diff --git a/include/linux/i2c-algo-bit.h b/include/linux/i2c-algo-bit.h
index d91dab8..9ee0f80 100644
--- a/include/linux/i2c-algo-bit.h
+++ b/include/linux/i2c-algo-bit.h
@@ -38,8 +38,10 @@
 	int  (*getscl) (void *data);
 
 	/* local settings */
-	int udelay;		/* half-clock-cycle time in microsecs */
-				/* i.e. clock is (500 / udelay) KHz */
+	int udelay;		/* half clock cycle time in us,
+				   minimum 2 us for fast-mode I2C,
+				   minimum 5 us for standard-mode I2C and SMBus,
+				   maximum 50 us for SMBus */
 	int timeout;		/* in jiffies */
 };