This is a note to let you know that I've just added the patch titled
i2c: rcar: ensure Gen3+ reset does not disturb local targets
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-rcar-ensure-gen3-reset-does-not-disturb-local-ta.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 7e879baa47a01f26512fcbc62c71a402a501b2be
Author: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Date: Thu Jul 11 10:30:44 2024 +0200
i2c: rcar: ensure Gen3+ reset does not disturb local targets
[ Upstream commit ea5ea84c9d3570dc06e8fc5ee2273eaa584aa3ac ]
R-Car Gen3+ needs a reset before every controller transfer. That erases
configuration of a potentially in parallel running local target
instance. To avoid this disruption, avoid controller transfers if a
local target is running. Also, disable SMBusHostNotify because it
requires being a controller and local target at the same time.
Fixes: 3b770017b03a ("i2c: rcar: handle RXDMA HW behaviour on Gen3")
Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index f0724c8e4b219..185a5d60f1019 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -883,6 +883,10 @@ static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv)
{
int ret;
+ /* Don't reset if a slave instance is currently running */
+ if (priv->slave)
+ return -EISCONN;
+
ret = reset_control_reset(priv->rstc);
if (ret)
return ret;
@@ -1175,6 +1179,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
if (of_property_read_bool(dev->of_node, "smbus"))
priv->flags |= ID_P_HOST_NOTIFY;
+ /* R-Car Gen3+ needs a reset before every transfer */
if (priv->devtype >= I2C_RCAR_GEN3) {
priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
if (IS_ERR(priv->rstc)) {
@@ -1185,6 +1190,9 @@ static int rcar_i2c_probe(struct platform_device *pdev)
ret = reset_control_status(priv->rstc);
if (ret < 0)
goto out_pm_put;
+
+ /* hard reset disturbs HostNotify local target, so disable it */
+ priv->flags &= ~ID_P_HOST_NOTIFY;
}
ret = platform_get_irq(pdev, 0);
