hwmon: (pmbus/ibm-cffps) Fixes for the LED subsystem

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 <[email protected]>

---
 drivers/hwmon/pmbus/ibm-cffps.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

drivers/hwmon/pmbus/ibm-cffps.c +6 -4

index d61547ed0da0..c6a00e83aac6 100644
@@ -297,8 +297,8 @@ 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);

@@ -316,9 +316,11 @@ 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,

@@ -356,7 +358,7 @@ 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);

The LED blink_set function incorrectly did not tell the PSU LED to blink if brightness was LED_OFF. Fix this, and also correct the LED_OFF command data, which should give control of the LED back to the PSU firmware. Also prevent I2C failures from getting the driver LED state out of sync and add some dev_dbg statements.

Signed-off-by Eddie James <[email protected]>

---
 drivers/hwmon/pmbus/ibm-cffps.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

drivers/hwmon/pmbus/ibm-cffps.c +19 -8

index c6a00e83aac6..d359b76bcb36 100644
@@ -44,9 +44,13 @@
 #define CFFPS_MFR_VAUX_FAULT			BIT(6)
 #define CFFPS_MFR_CURRENT_SHARE_WARNING		BIT(7)
 
+/*
+ * LED off state actually relinquishes LED control to PSU firmware, so it can
+ * turn on the LED for faults.
+ */
+#define CFFPS_LED_OFF				0
 #define CFFPS_LED_BLINK				BIT(0)
 #define CFFPS_LED_ON				BIT(1)
-#define CFFPS_LED_OFF				BIT(2)
 #define CFFPS_BLINK_RATE_MS			250
 
 enum {

@@ -301,23 +305,31 @@ static int ibm_cffps_led_brightness_set(struct led_classdev *led_cdev,
 					enum led_brightness brightness)
 {
 	int rc;
+	u8 next_led_state;
 	struct ibm_cffps *psu = container_of(led_cdev, struct ibm_cffps, led);
 
 	if (brightness == LED_OFF) {
-		psu->led_state = CFFPS_LED_OFF;
+		next_led_state = CFFPS_LED_OFF;
 	} else {
 		brightness = LED_FULL;
+
 		if (psu->led_state != CFFPS_LED_BLINK)
-			psu->led_state = CFFPS_LED_ON;
+			next_led_state = CFFPS_LED_ON;
+		else
+			next_led_state = CFFPS_LED_BLINK;
 	}
 
+	dev_dbg(&psu->client->dev, "LED brightness set: %d. Command: %d.\n",
+		brightness, next_led_state);
+
 	pmbus_set_page(psu->client, 0);
 
 	rc = i2c_smbus_write_byte_data(psu->client, CFFPS_SYS_CONFIG_CMD,
-				       psu->led_state);
+				       next_led_state);
 	if (rc < 0)
 		return rc;
 
+	psu->led_state = next_led_state;
 	led_cdev->brightness = brightness;
 
 	return 0;

@@ -330,10 +342,7 @@ static int ibm_cffps_led_blink_set(struct led_classdev *led_cdev,
 	int rc;
 	struct ibm_cffps *psu = container_of(led_cdev, struct ibm_cffps, led);
 
-	psu->led_state = CFFPS_LED_BLINK;
-
-	if (led_cdev->brightness == LED_OFF)
-		return 0;
+	dev_dbg(&psu->client->dev, "LED blink set.\n");
 
 	pmbus_set_page(psu->client, 0);
 

@@ -342,6 +351,8 @@ static int ibm_cffps_led_blink_set(struct led_classdev *led_cdev,
 	if (rc < 0)
 		return rc;
 
+	psu->led_state = CFFPS_LED_BLINK;
+	led_cdev->brightness = LED_FULL;
 	*delay_on = CFFPS_BLINK_RATE_MS;
 	*delay_off = CFFPS_BLINK_RATE_MS;