diff --git a/hw/adc/npcm7xx_adc.c b/hw/adc/npcm7xx_adc.c
index 47fb9e5f74..bc6f3f55e6 100644
--- a/hw/adc/npcm7xx_adc.c
+++ b/hw/adc/npcm7xx_adc.c
@@ -242,7 +242,7 @@ static void npcm7xx_adc_init(Object *obj)
 
     for (i = 0; i < NPCM7XX_ADC_NUM_INPUTS; ++i) {
         object_property_add_uint32_ptr(obj, "adci[*]",
-                &s->adci[i], OBJ_PROP_FLAG_WRITE);
+                &s->adci[i], OBJ_PROP_FLAG_READWRITE);
     }
     object_property_add_uint32_ptr(obj, "vref",
             &s->vref, OBJ_PROP_FLAG_WRITE);