net: pse-pd: Introduce PSE types enumeration

Introduce an enumeration to define PSE types (C33 or PoDL),
utilizing a bitfield for potential future support of both types.
Include 'pse_get_types' helper for external access to PSE type info.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://lore.kernel.org/r/20240417-feature_poe-v9-2-242293fd1900@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/uapi/linux/ethtool.h

@@ -752,6 +752,18 @@ enum ethtool_module_power_mode {
 	ETHTOOL_MODULE_POWER_MODE_HIGH,
 };
 
+/**
+ * enum ethtool_pse_types - Types of PSE controller.
+ * @ETHTOOL_PSE_UNKNOWN: Type of PSE controller is unknown
+ * @ETHTOOL_PSE_PODL: PSE controller which support PoDL
+ * @ETHTOOL_PSE_C33: PSE controller which support Clause 33 (PoE)
+ */
+enum ethtool_pse_types {
+	ETHTOOL_PSE_UNKNOWN =	1 << 0,
+	ETHTOOL_PSE_PODL =	1 << 1,
+	ETHTOOL_PSE_C33 =	1 << 2,
+};
+
 /**
  * enum ethtool_c33_pse_admin_state - operational state of the PoDL PSE
  *	functions. IEEE 802.3-2022 30.9.1.1.2 aPSEAdminState