This is a note to let you know that I've just added the patch titled can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery to the 5.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: can-flexcan-flexcan_chip_start-fix-erroneous-flexcan.patch and it can be found in the queue-5.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a96c73679da53d5207961e3020827d8903f96b64 Author: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Date: Wed Nov 18 16:01:48 2020 +0100 can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery [ Upstream commit cd9f13c59461351d7a5fd07924264fb49b287359 ] If the CAN controller goes into bus off, the do_set_mode() callback with CAN_MODE_START can be used to recover the controller, which then calls flexcan_chip_start(). If configured, this is done automatically by the framework or manually by the user. In flexcan_chip_start() there is an explicit call to flexcan_transceiver_enable(), which does a regulator_enable() on the transceiver regulator. This results in a net usage counter increase, as there is no corresponding flexcan_transceiver_disable() in the bus off code path. This further leads to the transceiver stuck enabled, even if the CAN interface is shut down. To fix this problem the flexcan_transceiver_enable()/flexcan_transceiver_disable() are moved out of flexcan_chip_start()/flexcan_chip_stop() into flexcan_open()/flexcan_close(). Fixes: e955cead0311 ("CAN: Add Flexcan CAN controller driver") Link: https://lore.kernel.org/r/20201118150148.2664024-1-mkl@xxxxxxxxxxxxxx Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 20a56f389c20c..4cbe8889f546f 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -1229,14 +1229,10 @@ static int flexcan_chip_start(struct net_device *dev) priv->write(reg_mecr, ®s->mecr); } - err = flexcan_transceiver_enable(priv); - if (err) - goto out_chip_disable; - /* synchronize with the can bus */ err = flexcan_chip_unfreeze(priv); if (err) - goto out_transceiver_disable; + goto out_chip_disable; priv->can.state = CAN_STATE_ERROR_ACTIVE; @@ -1254,8 +1250,6 @@ static int flexcan_chip_start(struct net_device *dev) return 0; - out_transceiver_disable: - flexcan_transceiver_disable(priv); out_chip_disable: flexcan_chip_disable(priv); return err; @@ -1285,7 +1279,6 @@ static int __flexcan_chip_stop(struct net_device *dev, bool disable_on_error) priv->write(priv->reg_ctrl_default & ~FLEXCAN_CTRL_ERR_ALL, ®s->ctrl); - flexcan_transceiver_disable(priv); priv->can.state = CAN_STATE_STOPPED; return 0; @@ -1321,10 +1314,14 @@ static int flexcan_open(struct net_device *dev) if (err) goto out_runtime_put; - err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev); + err = flexcan_transceiver_enable(priv); if (err) goto out_close; + err = request_irq(dev->irq, flexcan_irq, IRQF_SHARED, dev->name, dev); + if (err) + goto out_transceiver_disable; + priv->mb_size = sizeof(struct flexcan_mb) + CAN_MAX_DLEN; priv->mb_count = (sizeof(priv->regs->mb[0]) / priv->mb_size) + (sizeof(priv->regs->mb[1]) / priv->mb_size); @@ -1373,6 +1370,8 @@ static int flexcan_open(struct net_device *dev) can_rx_offload_del(&priv->offload); out_free_irq: free_irq(dev->irq, dev); + out_transceiver_disable: + flexcan_transceiver_disable(priv); out_close: close_candev(dev); out_runtime_put: @@ -1391,6 +1390,7 @@ static int flexcan_close(struct net_device *dev) can_rx_offload_del(&priv->offload); free_irq(dev->irq, dev); + flexcan_transceiver_disable(priv); close_candev(dev); pm_runtime_put(priv->dev);