Hi,
On Tue, Jan 13, 2015 at 5:05 PM, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
>> @@ -541,6 +541,18 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
>> * processed with a repeated start.
>> */
>> if (num > 1) {
>> + /*
>> + * This controller does not give completion interrupt after a
>> + * master receive transfer if HOLD bit is set (repeated start),
>> + * resulting in SW timeout. Hence, if a receive transfer is
>> + * followed by any other transfer, an error is returned
>> + * indicating that this sequence is not supported.
>> + */
>> + for (count = 0; count < num-1; count++) {
>> + if (msgs[count].flags & I2C_M_RD)
>> + dev_warn(adap->dev.parent, "No support for repeated start when receive is followed by a transfer\n");
>> + return -EOPNOTSUPP;
>> + }
>> id->bus_hold_flag = 1;
>> reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
>> reg |= CDNS_I2C_CR_HOLD;
>
> Have you ever tested this code? There is a huge bug in it :(
I'm sorry. I'll send another patch with the braces for the if statement.
I seem to have tested with only the return statement and no dev_warn.
>
> Also, in the comment, use "message" instead of "transfer". One transfer
> consists of multiple messages.
>
> Maybe the warning can be simplified, too: "can't do repeated start after
> read messages".
>
I'll do that.
Regards,
Harini
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
