[PATCH 2/2] net: dsa: qca8k: introduce SGMII configuration options

[Jonathan McDowell <noodles@earth.li>]

The QCA8337(N) has an SGMII port which can operate in MAC, PHY or BASE-X
mode depending on what it's connected to (e.g. CPU vs external PHY or
SFP). At present the driver does no configuration of this port even if
it is selected.

Add support for making sure the SGMII is enabled if it's in use, and
device tree support for configuring the connection details.

Signed-off-by: Jonathan McDowell <noodles@earth.li>
---
 drivers/net/dsa/qca8k.c | 44 ++++++++++++++++++++++++++++++++++++++++-
 drivers/net/dsa/qca8k.h | 12 +++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index 9f4205b4439b..5b7979aca9b9 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -418,6 +418,40 @@ qca8k_mib_init(struct qca8k_priv *priv)
 	mutex_unlock(&priv->reg_mutex);
 }
 
+static int
+qca8k_setup_sgmii(struct qca8k_priv *priv)
+{
+	const char *mode;
+	u32 val;
+
+	val = qca8k_read(priv, QCA8K_REG_SGMII_CTRL);
+
+	val |= QCA8K_SGMII_EN_PLL | QCA8K_SGMII_EN_RX |
+		QCA8K_SGMII_EN_TX | QCA8K_SGMII_EN_SD;
+
+	if (of_property_read_bool(priv->dev->of_node, "sgmii-delay"))
+		val |= QCA8K_SGMII_CLK125M_DELAY;
+
+	if (of_property_read_string(priv->dev->of_node, "sgmii-mode", &mode)) {
+		val &= ~QCA8K_SGMII_MODE_CTRL_MASK;
+
+		if (!strcasecmp(mode, "basex")) {
+			val |= QCA8K_SGMII_MODE_CTRL_BASEX;
+		} else if (!strcasecmp(mode, "mac")) {
+			val |= QCA8K_SGMII_MODE_CTRL_MAC;
+		} else if (!strcasecmp(mode, "phy")) {
+			val |= QCA8K_SGMII_MODE_CTRL_PHY;
+		} else {
+			pr_err("Unrecognised SGMII mode %s\n", mode);
+			return -EINVAL;
+		}
+	}
+
+	qca8k_write(priv, QCA8K_REG_SGMII_CTRL, val);
+
+	return 0;
+}
+
 static int
 qca8k_set_pad_ctrl(struct qca8k_priv *priv, int port, int mode)
 {
@@ -458,7 +492,8 @@ qca8k_set_pad_ctrl(struct qca8k_priv *priv, int port, int mode)
 		break;
 	case PHY_INTERFACE_MODE_SGMII:
 		qca8k_write(priv, reg, QCA8K_PORT_PAD_SGMII_EN);
-		break;
+
+		return qca8k_setup_sgmii(priv);
 	default:
 		pr_err("xMII mode %d not supported\n", mode);
 		return -EINVAL;
@@ -661,6 +696,13 @@ qca8k_setup(struct dsa_switch *ds)
 	if (ret)
 		return ret;
 
+	if (of_property_read_bool(priv->dev->of_node,
+				  "disable-serdes-autoneg")) {
+		mask = qca8k_read(priv, QCA8K_REG_PWS) |
+		       QCA8K_PWS_SERDES_AEN_DIS;
+		qca8k_write(priv, QCA8K_REG_PWS, mask);
+	}
+
 	/* Initialize CPU port pad mode (xMII type, delays...) */
 	ret = of_get_phy_mode(dsa_to_port(ds, QCA8K_CPU_PORT)->dn, &phy_mode);
 	if (ret) {
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index 42d6ea24eb14..cd97c212f3f8 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -36,6 +36,8 @@
 #define   QCA8K_MAX_DELAY				3
 #define   QCA8K_PORT_PAD_RGMII_RX_DELAY_EN		BIT(24)
 #define   QCA8K_PORT_PAD_SGMII_EN			BIT(7)
+#define QCA8K_REG_PWS					0x010
+#define   QCA8K_PWS_SERDES_AEN_DIS			BIT(7)
 #define QCA8K_REG_MODULE_EN				0x030
 #define   QCA8K_MODULE_EN_MIB				BIT(0)
 #define QCA8K_REG_MIB					0x034
@@ -77,6 +79,16 @@
 #define   QCA8K_PORT_HDR_CTRL_ALL			2
 #define   QCA8K_PORT_HDR_CTRL_MGMT			1
 #define   QCA8K_PORT_HDR_CTRL_NONE			0
+#define QCA8K_REG_SGMII_CTRL				0x0e0
+#define   QCA8K_SGMII_EN_PLL				BIT(1)
+#define   QCA8K_SGMII_EN_RX				BIT(2)
+#define   QCA8K_SGMII_EN_TX				BIT(3)
+#define   QCA8K_SGMII_EN_SD				BIT(4)
+#define   QCA8K_SGMII_CLK125M_DELAY			BIT(7)
+#define   QCA8K_SGMII_MODE_CTRL_MASK			(BIT(22) | BIT(23))
+#define   QCA8K_SGMII_MODE_CTRL_BASEX			0
+#define   QCA8K_SGMII_MODE_CTRL_PHY			BIT(22)
+#define   QCA8K_SGMII_MODE_CTRL_MAC			BIT(23)
 
 /* EEE control registers */
 #define QCA8K_REG_EEE_CTRL				0x100
-- 
2.20.1