hwmon: (pmbus) Enable PEC if the controller supports it

PMBus controllers optionally support PEC. Configure the driver
to use it if available to improve operational security.

Suggested-by: Michael Jones <mike@proclivis.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/pmbus/pmbus_core.c

@@ -1751,6 +1751,11 @@ static int pmbus_init_common(struct i2c_client *client, struct pmbus_data *data,
 		}
 	}
 
+	/* Enable PEC if the controller supports it */
+	ret = i2c_smbus_read_byte_data(client, PMBUS_CAPABILITY);
+	if (ret >= 0 && (ret & PB_CAPABILITY_ERROR_CHECK))
+		client->flags |= I2C_CLIENT_PEC;
+
 	pmbus_clear_faults(client);
 
 	if (info->identify) {