[net-next PATCH v4 02/13] net: dsa: qca8k: add support for sgmii falling edge

[Ansuel Smith <ansuelsmth@gmail.com>]

Add support for this in the qca8k driver. Also add support for SGMII
rx/tx clock falling edge. This is only present for pad0, pad5 and
pad6 have these bit reserved from Documentation. Add a comment that this
is hardcoded to PAD0 as qca8327/28/34/37 have an unique sgmii line and
setting falling in port0 applies to both configuration with sgmii used
for port0 or port6.

Signed-off-by: Matthew Hagan <mnhagan88@gmail.com>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
---
 drivers/net/dsa/qca8k.c | 25 +++++++++++++++++++++++++
 drivers/net/dsa/qca8k.h |  3 +++
 2 files changed, 28 insertions(+)

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index a892b897cd0d..3e4a12d6d61c 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1172,6 +1172,7 @@ qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 			 const struct phylink_link_state *state)
 {
 	struct qca8k_priv *priv = ds->priv;
+	struct dsa_port *dp;
 	u32 reg, val;
 	int ret;
 
@@ -1240,6 +1241,8 @@ qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 		break;
 	case PHY_INTERFACE_MODE_SGMII:
 	case PHY_INTERFACE_MODE_1000BASEX:
+		dp = dsa_to_port(ds, port);
+
 		/* Enable SGMII on the port */
 		qca8k_write(priv, reg, QCA8K_PORT_PAD_SGMII_EN);
 
@@ -1274,6 +1277,28 @@ qca8k_phylink_mac_config(struct dsa_switch *ds, int port, unsigned int mode,
 		}
 
 		qca8k_write(priv, QCA8K_REG_SGMII_CTRL, val);
+
+		/* For qca8327/qca8328/qca8334/qca8338 sgmii is unique and
+		 * falling edge is set writing in the PORT0 PAD reg
+		 */
+		if (priv->switch_id == QCA8K_ID_QCA8327 ||
+		    priv->switch_id == QCA8K_ID_QCA8337)
+			reg = QCA8K_REG_PORT0_PAD_CTRL;
+
+		val = 0;
+
+		/* SGMII Clock phase configuration */
+		if (of_property_read_bool(dp->dn, "qca,sgmii-rxclk-falling-edge"))
+			val |= QCA8K_PORT0_PAD_SGMII_RXCLK_FALLING_EDGE;
+
+		if (of_property_read_bool(dp->dn, "qca,sgmii-txclk-falling-edge"))
+			val |= QCA8K_PORT0_PAD_SGMII_TXCLK_FALLING_EDGE;
+
+		if (val)
+			ret = qca8k_rmw(priv, reg,
+					QCA8K_PORT0_PAD_SGMII_RXCLK_FALLING_EDGE |
+					QCA8K_PORT0_PAD_SGMII_TXCLK_FALLING_EDGE,
+					val);
 		break;
 	default:
 		dev_err(ds->dev, "xMII mode %s not supported for port %d\n",
diff --git a/drivers/net/dsa/qca8k.h b/drivers/net/dsa/qca8k.h
index fc7db94cc0c9..3fded69a6839 100644
--- a/drivers/net/dsa/qca8k.h
+++ b/drivers/net/dsa/qca8k.h
@@ -35,6 +35,9 @@
 #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_PORT0_PAD_CTRL_MAC06_EXCHG		BIT(31)
+#define   QCA8K_PORT0_PAD_SGMII_RXCLK_FALLING_EDGE	BIT(19)
+#define   QCA8K_PORT0_PAD_SGMII_TXCLK_FALLING_EDGE	BIT(18)
 #define QCA8K_REG_PORT5_PAD_CTRL			0x008
 #define QCA8K_REG_PORT6_PAD_CTRL			0x00c
 #define   QCA8K_PORT_PAD_RGMII_EN			BIT(26)
-- 
2.32.0