[PATCH v2 4/4] net: qcom/emac: add acpi shared mdio bus support

[Wang Dongsheng <dongsheng.wang@hxt-semitech.com>]

Parsing _DSD package "mdio-device".

Signed-off-by: Wang Dongsheng <dongsheng.wang@hxt-semitech.com>
---
 drivers/net/ethernet/qualcomm/emac/emac-phy.c | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/drivers/net/ethernet/qualcomm/emac/emac-phy.c b/drivers/net/ethernet/qualcomm/emac/emac-phy.c
index 4f98f9a0ed54..7a96bcf15d3f 100644
--- a/drivers/net/ethernet/qualcomm/emac/emac-phy.c
+++ b/drivers/net/ethernet/qualcomm/emac/emac-phy.c
@@ -97,6 +97,51 @@ static int emac_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
 	return 0;
 }
 
+static int acpi_device_match(struct device *dev, void *fwnode)
+{
+	return dev->fwnode == fwnode;
+}
+
+static int emac_acpi_get_shared_bus(struct platform_device *pdev,
+				    struct mii_bus **bus)
+{
+	struct fwnode_reference_args args;
+	struct fwnode_handle *fw_node;
+
+	struct device *shared_dev;
+	struct net_device *shared_netdev;
+	struct emac_adapter *shared_adpt;
+	int ret;
+
+	if (!has_acpi_companion(&pdev->dev))
+		return -ENODEV;
+
+	fw_node = acpi_fwnode_handle(ACPI_COMPANION(&pdev->dev));
+	ret = acpi_node_get_property_reference(fw_node, "mdio-device", 0,
+					       &args);
+	if (ACPI_FAILURE(ret) || !is_acpi_device_node(args.fwnode)) {
+		dev_err(&pdev->dev, "Missing mdio-device property\n");
+		return -ENODEV;
+	}
+
+	shared_dev = bus_find_device(&platform_bus_type, NULL,
+				     args.fwnode,
+				     acpi_device_match);
+	if (!shared_dev)
+		return -EPROBE_DEFER;
+
+	shared_netdev = dev_get_drvdata(shared_dev);
+	if (!shared_netdev)
+		return -EPROBE_DEFER;
+
+	shared_adpt = netdev_priv(shared_netdev);
+	if (!shared_adpt->mii_bus)
+		return -EPROBE_DEFER;
+
+	*bus = shared_adpt->mii_bus;
+	return 0;
+}
+
 static int emac_of_get_shared_bus(struct platform_device *pdev,
 				  struct mii_bus **bus)
 {
@@ -137,6 +182,12 @@ static int emac_of_get_shared_bus(struct platform_device *pdev,
 static int __do_get_emac_mido_shared_bus(struct platform_device *pdev,
 					 struct emac_adapter *adpt)
 {
+	int ret;
+
+	ret = emac_acpi_get_shared_bus(pdev, &adpt->mii_bus);
+	if (adpt->mii_bus || ret == -EPROBE_DEFER)
+		return ret;
+
 	return emac_of_get_shared_bus(pdev, &adpt->mii_bus);
 }
 
-- 
2.18.0