linux-kernel - [PATCH v3] i2c: aspeed: Reset the i2c controller when timeout occurs

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Date:   Wed, 6 Sep 2023 08:49:10 +0800
From:   Tommy Huang <tommy_huang@...eedtech.com>
To:     <brendan.higgins@...ux.dev>, <andi.shyti@...nel.org>,
        <p.zabel@...gutronix.de>, <linux-i2c@...r.kernel.org>,
        <openbmc@...ts.ozlabs.org>
CC:     <benh@...nel.crashing.org>, <joel@....id.au>, <andrew@...id.au>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-aspeed@...ts.ozlabs.org>, <linux-kernel@...r.kernel.org>,
        <BMC-SW@...eedtech.com>, <jae.hyun.yoo@...ux.intel.com>,
        <stable@...r.kernel.org>
Subject: [PATCH v3] i2c: aspeed: Reset the i2c controller when timeout occurs

Reset the i2c controller when an i2c transfer timeout occurs.
The remaining interrupts and device should be reset to avoid
unpredictable controller behavior.

Fixes: 2e57b7cebb98 ("i2c: aspeed: Add multi-master use case support")
Cc: Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>
Cc: <stable@...r.kernel.org> # v5.1+
Signed-off-by: Tommy Huang <tommy_huang@...eedtech.com>
Reviewed-by: Andi Shyti <andi.shyti@...nel.org>
---
V3: Submit this patch for clearing patch style typo.
---
 drivers/i2c/busses/i2c-aspeed.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 2e5acfeb76c8..5a416b39b818 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -698,13 +698,16 @@ static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
 
 	if (time_left == 0) {
 		/*
-		 * If timed out and bus is still busy in a multi master
-		 * environment, attempt recovery at here.
+		 * In a multi-master setup, if a timeout occurs, attempt
+		 * recovery. But if the bus is idle, we still need to reset the
+		 * i2c controller to clear the remaining interrupts.
 		 */
 		if (bus->multi_master &&
 		    (readl(bus->base + ASPEED_I2C_CMD_REG) &
 		     ASPEED_I2CD_BUS_BUSY_STS))
 			aspeed_i2c_recover_bus(bus);
+		else
+			aspeed_i2c_reset(bus);
 
 		/*
 		 * If timed out and the state is still pending, drop the pending
-- 
2.25.1