[PATCH 5.8 047/177] i2c: npcm7xx: Fix timeout calculation

Greg Kroah-Hartman
2020-09-15T23:38:42Z

From: Tali Perry <tali.perry1@gmail.com>

[ Upstream commit 06be67266a0c9a6a1ffb330a4ab50c2f21612e2b ]

timeout_usec value calculation was wrong, the calculated value
was in msec instead of usec.

Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
Signed-off-by: Tali Perry <tali.perry1@gmail.com>
Reviewed-by: Avi Fishman <avifishman70@gmail.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Alex Qiu <xqiu@google.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 75f07138a6fa2..dfcf04e1967f1 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);
--
2.25.1