On Thu, Jul 11, 2024 at 10:30:44AM +0200, Wolfram Sang wrote:
> 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.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Fixes: 3b770017b03a ("i2c: rcar: handle RXDMA HW behaviour on Gen3")
> ---
> drivers/i2c/busses/i2c-rcar.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c
> index 8f2ede534f30..29cbeda59f3e 100644
> --- a/drivers/i2c/busses/i2c-rcar.c
> +++ b/drivers/i2c/busses/i2c-rcar.c
> @@ -884,6 +884,10 @@ 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;
> @@ -1176,6 +1180,7 @@ 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)) {
> @@ -1186,6 +1191,9 @@ 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);
> --
> 2.43.0
>
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