[net-next,v6,7/7] net: pcs: rzn1-miic: Init RX clock early if MAC requires it

Commit Message

Romain Gantois March 11, 2024, 9:55 a.m. UTC

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.

Implement the pcs_pre_init() callback so that the RX clock signal can be
enabled early if necessary.

Reported-by: Clément Léger <[e-mail]>
Link: https://lore.kernel.org/linux-arm-kernel/[e-mail]/
Signed-off-by: Romain Gantois <[e-mail]>
Reviewed-by: Andrew Lunn <[e-mail]>
---
 drivers/net/pcs/pcs-rzn1-miic.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Patch

diff --git a/drivers/net/pcs/pcs-rzn1-miic.c b/drivers/net/pcs/pcs-rzn1-miic.c
index 4bd66fdde367..d0a722d43368 100644
--- a/drivers/net/pcs/pcs-rzn1-miic.c
+++ b/drivers/net/pcs/pcs-rzn1-miic.c
@@ -279,10 +279,38 @@  static int miic_validate(struct phylink_pcs *pcs, unsigned long *supported,
 	return -EINVAL;
 }
 
+static int miic_pre_init(struct phylink_pcs *pcs)
+{
+	struct miic_port *miic_port = phylink_pcs_to_miic_port(pcs);
+	struct miic *miic = miic_port->miic;
+	u32 val, mask;
+
+	/* Start RX clock if required */
+	if (pcs->rxc_always_on) {
+		/* In MII through mode, the clock signals will be driven by the
+		 * external PHY, which might not be initialized yet. Set RMII
+		 * as default mode to ensure that a reference clock signal is
+		 * generated.
+		 */
+		miic_port->interface = PHY_INTERFACE_MODE_RMII;
+
+		val = FIELD_PREP(MIIC_CONVCTRL_CONV_MODE, CONV_MODE_RMII) |
+		      FIELD_PREP(MIIC_CONVCTRL_CONV_SPEED, CONV_MODE_100MBPS);
+		mask = MIIC_CONVCTRL_CONV_MODE | MIIC_CONVCTRL_CONV_SPEED;
+
+		miic_reg_rmw(miic, MIIC_CONVCTRL(miic_port->port), mask, val);
+
+		miic_converter_enable(miic, miic_port->port, 1);
+	}
+
+	return 0;
+}
+
 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)