Re: [RFC PATCH 1/2] tpm: Make implementation of read16/read32/write32 optional

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

On Thu, Jul 18, 2019 at 07:03:54PM +0200, Alexander Steffen wrote:
> Only tpm_tis has a faster way to access multiple bytes at once, every other
> driver will just fall back to read_bytes/write_bytes. Therefore, move this
> common code out of tpm_tis_spi into tpm_tis_core, so that it is
> automatically used when low-level drivers do not implement the specialized
> methods.
> 
> Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
> ---
>  drivers/char/tpm/tpm_tis_core.h | 41 ++++++++++++++++++++++++++++++---
>  drivers/char/tpm/tpm_tis_spi.c  | 41 ---------------------------------
>  2 files changed, 38 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h
> index 7337819f5d7b..2c6557b29a1d 100644
> --- a/drivers/char/tpm/tpm_tis_core.h
> +++ b/drivers/char/tpm/tpm_tis_core.h
> @@ -122,13 +122,37 @@ static inline int tpm_tis_read8(struct tpm_tis_data *data, u32 addr, u8 *result)
>  static inline int tpm_tis_read16(struct tpm_tis_data *data, u32 addr,
>  				 u16 *result)
>  {
> -	return data->phy_ops->read16(data, addr, result);
> +	if (data->phy_ops->read16) {
> +		return data->phy_ops->read16(data, addr, result);
> +	} else {
> +		__le16 result_le;
> +		int rc;
> +
> +		rc = data->phy_ops->read_bytes(data, addr, sizeof(u16),
> +					       (u8 *)&result_le);
> +		if (!rc)
> +			*result = le16_to_cpu(result_le);
> +
> +		return rc;
> +	}

Looks great.

I prefer to have variable declarations in the beginning of function for
most of the time. Other than that looks legit.

/Jarkko