1 files changed, 39 insertions, 7 deletions

diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 64f4fdd02902..b8f956eece9c 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -6276,6 +6276,32 @@ static int mv88e6xxx_detect(struct mv88e6xxx_chip *chip)
 	return 0;
 }
 
+static int mv88e6xxx_single_chip_detect(struct mv88e6xxx_chip *chip,
+					struct mdio_device *mdiodev)
+{
+	int err;
+
+	/* dual_chip takes precedence over single/multi-chip modes */
+	if (chip->info->dual_chip)
+		return -EINVAL;
+
+	/* If the mdio addr is 16 indicating the first port address of a switch
+	 * (e.g. mv88e6*41) in single chip addressing mode the device may be
+	 * configured in single chip addressing mode. Setup the smi access as
+	 * single chip addressing mode and attempt to detect the model of the
+	 * switch, if this fails the device is not configured in single chip
+	 * addressing mode.
+	 */
+	if (mdiodev->addr != 16)
+		return -EINVAL;
+
+	err = mv88e6xxx_smi_init(chip, mdiodev->bus, 0);
+	if (err)
+		return err;
+
+	return mv88e6xxx_detect(chip);
+}
+
 static struct mv88e6xxx_chip *mv88e6xxx_alloc_chip(struct device *dev)
 {
 	struct mv88e6xxx_chip *chip;
@@ -6959,10 +6985,6 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
 
 	chip->info = compat_info;
 
-	err = mv88e6xxx_smi_init(chip, mdiodev->bus, mdiodev->addr);
-	if (err)
-		goto out;
-
 	chip->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(chip->reset)) {
 		err = PTR_ERR(chip->reset);
@@ -6971,9 +6993,19 @@ static int mv88e6xxx_probe(struct mdio_device *mdiodev)
 	if (chip->reset)
 		usleep_range(1000, 2000);
 
-	err = mv88e6xxx_detect(chip);
-	if (err)
-		goto out;
+	/* Detect if the device is configured in single chip addressing mode,
+	 * otherwise continue with address specific smi init/detection.
+	 */
+	err = mv88e6xxx_single_chip_detect(chip, mdiodev);
+	if (err) {
+		err = mv88e6xxx_smi_init(chip, mdiodev->bus, mdiodev->addr);
+		if (err)
+			goto out;
+
+		err = mv88e6xxx_detect(chip);
+		if (err)
+			goto out;
+	}
 
 	if (chip->info->edsa_support == MV88E6XXX_EDSA_SUPPORTED)
 		chip->tag_protocol = DSA_TAG_PROTO_EDSA;