[PATCH v2 net-next 4/5] net: dsa: mv88e6xxx: Add helper to determining if port has SERDES

[Andrew Lunn]

Refactor the existing code. This helper will be used for SERDES
statistics.

Signed-off-by: Andrew Lunn <and...@lunn.ch>
Tested-by: Florian Fainelli <f.faine...@gmail.com>
---
v2: Use Boolean return value
---
 drivers/net/dsa/mv88e6xxx/serdes.c | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/serdes.c 
b/drivers/net/dsa/mv88e6xxx/serdes.c
index f3c01119b3d1..4487d18132a4 100644
--- a/drivers/net/dsa/mv88e6xxx/serdes.c
+++ b/drivers/net/dsa/mv88e6xxx/serdes.c
@@ -55,18 +55,30 @@ static int mv88e6352_serdes_power_set(struct mv88e6xxx_chip 
*chip, bool on)
        return err;
 }
 
-int mv88e6352_serdes_power(struct mv88e6xxx_chip *chip, int port, bool on)
+static bool mv88e6352_port_has_serdes(struct mv88e6xxx_chip *chip, int port)
 {
-       int err;
        u8 cmode;
+       int err;
 
        err = mv88e6xxx_port_get_cmode(chip, port, &cmode);
-       if (err)
-               return err;
+       if (err) {
+               dev_err(chip->dev, "failed to read cmode\n");
+               return 0;
+       }
 
        if ((cmode == MV88E6XXX_PORT_STS_CMODE_100BASE_X) ||
            (cmode == MV88E6XXX_PORT_STS_CMODE_1000BASE_X) ||
-           (cmode == MV88E6XXX_PORT_STS_CMODE_SGMII)) {
+           (cmode == MV88E6XXX_PORT_STS_CMODE_SGMII))
+               return 1;
+
+       return 0;
+}
+
+int mv88e6352_serdes_power(struct mv88e6xxx_chip *chip, int port, bool on)
+{
+       int err;
+
+       if (mv88e6352_port_has_serdes(chip, port)) {
                err = mv88e6352_serdes_power_set(chip, on);
                if (err < 0)
                        return err;
-- 
2.16.2