ASoC: fsl_mqs: Fix error handling in probe

There are several problems in the error handling in fsl_mqs_probe().

1) "ret" isn't initialized on some paths.  GCC has a feature which
   warns about uninitialized variables but the code initializes "ret"
   to zero at the start of the function so the checking is turned off.
2) "gpr_np" is a pointer so initializing it to zero is confusing and
   generates a Sparse warning.
3) of_parse_phandle() doesn't return error pointers on error, it returns
   NULL.
4) If devm_snd_soc_register_component() fails then the function should
   free the "gpr_np".

Fixes: 9e28f653 ("ASoC: fsl_mqs: Add MQS component driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20191004102208.GB823@mwandaSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/fsl/fsl_mqs.c

@@ -178,10 +178,10 @@ static const struct regmap_config fsl_mqs_regmap_config = {
 static int fsl_mqs_probe(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
-	struct device_node *gpr_np = 0;
+	struct device_node *gpr_np = NULL;
 	struct fsl_mqs *mqs_priv;
 	void __iomem *regs;
-	int ret = 0;
+	int ret;
 
 	mqs_priv = devm_kzalloc(&pdev->dev, sizeof(*mqs_priv), GFP_KERNEL);
 	if (!mqs_priv)
@@ -198,17 +198,16 @@ static int fsl_mqs_probe(struct platform_device *pdev)
 
 	if (mqs_priv->use_gpr) {
 		gpr_np = of_parse_phandle(np, "gpr", 0);
-		if (IS_ERR(gpr_np)) {
+		if (!gpr_np) {
 			dev_err(&pdev->dev, "failed to get gpr node by phandle\n");
-			ret = PTR_ERR(gpr_np);
-			goto out;
+			return -EINVAL;
 		}
 
 		mqs_priv->regmap = syscon_node_to_regmap(gpr_np);
 		if (IS_ERR(mqs_priv->regmap)) {
 			dev_err(&pdev->dev, "failed to get gpr regmap\n");
 			ret = PTR_ERR(mqs_priv->regmap);
-			goto out;
+			goto err_free_gpr_np;
 		}
 	} else {
 		regs = devm_platform_ioremap_resource(pdev, 0);
@@ -229,7 +228,7 @@ static int fsl_mqs_probe(struct platform_device *pdev)
 		if (IS_ERR(mqs_priv->ipg)) {
 			dev_err(&pdev->dev, "failed to get the clock: %ld\n",
 				PTR_ERR(mqs_priv->ipg));
-			goto out;
+			return PTR_ERR(mqs_priv->ipg);
 		}
 	}
 
@@ -237,16 +236,20 @@ static int fsl_mqs_probe(struct platform_device *pdev)
 	if (IS_ERR(mqs_priv->mclk)) {
 		dev_err(&pdev->dev, "failed to get the clock: %ld\n",
 			PTR_ERR(mqs_priv->mclk));
-		goto out;
+		ret = PTR_ERR(mqs_priv->mclk);
+		goto err_free_gpr_np;
 	}
 
 	dev_set_drvdata(&pdev->dev, mqs_priv);
 	pm_runtime_enable(&pdev->dev);
 
-	return devm_snd_soc_register_component(&pdev->dev, &soc_codec_fsl_mqs,
+	ret = devm_snd_soc_register_component(&pdev->dev, &soc_codec_fsl_mqs,
 			&fsl_mqs_dai, 1);
-out:
-	if (!IS_ERR(gpr_np))
+	if (ret)
+		goto err_free_gpr_np;
+	return 0;
+
+err_free_gpr_np:
 	of_node_put(gpr_np);
 
 	return ret;