mtd: oxnas_nand: Handle clk_prepare_enable/clk_disable_unprepare.

- clk_prepare_enable() can fail here and we must check its return value.
 - oxnas_nand_probe() can fail here and we must disable clock.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>

drivers/mtd/nand/oxnas_nand.c

@@ -112,14 +112,19 @@ static int oxnas_nand_probe(struct platform_device *pdev)
 	if (count > 1)
 		return -EINVAL;
 
-	clk_prepare_enable(oxnas->clk);
+	err = clk_prepare_enable(oxnas->clk);
+	if (err)
+		return err;
+
 	device_reset_optional(&pdev->dev);
 
 	for_each_child_of_node(np, nand_np) {
 		chip = devm_kzalloc(&pdev->dev, sizeof(struct nand_chip),
 				    GFP_KERNEL);
-		if (!chip)
-			return -ENOMEM;
+		if (!chip) {
+			err = -ENOMEM;
+			goto err_clk_unprepare;
+		}
 
 		chip->controller = &oxnas->base;
 
@@ -139,12 +144,12 @@ static int oxnas_nand_probe(struct platform_device *pdev)
 		/* Scan to find existence of the device */
 		err = nand_scan(mtd, 1);
 		if (err)
-			return err;
+			goto err_clk_unprepare;
 
 		err = mtd_device_register(mtd, NULL, 0);
 		if (err) {
 			nand_release(mtd);
-			return err;
+			goto err_clk_unprepare;
 		}
 
 		oxnas->chips[nchips] = chip;
@@ -152,12 +157,18 @@ static int oxnas_nand_probe(struct platform_device *pdev)
 	}
 
 	/* Exit if no chips found */
-	if (!nchips)
-		return -ENODEV;
+	if (!nchips) {
+		err = -ENODEV;
+		goto err_clk_unprepare;
+	}
 
 	platform_set_drvdata(pdev, oxnas);
 
 	return 0;
+
+err_clk_unprepare:
+	clk_disable_unprepare(oxnas->clk);
+	return err;
 }
 
 static int oxnas_nand_remove(struct platform_device *pdev)