[PATCH 5/5] phy: bcm-ns-usb3: add MDIO driver using proper bus layer

[Rafał Miłecki]

From: Rafał Miłecki <rafal at milecki.pl>

As USB 3.0 PHY is attached to the MDIO bus this module should provide a
MDIO driver and use a proper bus layer. This is a proper (cleaner)
solution which doesn't require code to know this specific MDIO bus
details. It also allows reusing the driver with other MDIO buses.

Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
---
 drivers/phy/Kconfig           |  1 +
 drivers/phy/phy-bcm-ns-usb3.c | 98 ++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 98 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index afaf7b643eeb..2a9186b98ae0 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -29,6 +29,7 @@ config PHY_BCM_NS_USB3
 	depends on ARCH_BCM_IPROC || COMPILE_TEST
 	depends on HAS_IOMEM && OF
 	select GENERIC_PHY
+	select PHYLIB
 	help
 	  Enable this to support Broadcom USB 3.0 PHY connected to the USB
 	  controller on Northstar family.
diff --git a/drivers/phy/phy-bcm-ns-usb3.c b/drivers/phy/phy-bcm-ns-usb3.c
index 2c9a0d5f43d8..389f5e5a6238 100644
--- a/drivers/phy/phy-bcm-ns-usb3.c
+++ b/drivers/phy/phy-bcm-ns-usb3.c
@@ -16,7 +16,9 @@
 #include <linux/bcma/bcma.h>
 #include <linux/delay.h>
 #include <linux/err.h>
+#include <linux/mdio.h>
 #include <linux/module.h>
+#include <linux/of_address.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/phy/phy.h>
@@ -52,6 +54,7 @@ struct bcm_ns_usb3 {
 	enum bcm_ns_family family;
 	void __iomem *dmp;
 	void __iomem *ccb_mii;
+	struct mdio_device *mdiodev;
 	struct phy *phy;
 
 	int (*phy_write)(struct bcm_ns_usb3 *usb3, u16 reg, u16 value);
@@ -183,6 +186,77 @@ static const struct phy_ops ops = {
 };
 
 /**************************************************
+ * MDIO driver code
+ **************************************************/
+
+static int bcm_ns_usb3_mdiodev_phy_write(struct bcm_ns_usb3 *usb3, u16 reg,
+					 u16 value)
+{
+	struct mdio_device *mdiodev = usb3->mdiodev;
+
+	return mdiobus_write(mdiodev->bus, mdiodev->addr, reg, value);
+}
+
+static int bcm_ns_usb3_mdio_probe(struct mdio_device *mdiodev)
+{
+	struct device *dev = &mdiodev->dev;
+	const struct of_device_id *of_id;
+	struct phy_provider *phy_provider;
+	struct device_node *syscon_np;
+	struct bcm_ns_usb3 *usb3;
+	struct resource res;
+	int err;
+
+	usb3 = devm_kzalloc(dev, sizeof(*usb3), GFP_KERNEL);
+	if (!usb3)
+		return -ENOMEM;
+
+	usb3->dev = dev;
+	usb3->mdiodev = mdiodev;
+
+	of_id = of_match_device(bcm_ns_usb3_id_table, dev);
+	if (!of_id)
+		return -EINVAL;
+	usb3->family = (enum bcm_ns_family)of_id->data;
+
+	syscon_np = of_parse_phandle(dev->of_node, "usb3-dmp-syscon", 0);
+	err = of_address_to_resource(syscon_np, 0, &res);
+	of_node_put(syscon_np);
+	if (err)
+		return err;
+
+	usb3->dmp = devm_ioremap_resource(dev, &res);
+	if (IS_ERR(usb3->dmp)) {
+		dev_err(dev, "Failed to map DMP regs\n");
+		return PTR_ERR(usb3->dmp);
+	}
+
+	usb3->phy_write = bcm_ns_usb3_mdiodev_phy_write;
+
+	usb3->phy = devm_phy_create(dev, NULL, &ops);
+	if (IS_ERR(usb3->phy)) {
+		dev_err(dev, "Failed to create PHY\n");
+		return PTR_ERR(usb3->phy);
+	}
+
+	phy_set_drvdata(usb3->phy, usb3);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct mdio_driver bcm_ns_usb3_mdio_driver = {
+	.mdiodrv = {
+		.driver = {
+			.name = "bcm_ns_mdio_usb3",
+			.of_match_table = bcm_ns_usb3_id_table,
+		},
+	},
+	.probe = bcm_ns_usb3_mdio_probe,
+};
+
+/**************************************************
  * Platform driver code
  **************************************************/
 
@@ -297,6 +371,28 @@ static struct platform_driver bcm_ns_usb3_driver = {
 		.of_match_table = bcm_ns_usb3_id_table,
 	},
 };
-module_platform_driver(bcm_ns_usb3_driver);
+
+static int __init bcm_ns_usb3_module_init(void)
+{
+	int err;
+
+	err = mdio_driver_register(&bcm_ns_usb3_mdio_driver);
+	if (err)
+		return err;
+
+	err = platform_driver_register(&bcm_ns_usb3_driver);
+	if (err)
+		mdio_driver_unregister(&bcm_ns_usb3_mdio_driver);
+
+	return err;
+}
+module_init(bcm_ns_usb3_module_init);
+
+static void __exit bcm_ns_usb3_module_exit(void)
+{
+	platform_driver_unregister(&bcm_ns_usb3_driver);
+	mdio_driver_unregister(&bcm_ns_usb3_mdio_driver);
+}
+module_exit(bcm_ns_usb3_module_exit)
 
 MODULE_LICENSE("GPL v2");
-- 
2.11.0