On Sun, Sep 14, 2025 at 08:06:15PM +0300, Jarkko Sakkinen wrote: > 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 :-)
Ugh, no. Probably it is device tree given false data. I recall we have some ways to override device tree, so find the data sheet for the TPM and rewrite the ids I suppose. BR, Jarkko
