On Thu, Sep 11, 2025 at 03:52:33PM +0200, Alexander Wilhelm wrote: > Hello devs, > > I'm trying to bring up the SLM9670 TPM 2.0 device connected via SPI on a QorIQ > T1023-based board. Pin control is fully configured through the RCW, so I > haven't > added any additional properties in the device tree. The SPI controller > accesses > the TPM using `#CS0`. > > However, the driver reads an incorrect vendor ID (0x1000000) and hangs during > the startup sequence. A logic analyzer shows that the chip select line goes > high > immediately after transmitting 4 bytes, which, according to various forum > discussions, does not comply with the TPM specification. Unfortunately, I > haven't found a definitive solution to this issue.
So, at least the vendor ID is bogus meaning that TPM driver is doing right thing. > > Could this be a bug in the `spi-fsl-espi` driver, or is it possibly a hardware > limitation of the T1023? I've come across some suggestions that involve using > a > GPIO as an alternative chip select instead of the one provided by the SPI > controller. Can anyone confirm whether this workaround is viable? I’d prefer > to > avoid a PCB redesign unless it's absolutely necessary. My first guess would be that the firmware inside TPM actually does throw a broken vendor ID but it is exactly a guess :-) I'll follow this, and please cc me also to future threads but right now I'm clueless. > > > Best regards > Alexander Wilhelm BR, Jarkko
