net: phy: add phy_speed_down and phy_speed_up

Some network drivers include functionality to speed down the PHY when
suspending and just waiting for a WoL packet because this saves energy.
This functionality is quite generic, therefore let's factor it out to
phylib.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index c4aa360dedff20a55f24e2008aea033fc24f50b3..d2baedc4ea91fb6f7221984e1e54b7d7f94b20de 100644 (file)
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -551,6 +551,84 @@ int phy_start_aneg(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_start_aneg);
 
+static int phy_poll_aneg_done(struct phy_device *phydev)
+{
+       unsigned int retries = 100;
+       int ret;
+
+       do {
+               msleep(100);
+               ret = phy_aneg_done(phydev);
+       } while (!ret && --retries);
+
+       if (!ret)
+               return -ETIMEDOUT;
+
+       return ret < 0 ? ret : 0;
+}
+
+/**
+ * phy_speed_down - set speed to lowest speed supported by both link partners
+ * @phydev: the phy_device struct
+ * @sync: perform action synchronously
+ *
+ * Description: Typically used to save energy when waiting for a WoL packet
+ *
+ * WARNING: Setting sync to false may cause the system being unable to suspend
+ * in case the PHY generates an interrupt when finishing the autonegotiation.
+ * This interrupt may wake up the system immediately after suspend.
+ * Therefore use sync = false only if you're sure it's safe with the respective
+ * network chip.
+ */
+int phy_speed_down(struct phy_device *phydev, bool sync)
+{
+       u32 adv = phydev->lp_advertising & phydev->supported;
+       u32 adv_old = phydev->advertising;
+       int ret;
+
+       if (phydev->autoneg != AUTONEG_ENABLE)
+               return 0;
+
+       if (adv & PHY_10BT_FEATURES)
+               phydev->advertising &= ~(PHY_100BT_FEATURES |
+                                        PHY_1000BT_FEATURES);
+       else if (adv & PHY_100BT_FEATURES)
+               phydev->advertising &= ~PHY_1000BT_FEATURES;
+
+       if (phydev->advertising == adv_old)
+               return 0;
+
+       ret = phy_config_aneg(phydev);
+       if (ret)
+               return ret;
+
+       return sync ? phy_poll_aneg_done(phydev) : 0;
+}
+EXPORT_SYMBOL_GPL(phy_speed_down);
+
+/**
+ * phy_speed_up - (re)set advertised speeds to all supported speeds
+ * @phydev: the phy_device struct
+ *
+ * Description: Used to revert the effect of phy_speed_down
+ */
+int phy_speed_up(struct phy_device *phydev)
+{
+       u32 mask = PHY_10BT_FEATURES | PHY_100BT_FEATURES | PHY_1000BT_FEATURES;
+       u32 adv_old = phydev->advertising;
+
+       if (phydev->autoneg != AUTONEG_ENABLE)
+               return 0;
+
+       phydev->advertising = (adv_old & ~mask) | (phydev->supported & mask);
+
+       if (phydev->advertising == adv_old)
+               return 0;
+
+       return phy_config_aneg(phydev);
+}
+EXPORT_SYMBOL_GPL(phy_speed_up);
+
 /**
  * phy_start_machine - start PHY state machine tracking
  * @phydev: the phy_device struct

diff --git a/include/linux/phy.h b/include/linux/phy.h
index 6cd09098427c5bcd93d58f1d842165c2b9ffe7c0..075c2f770d3ef098b39dd8d0746416382d1d36ce 100644 (file)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -942,6 +942,8 @@ void phy_start(struct phy_device *phydev);
 void phy_stop(struct phy_device *phydev);
 int phy_start_aneg(struct phy_device *phydev);
 int phy_aneg_done(struct phy_device *phydev);
+int phy_speed_down(struct phy_device *phydev, bool sync);
+int phy_speed_up(struct phy_device *phydev);
 
 int phy_stop_interrupts(struct phy_device *phydev);
 int phy_restart_aneg(struct phy_device *phydev);