Re: [PATCH 4/8 v3] i2c: i801: check and return errors during byte-by-byte transfers

Jean Delvare
2012-06-27T16:51:57Z

On Wed, 27 Jun 2012 21:54:11 +0800, Daniel Kurtz wrote:
> If an error is detected in the polling loop, abort the transaction and
> return an error code.
>
> * DEV_ERR is set if the device does not respond with an acknowledge, and
> the SMBus controller times out (minimum 25ms).
> * BUS_ERR is set if a bus arbitration collision is detected. In other
> words, when the SMBus controller tries to generate a START condition, but
> detects that the SMBDATA is being held low, usually by another SMBus/I2C
> master.
> * FAILED is only set if a the transaction is set by software (using the
> SMBHSTCNT KILL bit).

Not quite sure what you mean with "set by software". Other than this,
patch looks good, applied, thanks.

>
> Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
> ---
> drivers/i2c/busses/i2c-i801.c | 10 ++++++----
> 1 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> index 6a53338..ba56b74 100644
> --- a/drivers/i2c/busses/i2c-i801.c
> +++ b/drivers/i2c/busses/i2c-i801.c
> @@ -131,9 +131,11 @@
> #define SMBHSTSTS_INTR 0x02
> #define SMBHSTSTS_HOST_BUSY 0x01
>
> -#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_FAILED | \
> - SMBHSTSTS_BUS_ERR | SMBHSTSTS_DEV_ERR | \
> - SMBHSTSTS_INTR)
> +#define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
> + SMBHSTSTS_DEV_ERR)
> +
> +#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \
> + STATUS_ERROR_FLAGS)
>
> /* Older devices have their ID defined in <linux/pci_ids.h> */
> #define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS 0x1c22
> @@ -385,7 +387,7 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv,
> do {
> usleep_range(250, 500);
> status = inb_p(SMBHSTSTS(priv));
> - } while ((!(status & SMBHSTSTS_BYTE_DONE))
> + } while (!(status & (SMBHSTSTS_BYTE_DONE | STATUS_ERROR_FLAGS))
> && (timeout++ < MAX_RETRIES));
>
> result = i801_check_post(priv, status, timeout > MAX_RETRIES);

--
Jean Delvare