can: flexcan: add LPSR mode support

On the i.MX7D in LPSR mode, the controller will be powered off and the
configuration state is lost after system resume. Upcoming i.MX8QM/QXP
will also completely power off the domain, the controller state is lost
and needs restore, too. So we need to set the pinctrl state again and
re-start chip to re-configuration after resume.

For the wakeup case, it should not set pinctrl to sleep state by
pinctrl_pm_select_sleep_state.

If the interface is down before suspend, we don't need to re-configure
it as it will be configured if the interface is brought up later.

Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Link: https://lore.kernel.org/r/20191204113249.3381-7-qiangqing.zhang@nxp.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index ed2ead7..35d0fa5 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -23,6 +23,7 @@
 #include <linux/netdevice.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regmap.h>
@@ -1742,7 +1743,7 @@ static int __maybe_unused flexcan_suspend(struct device *device)
 {
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
-       int err = 0;
+       int err;
 
        if (netif_running(dev)) {
                /* if wakeup is enabled, enter stop mode
@@ -1754,7 +1755,11 @@ static int __maybe_unused flexcan_suspend(struct device *device)
                        if (err)
                                return err;
                } else {
-                       err = flexcan_chip_disable(priv);
+                       err = flexcan_chip_stop(dev);
+                       if (err)
+                               return err;
+
+                       err = pinctrl_pm_select_sleep_state(device);
                        if (err)
                                return err;
                }
@@ -1763,14 +1768,14 @@ static int __maybe_unused flexcan_suspend(struct device *device)
        }
        priv->can.state = CAN_STATE_SLEEPING;
 
-       return err;
+       return 0;
 }
 
 static int __maybe_unused flexcan_resume(struct device *device)
 {
        struct net_device *dev = dev_get_drvdata(device);
        struct flexcan_priv *priv = netdev_priv(dev);
-       int err = 0;
+       int err;
 
        priv->can.state = CAN_STATE_ERROR_ACTIVE;
        if (netif_running(dev)) {
@@ -1782,11 +1787,17 @@ static int __maybe_unused flexcan_resume(struct device *device)
                        if (err)
                                return err;
                } else {
-                       err = flexcan_chip_enable(priv);
+                       err = pinctrl_pm_select_default_state(device);
+                       if (err)
+                               return err;
+
+                       err = flexcan_chip_start(dev);
+                       if (err)
+                               return err;
                }
        }
 
-       return err;
+       return 0;
 }
 
 static int __maybe_unused flexcan_runtime_suspend(struct device *device)