Commit 6c3f2d34 authored Jul 04, 2020 by Wolfram Sang Committed by Greg Kroah-Hartman Jul 29, 2020

i2c: rcar: always clear ICSAR to avoid side effects



[ Upstream commit eb01597158ffb1853a7a7fc2c57d4c844640f75e ]

On R-Car Gen2, we get a timeout when reading from the address set in
ICSAR, even though the slave interface is disabled. Clearing it fixes
this situation. Note that Gen3 is not affected.

To reproduce: bind and undbind an I2C slave on some bus, run
'i2cdetect' on that bus.

Fixes: de20d185 ("i2c: rcar: add slave support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 535f366f

drivers/i2c/busses/i2c-rcar.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -863,6 +863,7 @@ static int rcar_unreg_slave(struct i2c_client *slave)
		/* disable irqs and ensure none is running before clearing ptr */
		rcar_i2c_write(priv, ICSIER, 0);
		rcar_i2c_write(priv, ICSCR, 0);
		rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */

		synchronize_irq(priv->irq);
		priv->slave = NULL;
		@@ -966,6 +967,8 @@ static int rcar_i2c_probe(struct platform_device *pdev)
		if (ret < 0)
		goto out_pm_put;

		rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */

		if (priv->devtype == I2C_RCAR_GEN3) {
		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
		if (!IS_ERR(priv->rstc)) {