[PATCH 2/4] rust: phy: add paged register access and bit manipulation helpers
From: Artem Lytkin <hidden>
Date: 2026-03-23 20:19:51
Also in:
rust-for-linux
Subsystem:
ethernet phy library [rust], rust, the rest · Maintainers:
FUJITA Tomonori, Miguel Ojeda, Linus Torvalds
Add Device methods for register manipulation beyond simple read/write:
- write_paged(): Writes a register on a specific page, completing
the paged access surface (read_paged already existed upstream).
Wraps phy_write_paged().
- modify() / modify_paged(): Atomic read-modify-write operations
that clear bits in mask and set bits in set. Wraps phy_modify()
and phy_modify_paged(). These return Result (not the old register
value) since the C functions return 0 on success.
- set_bits() / clear_bits(): Convenience wrappers around modify()
for the common case of setting or clearing specific bits.
These helpers are heavily used by real-world PHY drivers for
configuring vendor-specific registers without races.
Signed-off-by: Artem Lytkin <redacted>
---
rust/kernel/net/phy.rs | 43 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs
index 646b2a78a2710..43d1ee360268b 100644
--- a/rust/kernel/net/phy.rs
+++ b/rust/kernel/net/phy.rs@@ -241,6 +241,49 @@ pub fn read_paged(&mut self, page: u16, regnum: u16) -> Result<u16> { to_result(ret).map(|()| ret as u16) } + /// Writes a paged register. + pub fn write_paged(&mut self, page: u16, regnum: u16, val: u16) -> Result { + let phydev = self.0.get(); + // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`. + // So it's just an FFI call. + let ret = + unsafe { bindings::phy_write_paged(phydev, page.into(), regnum.into(), val) }; + + to_result(ret) + } + + /// Performs a read-modify-write on a PHY register. + /// + /// Clears the bits set in `mask` and sets the bits in `set`. + pub fn modify(&mut self, regnum: u16, mask: u16, set: u16) -> Result { + let phydev = self.0.get(); + // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`. + // So it's just an FFI call. + to_result(unsafe { bindings::phy_modify(phydev, regnum.into(), mask, set) }) + } + + /// Performs a read-modify-write on a paged PHY register. + /// + /// Selects the page, performs the modify, and restores the original page. + pub fn modify_paged(&mut self, page: u16, regnum: u16, mask: u16, set: u16) -> Result { + let phydev = self.0.get(); + // SAFETY: `phydev` is pointing to a valid object by the type invariant of `Self`. + // So it's just an FFI call. + to_result(unsafe { + bindings::phy_modify_paged(phydev, page.into(), regnum.into(), mask, set) + }) + } + + /// Sets bits in a PHY register. + pub fn set_bits(&mut self, regnum: u16, val: u16) -> Result { + self.modify(regnum, 0, val) + } + + /// Clears bits in a PHY register. + pub fn clear_bits(&mut self, regnum: u16, val: u16) -> Result { + self.modify(regnum, val, 0) + } + /// Resolves the advertisements into PHY settings. pub fn resolve_aneg_linkmode(&mut self) { let phydev = self.0.get();
--
2.43.0