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i2c: rcar: always clear ICSAR to avoid side effects 

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: de20d1857d ("i2c: rcar: add slave support")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
zero-sugar-mainline-defconfig
Wolfram Sang 2020-07-04 15:38:29 +02:00 committed by Wolfram Sang
parent 436d17675b
commit eb01597158
1 changed files with 3 additions and 0 deletions
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3
drivers/i2c/busses/i2c-rcar.c
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@ -868,6 +868,7 @@ 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;
@ -969,6 +970,8 @@ 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)) {