netdev - [RFC/RFTv3 03/24] net: phy: Add helper to set EEE Clock stop enable bit

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Date:   Fri, 31 Mar 2023 02:54:57 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     netdev <netdev@...r.kernel.org>
Cc:     Florian Fainelli <f.fainelli@...il.com>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <rmk+kernel@...linux.org.uk>,
        Oleksij Rempel <linux@...pel-privat.de>,
        Andrew Lunn <andrew@...n.ch>
Subject: [RFC/RFTv3 03/24] net: phy: Add helper to set EEE Clock stop enable bit

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(). The helper
currently calls generic code, but it could in the future call a PHY
specific op if a PHY exports different registers to 802.3.

Signed-off-by: Andrew Lunn <andrew@...n.ch>
---
v2: Add missing EXPORT_SYMBOL_GPL
v3: Move register access into phy-c45.c
---
 drivers/net/phy/phy-c45.c | 24 ++++++++++++++++++++++++
 drivers/net/phy/phy.c     | 19 +++++++++++++++++++
 include/linux/phy.h       |  2 ++
 include/uapi/linux/mdio.h |  1 +
 4 files changed, 46 insertions(+)

diff --git a/drivers/net/phy/phy-c45.c b/drivers/net/phy/phy-c45.c
index fee514b96ab1..29479e142826 100644
--- a/drivers/net/phy/phy-c45.c
+++ b/drivers/net/phy/phy-c45.c
@@ -1386,6 +1386,30 @@ int genphy_c45_eee_is_active(struct phy_device *phydev, unsigned long *adv,
 }
 EXPORT_SYMBOL(genphy_c45_eee_is_active);
 
+/**
+ * genphy_c45_eee_clk_stop_enable - Clock should stop during LPI signalling
+ * @phydev: target phy_device struct
+ *
+ * Description: Program the MMD register 3.0 setting the "Clock stop enable"
+ * bit.
+ */
+int genphy_c45_eee_clk_stop_enable(struct phy_device *phydev)
+{
+	int ret;
+
+	/* IEEE 802.3:2018 - 45.2.3.2.6 Clock stop capable (3.1.6) */
+	ret = phy_read_mmd(phydev, MDIO_MMD_PCS, MDIO_STAT1);
+	if (ret < 0)
+		return ret;
+
+	if (ret & MDIO_STAT1_CLKSTOP_CAPABLE)
+		/* IEEE 802.3-2018 45.2.3.1.4 Clock stop enable (3.0.10) */
+		return phy_set_bits_mmd(phydev, MDIO_MMD_PCS, MDIO_CTRL1,
+					MDIO_PCS_CTRL1_CLKSTOP_EN);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(genphy_c45_eee_clk_stop_enable);
+
 /**
  * genphy_c45_ethtool_get_eee - get EEE supported and status
  * @phydev: target phy_device struct
diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 150df69d9e08..6fc6a59d2f56 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -1573,6 +1573,25 @@ int phy_get_eee_err(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_get_eee_err);
 
+/**
+ * phy_eee_clk_stop_enable - Clock should stop during LIP
+ * @phydev: target phy_device struct
+ *
+ * Description: Program the PHY to stop the clock when EEE is
+ * signalling LPI
+ */
+int phy_eee_clk_stop_enable(struct phy_device *phydev)
+{
+	int ret;
+
+	mutex_lock(&phydev->lock);
+	ret = genphy_c45_eee_clk_stop_enable(phydev);
+	mutex_unlock(&phydev->lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_eee_clk_stop_enable);
+
 /**
  * phy_ethtool_get_eee - get EEE supported and status
  * @phydev: target phy_device struct
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 2508f1d99777..dea707b3189b 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1773,6 +1773,7 @@ int genphy_c45_ethtool_set_eee(struct phy_device *phydev,
 int genphy_c45_write_eee_adv(struct phy_device *phydev, unsigned long *adv);
 int genphy_c45_an_config_eee_aneg(struct phy_device *phydev);
 int genphy_c45_read_eee_adv(struct phy_device *phydev, unsigned long *adv);
+int genphy_c45_eee_clk_stop_enable(struct phy_device *phydev);
 
 /* Generic C45 PHY driver */
 extern struct phy_driver genphy_c45_driver;
@@ -1847,6 +1848,7 @@ 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_get_eee_err(struct phy_device *phydev);
+int phy_eee_clk_stop_enable(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);
 int phy_ethtool_set_wol(struct phy_device *phydev, struct ethtool_wolinfo *wol);
diff --git a/include/uapi/linux/mdio.h b/include/uapi/linux/mdio.h
index 256b463e47a6..e810abb1a4d3 100644
--- a/include/uapi/linux/mdio.h
+++ b/include/uapi/linux/mdio.h
@@ -121,6 +121,7 @@
 /* Status register 1. */
 #define MDIO_STAT1_LPOWERABLE		0x0002	/* Low-power ability */
 #define MDIO_STAT1_LSTATUS		BMSR_LSTATUS
+#define MDIO_STAT1_CLKSTOP_CAPABLE	0x0040	/* Clock stop capable */
 #define MDIO_STAT1_FAULT		0x0080	/* Fault */
 #define MDIO_AN_STAT1_LPABLE		0x0001	/* Link partner AN ability */
 #define MDIO_AN_STAT1_ABLE		BMSR_ANEGCAPABLE
-- 
2.40.0