diff --git a/drivers/mfd/at91-usart.c b/drivers/mfd/at91-usart.c
index d20747f612c1..684d3a8db661 100644
--- a/drivers/mfd/at91-usart.c
+++ b/drivers/mfd/at91-usart.c
@@ -15,15 +15,15 @@
 #include <linux/of.h>
 #include <linux/property.h>
 
-static struct mfd_cell at91_usart_spi_subdev = {
-		.name = "at91_usart_spi",
-		.of_compatible = "microchip,at91sam9g45-usart-spi",
-	};
+static const struct mfd_cell at91_usart_spi_subdev = {
+	.name = "at91_usart_spi",
+	.of_compatible = "microchip,at91sam9g45-usart-spi",
+};
 
-static struct mfd_cell at91_usart_serial_subdev = {
-		.name = "atmel_usart_serial",
-		.of_compatible = "atmel,at91rm9200-usart-serial",
-	};
+static const struct mfd_cell at91_usart_serial_subdev = {
+	.name = "atmel_usart_serial",
+	.of_compatible = "atmel,at91rm9200-usart-serial",
+};
 
 static int at91_usart_mode_probe(struct platform_device *pdev)
 {