[PATCH] can: m_can: Process interrupt only when not runtime suspended

From: Jarkko Nikula <jarkko.nikula@linux.intel.com>
To: linux-can@vger.kernel.org
Cc: Dan Murphy <dmurphy@ti.com>,
	Sriram Dash <sriram.dash@samsung.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	Patrik Flykt <patrik.flykt@linux.intel.com>,
	Jarkko Nikula <jarkko.nikula@linux.intel.com>
Subject: [PATCH] can: m_can: Process interrupt only when not runtime suspended
Date: Tue, 15 Sep 2020 16:47:15 +0300	[thread overview]
Message-ID: <20200915134715.696303-1-jarkko.nikula@linux.intel.com> (raw)

Avoid processing bogus interrupt statuses when the HW is runtime
suspended and the M_CAN_IR register read may get all bits 1's. Handler
can be called if the interrupt request is shared with other peripherals
or at the end of free_irq().

Therefore check the runtime suspended status before processing.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
---
 drivers/net/can/m_can/m_can.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 02c5795b7393..81b32b03e246 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -956,6 +956,8 @@ static irqreturn_t m_can_isr(int irq, void *dev_id)
 	struct net_device_stats *stats = &dev->stats;
 	u32 ir;
 
+	if (pm_runtime_suspended(cdev->dev))
+		return IRQ_NONE;
 	ir = m_can_read(cdev, M_CAN_IR);
 	if (!ir)
 		return IRQ_NONE;
-- 
2.28.0

