[PATCH] drivers: tpm2: update reset gpio semantics

[Bruno Thomsen]

Den tor. 27. maj 2021 kl. 09.15 skrev Michal Simek <michal.simek at xilinx.com>:
>
>
>
> On 5/26/21 9:57 PM, Jorge Ramirez-Ortiz wrote:
> > Use the more generic reset-gpios propery name.
> >
> > Signed-off-by: Jorge Ramirez-Ortiz <jorge at foundries.io>
> > ---
> >  doc/device-tree-bindings/tpm2/tis-tpm2-spi.txt | 2 +-
> >  drivers/tpm/tpm2_tis_spi.c                     | 2 +-
> >  2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/doc/device-tree-bindings/tpm2/tis-tpm2-spi.txt b/doc/device-tree-bindings/tpm2/tis-tpm2-spi.txt
> > index 3a2ee4bd17..bbcd12950f 100644
> > --- a/doc/device-tree-bindings/tpm2/tis-tpm2-spi.txt
> > +++ b/doc/device-tree-bindings/tpm2/tis-tpm2-spi.txt
> > @@ -6,7 +6,7 @@ Required properties:
> >  - reg                        : SPI Chip select
> >
> >  Optional properties:
> > -- gpio-reset         : Reset GPIO (if not connected to the SoC reset line)
> > +- reset-gpios                : Reset GPIO (if not connected to the SoC reset line)
> >  - spi-max-frequency  : See spi-bus.txt
> >
> >  Example:
> > diff --git a/drivers/tpm/tpm2_tis_spi.c b/drivers/tpm/tpm2_tis_spi.c
> > index 4b33ac8fd3..94ac52d9ce 100644
> > --- a/drivers/tpm/tpm2_tis_spi.c
> > +++ b/drivers/tpm/tpm2_tis_spi.c
> > @@ -589,7 +589,7 @@ static int tpm_tis_spi_probe(struct udevice *dev)
> >       if (CONFIG_IS_ENABLED(DM_GPIO)) {
> >               struct gpio_desc reset_gpio;
> >
> > -             ret = gpio_request_by_name(dev, "gpio-reset", 0,
> > +             ret = gpio_request_by_name(dev, "reset-gpios", 0,
> >                                          &reset_gpio, GPIOD_IS_OUT);
> >               if (ret) {
> >                       log(LOGC_NONE, LOGL_NOTICE, "%s: missing reset GPIO\n",
> >
>
> I think you should deprecate gpio-reset but keep supporting that option
> with any warning and add code for reset-gpios.
>
> Also would be good to add it as optional property to Linux kernel to
> keep it in sync.

Hi

The reason the Linux kernel does not have a TPM reset signal, is
that being able to reset the chip from software is a vulnerability.
There was a discussion on it over on the Barebox mailing list
a while ago.

TLDR: TPM reset needs to follow SOC reset.

/Bruno