linux-kernel - [PATCH 4.19 06/67] i2c: rcar: check bus state before reinitializing

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Message-Id: <20181220085903.822192733@linuxfoundation.org>
Date:   Thu, 20 Dec 2018 10:18:18 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Wolfram Sang <wsa@...-dreams.de>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 06/67] i2c: rcar: check bus state before reinitializing

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 0b57436f15bf40e432487086c4f2d01fd3529393 ]

We should check the bus state before reinitializing the IP core.
Otherwise, the internal bus busy state which also tracks multi-master
activity is lost.

Credits go to the Renesas BSP team for suggesting this change.

Reported-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Fixes: ae481cc13965 ("i2c: rcar: fix resume by always initializing registers before transfer")
Signed-off-by: Wolfram Sang <wsa@...-dreams.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/i2c/busses/i2c-rcar.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 4aa7dde876f3..254e6219e538 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -779,6 +779,11 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 	pm_runtime_get_sync(dev);
 
+	/* Check bus state before init otherwise bus busy info will be lost */
+	ret = rcar_i2c_bus_barrier(priv);
+	if (ret < 0)
+		goto out;
+
 	/* Gen3 needs a reset before allowing RXDMA once */
 	if (priv->devtype == I2C_RCAR_GEN3) {
 		priv->flags |= ID_P_NO_RXDMA;
@@ -791,10 +796,6 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 	rcar_i2c_init(priv);
 
-	ret = rcar_i2c_bus_barrier(priv);
-	if (ret < 0)
-		goto out;
-
 	for (i = 0; i < num; i++)
 		rcar_i2c_request_dma(priv, msgs + i);
 
-- 
2.19.1