[RFC PATCH net-next v2 09/17] net: dsa: qca8k: add support for switch rev

[Ansuel Smith <ansuelsmth@gmail.com>]

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>
---
 drivers/net/dsa/qca8k.c | 46 +++++++++++++++++++++++++++--------------
 drivers/net/dsa/qca8k.h |  6 ++++--
 2 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 3f42d731756c..5478bee39c6e 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1578,13 +1578,39 @@ 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;
+	int ret;
+	u32 val;
+	u8 id;
+
+	/* get the switches ID from the compatible */
+	data = of_device_get_match_data(priv->dev);
+	if (!data)
+		return -ENODEV;
+
+	ret = qca8k_read(priv, QCA8K_REG_MASK_CTRL, &val);
+	if (ret)
+		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;
+	}
+
+	/* 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;
 	int ret;
-	u32 id;
 
 	/* allocate the private data struct so that we can probe the switches
 	 * ID register
@@ -1610,23 +1636,11 @@ 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 */
-	ret = qca8k_read(priv, QCA8K_REG_MASK_CTRL, &id);
+	/* Check the detected switch id */
+	ret = qca8k_read_switch_id(priv);
 	if (ret)
 		return ret;
 
-	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;
-	}
-
 	priv->ds = devm_kzalloc(&mdiodev->dev, sizeof(*priv->ds), GFP_KERNEL);
 	if (!priv->ds)
 		return -ENOMEM;
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index 5fb68dbfa85a..0b503f78bf92 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -28,8 +28,10 @@
 
 /* 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
-- 
2.30.2