hwmon: (pmbus/ibm-cffps) Switch LEDs to blocking brightness call

Since i2c_smbus functions can sleep, the brightness setting function
for this driver must be the blocking version to avoid scheduling while
atomic.
Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20191106200106.29519-2-eajames@linux.ibm.com
Fixes: ef9e1cdf ("hwmon: (pmbus/cffps) Add led class device for power supply fault led")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/ibm-cffps.c

@@ -292,8 +292,8 @@ static int ibm_cffps_read_word_data(struct i2c_client *client, int page,
 	return rc;
 }
 
-static void ibm_cffps_led_brightness_set(struct led_classdev *led_cdev,
-					 enum led_brightness brightness)
+static int ibm_cffps_led_brightness_set(struct led_classdev *led_cdev,
+					enum led_brightness brightness)
 {
 	int rc;
 	struct ibm_cffps *psu = container_of(led_cdev, struct ibm_cffps, led);
@@ -311,9 +311,11 @@ static void ibm_cffps_led_brightness_set(struct led_classdev *led_cdev,
 	rc = i2c_smbus_write_byte_data(psu->client, CFFPS_SYS_CONFIG_CMD,
 				       psu->led_state);
 	if (rc < 0)
-		return;
+		return rc;
 
 	led_cdev->brightness = brightness;
+
+	return 0;
 }
 
 static int ibm_cffps_led_blink_set(struct led_classdev *led_cdev,
@@ -351,7 +353,7 @@ static void ibm_cffps_create_led_class(struct ibm_cffps *psu)
 		 client->addr);
 	psu->led.name = psu->led_name;
 	psu->led.max_brightness = LED_FULL;
-	psu->led.brightness_set = ibm_cffps_led_brightness_set;
+	psu->led.brightness_set_blocking = ibm_cffps_led_brightness_set;
 	psu->led.blink_set = ibm_cffps_led_blink_set;
 
 	rc = devm_led_classdev_register(dev, &psu->led);