i2c: rcar: make sure irq is not threaded on Gen2 and earlier

Ensure this irq runs as fast as possible.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-rcar.c

@@ -928,6 +928,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	struct rcar_i2c_priv *priv;
 	struct i2c_adapter *adap;
 	struct device *dev = &pdev->dev;
+	unsigned long irqflags = 0;
 	int ret;
 
 	/* Otherwise logic will break because some bytes must always use PIO */
@@ -976,6 +977,9 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 
 	rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
 
+	if (priv->devtype < I2C_RCAR_GEN3)
+		irqflags |= IRQF_NO_THREAD;
+
 	if (priv->devtype == I2C_RCAR_GEN3) {
 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 		if (!IS_ERR(priv->rstc)) {
@@ -995,7 +999,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 		priv->flags |= ID_P_HOST_NOTIFY;
 
 	priv->irq = platform_get_irq(pdev, 0);
-	ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, 0, dev_name(dev), priv);
+	ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, irqflags, dev_name(dev), priv);
 	if (ret < 0) {
 		dev_err(dev, "cannot get irq %d\n", priv->irq);
 		goto out_pm_disable;