Hi Sachin, I could finally solve the problem. I added the GPIO configuration in a table in Stage1B, but I forget to modify also same GPIO in Stage2 phase, so GPIO configuration was being overwritten. Now I can see TPM driver working in Linux kernel 4.14 too. Thanks for your support. Regards, Javier -----Mensaje original----- De: Agrawal, Sachin [mailto:sachin.agrawal@intel.com] Enviado el: jueves, 11 de abril de 2019 7:21 Para: sbl-devel(a)lists.01.org; Javier Santos Romo <jsantos(a)gmv.com&gt; Asunto: RE: : [Sbl-devel] TPM Support on Fast SPI Bus Hi Javier, SBL communicate the type of TPM interface to OS using 'StartMethod' field in TPM2 ACPI table. Device info about TPM is published via TPM SSDT table. These tables are available in "Platform/CommonBoardPkg/AcpiTables/Tpm" directory. They are updated by TpmLib during Stage2 execution. I have a test setup here with Linux kernel 4.14 and it is able to detect SPI TPM device and install 'tpm_tis' kernel driver. Can you check your kernel dmesg log and see if tpm driver is generating any error message? Thanks Sachin Date: Wed, 10 Apr 2019 16:58:55 +0000 From: Javier Santos Romo <jsantos(a)gmv.com&gt; To: &quot;sbl-devel(a)lists.01.org&quot; <sbl-devel(a)lists.01.org&gt; Subject: Re: [Sbl-devel] TPM Support on Fast SPI Bus Message-ID: <c9161b0a100a4c71b9b458056c482f88(a)gmv.com&gt; Content-Type: text/plain; charset="iso-8859-1" Hi Sachin, Thanks for your answer. Following your guidelines I could finally verify TPM functionality in SBL. However, I have tested that linux kernel doesn't detect the device. I think is something related to ACPI like I told you in our last email. Do you have any example or code snippet where TPM on FAST SPI is configured in a ACPI table? Thanks, Javier -----Mensaje original----- De: Agrawal, Sachin [mailto:sachin.agrawal@intel.com] Enviado el: mi?rcoles, 10 de abril de 2019 0:01 Para: sbl-devel(a)lists.01.org; Javier Santos Romo <jsantos(a)gmv.com&gt; Asunto: Re: [Sbl-devel] TPM Support on Fast SPI Bus Hi Javier, Yes. If you want to use interrupt functionality for TPM device, you may have to report it via ACPI table to OS. Currently I believe it is working because OS driver is probably using polling mechanism. Thanks Sachin Date: Tue, 9 Apr 2019 10:22:25 +0000 From: Javier Santos Romo <jsantos(a)gmv.com&gt; To: &quot;sbl-devel(a)lists.01.org&quot; <sbl-devel(a)lists.01.org&gt; Subject: Re: [Sbl-devel] TPM Support on Fast SPI Bus Message-ID: <70bf0ebfbd874530ae1dcbaa6b60b39e(a)gmv.com&gt; Content-Type: text/plain; charset="iso-8859-1" Hi Sachin, OK, that GPIO configuration is right according to Apollo Lake Soc. Just one last question. Then, if GPIO_9 is configured as TPM interrupt signal, is not it necessary to configure this pin as TPM interrupt pin in some place around SBL code? I mean, to be able to use this pin as interrupt I suppose it would have to be indicated in ACPI table or something like that, isn?t it? Thanks, Javier P Please consider the environment before printing this e-mail.