Hi pau, thanks for your answer, SPI is enabled in DT and compiled in TPM is enabled in DT via overlay and compiled in. I have a working /dev/tpm0 However, the problem lays elsewhere - I added some debug prints to figure out what is going on: It looks like this [ 0.027898] RPIFirmware: Calling rpi_firmware_get [ 0.027929] bcm2835-clk 3f101000.cprman: Probing FW [ 0.027949] bcm2835-clk 3f101000.cprman: FW not ready, defering probe [ 0.028385] bcm2835-mbox 3f00b880.mailbox: mailbox enabled [ 0.028847] uart-pl011 3f201000.serial: could not find pctldev for node /soc/gpio@7e200000/uart0_pins, deferring probe [ 0.061353] bcm2835-dma 3f007000.dma: DMA legacy API manager at bb80f000, dmachans=0x1 [ 0.062828] SCSI subsystem initialized [ 0.062950] usbcore: registered new interface driver usbfs [ 0.063001] usbcore: registered new interface driver hub [ 0.063084] usbcore: registered new device driver usb [ 0.063362] raspberrypi-firmware soc:firmware: Calling rpi_firmware_probe So the bcm2835-clk calls rpi_firmware_get, which returns with NULL since the pdev has not been set yet, as the rpi_firmware_probe gets called only later :/ That defers the probing of the bcm2835-clk, so it it not available for the bcm2835-spi which also gets defered, consequently making the tpm not available until ima is done :/ Peter
