Re: [PATCH 3/4] i2c: i801: Improve i801_block_transaction_byte_by_byte

[Andi Shyti <andi.shyti@kernel.org>]

Hi Heiner,

On Sat, Mar 04, 2023 at 10:36:34PM +0100, Heiner Kallweit wrote:
> Here we don't have to write SMBHSTCNT in each iteration of the loop.
> Bit SMBHSTCNT_START is internally cleared immediately, therefore
> we don't have to touch the value of SMBHSTCNT until the last byte.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 7641bd0ac..e1350a8cc 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -677,11 +677,11 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>  	for (i = 1; i <= len; i++) {
>  		if (i == len && read_write == I2C_SMBUS_READ)
>  			smbcmd |= SMBHSTCNT_LAST_BYTE;
> -		outb_p(smbcmd, SMBHSTCNT(priv));
>  
>  		if (i == 1)
> -			outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START,
> -			       SMBHSTCNT(priv));
> +			outb_p(smbcmd | SMBHSTCNT_START, SMBHSTCNT(priv));
> +		else if (smbcmd & SMBHSTCNT_LAST_BYTE)
> +			outb_p(smbcmd, SMBHSTCNT(priv));

Looks reasonable to me... Jean, any opinion here?

Andi