can: flexcan: fix resume function

On a imx6ul-pico board the following error is seen during system suspend:

dpm_run_callback(): platform_pm_resume+0x0/0x54 returns -110
PM: Device 2090000.flexcan failed to resume: error -110

The reason for this suspend error is because when the CAN interface is not
active the clocks are disabled and then flexcan_chip_enable() will
always fail due to a timeout error.

In order to fix this issue, only call flexcan_chip_enable/disable()
when the CAN interface is active.

Based on a patch from Dong Aisheng in the NXP kernel.

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 41c0fc9..16f7cad 100644 (file)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -1268,11 +1268,10 @@ static int __maybe_unused flexcan_suspend(struct device *device)
        struct flexcan_priv *priv = netdev_priv(dev);
        int err;
 
-       err = flexcan_chip_disable(priv);
-       if (err)
-               return err;
-
        if (netif_running(dev)) {
+               err = flexcan_chip_disable(priv);
+               if (err)
+                       return err;
                netif_stop_queue(dev);
                netif_device_detach(dev);
        }
@@ -1285,13 +1284,17 @@ 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;
 
        priv->can.state = CAN_STATE_ERROR_ACTIVE;
        if (netif_running(dev)) {
                netif_device_attach(dev);
                netif_start_queue(dev);
+               err = flexcan_chip_enable(priv);
+               if (err)
+                       return err;
        }
-       return flexcan_chip_enable(priv);
+       return 0;
 }
 
 static SIMPLE_DEV_PM_OPS(flexcan_pm_ops, flexcan_suspend, flexcan_resume);