netdev - [PATCH net-next 13/13] can: m_can: m_can_get_berr_counter(): don't wake up controller if interface is down

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Message-ID: <20251017150819.1415685-14-mkl@pengutronix.de>
Date: Fri, 17 Oct 2025 17:04:21 +0200
From: Marc Kleine-Budde <mkl@...gutronix.de>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net,
	kuba@...nel.org,
	linux-can@...r.kernel.org,
	kernel@...gutronix.de,
	Marc Kleine-Budde <mkl@...gutronix.de>,
	Markus Schneider-Pargmann <msp@...libre.com>
Subject: [PATCH net-next 13/13] 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.

Reviewed-by: Markus Schneider-Pargmann <msp@...libre.com>
Link: https://patch.msgid.link/20251008-m_can-cleanups-v1-7-1784a18eaa84@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.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 713d3df296df..eb856547ae7d 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -791,6 +791,10 @@ 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;
-- 
2.51.0