[PATCH v1 2/2] net: sja1105: add function to configure CPU port

[Oleksij Rempel <o.rempel@pengutronix.de>]

Introduce sja1105_cpu_port_enable() to configure the CPU port.
Typically, dedicated Ethernet devices attach to a PHY with an adjust
link function for the networking framework to handle link adjustments.
However, for the CPU port, we face a unique scenario where the device
tree defines two Ethernet devices each with a fixed link: CPU == fixed
link and fixed link == Switch.

This function reflects the model where fixed link driver extracts all
needed information from the device tree, but we do not create an
Ethernet device for the fixed link == Switch bundle, only for the
CPU == fixed link part. Thus, instead of adding adjust link support for
non-dedicated Ethernet devices or making them official Ethernet devices,
we opt to use a port_enable call in the DSA framework.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 drivers/net/sja1105.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/net/sja1105.c b/drivers/net/sja1105.c
index c759c40b36..4ef30b8c81 100644
--- a/drivers/net/sja1105.c
+++ b/drivers/net/sja1105.c
@@ -2840,8 +2840,35 @@ static int sja1105_rcv(struct dsa_switch *ds, int *port, void *packet,
 	return 0;
 }
 
+static int sja1105_cpu_port_enable(struct dsa_port *dp, int port,
+				   struct phy_device *phy)
+{
+	struct device *dev = dp->ds->dev;
+	struct sja1105_private *priv = dev_get_priv(dev);
+	phy_interface_t phy_mode = phy->interface;
+	struct dsa_switch *ds = &priv->ds;
+	int cpu = ds->cpu_port;
+	int ret;
+
+	if (port != cpu)
+		return 0;
+
+	sja1105_set_speed(dp, port, phy->speed);
+
+	ret = sja1105_port_set_mode(dp, port, phy_mode);
+	if (ret)
+		return ret;
+
+	ret = sja1105_set_rgmii_delay(priv, port, phy_mode);
+	if (ret)
+		return ret;
+
+	return sja1105_static_config_reload(priv);
+}
+
 static const struct dsa_switch_ops sja1105_dsa_ops = {
 	.port_pre_enable	= sja1105_port_pre_enable,
+	.port_enable		= sja1105_cpu_port_enable,
 	.adjust_link		= sja1105_adjust_link,
 	.xmit			= sja1105_xmit,
 	.rcv			= sja1105_rcv,
-- 
2.39.2