can: m_can: Read register PSR only on error

Only read register PSR if there is an error indicated in irqstatus.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Link: https://lore.kernel.org/all/20221206115728.1056014-4-msp@baylibre.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 8399e55..045679a 100644 (file)
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -910,7 +910,6 @@ static int m_can_rx_handler(struct net_device *dev, int quota, u32 irqstatus)
        struct m_can_classdev *cdev = netdev_priv(dev);
        int rx_work_or_err;
        int work_done = 0;
-       u32 psr;
 
        if (!irqstatus)
                goto end;
@@ -936,13 +935,13 @@ static int m_can_rx_handler(struct net_device *dev, int quota, u32 irqstatus)
                }
        }
 
-       psr = m_can_read(cdev, M_CAN_PSR);
-
        if (irqstatus & IR_ERR_STATE)
-               work_done += m_can_handle_state_errors(dev, psr);
+               work_done += m_can_handle_state_errors(dev,
+                                                      m_can_read(cdev, M_CAN_PSR));
 
        if (irqstatus & IR_ERR_BUS_30X)
-               work_done += m_can_handle_bus_errors(dev, irqstatus, psr);
+               work_done += m_can_handle_bus_errors(dev, irqstatus,
+                                                    m_can_read(cdev, M_CAN_PSR));
 
        if (irqstatus & IR_RF0N) {
                rx_work_or_err = m_can_do_rx_poll(dev, (quota - work_done));