rust: net::phy unified genphy_read_status function for C22 and C45 registers

Add unified genphy_read_status function for C22 and C45
registers. Instead of having genphy_c22 and genphy_c45 methods, this
unifies genphy_read_status functions for C22 and C45.
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rust/kernel/net/phy.rs

@@ -252,16 +252,8 @@ pub fn genphy_suspend(&mut self) -> Result {
     }
 
     /// Checks the link status and updates current link state.
-    pub fn genphy_read_status(&mut self) -> Result<u16> {
-        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::genphy_read_status(phydev) };
-        if ret < 0 {
-            Err(Error::from_errno(ret))
-        } else {
-            Ok(ret as u16)
-        }
+    pub fn genphy_read_status<R: reg::Register>(&mut self) -> Result<u16> {
+        R::read_status(self)
     }
 
     /// Updates the link status.

rust/kernel/net/phy/reg.rs

@@ -31,6 +31,13 @@ pub trait Sealed {}
 ///     dev.read(C22::BMCR);
 ///     // read C45 PMA/PMD control 1 register
 ///     dev.read(C45::new(Mmd::PMAPMD, 0));
+///
+///     // Checks the link status as reported by registers in the C22 namespace
+///     // and updates current link state.
+///     dev.genphy_read_status::<phy::C22>();
+///     // Checks the link status as reported by registers in the C45 namespace
+///     // and updates current link state.
+///     dev.genphy_read_status::<phy::C45>();
 /// }
 /// ```
 pub trait Register: private::Sealed {
@@ -39,6 +46,9 @@ pub trait Register: private::Sealed {
 
     /// Writes a PHY register.
     fn write(&self, dev: &mut Device, val: u16) -> Result;
+
+    /// Checks the link status and updates current link state.
+    fn read_status(dev: &mut Device) -> Result<u16>;
 }
 
 /// A single MDIO clause 22 register address (5 bits).
@@ -113,6 +123,15 @@ fn write(&self, dev: &mut Device, val: u16) -> Result {
             bindings::mdiobus_write((*phydev).mdio.bus, (*phydev).mdio.addr, self.0.into(), val)
         })
     }
+
+    fn read_status(dev: &mut Device) -> Result<u16> {
+        let phydev = dev.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::genphy_read_status(phydev) };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
 }
 
 /// A single MDIO clause 45 register device and address.
@@ -193,4 +212,13 @@ fn write(&self, dev: &mut Device, val: u16) -> Result {
             bindings::phy_write_mmd(phydev, self.devad.0.into(), self.regnum.into(), val)
         })
     }
+
+    fn read_status(dev: &mut Device) -> Result<u16> {
+        let phydev = dev.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::genphy_c45_read_status(phydev) };
+        to_result(ret)?;
+        Ok(ret as u16)
+    }
 }