[PATCH AUTOSEL 5.4 028/266] i2c: pxa: clear all master action bits in i2c_pxa_stop_message()

From: Sasha Levin
Date: Wed Jun 17 2020 - 22:26:15 EST


From: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>

[ Upstream commit e81c979f4e071d516aa27cf5a0c3939da00dc1ca ]

If we timeout during a message transfer, the control register may
contain bits that cause an action to be set. Read-modify-writing the
register leaving these bits set may trigger the hardware to attempt
one of these actions unintentionally.

Always clear these bits when cleaning up after a message or after
a timeout.

Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-pxa.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index 2c3c3d6935c0..c9cbc9894bac 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -706,11 +706,9 @@ static inline void i2c_pxa_stop_message(struct pxa_i2c *i2c)
{
u32 icr;

- /*
- * Clear the STOP and ACK flags
- */
+ /* Clear the START, STOP, ACK, TB and MA flags */
icr = readl(_ICR(i2c));
- icr &= ~(ICR_STOP | ICR_ACKNAK);
+ icr &= ~(ICR_START | ICR_STOP | ICR_ACKNAK | ICR_TB | ICR_MA);
writel(icr, _ICR(i2c));
}

--
2.25.1