From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Chandrasekar Ramakrishnan <rcsekar@samsung.com>,
Vincent Mailhol <mailhol@kernel.org>,
Patrik Flykt <patrik.flykt@linux.intel.com>,
Dong Aisheng <b29396@freescale.com>,
Varka Bhadram <varkabhadram@gmail.com>,
Wu Bo <wubo.oduw@gmail.com>,
Markus Schneider-Pargmann <msp@baylibre.com>,
Philipp Zabel <p.zabel@pengutronix.de>
Cc: linux-can@vger.kernel.org, kernel@pengutronix.de,
Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH v3 5/6] can: m_can: m_can_get_berr_counter(): don't wake up controller if interface is down
Date: Tue, 23 Sep 2025 11:17:18 +0200 [thread overview]
Message-ID: <20250923-m_can-fix-state-handling-v3-5-06d8baccadbf@pengutronix.de> (raw)
In-Reply-To: <20250923-m_can-fix-state-handling-v3-0-06d8baccadbf@pengutronix.de>
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@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 c82ea6043d40..afbab6ca5833 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;
--
2.51.0
next prev parent reply other threads:[~2025-09-23 9:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-23 9:17 [PATCH v3 0/6] can: m_can: fix pm_runtime and CAN state handling Marc Kleine-Budde
2025-09-23 9:17 ` [PATCH v3 1/6] can: m_can: m_can_plat_remove(): add missing pm_runtime_disable() Marc Kleine-Budde
2025-09-23 9:17 ` [PATCH v3 2/6] can: m_can: m_can_handle_state_errors(): fix CAN state transition to Error Active Marc Kleine-Budde
2025-09-23 9:17 ` [PATCH v3 3/6] can: m_can: m_can_chip_config(): bring up interface in correct state Marc Kleine-Budde
2025-09-23 9:17 ` [PATCH v3 4/6] can: m_can: fix CAN state in system PM Marc Kleine-Budde
2025-09-23 9:17 ` Marc Kleine-Budde [this message]
2025-09-23 12:09 ` [PATCH v3 5/6] can: m_can: m_can_get_berr_counter(): don't wake up controller if interface is down Markus Schneider-Pargmann
2025-09-23 9:17 ` [PATCH v3 6/6] can: m_can: add optional support for reset Marc Kleine-Budde
2025-09-23 12:06 ` Markus Schneider-Pargmann
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