[PATCH] hwmon: (pmbus) Fix return value from pmbus_update_byte_data()

[Guenter Roeck <linux@roeck-us.net>]

pmbus_update_byte_data() is supposed to return a negative error code or 0.
However, if no change is made to the register, it actually returns the
register value. This can result in problems if the calling code explicitly
expects to see an error code or 0.

Fix it to return 0 on success or the error code as expected.

Fixes: 11c119986f270 ("hwmon: (pmbus) add helpers for byte write and read modify write")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
 drivers/hwmon/pmbus/pmbus_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 24c4d502733c..aac86d4f64b5 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -513,7 +513,7 @@ int pmbus_update_byte_data(struct i2c_client *client, int page, u8 reg,
 	if (tmp != rv)
 		rv = _pmbus_write_byte_data(client, page, reg, tmp);
 
-	return rv;
+	return rv < 0 ? rv : 0;
 }
 EXPORT_SYMBOL_NS_GPL(pmbus_update_byte_data, "PMBUS");
 
-- 
2.45.2