[v3] i2c: i2c-cros-ec-tunnel: Reduce logging noise

If an i2c access through i2c-cros-ec-tunnel returns an error, the following
log message is seen on the console.

cros-ec-i2c-tunnel ff200000.spi:ec@0:i2c-tunnel:
			Error parsing EC i2c message -121

This can happen a lot if, for example, the i2c-detect command is executed.

Since it is perfectly normal for an i2c controller to report an error,
drop the message. Also, report -ENXIO instead of -EREMOTEIO if the access
error is due to NAK from the device, and return -EIO instead of -EREMOTEIO
for other errors, as suggested in Documentation/i2c/fault-codes.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v3: Do not assume that unknown status bits reflect an error.
v2: Drop message entirely instead of replacing it with dev_dbg,
    and return -EIO instead of -EREMOTEIO for unknown errors.

 drivers/i2c/busses/i2c-cros-ec-tunnel.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

Hi

On Tue, Jul 26, 2016 at 3:34 PM, Guenter Roeck <linux@roeck-us.net> wrote:
> If an i2c access through i2c-cros-ec-tunnel returns an error, the following
> log message is seen on the console.
>
> cros-ec-i2c-tunnel ff200000.spi:ec@0:i2c-tunnel:
>                         Error parsing EC i2c message -121
>
> This can happen a lot if, for example, the i2c-detect command is executed.
>
> Since it is perfectly normal for an i2c controller to report an error,
> drop the message. Also, report -ENXIO instead of -EREMOTEIO if the access
> error is due to NAK from the device, and return -EIO instead of -EREMOTEIO
> for other errors, as suggested in Documentation/i2c/fault-codes.
>
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> v3: Do not assume that unknown status bits reflect an error.
> v2: Drop message entirely instead of replacing it with dev_dbg,
>     and return -EIO instead of -EREMOTEIO for unknown errors.
>
>  drivers/i2c/busses/i2c-cros-ec-tunnel.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cros-ec-tunnel.c b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> index a0d95ff682ae..0e9653852069 100644
> --- a/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> +++ b/drivers/i2c/busses/i2c-cros-ec-tunnel.c
> @@ -154,8 +154,10 @@ static int ec_i2c_parse_response(const u8 *buf, struct i2c_msg i2c_msgs[],
>         resp = (const struct ec_response_i2c_passthru *)buf;
>         if (resp->i2c_status & EC_I2C_STATUS_TIMEOUT)
>                 return -ETIMEDOUT;
> +       else if (resp->i2c_status & EC_I2C_STATUS_NAK)
> +               return -ENXIO;
>         else if (resp->i2c_status & EC_I2C_STATUS_ERROR)
> -               return -EREMOTEIO;
> +               return -EIO;
>
>         /* Other side could send us back fewer messages, but not more */
>         if (resp->num_msgs > *num)
> @@ -222,10 +224,8 @@ static int ec_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg i2c_msgs[],
>         }
>
>         result = ec_i2c_parse_response(msg->data, i2c_msgs, &num);
> -       if (result < 0) {
> -               dev_err(dev, "Error parsing EC i2c message %d\n", result);
> +       if (result < 0)
>                 goto exit;
> -       }
>
>         /* Indicate success by saying how many messages were sent */
>         result = num;

Reviewed-by: Douglas Anderson <dianders@chromium.org>
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On Tue, Jul 26, 2016 at 03:34:01PM -0700, Guenter Roeck wrote:
> If an i2c access through i2c-cros-ec-tunnel returns an error, the following
> log message is seen on the console.
> 
> cros-ec-i2c-tunnel ff200000.spi:ec@0:i2c-tunnel:
> 			Error parsing EC i2c message -121
> 
> This can happen a lot if, for example, the i2c-detect command is executed.
> 
> Since it is perfectly normal for an i2c controller to report an error,
> drop the message. Also, report -ENXIO instead of -EREMOTEIO if the access
> error is due to NAK from the device, and return -EIO instead of -EREMOTEIO
> for other errors, as suggested in Documentation/i2c/fault-codes.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Reviewed-by: Douglas Anderson <dianders@chromium.org>

Applied to for-next, thanks!