[PATCH v5 6/8] net: can: c_can: Disable pins when CAN interface is down

@@ -35,6 +35,7 @@
 #include <linux/list.h>
 #include <linux/io.h>
 #include <linux/pm_runtime.h>
+#include <linux/pinctrl/consumer.h>
 
 #include <linux/can.h>
 #include <linux/can/dev.h>

@@ -587,6 +588,21 @@ static int c_can_chip_config(struct net_device *dev)
 	return c_can_set_bittiming(dev);
 }
 
+/*
+ * Selects the pinctrl state specified in the name.
+ */
+static void c_can_pinctrl_select_state(struct c_can_priv *priv,
+				      const char *name)
+{
+	if (!IS_ERR(priv->pinctrl)) {
+		struct pinctrl_state *s;
+
+		s = pinctrl_lookup_state(priv->pinctrl, name);
+		if (!IS_ERR(s))
+			pinctrl_select_state(priv->pinctrl, s);
+	}
+}
+
 static int c_can_start(struct net_device *dev)
 {
 	struct c_can_priv *priv = netdev_priv(dev);

@@ -603,6 +619,8 @@ static int c_can_start(struct net_device *dev)
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
+	/* activate pins */
+	c_can_pinctrl_select_state(priv, PINCTRL_STATE_DEFAULT);
 	return 0;
 }
 

@@ -611,6 +629,9 @@ static void c_can_stop(struct net_device *dev)
 	struct c_can_priv *priv = netdev_priv(dev);
 
 	c_can_irq_control(priv, false);
+
+	/* deactivate pins */
+	c_can_pinctrl_select_state(priv, PINCTRL_STATE_SLEEP);
 	priv->can.state = CAN_STATE_STOPPED;
 }
 

@@ -1244,6 +1265,22 @@ int register_c_can_dev(struct net_device *dev)
 	struct c_can_priv *priv = netdev_priv(dev);
 	int err;
 
+	priv->pinctrl = devm_pinctrl_get(dev->dev.parent);
+	if (!IS_ERR(priv->pinctrl)) {
+		struct pinctrl_state *s;
+
+		/* Deactivate pins to prevent DRA7 DCAN IP from being
+		 * stuck in transition when module is disabled.
+		 * Pins are activated in c_can_start() and deactivated
+		 * in c_can_stop()
+		 */
+		s = pinctrl_lookup_state(priv->pinctrl, PINCTRL_STATE_SLEEP);
+		if (!IS_ERR(s))
+			pinctrl_select_state(priv->pinctrl, s);
+	} else {
+		netdev_dbg(dev, "failed to get pinctrl\n");
+	}
+
 	c_can_pm_runtime_enable(priv);
 
 	dev->flags |= IFF_ECHO;	/* we support local echo */

@@ -210,6 +210,7 @@ struct c_can_priv {
 	u32 comm_rcv_high;
 	u32 rxmasked;
 	u32 dlc[C_CAN_MSG_OBJ_TX_NUM];
+	struct pinctrl *pinctrl;
 };
 
 struct net_device *alloc_c_can_dev(void);