net: dsa: qca8k: add support for switch rev

qca8k internal phy driver require some special debug value to be set
based on the switch revision. Rework the switch id read function to
also read the chip revision.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/qca8k.c

@@ -1579,12 +1579,40 @@ static const struct dsa_switch_ops qca8k_switch_ops = {
 	.phylink_mac_link_up	= qca8k_phylink_mac_link_up,
 };
 
+static int qca8k_read_switch_id(struct qca8k_priv *priv)
+{
+	const struct qca8k_match_data *data;
+	u32 val;
+	u8 id;
+
+	/* get the switches ID from the compatible */
+	data = of_device_get_match_data(priv->dev);
+	if (!data)
+		return -ENODEV;
+
+	val = qca8k_read(priv, QCA8K_REG_MASK_CTRL);
+	if (val < 0)
+		return -ENODEV;
+
+	id = QCA8K_MASK_CTRL_DEVICE_ID(val & QCA8K_MASK_CTRL_DEVICE_ID_MASK);
+	if (id != data->id) {
+		dev_err(priv->dev, "Switch id detected %x but expected %x", id, data->id);
+		return -ENODEV;
+	}
+
+	priv->switch_id = id;
+
+	/* Save revision to communicate to the internal PHY driver */
+	priv->switch_revision = (val & QCA8K_MASK_CTRL_REV_ID_MASK);
+
+	return 0;
+}
+
 static int
 qca8k_sw_probe(struct mdio_device *mdiodev)
 {
-	const struct qca8k_match_data *data;
 	struct qca8k_priv *priv;
-	u32 id;
+	int ret;
 
 	/* allocate the private data struct so that we can probe the switches
 	 * ID register
@@ -1610,24 +1638,11 @@ qca8k_sw_probe(struct mdio_device *mdiodev)
 		gpiod_set_value_cansleep(priv->reset_gpio, 0);
 	}
 
-	/* get the switches ID from the compatible */
-	data = of_device_get_match_data(&mdiodev->dev);
-	if (!data)
-		return -ENODEV;
-
-	/* read the switches ID register */
-	id = qca8k_read(priv, QCA8K_REG_MASK_CTRL);
-	if (id < 0)
-		return id;
-
-	id >>= QCA8K_MASK_CTRL_ID_S;
-	id &= QCA8K_MASK_CTRL_ID_M;
-	if (id != data->id) {
-		dev_err(&mdiodev->dev, "Switch id detected %x but expected %x", id, data->id);
-		return -ENODEV;
-	}
+	/* Check the detected switch id */
+	ret = qca8k_read_switch_id(priv);
+	if (ret)
+		return ret;
 
-	priv->switch_id = id;
 	priv->ds = devm_kzalloc(&mdiodev->dev, sizeof(*priv->ds), GFP_KERNEL);
 	if (!priv->ds)
 		return -ENOMEM;

drivers/net/dsa/qca8k.h

@@ -30,8 +30,10 @@
 
 /* Global control registers */
 #define QCA8K_REG_MASK_CTRL				0x000
-#define   QCA8K_MASK_CTRL_ID_M				0xff
-#define   QCA8K_MASK_CTRL_ID_S				8
+#define   QCA8K_MASK_CTRL_REV_ID_MASK			GENMASK(7, 0)
+#define   QCA8K_MASK_CTRL_REV_ID(x)			((x) >> 0)
+#define   QCA8K_MASK_CTRL_DEVICE_ID_MASK		GENMASK(15, 8)
+#define   QCA8K_MASK_CTRL_DEVICE_ID(x)			((x) >> 8)
 #define QCA8K_REG_PORT0_PAD_CTRL			0x004
 #define QCA8K_REG_PORT5_PAD_CTRL			0x008
 #define QCA8K_REG_PORT6_PAD_CTRL			0x00c
@@ -251,6 +253,7 @@ struct qca8k_match_data {
 
 struct qca8k_priv {
 	u8 switch_id;
+	u8 switch_revision;
 	struct regmap *regmap;
 	struct mii_bus *bus;
 	struct ar8xxx_port_status port_sts[QCA8K_NUM_PORTS];