serial: sccnxp: Disable regulator on error

The patch disables the regulator in case of errors, if we have it.
In addition, the patch adds support for deferred regulator probe and
makes error path are a bit clean.

Signed-off-by: Alexander Shiyan <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/tty/serial/sccnxp.c

···
 	struct sccnxp_port *s;
 	void __iomem *membase;
 
-	if (!res) {
-		dev_err(&pdev->dev, "Missing memory resource data\n");
-		return -EADDRNOTAVAIL;
-	}
+	membase = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(membase))
+		return PTR_ERR(membase);
 
 	s = devm_kzalloc(&pdev->dev, sizeof(struct sccnxp_port), GFP_KERNEL);
 	if (!s) {
···
 		break;
 	default:
 		dev_err(&pdev->dev, "Unsupported chip type %i\n", chiptype);
-		ret = -ENOTSUPP;
-		goto err_out;
+		return -ENOTSUPP;
 	}
+
+	s->regulator = devm_regulator_get(&pdev->dev, "vcc");
+	if (!IS_ERR(s->regulator)) {
+		ret = regulator_enable(s->regulator);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"Failed to enable regulator: %i\n", ret);
+			return ret;
+		}
+	} else if (PTR_ERR(s->regulator) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
 
 	if (!pdata) {
 		dev_warn(&pdev->dev,
···
 	    (s->pdata.frequency > freq_max)) {
 		dev_err(&pdev->dev, "Frequency out of bounds\n");
 		ret = -EINVAL;
-		goto err_out;
-	}
-
-	s->regulator = devm_regulator_get(&pdev->dev, "VCC");
-	if (!IS_ERR(s->regulator)) {
-		ret = regulator_enable(s->regulator);
-		if (ret) {
-			dev_err(&pdev->dev,
-				"Failed to enable regulator: %i\n", ret);
-			return ret;
-		}
-	}
-
-	membase = devm_ioremap_resource(&pdev->dev, res);
-	if (IS_ERR(membase)) {
-		ret = PTR_ERR(membase);
 		goto err_out;
 	}
 
···
 	}
 
 err_out:
+	if (!IS_ERR(s->regulator))
+		return regulator_disable(s->regulator);
+
 	return ret;
 }