can: c_can: Add runtime PM support to Bosch C_CAN/D_CAN controller

Add Runtime PM support to C_CAN/D_CAN controller. The runtime PM
APIs control clocks for C_CAN/D_CAN IP and prevent access to the
register of C_CAN/D_CAN IP when clock is turned off.

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

3 files changed, 49 insertions, 2 deletions

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 4c538e388655..768bb481b077 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -34,6 +34,7 @@
 #include <linux/if_ether.h>
 #include <linux/list.h>
 #include <linux/io.h>
+#include <linux/pm_runtime.h>
 
 #include <linux/can.h>
 #include <linux/can/dev.h>
@@ -201,6 +202,30 @@ static const struct can_bittiming_const c_can_bittiming_const = {
         .brp_inc = 1,
 };
 
+static inline void c_can_pm_runtime_enable(const struct c_can_priv *priv)
+{
+        if (priv->device)
+                pm_runtime_enable(priv->device);
+}
+
+static inline void c_can_pm_runtime_disable(const struct c_can_priv *priv)
+{
+        if (priv->device)
+                pm_runtime_disable(priv->device);
+}
+
+static inline void c_can_pm_runtime_get_sync(const struct c_can_priv *priv)
+{
+        if (priv->device)
+                pm_runtime_get_sync(priv->device);
+}
+
+static inline void c_can_pm_runtime_put_sync(const struct c_can_priv *priv)
+{
+        if (priv->device)
+                pm_runtime_put_sync(priv->device);
+}
+
 static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
 {
         return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +
@@ -673,11 +698,15 @@ static int c_can_get_berr_counter(const struct net_device *dev,
         unsigned int reg_err_counter;
         struct c_can_priv *priv = netdev_priv(dev);
 
+        c_can_pm_runtime_get_sync(priv);
+
         reg_err_counter = priv->read_reg(priv, C_CAN_ERR_CNT_REG);
         bec->rxerr = (reg_err_counter & ERR_CNT_REC_MASK) >>
                                 ERR_CNT_REC_SHIFT;
         bec->txerr = reg_err_counter & ERR_CNT_TEC_MASK;
 
+        c_can_pm_runtime_put_sync(priv);
+
         return 0;
 }
 
@@ -1053,11 +1082,13 @@ static int c_can_open(struct net_device *dev)
         int err;
         struct c_can_priv *priv = netdev_priv(dev);
 
+        c_can_pm_runtime_get_sync(priv);
+
         /* open the can device */
         err = open_candev(dev);
         if (err) {
                 netdev_err(dev, "failed to open can device\n");
-                return err;
+                goto exit_open_fail;
         }
 
         /* register interrupt handler */
@@ -1079,6 +1110,8 @@ static int c_can_open(struct net_device *dev)
 
 exit_irq_fail:
         close_candev(dev);
+exit_open_fail:
+        c_can_pm_runtime_put_sync(priv);
         return err;
 }
 
@@ -1091,6 +1124,7 @@ static int c_can_close(struct net_device *dev)
         c_can_stop(dev);
         free_irq(dev->irq, dev);
         close_candev(dev);
+        c_can_pm_runtime_put_sync(priv);
 
         return 0;
 }
@@ -1133,10 +1167,19 @@ static const struct net_device_ops c_can_netdev_ops = {
 
 int register_c_can_dev(struct net_device *dev)
 {
+        struct c_can_priv *priv = netdev_priv(dev);
+        int err;
+
+        c_can_pm_runtime_enable(priv);
+
         dev->flags |= IFF_ECHO; /* we support local echo */
         dev->netdev_ops = &c_can_netdev_ops;
 
-        return register_candev(dev);
+        err = register_candev(dev);
+        if (err)
+                c_can_pm_runtime_disable(priv);
+
+        return err;
 }
 EXPORT_SYMBOL_GPL(register_c_can_dev);
 
@@ -1148,6 +1191,8 @@ void unregister_c_can_dev(struct net_device *dev)
         c_can_enable_all_interrupts(priv, DISABLE_ALL_INTERRUPTS);
 
         unregister_candev(dev);
+
+        c_can_pm_runtime_disable(priv);
 }
 EXPORT_SYMBOL_GPL(unregister_c_can_dev);
 
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 4e56baa9c2da..1437a6dbdca5 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -153,6 +153,7 @@ struct c_can_priv {
         struct can_priv can;    /* must be the first member */
         struct napi_struct napi;
         struct net_device *dev;
+        struct device *device;
         int tx_object;
         int current_status;
         int last_status;
diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
index d0a66cf298ba..7b8b7a485d72 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -179,6 +179,7 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
 
         dev->irq = irq;
         priv->base = addr;
+        priv->device = &pdev->dev;
         priv->can.clock.freq = clk_get_rate(clk);
         priv->priv = clk;