i2c: rcar: check bus state before reinitializing

BugLink: https://bugs.launchpad.net/bugs/1837257
[ 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@renesas.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Fixes: ae481cc13965 ("i2c: rcar: fix resume by always initializing registers before transfer")
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 3415733a93645338f87ff38f10f965a9d35b737b..782c2c41c104b4c9ed87ccbaef9eb30301ac0f61 100644 (file)
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -728,6 +728,11 @@ 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;
@@ -740,10 +745,6 @@ 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++) {
                /* This HW can't send STOP after address phase */
                if (msgs[i].len == 0) {