Add OPAL_READ_TPO and OPAL_WRITE_TPO documentation

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

1 files changed, 15 insertions, 0 deletions

diff --git a/doc/opal-api/opal-read-write-tpo-103-104.txt b/doc/opal-api/opal-read-write-tpo-103-104.txt
new file mode 100644
index 0000000..0040615
--- /dev/null
+++ b/doc/opal-api/opal-read-write-tpo-103-104.txt
@@ -0,0 +1,15 @@
+OPAL_READ_TPO and OPAL_WRITE_TPO
+--------------------------------
+
+TPO is a Timed Power On facility.
+
+It is an OPTIONAL part of the OPAL spec.
+
+If a platform supports Timed Power On (TPO), the RTC node in the device tree (itself under the "ibm,opal" node will have the has-tpo property:
+
+rtc {
+     compatible = "ibm,opal-rtc";
+     has-tpo;
+};
+
+If the "has-tpo" proprety is *NOT* present then OPAL does *NOT* support TPO.