[PATCH net-next v3 2/5] net: phy: mxl-gpy: add MxL86211C VDDP supply

[Robert Marko]

Optionally read the VDDP supply voltage and configure the MxL86211C
MDIO, MDC, and MDINT pads for the matching 1.8 V or 3.3 V level.

Enable an explicitly provided VDDP regulator for the PHY lifetime. Existing
device trees do not describe the supply, so preserve the hardware reset
default when it is absent.

Keep the shared GPY driver buildable without regulator support.

Signed-off-by: Robert Marko <robert.marko@xxxxxxxxxx>
---
Changes in v3:
- Make the VDDP supply optional for existing device trees.
- Enable an explicitly provided regulator for the PHY lifetime.
- Keep the hardware reset default when no supply is described.

Changes in v2:
- Replace the MDIO regulator provider with a VDDP supply consumer.
- Set the pad voltage from the supply's reported voltage.
- Keep the shared driver buildable with CONFIG_REGULATOR=n.

 drivers/net/phy/mxl-gpy.c | 78 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 77 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/mxl-gpy.c b/drivers/net/phy/mxl-gpy.c
index 089a1a9e5bc61..952272faac1e8 100644
--- a/drivers/net/phy/mxl-gpy.c
+++ b/drivers/net/phy/mxl-gpy.c
@@ -14,6 +14,7 @@
 #include <linux/polynomial.h>
 #include <linux/property.h>
 #include <linux/netdevice.h>
+#include <linux/regulator/consumer.h>
 
 /* PHY ID */
 #define PHY_ID_GPYx15B_MASK	0xFFFFFFFC
@@ -110,6 +111,10 @@
 #define VSPEC1_SGMII_ANEN_ANRS	(VSPEC1_SGMII_CTRL_ANEN | \
 				 VSPEC1_SGMII_CTRL_ANRS)
 
+/* Packet Manager Control */
+#define VSPEC1_PM_CTRL		0x0c
+#define VSPEC1_PM_CTRL_MDIO_VOL	BIT(14)
+
 /* Temperature sensor */
 #define VSPEC1_TEMP_STA	0x0E
 #define VSPEC1_TEMP_STA_DATA	GENMASK(9, 0)
@@ -140,6 +145,7 @@ struct gpy_priv {
 	u8 fw_minor;
 	u32 wolopts;
 	u64 rx_errors;
+	struct regulator *vddp;
 
 	/* It takes 3 seconds to fully switch out of loopback mode before
 	 * it can safely re-enter loopback mode. Record the time when
@@ -390,6 +396,76 @@ static int gpy_probe(struct phy_device *phydev)
 	return 0;
 }
 
+static int mxl86211c_configure_mdio_voltage(struct phy_device *phydev,
+					    struct regulator *vddp)
+{
+	int voltage;
+	int val;
+
+	voltage = regulator_get_voltage(vddp);
+	if (voltage < 0)
+		return voltage;
+
+	switch (voltage) {
+	case 1800000:
+		val = VSPEC1_PM_CTRL_MDIO_VOL;
+		break;
+	case 3300000:
+		val = 0;
+		break;
+	default:
+		phydev_err(phydev, "unsupported VDDP voltage: %d\n", voltage);
+		return -EINVAL;
+	}
+
+	return phy_modify_mmd(phydev, MDIO_MMD_VEND1, VSPEC1_PM_CTRL,
+			      VSPEC1_PM_CTRL_MDIO_VOL, val);
+}
+
+static void mxl86211c_disable_vddp(void *data)
+{
+	regulator_disable(data);
+}
+
+static int mxl86211c_probe(struct phy_device *phydev)
+{
+	struct device *dev = &phydev->mdio.dev;
+	struct gpy_priv *priv;
+	struct regulator *vddp;
+	int ret;
+
+	vddp = devm_regulator_get_optional(dev, "vddp");
+	if (PTR_ERR_OR_ZERO(vddp) == -ENODEV)
+		vddp = NULL;
+	else if (IS_ERR(vddp))
+		return dev_err_probe(dev, PTR_ERR(vddp),
+				     "failed to get VDDP supply\n");
+
+	if (vddp) {
+		ret = regulator_enable(vddp);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "failed to enable VDDP supply\n");
+
+		ret = devm_add_action_or_reset(dev, mxl86211c_disable_vddp, vddp);
+		if (ret)
+			return ret;
+
+		ret = mxl86211c_configure_mdio_voltage(phydev, vddp);
+		if (ret)
+			return ret;
+	}
+
+	ret = gpy_probe(phydev);
+	if (ret)
+		return ret;
+
+	priv = phydev->priv;
+	priv->vddp = vddp;
+
+	return 0;
+}
+
 static bool gpy_sgmii_need_reaneg(struct phy_device *phydev)
 {
 	struct gpy_priv *priv = phydev->priv;
@@ -1406,7 +1482,7 @@ static struct phy_driver gpy_drivers[] = {
 		.name		= "Maxlinear Ethernet MxL86211C",
 		.get_features	= genphy_c45_pma_read_abilities,
 		.config_init	= gpy21x_config_init,
-		.probe		= gpy_probe,
+		.probe		= mxl86211c_probe,
 		.inband_caps	= gpy_inband_caps,
 		.config_inband	= gpy_config_inband,
 		.suspend	= genphy_suspend,
-- 
2.56.0