[RFC/RFT 03/23] net: phy: Add helper to set EEE Clock stop enable bit

[Andrew Lunn <andrew@lunn.ch>]

The MAC driver can request that the PHY stops the clock during EEE
LPI. This has normally been does as part of phy_init_eee(), however
that function is overly complex and often wrongly used. Add a
standalone helper, to aid removing phy_init_eee().

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
---
v2: Add missing EXPORT_SYMBOL_GPL
---
 drivers/net/phy/phy.c | 20 ++++++++++++++++++++
 include/linux/phy.h   |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 68e1ce942dd6..d3d6ff4ed488 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -1503,6 +1503,26 @@ void phy_mac_interrupt(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_mac_interrupt);
 
+/**
+ * phy_eee_clk_stop_enable - Clock should stop during LIP
+ * @phydev: target phy_device struct
+ *
+ * Description: Program the MMD register 3.0 setting the "Clock stop enable"
+ * bit.
+ */
+int phy_eee_clk_stop_enable(struct phy_device *phydev)
+{
+	int ret;
+
+	mutex_lock(&phydev->lock);
+	ret = phy_set_bits_mmd(phydev, MDIO_MMD_PCS, MDIO_CTRL1,
+			       MDIO_PCS_CTRL1_CLKSTOP_EN);
+	mutex_unlock(&phydev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_eee_clk_stop_enable);
+
 /**
  * phy_init_eee - init and check the EEE feature
  * @phydev: target phy_device struct
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 2508f1d99777..12addd1c29f2 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1846,6 +1846,7 @@ int phy_unregister_fixup_for_id(const char *bus_id);
 int phy_unregister_fixup_for_uid(u32 phy_uid, u32 phy_uid_mask);
 
 int phy_init_eee(struct phy_device *phydev, bool clk_stop_enable);
+int phy_eee_clk_stop_enable(struct phy_device *phydev);
 int phy_get_eee_err(struct phy_device *phydev);
 int phy_ethtool_set_eee(struct phy_device *phydev, struct ethtool_eee *data);
 int phy_ethtool_get_eee(struct phy_device *phydev, struct ethtool_eee *data);
-- 
2.39.2