can: m_can: add deep Suspend/Resume support

This adds Power Management deep Suspend/Resume support for Bosch M_CAN
chip.

When entering deep sleep, the clocks are gated, the interrupts are
disabled. When resuming from deep sleep, the chip needs to be
reinitialized, the clocks ungated and the interrupts enabled.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 653b304d709104c7e136c7a1354a41be2bcf76ca..f4947a74b65f3d4eb12bfc42bd927c2c1d506207 100644 (file)
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1668,6 +1668,8 @@ failed_ret:
        return ret;
 }
 
+/* TODO: runtime PM with power down or sleep mode  */
+
 static __maybe_unused int m_can_suspend(struct device *dev)
 {
        struct net_device *ndev = dev_get_drvdata(dev);
@@ -1676,10 +1678,10 @@ static __maybe_unused int m_can_suspend(struct device *dev)
        if (netif_running(ndev)) {
                netif_stop_queue(ndev);
                netif_device_detach(ndev);
+               m_can_stop(ndev);
+               m_can_clk_stop(priv);
        }
 
-       /* TODO: enter low power */
-
        priv->can.state = CAN_STATE_SLEEPING;
 
        return 0;
@@ -1690,11 +1692,18 @@ static __maybe_unused int m_can_resume(struct device *dev)
        struct net_device *ndev = dev_get_drvdata(dev);
        struct m_can_priv *priv = netdev_priv(ndev);
 
-       /* TODO: exit low power */
+       m_can_init_ram(priv);
 
        priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
        if (netif_running(ndev)) {
+               int ret;
+
+               ret = m_can_clk_start(priv);
+               if (ret)
+                       return ret;
+
+               m_can_start(ndev);
                netif_device_attach(ndev);
                netif_start_queue(ndev);
        }