AM6442: Problem with communication TPM SLB9670 with AM6442 board

Hello

I am posting this post because I read similar threads on the forum and unfortunately they did not help me solve the problem (

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1092026/processor-sdk-am64x-am64x-tpm-slb9670/4065893?tisearch=e2e-sitesearch&keymatch=slb9670#4065893

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/932918/am3352-u-boot-use-tpm2-0-via-spi1)

I have a problem to communicate TPM SLB9670 with AM6442-SK over SPI protocol.

The problem is that although the TPM device is connected to the board, initialization of device fails. The tpm_tis_core_init () function returns the code -110 (ETIMEDOUT) or -19 (ENODEV). The result returned by this function depends on whether the MISO line to TPM is connected. If MISO is connected function returns -110, if not - then -19.

I also connected the oscilloscope probes to the appropriate pins. The waveform below indicates that a configuration message is being sent to the TPM. What's more interesting, if I connect the oscilloscope probe to the MISO pin, the tpm_tis_core_init () function returns -110, and if I do not connect the probe, it returns -19. This is a very strange behavior and it was detected on two same AM6442 boards.

 Below is kernel configuration and k3-am642-sk device-tree overlay:

CONFIG_SPI=y

CONFIG_SPI_MASTER=y

CONFIG_TCG_TPM=y

CONFIG_TCG_TIS_SPI=y

CONFIG_TCG_INFINEON=y

CONFIG_TCG_CRB=y

CONFIG_TCG_TIS=y

CONFIG_TCG_TIS_CORE=y

CONFIG_TCG_TIS_I2C_ATMEL=n

CONFIG_TCG_TIS_I2C_INFINEON=n

CONFIG_TCG_TIS_I2C_NUVOTON=n

 =========================================================

/dts-v1/;

/plugin/;

 #include "dt-bindings/pinctrl/k3.h"

/ {

        compatible = "ti,am642-sk", "ti,am642", "ti,am642-evm";

        fragment@0 {

                target = <&main_pmx0>;

                __overlay__ {

                        main_spi0_pins_default: main-spi0-pins-default {

                                pinctrl-single,pins = <

                                        AM64X_IOPAD(0x0210, PIN_INPUT, 0) /* (D13) SPI0_CLK */

                                        AM64X_IOPAD(0x0208, PIN_OUTPUT, 0) /* (D12) SPI0_CS0 */

                                        AM64X_IOPAD(0x020C, PIN_OUTPUT, 0) /* (C13) SPI0_CS1 */

                                        AM64X_IOPAD(0x0214, PIN_OUTPUT, 0) /* (A13) SPI0_D0 */

                                        AM64X_IOPAD(0x0218, PIN_INPUT, 0) /* (A14) SPI0_D1 */

                                >;

                        };

                };

 

        };


        fragment@1 {

                target = <&main_spi0>;

                __overlay__ {

                        #address-cells = <1>;

                        #size-cells = <0>;

                        status = "okay";

                        pinctrl-names = "default";

                        pinctrl-0 = <&main_spi0_pins_default>;

                        ti,pindir-d0-out-d1-in = <1>;

                        ti,spi-num-cs = <1>;

                        slb9670: slb9670@0 {

                                compatible = "infineon,slb9670";

                                reg = <0>;      /* CE0 */

                                #address-cells = <1>;

                                #size-cells = <0>;

                                spi-max-frequency = <100000>;

                                status = "okay";

                        };

                };

        };

};

I am using Yocto to build the image. I patched the tpm and spi driver to add some traces to have more verbose output. bellow screens:

How to resolve this problem?

Thanks,

Jakub