phy: power management support

This patch adds the power management support into the physical
abstraction layer.

Suspend and resume functions respectively turns on/off the bit 11
into the PHY Basic mode control register.
Generic PHY device starts supporting PM.

In order to support the wake-on LAN and avoid to put in power down
the PHY device, the MDIO is aware of what the Ethernet device wants to do.

Voluntary, no CONFIG_PM defines were added into the sources.
Also generic suspend/resume functions are exported to allow
other drivers use them (such as genphy_config_aneg etc.).

Within the phy_driver_register function, we need to remove the
memset. It overrides the device driver owner and it is not good.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 42 insertions, 5 deletions

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 868812ff6de8..8755d8cd4166 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -284,9 +284,12 @@ static int mdio_bus_suspend(struct device * dev, pm_message_t state)
 {
         int ret = 0;
         struct device_driver *drv = dev->driver;
+        struct phy_driver *phydrv = to_phy_driver(drv);
+        struct phy_device *phydev = to_phy_device(dev);
 
-        if (drv && drv->suspend)
-                ret = drv->suspend(dev, state);
+        if ((!device_may_wakeup(phydev->dev.parent)) &&
+                (phydrv && phydrv->suspend))
+                        ret = phydrv->suspend(phydev);
 
         return ret;
 }
@@ -295,9 +298,12 @@ static int mdio_bus_resume(struct device * dev)
 {
         int ret = 0;
         struct device_driver *drv = dev->driver;
+        struct phy_driver *phydrv = to_phy_driver(drv);
+        struct phy_device *phydev = to_phy_device(dev);
 
-        if (drv && drv->resume)
-                ret = drv->resume(dev);
+        if ((!device_may_wakeup(phydev->dev.parent)) &&
+                (phydrv && phydrv->resume))
+                ret = phydrv->resume(phydev);
 
         return ret;
 }
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 29546a206045..4cc75a290c06 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -779,7 +779,35 @@ static int genphy_config_init(struct phy_device *phydev)
 
         return 0;
 }
+int genphy_suspend(struct phy_device *phydev)
+{
+        int value;
+
+        mutex_lock(&phydev->lock);
+
+        value = phy_read(phydev, MII_BMCR);
+        phy_write(phydev, MII_BMCR, (value | BMCR_PDOWN));
+
+        mutex_unlock(&phydev->lock);
+
+        return 0;
+}
+EXPORT_SYMBOL(genphy_suspend);
 
+int genphy_resume(struct phy_device *phydev)
+{
+        int value;
+
+        mutex_lock(&phydev->lock);
+
+        value = phy_read(phydev, MII_BMCR);
+        phy_write(phydev, MII_BMCR, (value & ~BMCR_PDOWN));
+
+        mutex_unlock(&phydev->lock);
+
+        return 0;
+}
+EXPORT_SYMBOL(genphy_resume);
 
 /**
  * phy_probe - probe and init a PHY device
@@ -855,7 +883,6 @@ int phy_driver_register(struct phy_driver *new_driver)
 {
         int retval;
 
-        memset(&new_driver->driver, 0, sizeof(new_driver->driver));
         new_driver->driver.name = new_driver->name;
         new_driver->driver.bus = &mdio_bus_type;
         new_driver->driver.probe = phy_probe;
@@ -890,6 +917,8 @@ static struct phy_driver genphy_driver = {
         .features       = 0,
         .config_aneg    = genphy_config_aneg,
         .read_status    = genphy_read_status,
+        .suspend        = genphy_suspend,
+        .resume         = genphy_resume,
         .driver         = {.owner= THIS_MODULE, },
 };
 
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 77c4ed60b982..d7e54d98869f 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -467,6 +467,8 @@ int genphy_restart_aneg(struct phy_device *phydev);
 int genphy_config_aneg(struct phy_device *phydev);
 int genphy_update_link(struct phy_device *phydev);
 int genphy_read_status(struct phy_device *phydev);
+int genphy_suspend(struct phy_device *phydev);
+int genphy_resume(struct phy_device *phydev);
 void phy_driver_unregister(struct phy_driver *drv);
 int phy_driver_register(struct phy_driver *new_driver);
 void phy_prepare_link(struct phy_device *phydev,