usb: dwc3: of-simple: allow glues without clocks

Instead of erroring out when we don't have clocks,
let's just avoid any calls to the clk API.
Tested-by: NSteven J. Hill <Steven.Hill@cavium.com>
Signed-off-by: NFelipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc3/dwc3-of-simple.c

@@ -36,36 +36,25 @@ struct dwc3_of_simple {
 	int			num_clocks;
 };
 
-static int dwc3_of_simple_probe(struct platform_device *pdev)
+static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count)
 {
-	struct dwc3_of_simple	*simple;
-	struct device		*dev = &pdev->dev;
+	struct device		*dev = simple->dev;
 	struct device_node	*np = dev->of_node;
-
-	unsigned int		count;
-	int			ret;
 	int			i;
 
-	simple = devm_kzalloc(dev, sizeof(*simple), GFP_KERNEL);
-	if (!simple)
-		return -ENOMEM;
+	simple->num_clocks = count;
 
-	count = of_clk_get_parent_count(np);
 	if (!count)
-		return -ENOENT;
-
-	simple->num_clocks = count;
+		return 0;
 
 	simple->clks = devm_kcalloc(dev, simple->num_clocks,
 			sizeof(struct clk *), GFP_KERNEL);
 	if (!simple->clks)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, simple);
-	simple->dev = dev;
-
 	for (i = 0; i < simple->num_clocks; i++) {
 		struct clk	*clk;
+		int		ret;
 
 		clk = of_clk_get(np, i);
 		if (IS_ERR(clk)) {
@@ -88,6 +77,29 @@ static int dwc3_of_simple_probe(struct platform_device *pdev)
 		simple->clks[i] = clk;
 	}
 
+	return 0;
+}
+
+static int dwc3_of_simple_probe(struct platform_device *pdev)
+{
+	struct dwc3_of_simple	*simple;
+	struct device		*dev = &pdev->dev;
+	struct device_node	*np = dev->of_node;
+
+	int			ret;
+	int			i;
+
+	simple = devm_kzalloc(dev, sizeof(*simple), GFP_KERNEL);
+	if (!simple)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, simple);
+	simple->dev = dev;
+
+	ret = dwc3_of_simple_clk_init(simple, of_clk_get_parent_count(np));
+	if (ret)
+		return ret;
+
 	ret = of_platform_populate(np, NULL, NULL, dev);
 	if (ret) {
 		for (i = 0; i < simple->num_clocks; i++) {