Re: Regarding recently Added TPM2.0 support to the Nuvoton i2c driver

[Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>]

On Tue, Jul 26, 2016 at 11:44:43PM +0530, Nayna wrote:
> I got these questions while testing some TPM2.0 stuff using the kernel 
> code from repo having this patch and am using Nuvoton TPM.
> 
> #1. It seems that support is added only for following device-ids.
>          {.compatible = "nuvoton,npct501"},
>          {.compatible = "winbond,wpct301"},
>          {.compatible = "nuvoton,npct601", .data = OF_IS_TPM2},
> 
> So, was wondering about why device id nuvoton,npct650  wasn't added for 
> the support ?

Yes, that was the device ID list for Nuvoton.

It is convention in device tree to include older device IDs if the
device is compatible.

So you might do

 compatible = "nuvoton,npct650", "nuvoton,npct601"

Andrew, is 601 even the right name?

> Was it expected to work with some wild-card type device-id as specified 
> in the first line of description comment of file i.e. npct6XX. ?

No.

> So, why is there hard-coded checking and not using tpm2_probe() method 
> which is itself based on direct TPM hardware response for setting the 
> TPM2 flag. ? Is there something I am missing in the design which 
> mandates to have .data set as OF_IS_TPM2.

Generally speaking probing is somewhat discouraged, currently we only
probe for PC platform tis (and even that might be a mistake), all
other drivers are designed to be explicit.

Jason

------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are 
consuming the most bandwidth. Provides multi-vendor support for NetFlow, 
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev