spi: s3c64xx: introduce s3c64xx_spi_set_port_id()

Prepare driver to get rid of the of alias ID dependency. Split the
port_id logic into a dedicated method.

Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Link: https://msgid.link/r/20240216070555.2483977-9-tudor.ambarus@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-s3c64xx.c

@@ -1200,6 +1200,27 @@ static inline const struct s3c64xx_spi_port_config *s3c64xx_spi_get_port_config(
 	return (const struct s3c64xx_spi_port_config *)platform_get_device_id(pdev)->driver_data;
 }
 
+static int s3c64xx_spi_set_port_id(struct platform_device *pdev,
+				   struct s3c64xx_spi_driver_data *sdd)
+{
+	int ret;
+
+	if (pdev->dev.of_node) {
+		ret = of_alias_get_id(pdev->dev.of_node, "spi");
+		if (ret < 0)
+			return dev_err_probe(&pdev->dev, ret,
+					     "Failed to get alias id\n");
+		sdd->port_id = ret;
+	} else {
+		if (pdev->id < 0)
+			return dev_err_probe(&pdev->dev, -EINVAL,
+					     "Negative platform ID is not allowed\n");
+		sdd->port_id = pdev->id;
+	}
+
+	return 0;
+}
+
 static void s3c64xx_spi_set_fifomask(struct s3c64xx_spi_driver_data *sdd)
 {
 	const struct s3c64xx_spi_port_config *port_conf = sdd->port_conf;
@@ -1252,18 +1273,10 @@ static int s3c64xx_spi_probe(struct platform_device *pdev)
 	sdd->host = host;
 	sdd->cntrlr_info = sci;
 	sdd->pdev = pdev;
-	if (pdev->dev.of_node) {
-		ret = of_alias_get_id(pdev->dev.of_node, "spi");
-		if (ret < 0)
-			return dev_err_probe(&pdev->dev, ret,
-					     "Failed to get alias id\n");
-		sdd->port_id = ret;
-	} else {
-		if (pdev->id < 0)
-			return dev_err_probe(&pdev->dev, -EINVAL,
-					     "Negative platform ID is not allowed\n");
-		sdd->port_id = pdev->id;
-	}
+
+	ret = s3c64xx_spi_set_port_id(pdev, sdd);
+	if (ret)
+		return ret;
 
 	if (sdd->port_conf->fifo_depth)
 		sdd->fifo_depth = sdd->port_conf->fifo_depth;