i2c: rcar: introduce Gen4 devices

So far, we treated Gen4 as Gen3. But we are soon adding FM+ as a Gen4
specific feature, so prepare the code for the new devtype.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

Author: Wolfram Sang

drivers/i2c/busses/i2c-rcar.c

@@ -132,6 +132,7 @@ enum rcar_i2c_type {
 	I2C_RCAR_GEN1,
 	I2C_RCAR_GEN2,
 	I2C_RCAR_GEN3,
+	I2C_RCAR_GEN4,
 };
 
 struct rcar_i2c_priv {
@@ -431,8 +432,8 @@ static void rcar_i2c_cleanup_dma(struct rcar_i2c_priv *priv, bool terminate)
 	dma_unmap_single(chan->device->dev, sg_dma_address(&priv->sg),
 			 sg_dma_len(&priv->sg), priv->dma_direction);
 
-	/* Gen3 can only do one RXDMA per transfer and we just completed it */
-	if (priv->devtype == I2C_RCAR_GEN3 &&
+	/* Gen3+ can only do one RXDMA per transfer and we just completed it */
+	if (priv->devtype >= I2C_RCAR_GEN3 &&
 	    priv->dma_direction == DMA_FROM_DEVICE)
 		priv->flags |= ID_P_NO_RXDMA;
 
@@ -886,8 +887,8 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap,
 	if (ret < 0)
 		goto out;
 
-	/* Gen3 needs a reset before allowing RXDMA once */
-	if (priv->devtype == I2C_RCAR_GEN3) {
+	/* Gen3+ needs a reset. That also allows RXDMA once */
+	if (priv->devtype >= I2C_RCAR_GEN3) {
 		priv->flags &= ~ID_P_NO_RXDMA;
 		ret = rcar_i2c_do_reset(priv);
 		if (ret)
@@ -1075,7 +1076,7 @@ static const struct of_device_id rcar_i2c_dt_ids[] = {
 	{ .compatible = "renesas,rcar-gen1-i2c", .data = (void *)I2C_RCAR_GEN1 },
 	{ .compatible = "renesas,rcar-gen2-i2c", .data = (void *)I2C_RCAR_GEN2 },
 	{ .compatible = "renesas,rcar-gen3-i2c", .data = (void *)I2C_RCAR_GEN3 },
-	{ .compatible = "renesas,rcar-gen4-i2c", .data = (void *)I2C_RCAR_GEN3 },
+	{ .compatible = "renesas,rcar-gen4-i2c", .data = (void *)I2C_RCAR_GEN4 },
 	{},
 };
 MODULE_DEVICE_TABLE(of, rcar_i2c_dt_ids);
@@ -1151,7 +1152,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
 	if (of_property_read_bool(dev->of_node, "smbus"))
 		priv->flags |= ID_P_HOST_NOTIFY;
 
-	if (priv->devtype == I2C_RCAR_GEN3) {
+	if (priv->devtype >= I2C_RCAR_GEN3) {
 		priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
 		if (IS_ERR(priv->rstc)) {
 			ret = PTR_ERR(priv->rstc);