[PATCH v3 3/3] net: mdio: Add RTL9300 MDIO driver

From: Chris Packham
Date: Tue Dec 17 2024 - 17:45:57 EST

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Add a driver for the MDIO controller on the RTL9300 family of Ethernet
switches with integrated SoC. There are 4 physical SMI interfaces on the
RTL9300 but access is done using the switch ports so a single MDIO bus
is presented to the rest of the system.

Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
---

Notes:
Changes in v3:
- Fix (another) off-by-one error
Changes in v2:
- Add clause 22 support
- Remove commented out code
- Formatting cleanup
- Set MAX_PORTS correctly for MDIO interface
- Fix off-by-one error in pn check

drivers/net/mdio/Kconfig | 7 +
drivers/net/mdio/Makefile | 1 +
drivers/net/mdio/mdio-realtek-rtl.c | 341 ++++++++++++++++++++++++++++
3 files changed, 349 insertions(+)
create mode 100644 drivers/net/mdio/mdio-realtek-rtl.c

diff --git a/drivers/net/mdio/Kconfig b/drivers/net/mdio/Kconfig
index 4a7a303be2f7..0c6240c4a7e9 100644
--- a/drivers/net/mdio/Kconfig
+++ b/drivers/net/mdio/Kconfig
@@ -185,6 +185,13 @@ config MDIO_IPQ8064
This driver supports the MDIO interface found in the network
interface units of the IPQ8064 SoC

+config MDIO_REALTEK_RTL
+ tristate "Realtek RTL9300 MDIO interface support"
+ depends on MACH_REALTEK_RTL || COMPILE_TEST
+ help
+ This driver supports the MDIO interface found in the Realtek
+ RTL9300 family of Ethernet switches with integrated SoC.
+
config MDIO_REGMAP
tristate
help
diff --git a/drivers/net/mdio/Makefile b/drivers/net/mdio/Makefile
index 1015f0db4531..2cd8b491f301 100644
--- a/drivers/net/mdio/Makefile
+++ b/drivers/net/mdio/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_MDIO_MOXART) += mdio-moxart.o
obj-$(CONFIG_MDIO_MSCC_MIIM) += mdio-mscc-miim.o
obj-$(CONFIG_MDIO_MVUSB) += mdio-mvusb.o
obj-$(CONFIG_MDIO_OCTEON) += mdio-octeon.o
+obj-$(CONFIG_MDIO_REALTEK_RTL) += mdio-realtek-rtl.o
obj-$(CONFIG_MDIO_REGMAP) += mdio-regmap.o
obj-$(CONFIG_MDIO_SUN4I) += mdio-sun4i.o
obj-$(CONFIG_MDIO_THUNDER) += mdio-thunder.o
diff --git a/drivers/net/mdio/mdio-realtek-rtl.c b/drivers/net/mdio/mdio-realtek-rtl.c
new file mode 100644
index 000000000000..d61a9273e86f
--- /dev/null
+++ b/drivers/net/mdio/mdio-realtek-rtl.c
@@ -0,0 +1,341 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MDIO controller for RTL9300 switches with integrated SoC.
+ *
+ * The MDIO communication is abstracted by the switch. At the software level
+ * communication uses the switch port to address the PHY with the actual MDIO
+ * bus and address having been setup via the realtek,smi-address property.
+ */
+
+#include <linux/mdio.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mod_devicetable.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+#define SMI_GLB_CTRL 0x000
+#define GLB_CTRL_INTF_SEL(intf) BIT(16 + (intf))
+#define SMI_PORT0_15_POLLING_SEL 0x008
+#define SMI_ACCESS_PHY_CTRL_0 0x170
+#define SMI_ACCESS_PHY_CTRL_1 0x174
+#define PHY_CTRL_RWOP BIT(2)
+#define PHY_CTRL_TYPE BIT(1)
+#define PHY_CTRL_CMD BIT(0)
+#define PHY_CTRL_FAIL BIT(25)
+#define SMI_ACCESS_PHY_CTRL_2 0x178
+#define SMI_ACCESS_PHY_CTRL_3 0x17c
+#define SMI_PORT0_5_ADDR_CTRL 0x180
+
+#define MAX_PORTS 28
+#define MAX_SMI_BUSSES 4
+#define MAX_SMI_ADDR 0x1f
+
+struct realtek_mdio_priv {
+ struct regmap *regmap;
+ u8 smi_bus[MAX_PORTS];
+ u8 smi_addr[MAX_PORTS];
+ bool smi_bus_isc45[MAX_SMI_BUSSES];
+ u32 reg_base;
+};
+
+static int realtek_mdio_wait_ready(struct realtek_mdio_priv *priv)
+{
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 val;
+
+ return regmap_read_poll_timeout(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ val, !(val & PHY_CTRL_CMD), 10, 500);
+}
+
+static int realtek_mdio_read_c22(struct mii_bus *bus, int phy_id, int regnum)
+{
+ struct realtek_mdio_priv *priv = bus->priv;
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 val;
+ int err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, phy_id << 16);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ regnum << 20 | 0x1f << 15 | 0xfff << 3 | PHY_CTRL_CMD);
+ if (err)
+ return err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_read(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, &val);
+ if (err)
+ return err;
+
+ return val & 0xffff;
+}
+
+static int realtek_mdio_write_c22(struct mii_bus *bus, int phy_id, int regnum, u16 value)
+{
+ struct realtek_mdio_priv *priv = bus->priv;
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 val;
+ int err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_0, BIT(phy_id));
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, value << 16);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ regnum << 20 | 0x1f << 15 | 0xfff << 3 | PHY_CTRL_RWOP | PHY_CTRL_CMD);
+ if (err)
+ return err;
+
+ err = regmap_read_poll_timeout(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ val, !(val & PHY_CTRL_CMD), 10, 100);
+ if (err)
+ return err;
+
+ if (val & PHY_CTRL_FAIL)
+ return -ENXIO;
+
+ return 0;
+}
+
+static int realtek_mdio_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, int regnum)
+{
+ struct realtek_mdio_priv *priv = bus->priv;
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 val;
+ int err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, phy_id << 16);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_3,
+ dev_addr << 16 | (regnum & 0xffff));
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ PHY_CTRL_TYPE | PHY_CTRL_CMD);
+ if (err)
+ return err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_read(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, &val);
+ if (err)
+ return err;
+
+ return val & 0xffff;
+}
+
+static int realtek_mdio_write_c45(struct mii_bus *bus, int phy_id, int dev_addr,
+ int regnum, u16 value)
+{
+ struct realtek_mdio_priv *priv = bus->priv;
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 val;
+ int err;
+
+ err = realtek_mdio_wait_ready(priv);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_0, BIT(phy_id));
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_2, value << 16);
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_3,
+ dev_addr << 16 | (regnum & 0xffff));
+ if (err)
+ return err;
+
+ err = regmap_write(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ PHY_CTRL_RWOP | PHY_CTRL_TYPE | PHY_CTRL_CMD);
+ if (err)
+ return err;
+
+ err = regmap_read_poll_timeout(regmap, reg_base + SMI_ACCESS_PHY_CTRL_1,
+ val, !(val & PHY_CTRL_CMD), 10, 100);
+ if (err)
+ return err;
+
+ if (val & PHY_CTRL_FAIL)
+ return -ENXIO;
+
+ return 0;
+}
+
+static int realtek_mdiobus_init(struct realtek_mdio_priv *priv)
+{
+ u32 glb_ctrl_mask = 0, glb_ctrl_val = 0;
+ struct regmap *regmap = priv->regmap;
+ u32 reg_base = priv->reg_base;
+ u32 port_addr[5] = { 0 };
+ u32 poll_sel[2] = { 0 };
+ int i, err;
+
+ /* Associate the port with the SMI interface and PHY */
+ for (i = 0; i < MAX_PORTS; i++) {
+ int pos;
+
+ if (priv->smi_bus[i] > 3)
+ continue;
+
+ pos = (i % 6) * 5;
+ port_addr[i / 6] |= priv->smi_addr[i] << pos;
+
+ pos = (i % 16) * 2;
+ poll_sel[i / 16] |= priv->smi_bus[i] << pos;
+ }
+
+ /* Put the interfaces into C45 mode if required */
+ for (i = 0; i < MAX_SMI_BUSSES; i++) {
+ if (priv->smi_bus_isc45[i]) {
+ glb_ctrl_mask |= GLB_CTRL_INTF_SEL(i);
+ glb_ctrl_val |= GLB_CTRL_INTF_SEL(i);
+ }
+ }
+
+ err = regmap_bulk_write(regmap, reg_base + SMI_PORT0_5_ADDR_CTRL,
+ port_addr, 5);
+ if (err)
+ return err;
+
+ err = regmap_bulk_write(regmap, reg_base + SMI_PORT0_15_POLLING_SEL,
+ poll_sel, 2);
+ if (err)
+ return err;
+
+ err = regmap_update_bits(regmap, reg_base + SMI_GLB_CTRL,
+ glb_ctrl_mask, glb_ctrl_val);
+ if (err)
+ return err;
+
+ return 0;
+}
+
+static int realtek_mdiobus_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct realtek_mdio_priv *priv;
+ struct fwnode_handle *child;
+ struct mii_bus *bus;
+ int err;
+
+ bus = devm_mdiobus_alloc_size(dev, sizeof(*priv));
+ if (!bus)
+ return -ENOMEM;
+
+ bus->name = "Reaktek Switch MDIO Bus";
+ bus->read = realtek_mdio_read_c22;
+ bus->write = realtek_mdio_write_c22;
+ bus->read_c45 = realtek_mdio_read_c45;
+ bus->write_c45 = realtek_mdio_write_c45;
+ bus->parent = dev;
+ priv = bus->priv;
+
+ priv->regmap = syscon_node_to_regmap(dev->parent->of_node);
+ if (IS_ERR(priv->regmap))
+ return PTR_ERR(priv->regmap);
+
+ err = device_property_read_u32(dev, "reg", &priv->reg_base);
+ if (err)
+ return err;
+
+ snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
+
+ device_for_each_child_node(dev, child) {
+ u32 pn, smi_addr[2];
+
+ err = fwnode_property_read_u32(child, "reg", &pn);
+ if (err)
+ return err;
+
+ if (pn >= MAX_PORTS)
+ return dev_err_probe(dev, -EINVAL, "illegal port number %d\n", pn);
+
+ err = fwnode_property_read_u32_array(child, "realtek,smi-address", smi_addr, 2);
+ if (err) {
+ smi_addr[0] = 0;
+ smi_addr[1] = pn;
+ }
+
+ if (smi_addr[0] >= MAX_SMI_BUSSES)
+ return dev_err_probe(dev, -EINVAL, "illegal smi bus number %d\n",
+ smi_addr[0]);
+
+ if (smi_addr[1] > MAX_SMI_ADDR)
+ return dev_err_probe(dev, -EINVAL, "illegal smi addr %d\n", smi_addr[1]);
+
+ if (fwnode_device_is_compatible(child, "ethernet-phy-ieee802.3-c45"))
+ priv->smi_bus_isc45[smi_addr[0]] = true;
+
+ priv->smi_bus[pn] = smi_addr[0];
+ priv->smi_addr[pn] = smi_addr[1];
+ }
+
+ err = realtek_mdiobus_init(priv);
+ if (err)
+ return dev_err_probe(dev, err, "failed to initialise MDIO bus controller\n");
+
+ err = devm_of_mdiobus_register(dev, bus, dev->of_node);
+ if (err)
+ return dev_err_probe(dev, err, "cannot register MDIO bus\n");
+
+ return 0;
+}
+
+static const struct of_device_id realtek_mdio_ids[] = {
+ { .compatible = "realtek,rtl9301-mdio" },
+ { .compatible = "realtek,rtl9302b-mdio" },
+ { .compatible = "realtek,rtl9302c-mdio" },
+ { .compatible = "realtek,rtl9303-mdio" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, realtek_mdio_ids);
+
+static struct platform_driver rtl9300_mdio_driver = {
+ .probe = realtek_mdiobus_probe,
+ .driver = {
+ .name = "mdio-rtl9300",
+ .of_match_table = realtek_mdio_ids,
+ },
+};
+
+module_platform_driver(rtl9300_mdio_driver);
+
+MODULE_DESCRIPTION("RTL9300 MDIO driver");
+MODULE_LICENSE("GPL");
--
2.47.1

Next message: Chris Packham: "[PATCH v3 2/3] mips: dts: realtek: Add MDIO controller"
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