diff --git a/drivers/mfd/ucb1400_core.c b/drivers/mfd/ucb1400_core.c
index 85fd942..dbe2801 100644
--- a/drivers/mfd/ucb1400_core.c
+++ b/drivers/mfd/ucb1400_core.c
@@ -22,6 +22,7 @@
 
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/slab.h>
 #include <linux/ucb1400.h>
 
 unsigned int ucb1400_adc_read(struct snd_ac97 *ac97, u16 adc_channel,