diff --git a/drivers/mfd/jz4740-adc.c b/drivers/mfd/jz4740-adc.c
index 3ad492c..9dd1b33 100644
--- a/drivers/mfd/jz4740-adc.c
+++ b/drivers/mfd/jz4740-adc.c
@@ -153,7 +153,7 @@
 	if (enabled)
 		val |= BIT(engine);
 	else
-		val &= BIT(engine);
+		val &= ~BIT(engine);
 	writeb(val, adc->base + JZ_REG_ADC_ENABLE);
 
 	spin_unlock_irqrestore(&adc->lock, flags);