diff --git a/hw/pl031.c b/hw/pl031.c
index 8416a60..a20c625 100644
--- a/hw/pl031.c
+++ b/hw/pl031.c
@@ -32,6 +32,11 @@ do { printf("pl031: " fmt , ## __VA_ARGS__); } while (0)
 #define RTC_MIS     0x18    /* Masked interrupt status register */
 #define RTC_ICR     0x1c    /* Interrupt clear register */

+/**
+ * pl031_state:
+ * @im: Interrupt mask.
+ * @is: Interrupt state.
+ */
 typedef struct {
     SysBusDevice busdev;
     MemoryRegion iomem;