linux-kernel - RE: [PATCH v2 2/2] i2c: qup: support SMBus block read

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Message-ID: <000501d1b271$fef3bc90$fcdb35b0$@codeaurora.org>
Date:	Fri, 20 May 2016 14:01:17 +0530
From:	"Sricharan" <sricharan@...eaurora.org>
To:	"'Naveen Kaje'" <nkaje@...eaurora.org>, <wsa@...-dreams.de>,
	<linux-i2c@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Cc:	<linux-arm-msm@...r.kernel.org>, <rruigrok@...eaurora.org>,
	<timur@...eaurora.org>, <cov@...eaurora.org>,
	<austinwc@...eaurora.org>, <linux-arm-kernel@...ts.infradead.org>,
	"'Sricharan'" <sricharan@...eaurora.org>
Subject: RE: [PATCH v2 2/2] i2c: qup: support SMBus block read

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