[net-next PATCH v8 4/4] net: phy: add support for PHY package MMD read/write

[Christian Marangi <ansuelsmth@gmail.com>]

Some PHY in PHY package may require to read/write MMD regs to correctly
configure the PHY package.

Add support for these additional required function in both lock and no
lock variant.

It's assumed that the entire PHY package is either C22 or C45. We use
C22 or C45 way of writing/reading to mmd regs based on the passed phydev
whether it's C22 or C45.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
Changesv8:
- Use helper to validate final addr 
Changes v7:
- Change addr to u8
Changes v6:
- Fix copy paste error for kdoc
Changes v5:
- Improve function description
Changes v4:
- Drop function comments in header file
Changes v3:
- Move in phy-core.c from phy.h
- Base c45 from phydev
Changes v2:
- Rework to use newly introduced helper
- Add common check for regnum and devad

 drivers/net/phy/phy-core.c | 140 +++++++++++++++++++++++++++++++++++++
 include/linux/phy.h        |  16 +++++
 2 files changed, 156 insertions(+)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index b729ac8b2640..15f349e5995a 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -650,6 +650,146 @@ int phy_write_mmd(struct phy_device *phydev, int devad, u32 regnum, u16 val)
 }
 EXPORT_SYMBOL(phy_write_mmd);
 
+/**
+ * __phy_package_read_mmd - read MMD reg relative to PHY package base addr
+ * @phydev: The phy_device struct
+ * @addr_offset: The offset to be added to PHY package base_addr
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ *
+ * Convenience helper for reading a register of an MMD on a given PHY
+ * using the PHY package base address. The base address is added to
+ * the addr_offset value.
+ *
+ * Same calling rules as for __phy_read();
+ *
+ * NOTE: It's assumed that the entire PHY package is either C22 or C45.
+ */
+int __phy_package_read_mmd(struct phy_device *phydev,
+			   unsigned int addr_offset, int devad,
+			   u32 regnum)
+{
+	int addr = phy_package_address(phydev, addr_offset);
+
+	if (addr < 0)
+		return addr;
+
+	if (regnum > (u16)~0 || devad > 32)
+		return -EINVAL;
+
+	return mmd_phy_read(phydev->mdio.bus, addr, phydev->is_c45, devad,
+			    regnum);
+}
+EXPORT_SYMBOL(__phy_package_read_mmd);
+
+/**
+ * phy_package_read_mmd - read MMD reg relative to PHY package base addr
+ * @phydev: The phy_device struct
+ * @addr_offset: The offset to be added to PHY package base_addr
+ * @devad: The MMD to read from
+ * @regnum: The register on the MMD to read
+ *
+ * Convenience helper for reading a register of an MMD on a given PHY
+ * using the PHY package base address. The base address is added to
+ * the addr_offset value.
+ *
+ * Same calling rules as for phy_read();
+ *
+ * NOTE: It's assumed that the entire PHY package is either C22 or C45.
+ */
+int phy_package_read_mmd(struct phy_device *phydev,
+			 unsigned int addr_offset, int devad,
+			 u32 regnum)
+{
+	int addr = phy_package_address(phydev, addr_offset);
+	int val;
+
+	if (addr < 0)
+		return addr;
+
+	if (regnum > (u16)~0 || devad > 32)
+		return -EINVAL;
+
+	phy_lock_mdio_bus(phydev);
+	val = mmd_phy_read(phydev->mdio.bus, addr, phydev->is_c45, devad,
+			   regnum);
+	phy_unlock_mdio_bus(phydev);
+
+	return val;
+}
+EXPORT_SYMBOL(phy_package_read_mmd);
+
+/**
+ * __phy_package_write_mmd - write MMD reg relative to PHY package base addr
+ * @phydev: The phy_device struct
+ * @addr_offset: The offset to be added to PHY package base_addr
+ * @devad: The MMD to write to
+ * @regnum: The register on the MMD to write
+ * @val: value to write to @regnum
+ *
+ * Convenience helper for writing a register of an MMD on a given PHY
+ * using the PHY package base address. The base address is added to
+ * the addr_offset value.
+ *
+ * Same calling rules as for __phy_write();
+ *
+ * NOTE: It's assumed that the entire PHY package is either C22 or C45.
+ */
+int __phy_package_write_mmd(struct phy_device *phydev,
+			    unsigned int addr_offset, int devad,
+			    u32 regnum, u16 val)
+{
+	int addr = phy_package_address(phydev, addr_offset);
+
+	if (addr < 0)
+		return addr;
+
+	if (regnum > (u16)~0 || devad > 32)
+		return -EINVAL;
+
+	return mmd_phy_write(phydev->mdio.bus, addr, phydev->is_c45, devad,
+			     regnum, val);
+}
+EXPORT_SYMBOL(__phy_package_write_mmd);
+
+/**
+ * phy_package_write_mmd - write MMD reg relative to PHY package base addr
+ * @phydev: The phy_device struct
+ * @addr_offset: The offset to be added to PHY package base_addr
+ * @devad: The MMD to write to
+ * @regnum: The register on the MMD to write
+ * @val: value to write to @regnum
+ *
+ * Convenience helper for writing a register of an MMD on a given PHY
+ * using the PHY package base address. The base address is added to
+ * the addr_offset value.
+ *
+ * Same calling rules as for phy_write();
+ *
+ * NOTE: It's assumed that the entire PHY package is either C22 or C45.
+ */
+int phy_package_write_mmd(struct phy_device *phydev,
+			  unsigned int addr_offset, int devad,
+			  u32 regnum, u16 val)
+{
+	int addr = phy_package_address(phydev, addr_offset);
+	int ret;
+
+	if (addr < 0)
+		return addr;
+
+	if (regnum > (u16)~0 || devad > 32)
+		return -EINVAL;
+
+	phy_lock_mdio_bus(phydev);
+	ret = mmd_phy_write(phydev->mdio.bus, addr, phydev->is_c45, devad,
+			    regnum, val);
+	phy_unlock_mdio_bus(phydev);
+
+	return ret;
+}
+EXPORT_SYMBOL(phy_package_write_mmd);
+
 /**
  * phy_modify_changed - Function for modifying a PHY register
  * @phydev: the phy_device struct
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 85fdba43b813..191762d89ed8 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2060,6 +2060,22 @@ static inline int __phy_package_write(struct phy_device *phydev,
 	return __mdiobus_write(phydev->mdio.bus, addr, regnum, val);
 }
 
+int __phy_package_read_mmd(struct phy_device *phydev,
+			   unsigned int addr_offset, int devad,
+			   u32 regnum);
+
+int phy_package_read_mmd(struct phy_device *phydev,
+			 unsigned int addr_offset, int devad,
+			 u32 regnum);
+
+int __phy_package_write_mmd(struct phy_device *phydev,
+			    unsigned int addr_offset, int devad,
+			    u32 regnum, u16 val);
+
+int phy_package_write_mmd(struct phy_device *phydev,
+			  unsigned int addr_offset, int devad,
+			  u32 regnum, u16 val);
+
 static inline bool __phy_package_set_once(struct phy_device *phydev,
 					  unsigned int b)
 {
-- 
2.40.1