net: stmmac: restore pinstate in pm resume.

This patch adds code to restore default pinstate of the pins when it
comes back from low power state. Without this patch the state of the
pins would be unknown and the driver would not work.

This patch also adds code to put the pins in to sleep state when the
driver enters low power state.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
Acked-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c1298a0..df7d8d6 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -43,6 +43,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
 #include <linux/prefetch.h>
+#include <linux/pinctrl/consumer.h>
 #ifdef CONFIG_STMMAC_DEBUG_FS
 #include <linux/debugfs.h>
 #include <linux/seq_file.h>
@@ -2864,6 +2865,7 @@
 		priv->hw->mac->pmt(priv->ioaddr, priv->wolopts);
 	else {
 		stmmac_set_mac(priv->ioaddr, false);
+		pinctrl_pm_select_sleep_state(priv->device);
 		/* Disable clock in case of PWM is off */
 		clk_disable_unprepare(priv->stmmac_clk);
 	}
@@ -2890,6 +2892,7 @@
 	if (device_may_wakeup(priv->device)) {
 		priv->hw->mac->pmt(priv->ioaddr, 0);
 	} else {
+		pinctrl_pm_select_default_state(priv->device);
 		/* enable the clk prevously disabled */
 		clk_prepare_enable(priv->stmmac_clk);
 		/* reset the phy so that it's ready */