[PATCH net-next v2 7/7] net: pcs: rzn1-miic: Init RX clock early if MAC requires it

[Romain Gantois <romain.gantois@bootlin.com>]

The GMAC1 controller in the RZN1 IP requires the RX MII clock signal to be
started before it initializes its own hardware, thus before it calls
phylink_start.

Check the rxc_always_on pcs flag and enable the clock signal during the
link validation phase.

Reported-by: Clément Léger <clement.leger@bootlin.com>
Link: https://lore.kernel.org/linux-arm-kernel/20230116103926.276869-4-clement.leger@bootlin.com/
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
---
 drivers/net/pcs/pcs-rzn1-miic.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index d93f84fbb1fd..7ca10b7330ef 100644
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -279,10 +279,26 @@ static int miic_validate(struct phylink_pcs *pcs, unsigned long *supported,
 	return -EINVAL;
 }
 
+static int miic_pre_init(struct phylink_pcs *pcs,
+			 phy_interface_t interface)
+{
+	int ret = 0;
+
+	/* Start RX clock if required */
+	if (pcs->rxc_always_on) {
+		ret = miic_config(pcs, 0, interface, NULL, false);
+		if (ret)
+			pr_err("Error: Failed to init RX clock in RZN1 MIIC PCS!");
+	}
+
+	return ret;
+}
+
 static const struct phylink_pcs_ops miic_phylink_ops = {
 	.pcs_validate = miic_validate,
 	.pcs_config = miic_config,
 	.pcs_link_up = miic_link_up,
+	.pcs_pre_init = miic_pre_init,
 };
 
 struct phylink_pcs *miic_create(struct device *dev, struct device_node *np)

-- 
2.43.0