pinctrl: at91: disable PD or PU before enabling PU or PD

Disable Pull-Down or Pull-Up property before enabling Pull-Up or
Pull-Down, because the pin's Pull-Up and Pull-Down property is
mutually exclusive.
Signed-off-by: NWenyou Yang <wenyou.yang@atmel.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-at91.c

@@ -371,6 +371,9 @@ static unsigned at91_mux_get_pullup(void __iomem *pio, unsigned pin)
 
 static void at91_mux_set_pullup(void __iomem *pio, unsigned mask, bool on)
 {
+	if (on)
+		writel_relaxed(mask, pio + PIO_PPDDR);
+
 	writel_relaxed(mask, pio + (on ? PIO_PUER : PIO_PUDR));
 }
 
@@ -499,6 +502,9 @@ static bool at91_mux_pio3_get_pulldown(void __iomem *pio, unsigned pin)
 
 static void at91_mux_pio3_set_pulldown(void __iomem *pio, unsigned mask, bool is_on)
 {
+	if (is_on)
+		__raw_writel(mask, pio + PIO_PUDR);
+
 	__raw_writel(mask, pio + (is_on ? PIO_PPDER : PIO_PPDDR));
 }