can: c_can: Add d_can suspend resume support

Adds suspend resume support to DCAN driver which enables
DCAN power down mode bit (PDR). Then DCAN will ack the local
power-down mode by setting PDA bit in STATUS register.

Signed-off-by: AnilKumar Ch <anilkumar@ti.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 768bb481b077..2c4a21f98442 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -46,6 +46,9 @@
 #define IF_ENUM_REG_LEN		11
 #define C_CAN_IFACE(reg, iface)	(C_CAN_IF1_##reg + (iface) * IF_ENUM_REG_LEN)
 
+/* control extension register D_CAN specific */
+#define CONTROL_EX_PDR		BIT(8)
+
 /* control register */
 #define CONTROL_TEST		BIT(7)
 #define CONTROL_CCE		BIT(6)
@@ -65,6 +68,7 @@
 #define TEST_BASIC		BIT(2)
 
 /* status register */
+#define STATUS_PDA		BIT(10)
 #define STATUS_BOFF		BIT(7)
 #define STATUS_EWARN		BIT(6)
 #define STATUS_EPASS		BIT(5)
@@ -164,6 +168,9 @@
 /* minimum timeout for checking BUSY status */
 #define MIN_TIMEOUT_VALUE	6
 
+/* Wait for ~1 sec for INIT bit */
+#define INIT_WAIT_MS		1000
+
 /* napi related */
 #define C_CAN_NAPI_WEIGHT	C_CAN_MSG_OBJ_RX_NUM
 
@@ -1153,6 +1160,77 @@ struct net_device *alloc_c_can_dev(void)
 }
 EXPORT_SYMBOL_GPL(alloc_c_can_dev);
 
+#ifdef CONFIG_PM
+int c_can_power_down(struct net_device *dev)
+{
+	u32 val;
+	unsigned long time_out;
+	struct c_can_priv *priv = netdev_priv(dev);
+
+	if (!(dev->flags & IFF_UP))
+		return 0;
+
+	WARN_ON(priv->type != BOSCH_D_CAN);
+
+	/* set PDR value so the device goes to power down mode */
+	val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
+	val |= CONTROL_EX_PDR;
+	priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
+
+	/* Wait for the PDA bit to get set */
+	time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
+	while (!(priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
+				time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out))
+		return -ETIMEDOUT;
+
+	c_can_stop(dev);
+
+	c_can_pm_runtime_put_sync(priv);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(c_can_power_down);
+
+int c_can_power_up(struct net_device *dev)
+{
+	u32 val;
+	unsigned long time_out;
+	struct c_can_priv *priv = netdev_priv(dev);
+
+	if (!(dev->flags & IFF_UP))
+		return 0;
+
+	WARN_ON(priv->type != BOSCH_D_CAN);
+
+	c_can_pm_runtime_get_sync(priv);
+
+	/* Clear PDR and INIT bits */
+	val = priv->read_reg(priv, C_CAN_CTRL_EX_REG);
+	val &= ~CONTROL_EX_PDR;
+	priv->write_reg(priv, C_CAN_CTRL_EX_REG, val);
+	val = priv->read_reg(priv, C_CAN_CTRL_REG);
+	val &= ~CONTROL_INIT;
+	priv->write_reg(priv, C_CAN_CTRL_REG, val);
+
+	/* Wait for the PDA bit to get clear */
+	time_out = jiffies + msecs_to_jiffies(INIT_WAIT_MS);
+	while ((priv->read_reg(priv, C_CAN_STS_REG) & STATUS_PDA) &&
+				time_after(time_out, jiffies))
+		cpu_relax();
+
+	if (time_after(jiffies, time_out))
+		return -ETIMEDOUT;
+
+	c_can_start(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(c_can_power_up);
+#endif
+
 void free_c_can_dev(struct net_device *dev)
 {
 	free_candev(dev);