[net-next RFC PATCH 08/14] net: phy: add support for PHY package interface mode

[Christian Marangi <ansuelsmth@gmail.com>]

Some PHY in PHY package supports running only at a specific mode for
each PHY in the package. Add support for enforcing this special thing a
verify consistency with the requested mode to prevent misconfiguration.

To set the PHY package mode, simply set "phy-mode" in the phy-package
node. Each PHY on init will verify if the requested mode match the one
set for the PHY package and will return -EINVAL if this is not true.

If PHY package doesn't specify any mode, it's assumed that PHY in the
package doesn't have such limitation.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/phy/phy_device.c | 37 ++++++++++++++++++++++++++++++++++++
 include/linux/phy.h          |  6 ++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 0b7ba6995929..73af4197a7af 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -25,6 +25,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_net.h>
 #include <linux/netdevice.h>
 #include <linux/phy.h>
 #include <linux/phylib_stubs.h>
@@ -1225,8 +1226,17 @@ static int phy_poll_reset(struct phy_device *phydev)
 
 int phy_init_hw(struct phy_device *phydev)
 {
+	phy_interface_t package_interface;
 	int ret = 0;
 
+	/* Validate we are requesting consistent mode if we
+	 * are in a PHY package and the PHY package requires a
+	 * specific mode.
+	 */
+	ret = phy_package_get_mode(phydev, &package_interface);
+	if (!ret && phydev->interface != package_interface)
+		return -EINVAL;
+
 	/* Deassert the reset signal */
 	phy_device_reset(phydev, 0);
 
@@ -1776,6 +1786,32 @@ void phy_package_leave(struct phy_device *phydev)
 }
 EXPORT_SYMBOL_GPL(phy_package_leave);
 
+/**
+ * phy_package_get_mode - get PHY interface mode for PHY package
+ * @phydev: target phy_device struct
+ * @interface: phy_interface_t pointer where to save the PHY package mode
+ *
+ * Gets PHY interface mode for the shared data of the PHY package.
+ * Returns 0 and updates @interface with the PHY package value, or -ENODEV
+ * if PHY is not in PHY package or -EINVAL if a PHY package interface mode
+ * is not set.
+ */
+int phy_package_get_mode(struct phy_device *phydev, phy_interface_t *interface)
+{
+	struct phy_package_shared *shared = phydev->shared;
+
+	if (!shared)
+		return -ENODEV;
+
+	if (shared->package_interface == PHY_INTERFACE_MODE_NA)
+		return -EINVAL;
+
+	*interface = shared->package_interface;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(phy_package_get_mode);
+
 static void devm_phy_package_leave(struct device *dev, void *res)
 {
 	phy_package_leave(*(struct phy_device **)res);
@@ -3270,6 +3306,7 @@ static int of_phy_package(struct phy_device *phydev)
 		goto exit;
 
 	phydev->shared->np = package_node;
+	of_get_phy_mode(package_node, &phydev->shared->package_interface);
 
 exit:
 	kfree(global_phy_addrs);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 1849fc637196..8af0a8a72b88 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -341,6 +341,11 @@ struct mdio_bus_stats {
 struct phy_package_shared {
 	/* With PHY package defined in DT this points to the PHY package node */
 	struct device_node *np;
+	/* PHY package interface
+	 * If defined, each PHY of the package MUST have the interface
+	 * set to the PHY package.
+	 */
+	phy_interface_t package_interface;
 	/* addrs list pointer */
 	/* note that this pointer is shared between different phydevs.
 	 * It is allocated and freed automatically by phy_package_join() and
@@ -2014,6 +2019,7 @@ int phy_ethtool_nway_reset(struct net_device *ndev);
 int phy_package_join(struct phy_device *phydev, int *addrs, size_t addrs_num,
 		     size_t priv_size);
 void phy_package_leave(struct phy_device *phydev);
+int phy_package_get_mode(struct phy_device *phydev, phy_interface_t *interface);
 int devm_phy_package_join(struct device *dev, struct phy_device *phydev,
 			  int *addrs, size_t addrs_num, size_t priv_size);
 
-- 
2.40.1