[PATCH net 5/5] net: pcs: rzn1-miic: Init RX clock early if MAC requires it

[Romain Gantois]

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 at bootlin.com>
Link: https://lore.kernel.org/linux-arm-kernel/20230116103926.276869-4-clement.leger@bootlin.com/
Signed-off-by: Romain Gantois <romain.gantois at bootlin.com>
---
 drivers/net/pcs/pcs-rzn1-miic.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index 97139c07130f..bf796491b826 100644
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -271,12 +271,20 @@ static void miic_link_up(struct phylink_pcs *pcs, unsigned int mode,
 static int miic_validate(struct phylink_pcs *pcs, unsigned long *supported,
 			 const struct phylink_link_state *state)
 {
-	if (phy_interface_mode_is_rgmii(state->interface) ||
-	    state->interface == PHY_INTERFACE_MODE_RMII ||
-	    state->interface == PHY_INTERFACE_MODE_MII)
-		return 1;
+	int ret = 1;
 
-	return -EINVAL;
+	if (!phy_interface_mode_is_rgmii(state->interface) &&
+	    state->interface != PHY_INTERFACE_MODE_RMII &&
+	    state->interface != PHY_INTERFACE_MODE_MII)
+		return -EINVAL;
+
+	if (pcs->rxc_always_on) {
+		ret = miic_config(pcs, 0, state->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 = {
-- 
2.43.0