[PATCH v2 0/2] can: m_can: Fix suspend deinit() error path

[PATCH v2 0/2] can: m_can: Fix suspend deinit() error path

[Markus Schneider-Pargmann (TI)]

Hi,

this small series tries to make the suspend error path of m_can a bit
better.

Best,
Markus

Signed-off-by: Markus Schneider-Pargmann (TI) <msp@baylibre.com>
---
Changes in v2:
- Add a patch for tcan suspend
- Start the hrtimer if coalescing is active and suspend is cancelled
  instead of modifying active_interrupts
- Link to v1: https://patch.msgid.link/20260918-v7-3-topic-mcan-suspend-fix-fix-v1-1-e24fa70c754e@baylibre.com

To: Markus Schneider-Pargmann <msp@baylibre.com>
To: Marc Kleine-Budde <mkl@pengutronix.de>
To: Vincent Mailhol <mailhol@kernel.org>
To: Sean Nyekjaer <sean@geanix.com>
To: Martin Hundebøll <martin@geanix.com>
Cc: linux-can@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

---
Markus Schneider-Pargmann (1):
      can: tcan4x5x: Add suspend error handling

Markus Schneider-Pargmann (TI) (1):
      can: m_can: Fix suspend deinit() error path

 drivers/net/can/m_can/m_can.c         | 25 ++++++++++++++++++++++++-
 drivers/net/can/m_can/tcan4x5x-core.c | 11 ++++++++++-
 2 files changed, 34 insertions(+), 2 deletions(-)
---
base-commit: cee9395acd8043be0644b25c34bfa86623f2b935
change-id: 20260914-v7-3-topic-mcan-suspend-fix-fix-b943929d8fef

Best regards,
--  
Markus Schneider-Pargmann <msp@baylibre.com>

[PATCH v2 1/2] can: m_can: Fix suspend deinit() error path

[Markus Schneider-Pargmann (TI)]

When suspending mcan, deinit is called and its return value is returned,
but nothing is restored. Returning an error in the suspend function will
stop suspending and resume the system immediately. So on error the
device should be restored to its previous state. If coalescing is
active, the hrtimer is restarted.

Fixes: ad1ddb3bfb0c ("can: m_can: call deinit/init callback when going into suspend/resume")
Signed-off-by: Markus Schneider-Pargmann (TI) <msp@baylibre.com>
---
 drivers/net/can/m_can/m_can.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 16f80607e150..02a95a769a78 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -2612,8 +2612,14 @@ int m_can_class_suspend(struct device *dev)
 			hrtimer_cancel(&cdev->hrtimer);
 			m_can_write(cdev, M_CAN_IE, IR_RF0N);
 
-			if (cdev->ops->deinit)
+			if (cdev->ops->deinit) {
 				ret = cdev->ops->deinit(cdev);
+				if (ret) {
+					netdev_err(cdev->net, "failed to deinit device while suspending %pe\n",
+						   ERR_PTR(ret));
+					goto err_pm_wake_source;
+				}
+			}
 		} else {
 			m_can_stop(ndev);
 		}
@@ -2625,6 +2631,23 @@ int m_can_class_suspend(struct device *dev)
 	if (!m_can_class_wakeup_pinctrl_enabled(cdev))
 		pinctrl_pm_select_sleep_state(dev);
 
+	return 0;
+
+err_pm_wake_source:
+	if (netif_running(ndev)) {
+		if (cdev->pm_wake_source) {
+			bool coalescing_active = (cdev->active_interrupts & (IR_RF0N | IR_TEFN))
+						 != (IR_RF0N | IR_TEFN);
+			m_can_write(cdev, M_CAN_IE, cdev->active_interrupts);
+			if (coalescing_active)
+				hrtimer_start(&cdev->hrtimer,
+					      cdev->irq_timer_wait,
+					      HRTIMER_MODE_REL);
+		}
+		netif_device_attach(ndev);
+		netif_start_queue(ndev);
+	}
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(m_can_class_suspend);

-- 
2.55.0

[PATCH v2 2/2] can: tcan4x5x: Add suspend error handling

[Markus Schneider-Pargmann]

m_can_class_suspend() may return errors. On error we should first
restore the previous state and then pass the error code on. Otherwise we
keep the device in a misconfigured state for the running state.

Fixes: b6b640c04446 ("can: tcan4x5x: support resuming from rx interrupt signal")
Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
---
 drivers/net/can/m_can/tcan4x5x-core.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
index a5b8829aa519..b69312413d62 100644
--- a/drivers/net/can/m_can/tcan4x5x-core.c
+++ b/drivers/net/can/m_can/tcan4x5x-core.c
@@ -575,11 +575,20 @@ static int __maybe_unused tcan4x5x_suspend(struct device *dev)
 {
 	struct m_can_classdev *cdev = dev_get_drvdata(dev);
 	struct spi_device *spi = to_spi_device(dev);
+	int ret;
 
 	if (cdev->pm_wake_source)
 		enable_irq_wake(spi->irq);
 
-	return m_can_class_suspend(dev);
+	ret = m_can_class_suspend(dev);
+	if (ret)
+		goto err_disable_irq;
+	return 0;
+
+err_disable_irq:
+	if (cdev->pm_wake_source)
+		disable_irq_wake(spi->irq);
+	return ret;
 }
 
 static int __maybe_unused tcan4x5x_resume(struct device *dev)

-- 
2.55.0

Re: [PATCH v2 2/2] can: tcan4x5x: Add suspend error handling

[Martin Hundebøll]

Hi Markus,

On Fri, 2026-10-16 at 11:57 +0200, Markus Schneider-Pargmann wrote:
> diff --git a/drivers/net/can/m_can/tcan4x5x-core.c
> b/drivers/net/can/m_can/tcan4x5x-core.c
> index a5b8829aa519..b69312413d62 100644
> --- a/drivers/net/can/m_can/tcan4x5x-core.c
> +++ b/drivers/net/can/m_can/tcan4x5x-core.c
> @@ -575,11 +575,20 @@ static int __maybe_unused
> tcan4x5x_suspend(struct device *dev)
>  {
>  	struct m_can_classdev *cdev = dev_get_drvdata(dev);
>  	struct spi_device *spi = to_spi_device(dev);
> +	int ret;
> 
>  	if (cdev->pm_wake_source)
>  		enable_irq_wake(spi->irq);
> 
> -	return m_can_class_suspend(dev);
> +	ret = m_can_class_suspend(dev);
> +	if (ret)
> +		goto err_disable_irq;
> +	return 0;
> +
> +err_disable_irq:
> +	if (cdev->pm_wake_source)
> +		disable_irq_wake(spi->irq);
> +	return ret;

Wouldn't this be better written in the shorter form:

	ret = m_can_class_suspend(dev);
	if (ret && dev->pm_wake_source)
		disable_irq_wake(spi->irq);

	return ret;

?

// Martin