> @@ -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 :(
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".
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