diff --git a/cpu/pxa/i2c.c b/cpu/pxa/i2c.c
index 722d949..92dd19f 100644
--- a/cpu/pxa/i2c.c
+++ b/cpu/pxa/i2c.c
@@ -457,7 +457,7 @@
 
 uchar i2c_reg_read (uchar chip, uchar reg)
 {
-	char buf;
+	uchar buf;
 
 	PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
 	i2c_read(chip, reg, 1, &buf, 1);