linux-libre/Documentation/devicetree/bindings/security/tpm/tpm_tis_spi.txt

Required properties:
- compatible: should be one of the following
    "st,st33htpm-spi"
    "infineon,slb9670"
    "tcg,tpm_tis-spi"
- spi-max-frequency: Maximum SPI frequency (depends on TPMs).

Optional SoC Specific Properties:
- pinctrl-names: Contains only one value - "default".
- pintctrl-0: Specifies the pin control groups used for this controller.

Example (for ARM-based BeagleBoard xM with TPM_TIS on SPI4):

&mcspi4 {

        status = "okay";

        tpm_tis@0 {

                compatible = "tcg,tpm_tis-spi";

                spi-max-frequency = <10000000>;
        };
};