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realtek: dsa: drop dsa builtin mdio bus

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For a long time the dsa driver has been providing a builtin mdio bus
via dsa default attribute user_mii_bus. This simply uses read/write
commands from the standard realtek otto bus (aka parent). The reason
has always been unclear.

Looking around the kernel 6.18 codebase there is only one case where
this is really needed. The only consumer is dsa_user_phy_setup().

ret = phylink_of_phy_connect(dp->pl, port_dn, phy_flags);
if (ret == -ENODEV && ds->user_mii_bus) {
	/* We could not connect to a designated PHY or SFP, so try to
	 * use the switch internal MDIO bus instead
	 */
	ret = dsa_user_phy_connect(user_dev, dp->index, phy_flags);
}

Luckily the phylink_of_phy_connect() works fine and the internal bus
access is not needed at all. No need to keep the bus alive. Drop it.

While we are here fix the error handling issue of this code

if (!of_device_is_available(dn))
	ret = -ENODEV;

Returncode was set to error but never handed back to the caller.

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/22799
Signed-off-by: Robert Marko <robimarko@gmail.com>
This commit is contained in:
Markus Stockhausen 2026-04-05 18:23:53 +02:00 committed by Robert Marko
parent a031f16348
commit ad087c20b8
3 changed files with 5 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
target/linux/realtek/files-6.18/drivers/net/dsa/rtl83xx/common.c
View File

@ -211,72 +211,20 @@ u64 rtl839x_get_port_reg_le(int reg)
return v;
}
static int rtldsa_bus_read(struct mii_bus *bus, int addr, int regnum)
{
struct rtl838x_switch_priv *priv = bus->priv;
return mdiobus_read_nested(priv->parent_bus, addr, regnum);
}
static int rtldsa_bus_write(struct mii_bus *bus, int addr, int regnum, u16 val)
{
struct rtl838x_switch_priv *priv = bus->priv;
return mdiobus_write_nested(priv->parent_bus, addr, regnum, val);
}
static int rtldsa_bus_c45_read(struct mii_bus *bus, int addr, int devad, int regnum)
{
struct rtl838x_switch_priv *priv = bus->priv;
return mdiobus_c45_read_nested(priv->parent_bus, addr, devad, regnum);
}
static int rtldsa_bus_c45_write(struct mii_bus *bus, int addr, int devad, int regnum, u16 val)
{
struct rtl838x_switch_priv *priv = bus->priv;
return mdiobus_c45_write_nested(priv->parent_bus, addr, devad, regnum, val);
}
static int rtl83xx_mdio_probe(struct rtl838x_switch_priv *priv)
{
struct device_node *dn, *phy_node, *pcs_node, *led_node;
struct device *dev = priv->dev;
struct mii_bus *bus;
int ret;
u32 pn;
/* Check if mdio bus is defined with status "okay" and already registered */
dn = of_find_compatible_node(NULL, NULL, "realtek,otto-mdio");
if (!dn)
if (!dn || !of_device_is_available(dn))
return -ENODEV;
if (!of_device_is_available(dn))
ret = -ENODEV;
priv->parent_bus = of_mdio_find_bus(dn);
if (!priv->parent_bus)
return -EPROBE_DEFER;
bus = devm_mdiobus_alloc(priv->ds->dev);
bus = of_mdio_find_bus(dn);
if (!bus)
return -ENOMEM;
bus->name = "rtldsa_mdio";
bus->read = rtldsa_bus_read;
bus->write = rtldsa_bus_write;
bus->read_c45 = rtldsa_bus_c45_read;
bus->write_c45 = rtldsa_bus_c45_write;
bus->phy_mask = priv->parent_bus->phy_mask;
snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", bus->name, dev->id);
bus->parent = dev;
priv->ds->user_mii_bus = bus;
priv->ds->user_mii_bus->priv = priv;
ret = mdiobus_register(priv->ds->user_mii_bus);
if (ret)
return ret;
return -EPROBE_DEFER;
put_device(&bus->dev);
dn = of_find_compatible_node(NULL, NULL, "realtek,otto-switch");
if (!dn) {

20
target/linux/realtek/files-6.18/drivers/net/dsa/rtl83xx/dsa.c
View File

@ -2498,20 +2498,6 @@ out:
return 0;
}
static int rtldsa_phy_read(struct dsa_switch *ds, int addr, int regnum)
{
struct rtl838x_switch_priv *priv = ds->priv;
return mdiobus_read_nested(priv->parent_bus, addr, regnum);
}
static int rtldsa_phy_write(struct dsa_switch *ds, int addr, int regnum, u16 val)
{
struct rtl838x_switch_priv *priv = ds->priv;
return mdiobus_write_nested(priv->parent_bus, addr, regnum, val);
}
static const struct flow_action_entry *rtldsa_rate_policy_extract(struct flow_cls_offload *cls)
{
struct flow_rule *rule;
@ -2635,9 +2621,6 @@ const struct dsa_switch_ops rtldsa_83xx_switch_ops = {
.get_tag_protocol = rtldsa_get_tag_protocol,
.setup = rtldsa_83xx_setup,
.phy_read = rtldsa_phy_read,
.phy_write = rtldsa_phy_write,
.phylink_get_caps = rtldsa_83xx_phylink_get_caps,
.get_strings = rtldsa_get_strings,
@ -2698,9 +2681,6 @@ const struct dsa_switch_ops rtldsa_93xx_switch_ops = {
.get_tag_protocol = rtldsa_get_tag_protocol,
.setup = rtldsa_93xx_setup,
.phy_read = rtldsa_phy_read,
.phy_write = rtldsa_phy_write,
.phylink_get_caps = rtldsa_93xx_phylink_get_caps,
.get_strings = rtldsa_get_strings,

1
target/linux/realtek/files-6.18/drivers/net/dsa/rtl83xx/rtl838x.h
View File

@ -1523,7 +1523,6 @@ struct rtl838x_switch_priv {
struct mutex pie_mutex; /* Mutex for Packet Inspection Engine */
int link_state_irq;
int mirror_group_ports[4];
struct mii_bus *parent_bus;
const struct rtldsa_config *r;
u64 irq_mask;
struct dentry *dbgfs_dir;