leds: pca963x: use flexible array

Instead of doing two allocations, allocate only once, by utilizing
flexible array members.
Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Peter Meerwald <p.meerwald@bct-electronic.com>
Cc: Ricardo Ribalda <ribalda@kernel.org>
Cc: Zahari Petkov <zahari@balena.io>
Signed-off-by: Pavel Machek <pavel@ucw.cz>

drivers/leds/leds-pca963x.c

@@ -96,15 +96,7 @@ static const struct i2c_device_id pca963x_id[] = {
 };
 MODULE_DEVICE_TABLE(i2c, pca963x_id);
 
-struct pca963x_led;
-
-struct pca963x {
-	struct pca963x_chipdef *chipdef;
-	struct mutex mutex;
-	struct i2c_client *client;
-	struct pca963x_led *leds;
-	unsigned long leds_on;
-};
+struct pca963x;
 
 struct pca963x_led {
 	struct pca963x *chip;
@@ -115,6 +107,14 @@ struct pca963x_led {
 	u8 gfrq;
 };
 
+struct pca963x {
+	struct pca963x_chipdef *chipdef;
+	struct mutex mutex;
+	struct i2c_client *client;
+	unsigned long leds_on;
+	struct pca963x_led leds[];
+};
+
 static int pca963x_brightness(struct pca963x_led *led,
 			      enum led_brightness brightness)
 {
@@ -367,7 +367,6 @@ static int pca963x_probe(struct i2c_client *client,
 	struct device *dev = &client->dev;
 	struct pca963x_chipdef *chipdef;
 	struct pca963x_platform_data *pdata;
-	struct pca963x_led *leds;
 	struct pca963x *chip;
 	int i, err;
 
@@ -389,26 +388,23 @@ static int pca963x_probe(struct i2c_client *client,
 		return -EINVAL;
 	}
 
-	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
+	chip = devm_kzalloc(dev, struct_size(chip, leds, chipdef->n_leds),
+			    GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
-	leds = devm_kcalloc(dev, chipdef->n_leds, sizeof(*leds), GFP_KERNEL);
-	if (!leds)
-		return -ENOMEM;
 
 	i2c_set_clientdata(client, chip);
 
 	mutex_init(&chip->mutex);
 	chip->chipdef = chipdef;
 	chip->client = client;
-	chip->leds = leds;
 
 	/* Turn off LEDs by default*/
 	for (i = 0; i < chipdef->n_leds / 4; i++)
 		i2c_smbus_write_byte_data(client, chipdef->ledout_base + i, 0x00);
 
 	for (i = 0; i < chipdef->n_leds; i++) {
-		struct pca963x_led *led = &leds[i];
+		struct pca963x_led *led = &chip->leds[i];
 
 		led->led_num = i;
 		led->chip = chip;