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# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/tpm/google,cr50.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#
title: Google Security Chip H1 (running Cr50 firmware)
maintainers:
- Andrey Pronin <apronin@chromium.org>
description: |
Google has designed a family of security chips called "Titan".
One member is the H1 built into Chromebooks and running Cr50 firmware:
https://www.osfc.io/2018/talks/google-secure-microcontroller-and-ccd-closed-case-debugging/
The chip provides several functions, including TPM 2.0 like functionality.
It communicates over SPI or I²C using the FIFO protocol described in the
TCG PC Client Platform TPM Profile Specification for TPM 2.0 (PTP), sec 6:
https://trustedcomputinggroup.org/resource/pc-client-platform-tpm-profile-ptp-specification/
properties:
compatible:
const: google,cr50
allOf:
- $ref: tpm-common.yaml#
anyOf:
- $ref: /schemas/spi/spi-peripheral-props.yaml#
- $ref: tcg,tpm-tis-i2c.yaml#/properties/reg
required:
- compatible
- reg
unevaluatedProperties: false
examples:
- |
spi {
#address-cells = <1>;
#size-cells = <0>;
tpm@0 {
reg = <0>;
compatible = "google,cr50";
spi-max-frequency = <800000>;
};
};
- |
#include <dt-bindings/interrupt-controller/irq.h>
i2c {
#address-cells = <1>;
#size-cells = <0>;
tpm@50 {
compatible = "google,cr50";
reg = <0x50>;
interrupts-extended = <&pio 88 IRQ_TYPE_EDGE_FALLING>;
pinctrl-names = "default";
pinctrl-0 = <&cr50_int>;
};
};
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