[PATCH v2 1/2] NFC: nxp-nci: Don't issue a zero length i2c_master_read()

From: Michael Walle <michael@walle.cc>
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: "Clément Perrochaud" <clement.perrochaud@nxp.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Michael Walle" <michael@walle.cc>
Subject: [PATCH v2 1/2] NFC: nxp-nci: Don't issue a zero length i2c_master_read()
Date: Mon, 27 Jun 2022 19:06:42 +0200	[thread overview]
Message-ID: <20220627170643.98239-1-michael@walle.cc> (raw)

There are packets which doesn't have a payload. In that case, the second
i2c_master_read() will have a zero length. But because the NFC
controller doesn't have any data left, it will NACK the I2C read and
-ENXIO will be returned. In case there is no payload, just skip the
second i2c master read.

Fixes: 6be88670fc59 ("NFC: nxp-nci_i2c: Add I2C support to NXP NCI driver")
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
changes since v1:
 - none

 drivers/nfc/nxp-nci/i2c.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/nfc/nxp-nci/i2c.c b/drivers/nfc/nxp-nci/i2c.c
index 7e451c10985d..e8f3b35afbee 100644
--- a/drivers/nfc/nxp-nci/i2c.c
+++ b/drivers/nfc/nxp-nci/i2c.c
@@ -162,6 +162,9 @@ static int nxp_nci_i2c_nci_read(struct nxp_nci_i2c_phy *phy,
 
 	skb_put_data(*skb, (void *)&header, NCI_CTRL_HDR_SIZE);
 
+	if (!header.plen)
+		return 0;
+
 	r = i2c_master_recv(client, skb_put(*skb, header.plen), header.plen);
 	if (r != header.plen) {
 		nfc_err(&client->dev,
-- 
2.30.2

