[PATCH] net: ravb: Fix NULL pointer access

[Biju Das]

Some phy's like rtl8211e do not support writeext() callback. Add a check to
avoid null pointer access before calling writeext() callback.

Signed-off-by: Biju Das <biju.das.jz at bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj at bp.renesas.com>
---
 drivers/net/ravb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ravb.c b/drivers/net/ravb.c
index 886f53ee82..623d377897 100644
--- a/drivers/net/ravb.c
+++ b/drivers/net/ravb.c
@@ -438,7 +438,8 @@ static int ravb_config(struct udevice *dev)
 
 	writel(mask, eth->iobase + RAVB_REG_ECMR);
 
-	phy->drv->writeext(phy, -1, 0x02, 0x08, (0x0f << 5) | 0x19);
+	if (phy->drv->writeext)
+		phy->drv->writeext(phy, -1, 0x02, 0x08, (0x0f << 5) | 0x19);
 
 	return 0;
 }
-- 
2.17.1