From: Marc Kleine-Budde Date: Tue, 12 Aug 2025 16:58:31 +0200 Subject: [PATCH] can: m_can: fix CAN state in system PM A suspend/resume cycle on a down interface results in the interface coming up in Error Active state. A suspend/resume cycle on an Up interface will always result in Error Active state, regardless of the actual CAN state. During suspend, only set running interfaces to CAN_STATE_SLEEPING. During resume only touch the CAN state of running interfaces. For wakeup sources, set the CAN state depending on the Protocol Status Regitser (PSR), for non wakeup source interfaces m_can_start() will do the same. Fixes: e0d1f4816f2a ("can: m_can: add Bosch M_CAN controller support") Signed-off-by: Marc Kleine-Budde Upstream-Status: Submitted [https://lore.kernel.org/all/20250812-m_can-fix-state-handling-v1-0-b739e06c0a3b@pengutronix.de] --- drivers/net/can/m_can/m_can.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c index e28f3d5f58f9..73f3524bfd1d 100644 --- a/drivers/net/can/m_can/m_can.c +++ b/drivers/net/can/m_can/m_can.c @@ -2507,12 +2507,11 @@ int m_can_class_suspend(struct device *dev) } m_can_clk_stop(cdev); + cdev->can.state = CAN_STATE_SLEEPING; } pinctrl_pm_select_sleep_state(dev); - cdev->can.state = CAN_STATE_SLEEPING; - return ret; } EXPORT_SYMBOL_GPL(m_can_class_suspend); @@ -2525,14 +2524,14 @@ int m_can_class_resume(struct device *dev) pinctrl_pm_select_default_state(dev); - cdev->can.state = CAN_STATE_ERROR_ACTIVE; - if (netif_running(ndev)) { ret = m_can_clk_start(cdev); if (ret) return ret; if (cdev->pm_wake_source) { + u32 reg_psr; + /* Restore active interrupts but disable coalescing as * we may have missed important waterlevel interrupts * between suspend and resume. Timers are already @@ -2544,6 +2543,9 @@ int m_can_class_resume(struct device *dev) if (cdev->ops->init) ret = cdev->ops->init(cdev); + reg_psr = m_can_read(cdev, M_CAN_PSR); + cdev->can.state = m_can_can_state_get_by_psr(reg_psr); + m_can_write(cdev, M_CAN_IE, cdev->active_interrupts); } else { ret = m_can_start(ndev);