[PATCH net-next v3 2/2] net: phy: add Rust reference driver for ET1011C

[Artem Lytkin <iprintercanon@gmail.com>]

Add a Rust reference driver for the LSI ET1011C PHY, following the
pattern established by the existing Rust Asix PHY driver
(ax88796b_rust.rs).

Unlike the C driver which uses a custom config_aneg that manually
clears BMCR bits and writes BMCR_RESET without polling, this driver
uses the soft_reset callback with genphy_soft_reset(). This properly
polls the self-clearing BMCR_RESET bit and handles both autoneg and
forced mode, following current best practices.

The read_status callback detects speed changes and reconfigures the
GMII interface and TX FIFO when switching to gigabit, matching the C
driver's functionality.

Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
---
 drivers/net/phy/Kconfig         |  9 +++++
 drivers/net/phy/Makefile        |  6 ++-
 drivers/net/phy/et1011c_rust.rs | 69 +++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/phy/et1011c_rust.rs

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 7b73332a13d9..41abf13662e6 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -254,6 +254,15 @@ config LSI_ET1011C_PHY
 	help
 	  Supports the LSI ET1011C PHY.
 
+config ET1011C_RUST_PHY
+	bool "Rust reference driver for LSI ET1011C PHY"
+	depends on RUST_PHYLIB_ABSTRACTIONS && LSI_ET1011C_PHY
+	help
+	  Uses the Rust reference driver for LSI ET1011C PHY
+	  (et1011c_rust.ko). The features are equivalent.
+	  It supports the LSI ET1011C PHY. If unsure,
+	  say N.
+
 config MARVELL_PHY
 	tristate "Marvell Alaska PHYs"
 	help
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 3a34917adea7..491469457a67 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -62,7 +62,11 @@ obj-$(CONFIG_DP83TG720_PHY)	+= dp83tg720.o
 obj-$(CONFIG_FIXED_PHY)		+= fixed_phy.o
 obj-$(CONFIG_ICPLUS_PHY)	+= icplus.o
 obj-$(CONFIG_INTEL_XWAY_PHY)	+= intel-xway.o
-obj-$(CONFIG_LSI_ET1011C_PHY)	+= et1011c.o
+ifdef CONFIG_ET1011C_RUST_PHY
+  obj-$(CONFIG_LSI_ET1011C_PHY)	+= et1011c_rust.o
+else
+  obj-$(CONFIG_LSI_ET1011C_PHY)	+= et1011c.o
+endif
 obj-$(CONFIG_LXT_PHY)		+= lxt.o
 obj-$(CONFIG_MARVELL_10G_PHY)	+= marvell10g.o
 obj-$(CONFIG_MARVELL_PHY)	+= marvell.o
diff --git a/drivers/net/phy/et1011c_rust.rs b/drivers/net/phy/et1011c_rust.rs
new file mode 100644
index 000000000000..93dbf9586da3
--- /dev/null
+++ b/drivers/net/phy/et1011c_rust.rs
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright (C) 2026 Artem Lytkin <iprintercanon@gmail.com>
+
+//! Rust LSI ET1011C PHY driver
+//!
+//! C version of this driver: [`drivers/net/phy/et1011c.c`](./et1011c.c)
+
+use kernel::{
+    net::phy::{self, reg::C22, DeviceId, Driver},
+    prelude::*,
+};
+
+kernel::module_phy_driver! {
+    drivers: [PhyET1011C],
+    device_table: [
+        DeviceId::new_with_driver::<PhyET1011C>()
+    ],
+    name: "rust_et1011c_phy",
+    authors: ["Artem Lytkin <iprintercanon@gmail.com>"],
+    description: "Rust LSI ET1011C PHY driver",
+    license: "GPL",
+}
+
+// Vendor-specific registers
+const ET1011C_STATUS_REG: C22 = C22::vendor_specific::<0x1A>();
+const ET1011C_CONFIG_REG: C22 = C22::vendor_specific::<0x16>();
+
+// ET1011C status register fields
+const ET1011C_SPEED_MASK: u16 = 0x0300;
+const ET1011C_GIGABIT_SPEED: u16 = 0x0200;
+
+// ET1011C config register fields
+const ET1011C_TX_FIFO_MASK: u16 = 0x3000;
+const ET1011C_TX_FIFO_DEPTH_16: u16 = 0x1000;
+const ET1011C_GMII_INTERFACE: u16 = 0x0002;
+const ET1011C_SYS_CLK_EN: u16 = 0x0010;
+
+struct PhyET1011C;
+
+#[vtable]
+impl Driver for PhyET1011C {
+    const NAME: &'static CStr = c"ET1011C";
+    const PHY_DEVICE_ID: DeviceId = DeviceId::new_with_model_mask(0x0282f014);
+
+    fn soft_reset(dev: &mut phy::Device) -> Result {
+        dev.genphy_soft_reset()
+    }
+
+    fn read_status(dev: &mut phy::Device) -> Result<u16> {
+        let old_speed = dev.speed();
+        dev.genphy_read_status::<C22>()?;
+
+        if old_speed != dev.speed() {
+            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,
+                )?;
+            }
+        }
+
+        Ok(0)
+    }
+}
-- 
2.43.0