[PATCH net 12/22] can: m_can: m_can_class_suspend(): fix suspend deinit() error path

[Marc Kleine-Budde <mkl@pengutronix.de>]

From: "Markus Schneider-Pargmann (TI)" <msp@baylibre.com>

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.

Fixes: ad1ddb3bfb0c ("can: m_can: call deinit/init callback when going into suspend/resume")
Signed-off-by: Markus Schneider-Pargmann (TI) <msp@baylibre.com>
Reviewed-by: Kendall Willis <k-willis@ti.com>
Link: https://patch.msgid.link/20260918-v7-3-topic-mcan-suspend-fix-fix-v1-1-e24fa70c754e@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/m_can/m_can.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 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..91a0c5eca260 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_restore_interface;
+				}
+			}
 		} else {
 			m_can_stop(ndev);
 		}
@@ -2625,6 +2631,21 @@ 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_restore_interface:
+	if (netif_running(ndev)) {
+		if (cdev->pm_wake_source) {
+			/* Enable interrupts that trigger immediately if
+			 * something is there and keep the hrtimer off
+			 */
+			cdev->active_interrupts |= IR_RF0N | IR_TEFN;
+			m_can_write(cdev, M_CAN_IE, cdev->active_interrupts);
+		}
+		netif_device_attach(ndev);
+		netif_start_queue(ndev);
+	}
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(m_can_class_suspend);
-- 
2.53.0