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Date:   Thu, 19 May 2022 12:50:19 +0000
From:   Adam Wujek <dev_public@wujek.eu>
Cc:     Adam Wujek <dev_public@wujek.eu>,
        Michal Simek <michal.simek@xilinx.com>,
        linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org,
        linux-kernel@vger.kernel.org
Reply-To: Adam Wujek <dev_public@wujek.eu>
Subject: [PATCH] i2c: busses: i2c-cadence: fix message length when receive block message
Message-ID: <20220519124946.387373-1-dev_public@wujek.eu>
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Needed by hwmon/pmbus_core driver to correctly calculate PEC.
The hwmon/pmbus_core driver relies on bus drivers to update the message len=
gth
of received block transfers. Only in this type of smbus transfer, in which =
the
length is not known before the transfer is started.

Signed-off-by: Adam Wujek <dev_public@wujek.eu>
---
 drivers/i2c/busses/i2c-cadence.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cade=
nce.c
index 20ac432a37ea..65f1979d4e6f 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -830,6 +830,11 @@ static int cdns_i2c_process_msg(struct cdns_i2c *id, s=
truct i2c_msg *msg,
 =09=09return -ETIMEDOUT;
 =09}

+=09/* Update message len, as i2c/smbus driver (function
+=09 * i2c_smbus_xfer_emulated) relies on i2c device drivers to do this */
+=09if ((msg->flags & I2C_M_RECV_LEN) && (msg->flags & I2C_M_RD))
+=09=09msg->len =3D msg->buf[0] + 2; /* add len byte + PEC byte */
+
 =09cdns_i2c_writereg(CDNS_I2C_IXR_ALL_INTR_MASK,
 =09=09=09  CDNS_I2C_IDR_OFFSET);

--
2.17.1