Add overlay for SLB9673 TPM

Device Tree overlay for the Infineon SLB9673 Trusted Platform Module
addon boards that communicate using I2C.

Signed-off-by: Andreas Fuchs <[email protected]>

Author: AndreasFuchsTPM

arch/arm/boot/dts/overlays/Makefile

@@ -243,6 +243,7 @@ dtbo-$(CONFIG_ARCH_BCM2835) += \
 	tc358743-audio.dtbo \
 	tinylcd35.dtbo \
 	tpm-slb9670.dtbo \
+	tpm-slb9673.dtbo \
 	uart0.dtbo \
 	uart1.dtbo \
 	uart2.dtbo \

arch/arm/boot/dts/overlays/README

@@ -4021,6 +4021,14 @@ Load:   dtoverlay=tpm-slb9670
 Params: <None>
 
 
+Name:   tpm-slb9673
+Info:   Enables support for Infineon SLB9673 Trusted Platform Module add-on
+        boards, which can be used as a secure key storage and hwrng
+        via the I2C protocol.
+Load:   dtoverlay=tpm-slb9673
+Params: <None>
+
+
 Name:   uart0
 Info:   Change the pin usage of uart0
 Load:   dtoverlay=uart0,<param>=<val>

arch/arm/boot/dts/overlays/tpm-slb9673-overlay.dts

@@ -0,0 +1,50 @@
+/*
+ * Device Tree overlay for the Infineon SLB9673 Trusted Platform Module add-on
+ * boards, which can be used as a secure key storage and hwrng.
+ */
+
+/dts-v1/;
+/plugin/;
+
+/ {
+	compatible = "brcm,bcm2835";
+
+	/* Due to issue https://github.com/raspberrypi/linux/issues/4884 the
+	   hardware I2C needs to be disabled and software I2C enabled */
+	fragment@0 {
+		target = <&i2c_arm>;
+		__overlay__ {
+			status = "disabled";
+		};
+	};
+
+	fragment@1 {
+		target-path = "/";
+		__overlay__ {
+			i2c1: i2c-gpio@1 {
+				#address-cells = <1>;
+				#size-cells = <0>;
+				compatible = "i2c-gpio";
+				gpios = <&gpio 2 6>, /* SDA GPIO_OPEN_DRAIN */
+				     	<&gpio 3 6>; /* CLK GPIO_OPEN_DRAIN */
+				clock-frequency = <400000>;
+				status = "okay";
+			};
+		};
+	};
+
+	/* Add the TPM */
+	fragment@2 {
+		target = <&i2c1>;
+		__overlay__ {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			slb9673: slb9673@2e {
+				compatible = "infineon,slb9673", "tcg,tpm-tis-i2c";
+				reg = <0x2e>;
+				status = "okay";
+			};
+		};
+	};
+};