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From:   Tali Perry <tali.perry1@gmail.com>
To:     kunyi@google.com, xqiu@google.com, benjaminfair@google.com,
        avifishman70@gmail.com, joel@jms.id.au, tmaimon77@gmail.com,
        wsa@the-dreams.de
Cc:     linux-i2c@vger.kernel.org, openbmc@lists.ozlabs.org,
        linux-kernel@vger.kernel.org, Tali Perry <tali.perry1@gmail.com>
Subject: [PATCH v3] i2c: npcm7xx: Fix timeout calculation
Date:   Mon, 31 Aug 2020 00:31:21 +0300
Message-Id: <20200830213121.239533-1-tali.perry1@gmail.com>
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timeout_usec value calculation was wrong, the calculated value
was in msec instead of usec.

Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Reviewed-by: Avi Fishman <avifishman70@gmail.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index 75f07138a6fa..dfcf04e1967f 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -2093,8 +2093,12 @@ static int npcm_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
 		}
 	}
 
-	/* Adaptive TimeOut: astimated time in usec + 100% margin */
-	timeout_usec = (2 * 10000 / bus->bus_freq) * (2 + nread + nwrite);
+	/*
+	 * Adaptive TimeOut: estimated time in usec + 100% margin:
+	 * 2: double the timeout for clock stretching case
+	 * 9: bits per transaction (including the ack/nack)
+	 */
+	timeout_usec = (2 * 9 * USEC_PER_SEC / bus->bus_freq) * (2 + nread + nwrite);
 	timeout = max(msecs_to_jiffies(35), usecs_to_jiffies(timeout_usec));
 	if (nwrite >= 32 * 1024 || nread >= 32 * 1024) {
 		dev_err(bus->dev, "i2c%d buffer too big\n", bus->num);

base-commit: d012a7190fc1fd72ed48911e77ca97ba4521bccd
-- 
2.22.0