[PATCH 4/8] dt-bindings: tpm: document properties for cr50

[Stephen Boyd <swboyd@chromium.org>]

From: Andrey Pronin <apronin@chromium.org>

Add TPM2.0 PTP FIFO compatible SPI interface for chips with Cr50
firmware.

Signed-off-by: Andrey Pronin <apronin@chromium.org>
Cc: Rob Herring <robh+dt@kernel.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
---

This is a resend of https://lkml.kernel.org/r/1469757314-116169-2-git-send-email-apronin@chromium.org
with status removed.

 .../bindings/security/tpm/cr50_spi.txt        | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/security/tpm/cr50_spi.txt

diff --git a/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt b/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt
new file mode 100644
index 000000000000..401f4ba281b7
--- /dev/null
+++ b/Documentation/devicetree/bindings/security/tpm/cr50_spi.txt
@@ -0,0 +1,19 @@
+* H1 Secure Microcontroller with Cr50 Firmware on SPI Bus.
+
+H1 Secure Microcontroller running Cr50 firmware provides several
+functions, including TPM-like functionality. It communicates over
+SPI using the FIFO protocol described in the PTP Spec, section 6.
+
+Required properties:
+- compatible: Should be "google,cr50".
+- spi-max-frequency: Maximum SPI frequency.
+
+Example:
+
+&spi0 {
+        cr50@0 {
+                compatible = "google,cr50";
+                reg = <0>;
+                spi-max-frequency = <800000>;
+        };
+};
-- 
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