Add overlay for SLB9760 Iridium /LetsTrust TPM

Device Tree overlay for the Infineon SLB9670 Trusted Platform Module add-on
boards, which can be used as a secure key storage and hwrng.
available as "Iridium SLB9670" by Infineon and "LetsTrust TPM" by
pi3g.

Signed-off-by: Peter Huewe <[email protected]>

Author: PeterHuewe

arch/arm/boot/dts/overlays/Makefile

@@ -129,6 +129,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	superaudioboard.dtbo \
 	sx150x.dtbo \
 	tinylcd35.dtbo \
+	tpm-slb9670.dtbo \
 	uart0.dtbo \
 	uart1.dtbo \
 	upstream.dtbo \

arch/arm/boot/dts/overlays/README

@@ -1861,6 +1861,14 @@ Params: speed                   Display SPI bus speed
                 dtoverlay=tinylcd35,touch,touchgpio=3
 
 
+Name:   tpm-slb9670
+Info:   Enables support for Infineon SLB9670 Trusted Platform Module add-on
+        boards, which can be used as a secure key storage and hwrng,
+        available as "Iridium SLB9670" by Infineon and "LetsTrust TPM" by pi3g.
+Load:   dtoverlay=tpm-slb9670
+Params: <None>
+
+
 Name:   uart0
 Info:   Change the pin usage of uart0
 Load:   dtoverlay=uart0,<param>=<val>

arch/arm/boot/dts/overlays/tpm-slb9670-overlay.dts

@@ -0,0 +1,44 @@
+/*
+ * Device Tree overlay for the Infineon SLB9670 Trusted Platform Module add-on
+ * boards, which can be used as a secure key storage and hwrng.
+ * available as "Iridium SLB9670" by Infineon and "LetsTrust TPM" by pi3g.
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
+
+	fragment@0 {
+		target = <&spi0>;
+		__overlay__ {
+			status = "okay";
+		};
+	};
+
+	fragment@1 {
+		target = <&spidev1>;
+		__overlay__ {
+			status = "disabled";
+		};
+	};
+
+	fragment@2 {
+		target = <&spi0>;
+		__overlay__ {
+			/* needed to avoid dtc warning */
+			#address-cells = <1>;
+			#size-cells = <0>;
+			slb9670: slb9670@1 {
+				compatible = "infineon,slb9670";
+				reg = <1>;	/* CE1 */
+				#address-cells = <1>;
+				#size-cells = <0>;
+				spi-max-frequency = <32000000>;
+				status = "okay";
+			};
+
+		};
+	};
+};