Re: [PATCH v2 2/2] i2c: qup: support SMBus block read

[Christ, Austin]

On 5/20/2016 2:31 AM, Sricharan wrote:
> Hi,
>
> <snip..>
> > > > @@ -1128,6 +1173,22 @@ static int qup_i2c_read_one_v2(struct
> > > > qup_i2c_dev *qup, struct i2c_msg *msg)
> > > >    			goto err;
> > > >
> > > >    		qup->blk.pos++;
> > > > +
> > > > +		/* Handle SMBus block read length */
> > > > +		if (qup_i2c_check_msg_len(msg) && (msg->len == 1)) {
> > > > +			if (msg->buf[0] > I2C_SMBUS_BLOCK_MAX) {
> > > > +				ret = -EPROTO;
> > > > +				goto err;
> > > > +			}
> > > > +			msg->len += msg->buf[0];
> > > > +			qup->pos = 0;
> > > > +			qup_i2c_set_read_mode_v2(qup, msg->len);
> > > > +			qup_i2c_issue_xfer_v2(qup, msg);
> > > > +			ret = qup_i2c_wait_for_complete(qup, msg);
> > > > +			if (ret)
> > > > +				goto err;
> > > 		Is the issue_xfer_v2 needed inside this here ?
> > No, qup_i2c_issue_xfer_v2 is needed so that we read rest of the data
> > that is indicated by the length we read earlier.
> So qup_i2c_issue_xfer_v2 writes the tags and there is one already in the loop above this
>   check. So if you just do qup_i2c_set_read_mode_v2 and qup_i2c_set_blk_data inside this
>   check, will not be enough ?
>
> Regards,
>   Sricharan
In testing, removing the call to qup_i2c_issue_xfer_v2() within the 
conditional statement for SMBus length causes failures. That transfer 
request is needed to read that block of data.

Thanks,
Austin