linux-kernel - Re: [v2,04/10] i2c-i801: Consolidate calls to i801_check

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Date:	Thu, 9 Jun 2016 11:44:02 +0200
From:	Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:	Corey Minyard <minyard@....org>
Cc:	Jean Delvare <jdelvare@...e.com>, linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org, Corey Minyard <cminyard@...sta.com>
Subject: Re: [v2,04/10] i2c-i801: Consolidate calls to i801_check_pre()

On May 29 2016 or thereabouts, Corey Minyard wrote:
> From: Corey Minyard <cminyard@...sta.com>
> 
> It was always done before starting the transaction, so do it
> in common code before the transaction start.
> 
> Signed-off-by: Corey Minyard <cminyard@...sta.com>
> ---
>  drivers/i2c/busses/i2c-i801.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 222be9c..8794e70 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -402,10 +402,6 @@ static int i801_transaction(struct i801_priv *priv, int xact)
>  	int result;
>  	const struct i2c_adapter *adap = &priv->adapter;
>  
> -	result = i801_check_pre(priv);
> -	if (result < 0)
> -		return result;
> -
>  	if (priv->features & FEATURE_IRQ) {
>  		outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START,
>  		       SMBHSTCNT(priv));
> @@ -562,10 +558,6 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
>  	int result;
>  	const struct i2c_adapter *adap = &priv->adapter;
>  
> -	result = i801_check_pre(priv);
> -	if (result < 0)
> -		return result;
> -
>  	len = data->block[0];
>  
>  	if (read_write == I2C_SMBUS_WRITE) {
> @@ -789,6 +781,10 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr,
>  		goto out;
>  	}
>  
> +	ret = i801_check_pre(priv);
> +	if (ret < 0)
> +		goto out;
> +

The calls looks identical (it gets called before each transaction), but
given that this is a status register, I wonder if this should not be
checked once the setup has been done, and not at the very early
beginning.

Cheers,
Benjamin

>  	if (block)
>  		ret = i801_block_transaction(priv, flags, data, read_write,
>  					     size);