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@baylibre.com>
Link: https://patch.msgid.link/20251008-m_can-cleanups-v1-7-1784a18eaa84@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 713d3df296df52f5ca02313cf1679dd50a7cac57..eb856547ae7df27a844b236a0c1d4498cbb8b60f 100644 (file)
--- 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;