Merge tag 'i2c-for-6.10-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c fixes from Wolfram Sang:
 "Fixes for the I2C testunit, the Renesas R-Car driver and some
  MAINTAINERS corrections"

* tag 'i2c-for-6.10-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: testunit: avoid re-issued work after read message
  i2c: rcar: ensure Gen3+ reset does not disturb local targets
  i2c: mark HostNotify target address as used
  i2c: testunit: correct Kconfig description
  MAINTAINERS: VIRTIO I2C loses a maintainer, gains a reviewer
  MAINTAINERS: delete entries for Thor Thayer
  i2c: rcar: clear NO_RXDMA flag after resetting
  i2c: rcar: bring hardware to known state when probing

4 files changed, 30 insertions, 7 deletions

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 9388823bb0bb..44710267d669 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -135,7 +135,7 @@ config I2C_SLAVE_EEPROM
 	  Documentation/i2c/slave-eeprom-backend.rst for further details.
 
 config I2C_SLAVE_TESTUNIT
-	tristate "I2C eeprom testunit driver"
+	tristate "I2C testunit driver"
 	help
 	  This backend can be used to trigger test cases for I2C bus masters
 	  which require a remote device with certain capabilities, e.g.
diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
index 828aa2ea0fe4..185a5d60f101 100644
--- a/drivers/i2c/busses/i2c-rcar.c
+++ b/drivers/i2c/busses/i2c-rcar.c
@@ -257,6 +257,14 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv)
 	}
 }
 
+static void rcar_i2c_reset_slave(struct rcar_i2c_priv *priv)
+{
+	rcar_i2c_write(priv, ICSIER, 0);
+	rcar_i2c_write(priv, ICSSR, 0);
+	rcar_i2c_write(priv, ICSCR, SDBS);
+	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
+}
+
 static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv)
 {
 	int ret;
@@ -875,6 +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;
@@ -903,10 +915,10 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 
 	/* Gen3+ needs a reset. That also allows RXDMA once */
 	if (priv->devtype >= I2C_RCAR_GEN3) {
-		priv->flags &= ~ID_P_NO_RXDMA;
 		ret = rcar_i2c_do_reset(priv);
 		if (ret)
 			goto out;
+		priv->flags &= ~ID_P_NO_RXDMA;
 	}
 
 	rcar_i2c_init(priv);
@@ -1033,11 +1045,8 @@ static int rcar_unreg_slave(struct i2c_client *slave)
 
 	/* ensure no irq is running before clearing ptr */
 	disable_irq(priv->irq);
-	rcar_i2c_write(priv, ICSIER, 0);
-	rcar_i2c_write(priv, ICSSR, 0);
+	rcar_i2c_reset_slave(priv);
 	enable_irq(priv->irq);
-	rcar_i2c_write(priv, ICSCR, SDBS);
-	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
 
 	priv->slave = NULL;
 
@@ -1152,7 +1161,9 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		goto out_pm_disable;
 	}
 
-	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
+	/* Bring hardware to known state */
+	rcar_i2c_init(priv);
+	rcar_i2c_reset_slave(priv);
 
 	if (priv->devtype < I2C_RCAR_GEN3) {
 		irqflags |= IRQF_NO_THREAD;
@@ -1168,6 +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)) {
@@ -1178,6 +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);
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index db0d1ac82910..7e7b15440832 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -1067,6 +1067,7 @@ EXPORT_SYMBOL(i2c_find_device_by_fwnode);
 
 static const struct i2c_device_id dummy_id[] = {
 	{ "dummy", 0 },
+	{ "smbus_host_notify", 0 },
 	{ },
 };
 
diff --git a/drivers/i2c/i2c-slave-testunit.c b/drivers/i2c/i2c-slave-testunit.c
index ca43e98cae1b..23a11e4e9256 100644
--- a/drivers/i2c/i2c-slave-testunit.c
+++ b/drivers/i2c/i2c-slave-testunit.c
@@ -118,6 +118,13 @@ static int i2c_slave_testunit_slave_cb(struct i2c_client *client,
 			queue_delayed_work(system_long_wq, &tu->worker,
 					   msecs_to_jiffies(10 * tu->regs[TU_REG_DELAY]));
 		}
+
+		/*
+		 * Reset reg_idx to avoid that work gets queued again in case of
+		 * STOP after a following read message. But do not clear TU regs
+		 * here because we still need them in the workqueue!
+		 */
+		tu->reg_idx = 0;
 		break;
 
 	case I2C_SLAVE_WRITE_REQUESTED: