From: Marc Kleine-Budde Date: Wed, 6 Aug 2025 12:20:44 +0200 Subject: [PATCH] can: m_can: m_can_get_berr_counter(): don't wake up controller if interface is down 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 Upstream-Status: Submitted [https://lore.kernel.org/all/20250812-m_can-fix-state-handling-v1-0-b739e06c0a3b@pengutronix.de] --- 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 73f3524bfd1d..22f131958a8c 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;