Thread (3 messages) flat view 3 messages, 1 author, 2024-09-09
DORMANTno replies

[PATCH can v2 2/2] can: m_can: m_can_close(): stop clocks after device has been shut down

From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2024-09-09 14:29:50
Also in: linux-can, lkml
Subsystem: can network drivers, mcan device driver, the rest · Maintainers: Marc Kleine-Budde, Vincent Mailhol, Markus Schneider-Pargmann, Linus Torvalds

After calling m_can_stop() an interrupt may be pending or NAPI might
still be executed. This means the driver might still touch registers
of the IP core after the clocks has been disabled. This is not good
practice and might lead to aborts depending on the SoC integration.

To avoid these potential problems, make m_can_close() symmetric to
m_can_open(), i.e. stop the clocks at the end, right before shutting
down the transceiver.

Fixes: e0d1f4816f2a ("can: m_can: add Bosch M_CAN controller support")
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/m_can.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 7754dd2d4cb110eee5b83885f5381aed9c67ce03..7aeb56bcd1d660e592b527919d3708add62bfb75 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1764,7 +1764,6 @@ static int m_can_close(struct net_device *dev)
 	netif_stop_queue(dev);
 
 	m_can_stop(dev);
-	m_can_clk_stop(cdev);
 	free_irq(dev->irq, dev);
 
 	/* disable NAPI after disabling interrupts */
@@ -1781,6 +1780,7 @@ static int m_can_close(struct net_device *dev)
 
 	close_candev(dev);
 
+	m_can_clk_stop(cdev);
 	phy_power_off(cdev->transceiver);
 
 	return 0;
-- 
2.45.2

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