linux-kernel - Re: [tpmdd-devel] [PATCH] tpm: do not suspend/resume if power stays on

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Date:   Wed, 1 Mar 2017 16:18:36 -0700
From:   Jason Gunthorpe <jgunthorpe@...idianresearch.com>
To:     Sonny Rao <sonnyrao@...omium.org>
Cc:     Mark Rutland <mark.rutland@....com>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        tpmdd-devel@...ts.sourceforge.net
Subject: Re: [tpmdd-devel] [PATCH] tpm: do not suspend/resume if power stays
 on

On Wed, Mar 01, 2017 at 02:39:09PM -0800, Sonny Rao wrote:

> > We recently added global suspend/resume callbacks to the TPM
> > core. Those call backs do not power off the TPM, they just prepare its
> > internal state to loose power to the chip. Skipping that process on
> > hardware that does not power-off the TPM makes sense to me.
> >
> > But, Sonny, perhaps this should be a global flag in tpm_chip, not a
> > per-interface-driver override?
> 
> It's a property of the board design not the chip -- maybe I'm
> misunderstanding?

I mean do not add the code to handle this to tpm_i2c_infineon.c but in
the common chip code instead.

tpm_i2c_infineon.c should only parse DT properties that are relavent
to the bus that delivers commands to the TPM, things that apply to how
a TPM chip operates should be handled in the core code because they
apply to any command transport bus.

Jason