined in stm32f429.dtsi and deleted
+ * here.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <st/stm32f429.dtsi>
+
+/ {
+	soc {
+		/delete-node/ &spi5;
+
+		/delete-node/ &spi6;
+	};
+};