[PATCH RFCv2 5/6] net: phy: suspend unused PHYs on mdio_bus in late_initcall

[Sebastian Hesselbarth]

Since phy_attach ensures PHYs are resumed, we can now suspend all
PHYs that have no attached netdev after initcalls.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth at gmail.com>
---
Changelog:
RFCv1->RFCv2:
- only check for phydev->attached_dev and let phy_suspend decide on
  performing suspend or not (Suggested by Florian)

@Florian: You suggested to 'make sure that the MDIO bus suspend policy
was set to "auto"'. I wasn't able to find any clue how to check that,
so I ignored that for now.

Cc: David Miller <davem at davemloft.net>
Cc: Florian Fainelli <f.fainelli at gmail.com>
Cc: Mugunthan V N <mugunthanvnm at ti.com>
Cc: netdev at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
---
 drivers/net/phy/mdio_bus.c |   25 +++++++++++++++++++++++++
 1 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 5617876..f533d17 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -320,6 +320,31 @@ static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 		(phydev->phy_id & phydrv->phy_id_mask));
 }
 
+static int mdio_bus_suspend_unused(struct device *busdev, void *data)
+{
+	struct mii_bus *bus = to_mii_bus(busdev);
+	struct phy_device *phydev;
+	int i;
+
+	for (i = 0; i < PHY_MAX_ADDR; i++) {
+		if (!bus->phy_map[i])
+			continue;
+
+		phydev = to_phy_device(&bus->phy_map[i]->dev);
+		if (!phydev->attached_dev)
+			phy_suspend(phydev);
+	}
+
+	return 0;
+}
+
+static int mdio_bus_class_suspend_unused(void)
+{
+	return class_for_each_device(&mdio_bus_class, NULL, NULL,
+				     mdio_bus_suspend_unused);
+}
+late_initcall_sync(mdio_bus_class_suspend_unused);
+
 #ifdef CONFIG_PM
 
 static bool mdio_bus_phy_may_suspend(struct phy_device *phydev)
-- 
1.7.2.5