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    Subject[PATCH 5.4 064/138] i2c: rcar: always clear ICSAR to avoid side effects
    Date
    From: Wolfram Sang <wsa+renesas@sang-engineering.com>

    [ 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: de20d1857dd6 ("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>
    ---
    drivers/i2c/busses/i2c-rcar.c | 3 +++
    1 file changed, 3 insertions(+)

    diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
    index 531c01100b560..36af8fdb66586 100644
    --- a/drivers/i2c/busses/i2c-rcar.c
    +++ b/drivers/i2c/busses/i2c-rcar.c
    @@ -865,6 +865,7 @@ 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;
    @@ -971,6 +972,8 @@ 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)) {
    --
    2.25.1


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