[PATCH v6 1/4] dt-bindings: net: ethernet-phy: add property enet-phy-pair-order

[PATCH v6 1/4] dt-bindings: net: ethernet-phy: add property enet-phy-pair-order

[Damien Dejean]

Add property enet-phy-pair-order to the device tree bindings to define
the pair order of the PHY. To simplify PCB design some manufacturers
allow to wire the pairs in a reverse order, and change the order in
software.

The property can be set to 0 to force the normal pair order (ABCD), or 1
to force the reverse pair order (DCBA).

Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
---
 Documentation/devicetree/bindings/net/ethernet-phy.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
index 58634fee9fc4..4a27547f7d7a 100644
--- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
@@ -126,6 +126,12 @@ properties:
       e.g. wrong bootstrap configuration caused by issues in PCB
       layout design.
 
+  enet-phy-pair-order:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    description:
+      For normal (0) or reverse (1) order of the pairs (ABCD -> DCBA).
+
   eee-broken-100tx:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
-- 
2.47.3

[PATCH v6 2/4] net: phy: realtek: add RTL8224 pair order support

[Damien Dejean]

The RTL8224 has a register to configure a pair swap (from ABCD order to
DCBA) providing PCB designers more flexbility when wiring the chip. The
swap parameter has to be set correctly for each of the 4 ports before
the chip can detect a link.

After a reset, this register is (unfortunately) left in a random state,
thus it has to be initialized. On most of the devices the bootloader
does it once for all and we can rely on the value set, on some other it
is not and the kernel has to do it.

The MDI pair swap can be set in the device tree using the property
enet-phy-pair-order. The property is set to 0 to keep the default order
(ABCD), or 1 to reverse the pairs (DCBA).

Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
---
 drivers/net/phy/realtek/Kconfig        |  1 +
 drivers/net/phy/realtek/realtek_main.c | 55 ++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)

diff --git a/drivers/net/phy/realtek/Kconfig b/drivers/net/phy/realtek/Kconfig
index b05c2a1e9024..a741b34d193e 100644
--- a/drivers/net/phy/realtek/Kconfig
+++ b/drivers/net/phy/realtek/Kconfig
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config REALTEK_PHY
 	tristate "Realtek PHYs"
+	select PHY_PACKAGE
 	help
 	  Currently supports RTL821x/RTL822x and fast ethernet PHYs
 
diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
index 75565fbdbf6d..4f0c1b72f7e0 100644
--- a/drivers/net/phy/realtek/realtek_main.c
+++ b/drivers/net/phy/realtek/realtek_main.c
@@ -171,6 +171,8 @@
 
 #define RTL8224_SRAM_RTCT_LEN(pair)		(0x8028 + (pair) * 4)
 
+#define RTL8224_VND1_MDI_PAIR_SWAP		0xa90
+
 #define RTL8366RB_POWER_SAVE			0x15
 #define RTL8366RB_POWER_SAVE_ON			BIT(12)
 
@@ -1820,6 +1822,57 @@ static int rtl8224_cable_test_get_status(struct phy_device *phydev, bool *finish
 	return rtl8224_cable_test_report(phydev, finished);
 }
 
+static int rtl8224_mdi_config_order(struct phy_device *phydev)
+{
+	struct device_node *np = phydev->mdio.dev.of_node;
+	u8 port_offset = phydev->mdio.addr & 3;
+	u32 order = 0;
+	int ret, val;
+
+	ret = of_property_read_u32(np, "enet-phy-pair-order", &order);
+
+	/* Do nothing in case the property is not present */
+	if (ret == -EINVAL)
+		return 0;
+
+	if (ret)
+		return ret;
+
+	if (order & ~1)
+		return -EINVAL;
+
+	phy_lock_mdio_bus(phydev);
+	val = __phy_package_read_mmd(phydev, 0, MDIO_MMD_VEND1,
+				     RTL8224_VND1_MDI_PAIR_SWAP);
+	if (val < 0) {
+		ret = val;
+		goto exit;
+	}
+
+	if (order)
+		val |= (1 << port_offset);
+	else
+		val &= ~(1 << port_offset);
+
+	ret = __phy_package_write_mmd(phydev, 0, MDIO_MMD_VEND1,
+				      RTL8224_VND1_MDI_PAIR_SWAP, val);
+exit:
+	phy_unlock_mdio_bus(phydev);
+	return ret;
+}
+
+static int rtl8224_config_init(struct phy_device *phydev)
+{
+	return rtl8224_mdi_config_order(phydev);
+}
+
+static int rtl8224_probe(struct phy_device *phydev)
+{
+	/* Chip exposes 4 ports, join all of them in the same package */
+	return devm_phy_package_join(&phydev->mdio.dev, phydev,
+				     phydev->mdio.addr & ~3, 0);
+}
+
 static bool rtlgen_supports_2_5gbps(struct phy_device *phydev)
 {
 	int val;
@@ -2392,6 +2445,8 @@ static struct phy_driver realtek_drvs[] = {
 		PHY_ID_MATCH_EXACT(0x001ccad0),
 		.name		= "RTL8224 2.5Gbps PHY",
 		.flags		= PHY_POLL_CABLE_TEST,
+		.probe		= rtl8224_probe,
+		.config_init	= rtl8224_config_init,
 		.get_features	= rtl822x_c45_get_features,
 		.config_aneg	= rtl822x_c45_config_aneg,
 		.read_status	= rtl822x_c45_read_status,
-- 
2.47.3

[PATCH v6 3/4] dt-bindings: net: ethernet-phy: add property enet-phy-pair-polarity

[Damien Dejean]

Add the property enet-phy-pair-polarity to describe the polarity of the
PHY pairs. To ease PCB designs some manufacturers allow to wire the
pairs with a reverse polarity and provide a way to configure it.

The property 'enet-phy-pair-polarity' sets the polarity of each pair.
Bit 0 to 3 configure the polarity or pairs A to D, if set to 1 the
polarity is reversed for this pair.

Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
---
 Documentation/devicetree/bindings/net/ethernet-phy.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
index 4a27547f7d7a..21a1a63506f0 100644
--- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml
@@ -132,6 +132,14 @@ properties:
     description:
       For normal (0) or reverse (1) order of the pairs (ABCD -> DCBA).
 
+  enet-phy-pair-polarity:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 0xf
+    description:
+      A bitmap to describe pair polarity swap. Bit 0 to swap polarity of pair A,
+      bit 1 to swap polarity of pair B, bit 2 to swap polarity of pair C and bit
+      3 to swap polarity of pair D.
+
   eee-broken-100tx:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
-- 
2.47.3

Re: [PATCH v6 3/4] dt-bindings: net: ethernet-phy: add property enet-phy-pair-polarity

[Rob Herring (Arm)]

On Sat, 07 Feb 2026 10:25:38 +0100, Damien Dejean wrote:
> Add the property enet-phy-pair-polarity to describe the polarity of the
> PHY pairs. To ease PCB designs some manufacturers allow to wire the
> pairs with a reverse polarity and provide a way to configure it.
> 
> The property 'enet-phy-pair-polarity' sets the polarity of each pair.
> Bit 0 to 3 configure the polarity or pairs A to D, if set to 1 the
> polarity is reversed for this pair.
> 
> Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
> ---
>  Documentation/devicetree/bindings/net/ethernet-phy.yaml | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

[PATCH v6 4/4] net: phy: realtek: add RTL8224 polarity support

[Damien Dejean]

The RTL8224 has a register to configure the polarity of every pair of
each port. It provides device designers more flexbility when wiring the
chip.

Unfortunately, the register is left in an unknown state after a reset.
Thus on devices where the bootloader don't initialize it, the driver has
to do it to detect and use a link.

The MDI polarity swap can be set in the device tree using the property
enet-phy-pair-polarity. The u32 value is a bitfield where bit[0..3]
control the polarity of pairs A..D.

Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
---
 drivers/net/phy/realtek/realtek_main.c | 45 +++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
index 4f0c1b72f7e0..d15d3b41e5d1 100644
--- a/drivers/net/phy/realtek/realtek_main.c
+++ b/drivers/net/phy/realtek/realtek_main.c
@@ -172,6 +172,7 @@
 #define RTL8224_SRAM_RTCT_LEN(pair)		(0x8028 + (pair) * 4)
 
 #define RTL8224_VND1_MDI_PAIR_SWAP		0xa90
+#define RTL8224_VND1_MDI_POLARITY_SWAP		0xa94
 
 #define RTL8366RB_POWER_SAVE			0x15
 #define RTL8366RB_POWER_SAVE_ON			BIT(12)
@@ -1861,9 +1862,51 @@ static int rtl8224_mdi_config_order(struct phy_device *phydev)
 	return ret;
 }
 
+static int rtl8224_mdi_config_polarity(struct phy_device *phydev)
+{
+	struct device_node *np = phydev->mdio.dev.of_node;
+	u8 offset = (phydev->mdio.addr & 3) * 4;
+	u32 polarity = 0;
+	int ret, val;
+
+	ret = of_property_read_u32(np, "enet-phy-pair-polarity", &polarity);
+
+	/* Do nothing if the property is not present */
+	if (ret == -EINVAL)
+		return 0;
+
+	if (ret)
+		return ret;
+
+	if (polarity & ~0xf)
+		return -EINVAL;
+
+	phy_lock_mdio_bus(phydev);
+	val = __phy_package_read_mmd(phydev, 0, MDIO_MMD_VEND1,
+				     RTL8224_VND1_MDI_POLARITY_SWAP);
+	if (val < 0) {
+		ret = val;
+		goto exit;
+	}
+
+	val &= ~(0xf << offset);
+	val |= polarity << offset;
+	ret = __phy_package_write_mmd(phydev, 0, MDIO_MMD_VEND1,
+				      RTL8224_VND1_MDI_POLARITY_SWAP, val);
+exit:
+	phy_unlock_mdio_bus(phydev);
+	return ret;
+}
+
 static int rtl8224_config_init(struct phy_device *phydev)
 {
-	return rtl8224_mdi_config_order(phydev);
+	int ret;
+
+	ret = rtl8224_mdi_config_order(phydev);
+	if (ret)
+		return ret;
+
+	return rtl8224_mdi_config_polarity(phydev);
 }
 
 static int rtl8224_probe(struct phy_device *phydev)
-- 
2.47.3

Re: [PATCH v6 4/4] net: phy: realtek: add RTL8224 polarity support

[Paolo Abeni]

On 2/7/26 10:25 AM, Damien Dejean wrote:
> diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
> index 4f0c1b72f7e0..d15d3b41e5d1 100644
> --- a/drivers/net/phy/realtek/realtek_main.c
> +++ b/drivers/net/phy/realtek/realtek_main.c
> @@ -172,6 +172,7 @@
>  #define RTL8224_SRAM_RTCT_LEN(pair)		(0x8028 + (pair) * 4)
>  
>  #define RTL8224_VND1_MDI_PAIR_SWAP		0xa90
> +#define RTL8224_VND1_MDI_POLARITY_SWAP		0xa94
>  
>  #define RTL8366RB_POWER_SAVE			0x15
>  #define RTL8366RB_POWER_SAVE_ON			BIT(12)
> @@ -1861,9 +1862,51 @@ static int rtl8224_mdi_config_order(struct phy_device *phydev)
>  	return ret;
>  }
>  
> +static int rtl8224_mdi_config_polarity(struct phy_device *phydev)
> +{
> +	struct device_node *np = phydev->mdio.dev.of_node;
> +	u8 offset = (phydev->mdio.addr & 3) * 4;
> +	u32 polarity = 0;
> +	int ret, val;
> +
> +	ret = of_property_read_u32(np, "enet-phy-pair-polarity", &polarity);
> +
> +	/* Do nothing if the property is not present */
> +	if (ret == -EINVAL)
> +		return 0;
> +
> +	if (ret)
> +		return ret;
> +
> +	if (polarity & ~0xf)
> +		return -EINVAL;
> +
> +	phy_lock_mdio_bus(phydev);
> +	val = __phy_package_read_mmd(phydev, 0, MDIO_MMD_VEND1,
> +				     RTL8224_VND1_MDI_POLARITY_SWAP);
> +	if (val < 0) {
> +		ret = val;
> +		goto exit;
> +	}
> +
> +	val &= ~(0xf << offset);
> +	val |= polarity << offset;
> +	ret = __phy_package_write_mmd(phydev, 0, MDIO_MMD_VEND1,
> +				      RTL8224_VND1_MDI_POLARITY_SWAP, val);
> +exit:
> +	phy_unlock_mdio_bus(phydev);
> +	return ret;
> +}
> +
>  static int rtl8224_config_init(struct phy_device *phydev)
>  {
> -	return rtl8224_mdi_config_order(phydev);
> +	int ret;
> +
> +	ret = rtl8224_mdi_config_order(phydev);
> +	if (ret)
> +		return ret;
> +
> +	return rtl8224_mdi_config_polarity(phydev);

This very close to what you implemented into patch 2/4. Likely you can
deduplicate the code a bit factoring out some common helper.

Side notes: you should include the target tree in the subj prefix -
'net-next' in this case, a per patch changelog for the introduced
changes WRT the previous revision and a cover letter.

Also note that net-next is now closed for the merge window; you will
have to wait unit ~23 Feb before reposting.

/P

>  }
>  
>  static int rtl8224_probe(struct phy_device *phydev)

Re: [PATCH v6 4/4] net: phy: realtek: add RTL8224 polarity support

[Damien Dejean]

Hi Paolo,

> Le 11 févr. 2026 à 12:36, Paolo Abeni <pabeni@redhat.com> a écrit :
> 
> This very close to what you implemented into patch 2/4. Likely you can
> deduplicate the code a bit factoring out some common helper.

Thanks for the feedback, let me rework this and repost once it is possible

Damien

> 
> Side notes: you should include the target tree in the subj prefix -
> 'net-next' in this case, a per patch changelog for the introduced
> changes WRT the previous revision and a cover letter.
> 
> Also note that net-next is now closed for the merge window; you will
> have to wait unit ~23 Feb before reposting.
> 
> /P
> 
>> }
>> 
>> static int rtl8224_probe(struct phy_device *phydev)
> 

Re: [PATCH v6 1/4] dt-bindings: net: ethernet-phy: add property enet-phy-pair-order

[Rob Herring (Arm)]

On Sat, 07 Feb 2026 10:25:36 +0100, Damien Dejean wrote:
> Add property enet-phy-pair-order to the device tree bindings to define
> the pair order of the PHY. To simplify PCB design some manufacturers
> allow to wire the pairs in a reverse order, and change the order in
> software.
> 
> The property can be set to 0 to force the normal pair order (ABCD), or 1
> to force the reverse pair order (DCBA).
> 
> Signed-off-by: Damien Dejean <dam.dejean@gmail.com>
> ---
>  Documentation/devicetree/bindings/net/ethernet-phy.yaml | 6 ++++++
>  1 file changed, 6 insertions(+)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>