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From:   Jes Klinke <jbk@google.com>
Date:   Tue, 19 Apr 2022 16:39:35 -0700
Message-ID: <CANMTAZS+UzqaoKybC6wy7JwDvtcrduvasvvC+hOrdmcsg2zMzQ@mail.gmail.com>
Subject: Re: [PATCH] tpm: cr50: Add new device/vendor ID 0x504a6666
To:     Jarkko Sakkinen <jarkko@kernel.org>
Cc:     Paul Menzel <pmenzel@molgen.mpg.de>,
        "Jes B. Klinke" <jbk@chromium.org>,
        linux-integrity@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>,
        Peter Huewe <peterhuewe@gmx.de>, linux-kernel@vger.kernel.org
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Thanks for your feedback, I have sent an updated patch to the list,
(as far as I could tell, the convention is to prefix with: [PATCH
v2]).

Regards
Jes

On Thu, Apr 14, 2022 at 9:53 AM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> On Thu, 2022-04-14 at 17:06 +0200, Paul Menzel wrote:
> > Dear Jarkko,
> >
> >
> > Am 14.04.22 um 14:08 schrieb Jarkko Sakkinen:
> > > On Thu, Apr 07, 2022 at 12:21:44PM +0200, Paul Menzel wrote:
> >
> > > > Thank you for your patch.
> > > >
> > > > Am 05.04.22 um 19:37 schrieb Jes B. Klinke:
> > > > > Accept one additional numerical value of DID:VID for next generat=
ion
> > > > > Google TPM, to be used in future Chromebooks.
> > > >
> > > > Maybe extend:
> > > >
> > > > =E2=80=A6 Google TPM with new firmware =E2=80=A6
> > > >
> > > > The TPM with the new firmware has the code name TI50, and going to =
use the
> > > > same interfaces.
> > > >
> > > > > This patch touches more lines than may seem necessary, as a resul=
t of
> > > > > the need to move the error case to sit after the two recognized c=
ases.
> > > > >
> > > > > Signed-off-by: Jes B. Klinke <jbk@chromium.org>
> > > > > ---
> > > > >
> > > > >    drivers/char/tpm/tpm_tis_i2c_cr50.c | 21 +++++++++++++--------
> > > > >    1 file changed, 13 insertions(+), 8 deletions(-)
> > > > >
> > > > > diff --git a/drivers/char/tpm/tpm_tis_i2c_cr50.c b/drivers/char/t=
pm/tpm_tis_i2c_cr50.c
> > > > > index f6c0affbb4567..bf54ebd6724b0 100644
> > > > > --- a/drivers/char/tpm/tpm_tis_i2c_cr50.c
> > > > > +++ b/drivers/char/tpm/tpm_tis_i2c_cr50.c
> > > > > @@ -31,6 +31,7 @@
> > > > >    #define TPM_CR50_TIMEOUT_SHORT_MS    2               /* Short =
timeout during transactions */
> > > > >    #define TPM_CR50_TIMEOUT_NOIRQ_MS    20              /* Timeou=
t for TPM ready without IRQ */
> > > > >    #define TPM_CR50_I2C_DID_VID         0x00281ae0L     /* Device=
 and vendor ID reg value */
> > > > > +#define TPM_TI50_I2C_DID_VID           0x504a6666L     /* Device=
 and vendor ID reg value */
> > > > >    #define TPM_CR50_I2C_MAX_RETRIES     3               /* Max re=
tries due to I2C errors */
> > > > >    #define TPM_CR50_I2C_RETRY_DELAY_LO  55              /* Min us=
ecs between retries on I2C */
> > > > >    #define TPM_CR50_I2C_RETRY_DELAY_HI  65              /* Max us=
ecs between retries on I2C */
> > > > > @@ -742,16 +743,20 @@ static int tpm_cr50_i2c_probe(struct i2c_cl=
ient *client)
> > > > >         }
> > > > >         vendor =3D le32_to_cpup((__le32 *)buf);
> > > > > -       if (vendor !=3D TPM_CR50_I2C_DID_VID) {
> > > > > -               dev_err(dev, "Vendor ID did not match! ID was %08=
x\n", vendor);
> > > > > -               tpm_cr50_release_locality(chip, true);
> > > > > -               return -ENODEV;
> > > > > +       if (vendor =3D=3D TPM_CR50_I2C_DID_VID) {
> > > > > +               dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id=
 0x%x)\n",
> > > > > +                        client->addr, client->irq, vendor >> 16)=
;
> > > > > +               return tpm_chip_register(chip);
> > > > > +       }
> > > > > +       if (vendor =3D=3D TPM_TI50_I2C_DID_VID) {
> > > > > +               dev_info(dev, "ti50 TPM 2.0 (i2c 0x%02x irq %d id=
 0x%x)\n",
> > > > > +                        client->addr, client->irq, vendor >> 16)=
;
> > > > > +               return tpm_chip_register(chip);
> > > > >         }
> > > >
> > > > Both branches are quite similar. Can a ternary operator be used?
> > > >
> > > >      dev_info(dev, "%s TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n",
> > > >          (vendor =3D=3D TPM_CR50_I2C_DID_VID) ? "cr50" : "ti50", cl=
ient->addr,
> > > > client->irq, vendor >> 16);
> > > >      return tpm_chip_register(chip);
> > > >
> > > > and the original flow be left? (A separate variable can also be add=
ed.)
> > > >
> > > > > -       dev_info(dev, "cr50 TPM 2.0 (i2c 0x%02x irq %d id 0x%x)\n=
",
> > > > > -                client->addr, client->irq, vendor >> 16);
> > > > > -
> > > > > -       return tpm_chip_register(chip);
> > > > > +       dev_err(dev, "Vendor ID did not match! ID was %08x\n", ve=
ndor);
> > > > > +       tpm_cr50_release_locality(chip, true);
> > > > > +       return -ENODEV;
> > > > >    }
> > > > >    /**
> >
> > > OK, these are legit suggestions. Paul, can you do these changes and a=
dd my
> > > reviewed-by for the +1 version?
> >
> > I guess you mean Jes?
> >
> >
> > Kind regards,
>
> Yeah, I meant Jes :-)
>
> /Jarkko