I think inside tpm_get_timeouts() I'd rather something along the lines
(with error handling and such details taken away):

rc = tpm_getcap(...);

if (rc == TPM_ERR_INVALID_POSTINIT) {
        tpm_startup(...);
        tpm_getca(...);
}

> +     if (rc) {
> +             dev_err(chip->pdev,
> +                     "Error %zd reading %s\n", rc, desc);
> +             return rc;
> +     }
> +
> +     if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
> +         be32_to_cpu(tpm_cmd.header.out.length)
> +         != sizeof(tpm_cmd.header.out) + sizeof(u32) + size * sizeof(u32)) {
> +             dev_err(chip->pdev,
> +                     "Bad return code or length reading %s\n", desc);
> +             return -EINVAL;
> +     }

This is bogus code. All this kind of checks should be contained in
tpm_transmit_cmd(). This is easily "fixed" by moving tpm_getcap() :)