can: mcp251x: avoid write to error flag register if it's unnecessary

Only two bits (RX0OVR and RX1OVR) are writable in EFLG, write is useless
if these bits aren't set.

Signed-off-by: Ed Spiridonov <edo.rus@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>

diff --git a/drivers/net/can/spi/mcp251x.c b/drivers/net/can/spi/mcp251x.c
index 575790e..74a7dfe 100644 (file)
--- a/drivers/net/can/spi/mcp251x.c
+++ b/drivers/net/can/spi/mcp251x.c
@@ -843,7 +843,7 @@ static irqreturn_t mcp251x_can_ist(int irq, void *dev_id)
                if (clear_intf)
                        mcp251x_write_bits(spi, CANINTF, clear_intf, 0x00);
 
-               if (eflag)
+               if (eflag & (EFLG_RX0OVR | EFLG_RX1OVR))
                        mcp251x_write_bits(spi, EFLG, eflag, 0x00);
 
                /* Update can state */