leds: leds-ns2: fix oops at module removal

This patch fixes a regression introduced by commit 72052fcc10
("leds: leds-ns2: add device tree binding").

When the driver is initialized with device tree data, platform_data
pointer is NULL. This causes a kernel oops at removal.

To fix this bug, num_leds is moved into driver_data and platform_data
is not longer used from ns2_led_remove().

Signed-off-by: Simon Guinot <simon.guinot@sequanux.org>
Signed-off-by: Bryan Wu <cooloney@gmail.com>

drivers/leds/leds-ns2.c

@@ -308,10 +308,21 @@ static const struct of_device_id of_ns2_leds_match[] = {
 };
 #endif /* CONFIG_OF_GPIO */
 
+struct ns2_led_priv {
+	int num_leds;
+	struct ns2_led_data leds_data[];
+};
+
+static inline int sizeof_ns2_led_priv(int num_leds)
+{
+	return sizeof(struct ns2_led_priv) +
+		      (sizeof(struct ns2_led_data) * num_leds);
+}
+
 static int ns2_led_probe(struct platform_device *pdev)
 {
 	struct ns2_led_platform_data *pdata = pdev->dev.platform_data;
-	struct ns2_led_data *leds_data;
+	struct ns2_led_priv *priv;
 	int i;
 	int ret;
 
@@ -332,21 +343,23 @@ static int ns2_led_probe(struct platform_device *pdev)
 		return -EINVAL;
 #endif /* CONFIG_OF_GPIO */
 
-	leds_data = devm_kzalloc(&pdev->dev, sizeof(struct ns2_led_data) *
-				 pdata->num_leds, GFP_KERNEL);
-	if (!leds_data)
+	priv = devm_kzalloc(&pdev->dev,
+			    sizeof_ns2_led_priv(pdata->num_leds), GFP_KERNEL);
+	if (!priv)
 		return -ENOMEM;
+	priv->num_leds = pdata->num_leds;
 
-	for (i = 0; i < pdata->num_leds; i++) {
-		ret = create_ns2_led(pdev, &leds_data[i], &pdata->leds[i]);
+	for (i = 0; i < priv->num_leds; i++) {
+		ret = create_ns2_led(pdev, &priv->leds_data[i],
+				     &pdata->leds[i]);
 		if (ret < 0) {
 			for (i = i - 1; i >= 0; i--)
-				delete_ns2_led(&leds_data[i]);
+				delete_ns2_led(&priv->leds_data[i]);
 			return ret;
 		}
 	}
 
-	platform_set_drvdata(pdev, leds_data);
+	platform_set_drvdata(pdev, priv);
 
 	return 0;
 }
@@ -354,13 +367,12 @@ static int ns2_led_probe(struct platform_device *pdev)
 static int ns2_led_remove(struct platform_device *pdev)
 {
 	int i;
-	struct ns2_led_platform_data *pdata = pdev->dev.platform_data;
-	struct ns2_led_data *leds_data;
+	struct ns2_led_priv *priv;
 
-	leds_data = platform_get_drvdata(pdev);
+	priv = platform_get_drvdata(pdev);
 
-	for (i = 0; i < pdata->num_leds; i++)
-		delete_ns2_led(&leds_data[i]);
+	for (i = 0; i < priv->num_leds; i++)
+		delete_ns2_led(&priv->leds_data[i]);
 
 	platform_set_drvdata(pdev, NULL);