[PATCH 6/7] can: m_can: m_can_get_berr_counter(): don't wake up controller if interface is down

[Marc Kleine-Budde]

If the interface is down, the CAN controller might be powered down,
the clock disabled, and/or it's external reset asserted.

Don't wake up the controller to read the CAN bus error counters, if
the interface is down.

Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
---
 drivers/net/can/m_can/m_can.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 149f3a8b5f7e..c24ea0e5599f 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -790,6 +790,10 @@ static int m_can_get_berr_counter(const struct net_device *dev,
 	struct m_can_classdev *cdev = netdev_priv(dev);
 	int err;
 
+	/* Avoid waking up the controller if the interface is down */
+	if (!(dev->flags & IFF_UP))
+		return 0;
+
 	err = m_can_clk_start(cdev);
 	if (err)
 		return err;

-- 
2.50.1