> +++ b/Documentation/networking/pse-pd/introduction.rst > @@ -0,0 +1,73 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +Power Sourcing Equipment (PSE) in IEEE 802.3 Standard > +===================================================== > + > +Overview > +-------- > + > +Power Sourcing Equipment (PSE) is essential in networks for delivering power > +along with data over Ethernet cables. It usually refers to devices like > +switches and hubs that supply power to Powered Devices (PDs) such as IP > +cameras, VoIP phones, and wireless access points. > + > +PSE vs. PoDL PSE > +---------------- > + > +PSE in the IEEE 802.3 standard generally refers to equipment that provides > +power alongside data over Ethernet cables, typically associated with Power over > +Ethernet (PoE). > + > +PoDL PSE, or Power over Data Lines PSE, specifically denotes PSEs operating > +with single balanced twisted-pair PHYs, as per Clause 104 of IEEE 802.3. PoDL > +is significant in contexts like automotive and industrial controls where power > +and data delivery over a single pair is advantageous. > + > +IEEE 802.3-2018 Addendums and Related Clauses > +---------------------------------------------- > + > +Key addenda to the IEEE 802.3-2018 standard relevant to power delivery over > +Ethernet are as follows: > + > +- **802.3af (Approved in 2003-06-12)**: Known as PoE in the market, detailed in > + Clause 33, delivering up to 15.4W of power. > +- **802.3at (Approved in 2009-09-11)**: Marketed as PoE+, enhancing PoE as > + covered in Clause 33, increasing power delivery to up to 30W. > +- **802.3bt (Approved in 2018-09-27)**: Known as 4PPoE in the market, outlined > + in Clause 33. Type 3 delivers up to 60W, and Type 4 up to 100W. > +- **802.3bu (Approved in 2016-12-07)**: Formerly referred to as PoDL, detailed > + in Clause 104. Introduces Classes 0 - 9. Class 9 PoDL PSE delivers up to ~65W > + > +Kernel Naming Convention Recommendations > +---------------------------------------- > + > +For clarity and consistency within the Linux kernel's networking subsystem, the > +following naming conventions are recommended: > + > +- For general PSE (PoE) code, use "c33_pse" key words. For example: > + ``enum ethtool_c33_pse_admin_state c33_admin_control;``. > + This aligns with Clause 33, encompassing various PoE forms. > + > +- For PoDL PSE - specific code, use "podl_pse". For example: > + ``enum ethtool_podl_pse_admin_state podl_admin_control;`` to differentiate > + PoDL PSE settings according to Clause 104. > + > +Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI) > +------------------------------------------------------------------------------------------- > + > +Clause 33 of the IEEE 802.3 standard defines the functional and electrical > +characteristics of Powered Device (PD) and Power Sourcing Equipment (PSE). > +These entities enable power delivery using the same generic cabling as for data > +transmission, integrating power with data communication for devices such as > +10BASE-T, 100BASE-TX, or 1000BASE-T. > + > +Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet > +------------------------------------------------------------------------------------------- > + > +Clause 104 of the IEEE 802.3 standard delineates the functional and electrical > +characteristics of PoDL Powered Devices (PDs) and PoDL Power Sourcing Equipment > +(PSEs). These are designed for use with single balanced twisted-pair Ethernet > +Physical Layers. In this clause, 'PSE' refers specifically to PoDL PSE, and > +'PD' to PoDL PD. The key intent is to provide devices with a unified interface > +for both data and the power required to process this data over a single > +balanced twisted-pair Ethernet connection. This is a nice summary of the different standard and naming. Thanks for adding this. The c33 prefix is not ideal in terms of 'marketing', but we now have a clear structure for how these two different schemes are same/different. Reviewed-by: Andrew Lunn <andrew@xxxxxxx> Andrew