[PATCH v2 02/22] net: sunxi_emac: chase DT nodes to find PHY regulator

[Andre Przywara <andre.przywara@arm.com>]

At the moment the sun4i EMAC driver relies on hardcoded CONFIG_MACPWR
Kconfig symbols to enable potential PHY regulators. As we want to get rid
of those, we need to find the regulator by chasing up the DT.

The sun4i-emac binding puts the PHY regulator into the MDIO node, which
is the parent of the PHY device. U-Boot does not have (and does not
need) an MDIO driver, so we need to chase down the regulator through the
EMAC node: we follow the "phy-handle" property to find the PHY node,
then go up to its parent, where we find the "phy-supply" link to the
regulator. Let U-Boot find the associated regulator device, and put that
into the private device struct, so we can find and enable the regulator
at probe time, later.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Sam Edwards <CFSworks@gmail.com>
---
 drivers/net/sunxi_emac.c | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/drivers/net/sunxi_emac.c b/drivers/net/sunxi_emac.c
index 4c90d4b4981..f1f0e5bbbb2 100644
--- a/drivers/net/sunxi_emac.c
+++ b/drivers/net/sunxi_emac.c
@@ -17,6 +17,7 @@
 #include <net.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>
+#include <power/regulator.h>
 
 /* EMAC register  */
 struct emac_regs {
@@ -165,6 +166,7 @@ struct emac_eth_dev {
 	struct phy_device *phydev;
 	int link_printed;
 	uchar rx_buf[EMAC_RX_BUFSIZE];
+	struct udevice *phy_reg;
 };
 
 struct emac_rxhdr {
@@ -572,6 +574,9 @@ static int sunxi_emac_eth_probe(struct udevice *dev)
 	if (ret)
 		return ret;
 
+	if (priv->phy_reg)
+		regulator_set_enable(priv->phy_reg, true);
+
 	return sunxi_emac_init_phy(priv, dev);
 }
 
@@ -585,9 +590,43 @@ static const struct eth_ops sunxi_emac_eth_ops = {
 static int sunxi_emac_eth_of_to_plat(struct udevice *dev)
 {
 	struct eth_pdata *pdata = dev_get_plat(dev);
+	struct emac_eth_dev *priv = dev_get_priv(dev);
+	struct ofnode_phandle_args args;
+	ofnode mdio_node;
+	int ret;
 
 	pdata->iobase = dev_read_addr(dev);
 
+	/* The PHY regulator is in the MDIO node, not the EMAC or PHY node. */
+	ret = dev_read_phandle_with_args(dev, "phy-handle", NULL, 0, 0, &args);
+	if (ret) {
+		dev_err(dev, "failed to get PHY node\n");
+		return ret;
+	}
+
+	/*
+	 * U-Boot does not have (and does not need) a device driver for the
+	 * MDIO device, so just "pass through" that DT node to get to the
+	 * regulator phandle.
+	 * The PHY regulator is optional, though: ignore if we cannot find
+	 * a phy-supply property.
+	 */
+	mdio_node = ofnode_get_parent(args.node);
+	ret= ofnode_parse_phandle_with_args(mdio_node, "phy-supply", NULL, 0, 0,
+					    &args);
+	if (ret && ret != -ENOENT) {
+		dev_err(dev, "failed to get PHY supply node\n");
+		return ret;
+	}
+	if (!ret) {
+		ret = uclass_get_device_by_ofnode(UCLASS_REGULATOR, args.node,
+						  &priv->phy_reg);
+		if (ret) {
+			dev_err(dev, "failed to get PHY regulator node\n");
+			return ret;
+		}
+	}
+
 	return 0;
 }
 
-- 
2.35.8