Merge branch 'net-phy-support-master-slave-config-via-device-tree'

Oleksij Rempel says:

====================
net: phy: Support master-slave config via device tree

This patch series adds support for configuring the master/slave role of
PHYs via the device tree. A new `master-slave` property is introduced in
the device tree bindings, allowing PHYs to be forced into either master
or slave mode. This is particularly necessary for Single Pair Ethernet
(SPE) PHYs (1000/100/10Base-T1), where hardware strap pins may not be
available or correctly configured, but it is applicable to all PHY
types.

changes v5:
- sync DT options with ethtool nameing.

changes v4:
- add Reviewed-by
- rebase against latest net-next

changes v3:
- rename  master-slave to timing-role
- add prefer-master/slave support
====================

Link: https://patch.msgid.link/20241004090100.1654353-1-o.rempel@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Documentation/devicetree/bindings/net/ethernet-phy.yaml

@@ -158,6 +158,27 @@ properties:
       Mark the corresponding energy efficient ethernet mode as
       broken and request the ethernet to stop advertising it.
 
+  timing-role:
+    $ref: /schemas/types.yaml#/definitions/string
+    enum:
+      - forced-master
+      - forced-slave
+      - preferred-master
+      - preferred-slave
+    description: |
+      Specifies the timing role of the PHY in the network link. This property is
+      required for setups where the role must be explicitly assigned via the
+      device tree due to limitations in hardware strapping or incorrect strap
+      configurations.
+      It is applicable to Single Pair Ethernet (1000/100/10Base-T1) and other
+      PHY types, including 1000Base-T, where it controls whether the PHY should
+      be a master (clock source) or a slave (clock receiver).
+
+      - 'forced-master': The PHY is forced to operate as a master.
+      - 'forced-slave': The PHY is forced to operate as a slave.
+      - 'preferred-master': Prefer the PHY to be master but allow negotiation.
+      - 'preferred-slave': Prefer the PHY to be slave but allow negotiation.
+
   pses:
     $ref: /schemas/types.yaml#/definitions/phandle-array
     maxItems: 1

drivers/net/phy/phy-core.c

@@ -412,6 +412,39 @@ void of_set_phy_eee_broken(struct phy_device *phydev)
 	phydev->eee_broken_modes = broken;
 }
 
+/**
+ * of_set_phy_timing_role - Set the master/slave mode of the PHY
+ *
+ * @phydev: The phy_device struct
+ *
+ * Set master/slave configuration of the PHY based on the device tree.
+ */
+void of_set_phy_timing_role(struct phy_device *phydev)
+{
+	struct device_node *node = phydev->mdio.dev.of_node;
+	const char *master;
+
+	if (!IS_ENABLED(CONFIG_OF_MDIO))
+		return;
+
+	if (!node)
+		return;
+
+	if (of_property_read_string(node, "timing-role", &master))
+		return;
+
+	if (strcmp(master, "forced-master") == 0)
+		phydev->master_slave_set = MASTER_SLAVE_CFG_MASTER_FORCE;
+	else if (strcmp(master, "forced-slave") == 0)
+		phydev->master_slave_set = MASTER_SLAVE_CFG_SLAVE_FORCE;
+	else if (strcmp(master, "preferred-master") == 0)
+		phydev->master_slave_set = MASTER_SLAVE_CFG_MASTER_PREFERRED;
+	else if (strcmp(master, "preferred-slave") == 0)
+		phydev->master_slave_set = MASTER_SLAVE_CFG_SLAVE_PREFERRED;
+	else
+		phydev_warn(phydev, "Unknown master-slave mode %s\n", master);
+}
+
 /**
  * phy_resolve_aneg_pause - Determine pause autoneg results
  *

drivers/net/phy/phy_device.c

@@ -3608,6 +3608,9 @@ static int phy_probe(struct device *dev)
 	 */
 	of_set_phy_eee_broken(phydev);
 
+	/* Get master/slave strap overrides */
+	of_set_phy_timing_role(phydev);
+
 	/* The Pause Frame bits indicate that the PHY can support passing
 	 * pause frames. During autonegotiation, the PHYs will determine if
 	 * they should allow pause frames to pass.  The MAC driver should then

include/linux/phy.h

@@ -1260,6 +1260,7 @@ size_t phy_speeds(unsigned int *speeds, size_t size,
 		  unsigned long *mask);
 void of_set_phy_supported(struct phy_device *phydev);
 void of_set_phy_eee_broken(struct phy_device *phydev);
+void of_set_phy_timing_role(struct phy_device *phydev);
 int phy_speed_down_core(struct phy_device *phydev);
 
 /**