doc/device-tree: add tpm.rst

This adds a documentation for the tpm device tree node.

Signed-off-by: Claudio Carvalho <cclaudio@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/doc/device-tree/tpm.rst b/doc/device-tree/tpm.rst
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+Trusted Platform Module (TPM)
+=============================
+
+The tpm node describes a TPM device present in the platform. It also includes
+event log information.
+
+Required properties
+-------------------
+
+All these properties are added by hostboot and consumed by skiboot and the
+linux kernel (tpm and vtpm codes)
+
+::
+
+    compatible :       manufacturer,model
+
+    linux,sml-base:    64-bit base address of the reserved memory allocated for firmware event log.
+                       sml stands for shared memory log.
+
+    linux,sml-size:    size of the memory allocated for firwmare event log.
+
+
+Optional properties
+-------------------
+
+::
+
+    status:            indicates whether the device is enabled or disabled. "okay" for
+                       enabled and "disabled" for disabled.
+
+Example
+-------
+
+::
+
+    tpm@57 {
+    	reg = <0x57>;
+    	compatible = "nuvoton,npct650", "nuvoton,npct601";
+    	linux,sml-base = <0x7f 0xfd450000>;
+    	linux,sml-size = <0x10000>;
+    	status = "okay";
+    	phandle = <0x10000017>;
+    	linux,phandle = <0x10000017>;
+    };
+