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SubjectRe: [PATCH v2 0/2] char: tpm: add new driver for tpm i2c ptp
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On Thu, 2019-07-04 at 13:29 +0200, Alexander Steffen wrote:
> On 04.07.2019 10:43, Jarkko Sakkinen wrote:
> > Check out tpm_tis_core.c and tpm_tis_spi.c. TPM TIS driver implements
> > that spec so you should only implement a new physical layer.
>
> I had the same thought. Unfortunately, the I2C-TIS specification
> introduces two relevant changes compared to tpm_tis/tpm_tis_spi:

I doubt that there was any comparison made.

> 1. Locality is not encoded into register addresses anymore, but stored
> in a separate register.
> 2. Several register addresses have changed (but still contain compatible
> contents).
>
> I'd still prefer not to duplicate all the high-level logic from
> tpm_tis_core. But this will probably mean to introduce some new
> interfaces between tpm_tis_core and the physical layers.

Agreed. Some plumbing needs to be done in tpm_tis_core to make it work
for this. We definitely do not want to duplicate code that has been
field tested for years.

> Also, shouldn't the new driver be called tpm_tis_i2c, to group it with
> all the other (TIS) drivers, that implement a vendor-independent
> protocol? With tpm_i2c_ptp users might assume that ptp is just another
> vendor.

Yes, absolutely. I guess the driver has been done without looking at
what already exist in the TPM kernel stack.

/Jarkko

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