net: dsa: mv88e6xxx: allow reading FID when handling ATU violations

For convenience the function mv88e6xxx_g1_atu_op() has been used to read
ATU violations, but the function has other purposes and does not enable
the possibility to read the FID when reading ATU violations.

The FID is needed to get hold of which VID was involved in the violation,
thus the need to be able to read the FID.

Signed-off-by: Hans Schultz <netdev@kapio-technology.com>

drivers/net/dsa/mv88e6xxx/global1_atu.c

@@ -114,6 +114,19 @@ static int mv88e6xxx_g1_atu_op_wait(struct mv88e6xxx_chip *chip)
 	return mv88e6xxx_g1_wait_bit(chip, MV88E6XXX_G1_ATU_OP, bit, 0);
 }
 
+static int mv88e6xxx_g1_read_atu_violation(struct mv88e6xxx_chip *chip)
+{
+	int err;
+
+	err = mv88e6xxx_g1_write(chip, MV88E6XXX_G1_ATU_OP,
+				 MV88E6XXX_G1_ATU_OP_BUSY |
+				 MV88E6XXX_G1_ATU_OP_GET_CLR_VIOLATION);
+	if (err)
+		return err;
+
+	return mv88e6xxx_g1_atu_op_wait(chip);
+}
+
 static int mv88e6xxx_g1_atu_op(struct mv88e6xxx_chip *chip, u16 fid, u16 op)
 {
 	u16 val;
@@ -359,8 +372,7 @@ static irqreturn_t mv88e6xxx_g1_atu_prob_irq_thread_fn(int irq, void *dev_id)
 
 	mv88e6xxx_reg_lock(chip);
 
-	err = mv88e6xxx_g1_atu_op(chip, 0,
-				  MV88E6XXX_G1_ATU_OP_GET_CLR_VIOLATION);
+	err = mv88e6xxx_g1_read_atu_violation(chip);
 	if (err)
 		goto out;