linux-kernel - [PATCH RFC net-next v2 3/8] net: phy: add error checks in __phy_mmd

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Date:   Fri, 25 Mar 2022 22:35:13 +0100
From:   Michael Walle <michael@...le.cc>
To:     Andrew Lunn <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        Russell King <linux@...linux.org.uk>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     "David S . Miller" <davem@...emloft.net>,
        Xu Liang <lxu@...linear.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        Michael Walle <michael@...le.cc>
Subject: [PATCH RFC net-next v2 3/8] net: phy: add error checks in __phy_mmd_indirect() and export it

Add missing error checks and export it so it can be reused. Rename the
function to have the common "phy_" prefix.

Signed-off-by: Michael Walle <michael@...le.cc>
---
 drivers/net/phy/phy-core.c | 34 ++++++++++++++++++++++++++--------
 include/linux/phy.h        |  2 ++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 2001f3329133..dd9b6b64757d 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -437,19 +437,37 @@ int phy_speed_down_core(struct phy_device *phydev)
 	return 0;
 }
 
-static void mmd_phy_indirect(struct mii_bus *bus, int phy_addr, int devad,
-			     u16 regnum)
+/**
+ * __phy_mmd_indirect - prepare an indirect C45 register access
+ *
+ * @bus: the target MII bus
+ * @phy_addr: PHY address on the MII bus
+ * @devad: The target MMD (0..31)
+ * @regnum: The target register on the MMD (0..65535)
+ *
+ * Prepare an indirect C45 read or write transfer using the MII_MMD_CTRL and
+ * MII_MMD_DATA registers in C22 space.
+ */
+int __phy_mmd_indirect(struct mii_bus *bus, int phy_addr, int devad,
+		       u16 regnum)
 {
+	int ret;
+
 	/* Write the desired MMD Devad */
-	__mdiobus_write(bus, phy_addr, MII_MMD_CTRL, devad);
+	ret = __mdiobus_write(bus, phy_addr, MII_MMD_CTRL, devad);
+	if (ret)
+		return ret;
 
 	/* Write the desired MMD register address */
-	__mdiobus_write(bus, phy_addr, MII_MMD_DATA, regnum);
+	ret = __mdiobus_write(bus, phy_addr, MII_MMD_DATA, regnum);
+	if (ret)
+		return ret;
 
 	/* Select the Function : DATA with no post increment */
-	__mdiobus_write(bus, phy_addr, MII_MMD_CTRL,
-			devad | MII_MMD_CTRL_NOINCR);
+	return __mdiobus_write(bus, phy_addr, MII_MMD_CTRL,
+			       devad | MII_MMD_CTRL_NOINCR);
 }
+EXPORT_SYMBOL(__phy_mmd_indirect);
 
 /**
  * __phy_read_mmd - Convenience function for reading a register
@@ -476,7 +494,7 @@ int __phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum)
 		struct mii_bus *bus = phydev->mdio.bus;
 		int phy_addr = phydev->mdio.addr;
 
-		mmd_phy_indirect(bus, phy_addr, devad, regnum);
+		__phy_mmd_indirect(bus, phy_addr, devad, regnum);
 
 		/* Read the content of the MMD's selected register */
 		val = __mdiobus_read(bus, phy_addr, MII_MMD_DATA);
@@ -532,7 +550,7 @@ int __phy_write_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val)
 		struct mii_bus *bus = phydev->mdio.bus;
 		int phy_addr = phydev->mdio.addr;
 
-		mmd_phy_indirect(bus, phy_addr, devad, regnum);
+		__phy_mmd_indirect(bus, phy_addr, devad, regnum);
 
 		/* Write the data into MMD's selected register */
 		__mdiobus_write(bus, phy_addr, MII_MMD_DATA, val);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 36ca2b5c2253..c81c209d4abd 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -1110,6 +1110,8 @@ int phy_read_mmd(struct phy_device *phydev, int devad, u32 regnum);
 	__ret; \
 })
 
+int __phy_mmd_indirect(struct mii_bus *bus, int phy_addr, int devad,
+		       u16 regnum);
 /*
  * __phy_read_mmd - Convenience function for reading a register
  * from an MMD on a given PHY.
-- 
2.30.2