net: mdio: realtek-rtl9300: use command runner for read_c45()

Convert the read_c45() path to the new command runner. This needs the
additional helper otto_emdio_read_cmd() that can issue the command runner
and process a read operation. It is basically nothing more than

- run the command
- read the command result thorugh the I/O register

With this in place convert the read_c45() like the alread existing write
C22/C45 implementation.

- bus calls otto_emdio_read_c45()
- this handed over to SoC specific otto_emdio_9300_read_c45()
- the registers are filled
- the otto_emdio_read_cmd() is issued
- that calls the command runner

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20260527163449.1294961-4-markus.stockhausen@gmx.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: plappermaul

drivers/net/mdio/mdio-realtek-rtl9300.c

@@ -91,13 +91,14 @@ struct otto_emdio_cmd_regs {
 
 struct otto_emdio_info {
 	u32 cmd_fail;
+	u32 cmd_read;
 	u32 cmd_write;
 	struct otto_emdio_cmd_regs cmd_regs;
 	u8 num_buses;
 	u8 num_ports;
 	u16 num_pages;
 	int (*read_c22)(struct mii_bus *bus, int phy_id, int regnum);
-	int (*read_c45)(struct mii_bus *bus, int phy_id, int dev_addr, int regnum);
+	int (*read_c45)(struct mii_bus *bus, int port, int dev_addr, int regnum, u32 *value);
 	int (*write_c22)(struct mii_bus *bus, int port, int regnum, u16 value);
 	int (*write_c45)(struct mii_bus *bus, int port, int dev_addr, int regnum, u16 value);
 };
@@ -182,6 +183,26 @@ static int otto_emdio_run_cmd(struct mii_bus *bus, u32 cmd,
 	return cmdstate & info->cmd_fail ? -ENXIO : 0;
 }
 
+static int otto_emdio_read_cmd(struct mii_bus *bus, u32 cmd,
+			       struct otto_emdio_cmd_regs *cmd_data, u32 *value)
+{
+	struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus);
+	int ret;
+
+	lockdep_assert_held(&priv->lock);
+	ret = otto_emdio_run_cmd(bus, cmd | priv->info->cmd_read, cmd_data);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(priv->regmap, priv->info->cmd_regs.io_data, value);
+	if (ret)
+		return ret;
+
+	*value = FIELD_GET(PHY_CTRL_DATA, *value);
+
+	return 0;
+}
+
 static int otto_emdio_write_cmd(struct mii_bus *bus, u32 cmd,
 				struct otto_emdio_cmd_regs *cmd_data)
 {
@@ -268,58 +289,16 @@ static int otto_emdio_9300_write_c22(struct mii_bus *bus, int port, int regnum,
 	return otto_emdio_write_cmd(bus, PHY_CTRL_TYPE_C22, &cmd_data);
 }
 
-static int otto_emdio_9300_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, int regnum)
+static int otto_emdio_9300_read_c45(struct mii_bus *bus, int port,
+				    int dev_addr, int regnum, u32 *value)
 {
-	struct otto_emdio_chan *chan = bus->priv;
-	struct otto_emdio_priv *priv;
-	u32 io_reg, cmd_reg, val;
-	struct regmap *regmap;
-	int port;
-	int err;
-
-	priv = chan->priv;
-	regmap = priv->regmap;
-	io_reg = priv->info->cmd_regs.io_data;
-	cmd_reg = priv->info->cmd_regs.c22_data; /* shared command/C22 register */
-
-	port = otto_emdio_phy_to_port(bus, phy_id);
-	if (port < 0)
-		return port;
-
-	mutex_lock(&priv->lock);
-	err = otto_emdio_wait_ready(priv);
-	if (err)
-		goto out_err;
-
-	val = FIELD_PREP(PHY_CTRL_INDATA, port);
-	err = regmap_write(regmap, io_reg, val);
-	if (err)
-		goto out_err;
-
-	val = FIELD_PREP(PHY_CTRL_MMD_DEVAD, dev_addr) |
-	      FIELD_PREP(PHY_CTRL_MMD_REG, regnum);
-	err = regmap_write(regmap, priv->info->cmd_regs.c45_data, val);
-	if (err)
-		goto out_err;
-
-	err = regmap_write(regmap, cmd_reg, PHY_CTRL_READ | PHY_CTRL_TYPE_C45 | PHY_CTRL_CMD);
-	if (err)
-		goto out_err;
-
-	err = otto_emdio_wait_ready(priv);
-	if (err)
-		goto out_err;
-
-	err = regmap_read(regmap, io_reg, &val);
-	if (err)
-		goto out_err;
-
-	mutex_unlock(&priv->lock);
-	return FIELD_GET(PHY_CTRL_DATA, val);
+	struct otto_emdio_cmd_regs cmd_data = {
+		.c45_data	= FIELD_PREP(PHY_CTRL_MMD_DEVAD, dev_addr) |
+				  FIELD_PREP(PHY_CTRL_MMD_REG, regnum),
+		.io_data	= FIELD_PREP(PHY_CTRL_INDATA, port),
+	};
 
-out_err:
-	mutex_unlock(&priv->lock);
-	return err;
+	return otto_emdio_read_cmd(bus, PHY_CTRL_TYPE_C45, &cmd_data, value);
 }
 
 static int otto_emdio_9300_write_c45(struct mii_bus *bus, int port,
@@ -350,6 +329,22 @@ static int otto_emdio_write_c22(struct mii_bus *bus, int phy_id, int regnum, u16
 	return ret;
 }
 
+static int otto_emdio_read_c45(struct mii_bus *bus, int phy_id, int dev_addr, int regnum)
+{
+	struct otto_emdio_priv *priv = otto_emdio_bus_to_priv(bus);
+	int ret, port;
+	u32 value;
+
+	port = otto_emdio_phy_to_port(bus, phy_id);
+	if (port < 0)
+		return port;
+
+	scoped_guard(mutex, &priv->lock)
+		ret = priv->info->read_c45(bus, port, dev_addr, regnum, &value);
+
+	return ret ? ret : value;
+}
+
 static int otto_emdio_write_c45(struct mii_bus *bus, int phy_id,
 				int dev_addr, int regnum, u16 value)
 {
@@ -439,7 +434,7 @@ static int otto_emdio_probe_one(struct device *dev, struct otto_emdio_priv *priv
 
 	bus->name = "Realtek Switch MDIO Bus";
 	if (priv->smi_bus_is_c45[mdio_bus]) {
-		bus->read_c45 = priv->info->read_c45;
+		bus->read_c45 = otto_emdio_read_c45;
 		bus->write_c45 = otto_emdio_write_c45;
 	} else {
 		bus->read = priv->info->read_c22;
@@ -561,6 +556,7 @@ static int otto_emdio_probe(struct platform_device *pdev)
 
 static const struct otto_emdio_info otto_emdio_9300_info = {
 	.cmd_fail = PHY_CTRL_FAIL,
+	.cmd_read = PHY_CTRL_READ,
 	.cmd_write = PHY_CTRL_WRITE,
 	.cmd_regs = {
 		.c22_data = RTL9300_SMI_ACCESS_PHY_CTRL_1,