From: Fabio Estevam <fabio.estevam@nxp.com>
Date: Wed, 17 Aug 2016 15:41:08 +0000 (-0300)
Subject: can: flexcan: fix resume function
X-Git-Tag: firefly_0821_release~176^2~4^2~27^2~18
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a68022d9b59c2fc1ebe3c4133f0e2f32b4cde065;p=firefly-linux-kernel-4.4.55.git

can: flexcan: fix resume function

commit 4de349e786a3a2d51bd02d56f3de151bbc3c3df9 upstream.

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>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 41c0fc9f3b14..16f7cadda5c3 100644
--- 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);