+    fn read_status(dev: &mut phy::Device) -> Result<u16> {
+        dev.genphy_read_status::<C22>()?;
+
+        let val = dev.read(ET1011C_STATUS_REG)?;
+        if (val & ET1011C_SPEED_MASK) == ET1011C_GIGABIT_SPEED {
+            let cfg = dev.read(ET1011C_CONFIG_REG)?;
+            let cfg = cfg & !ET1011C_TX_FIFO_MASK;
+            dev.write(
+                ET1011C_CONFIG_REG,
+                cfg | ET1011C_GMII_INTERFACE | ET1011C_SYS_CLK_EN | ET1011C_TX_FIFO_DEPTH_16,
+            )?;
+        }

This is not the same as the C code. read_status() will be called once
per second. The C code only does the read/modify/write when the speed
reported by genphy_read_status() is different to the previous
value. This code appears to do it every second.

       Andrew