Re: [PATCH net-next v2 2/8] ethtool: Expand Ethernet Power Equipment with c33 (PoE) alongside PoDL

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Fri, Dec 01, 2023 at 06:10:24PM +0100, Kory Maincent wrote:
> In the current PSE interface for Ethernet Power Equipment, support is
> limited to PoDL. This patch extends the interface to accommodate the
> objects specified in IEEE 802.3-2022 145.2 for Power sourcing
> Equipment (PSE).
> 
> The following objects are now supported and considered mandatory:
> - IEEE 802.3-2022 30.9.1.1.5 aPSEPowerDetectionStatus
> - IEEE 802.3-2022 30.9.1.1.2 aPSEAdminState
> - IEEE 802.3-2022 30.9.1.2.1 aPSEAdminControl
> 
> To avoid confusion between "PoDL PSE" and "PoE PSE", which have similar
> names but distinct values, we have followed the suggestion of Oleksij
> Rempel and Andrew Lunn to maintain separate naming schemes for each,
> using c33 (clause 33) prefix for "PoE PSE".
> You can find more details in the discussion threads here:
> https://lore.kernel.org/netdev/20230912110637.GI780075@pengutronix.de/
> https://lore.kernel.org/netdev/2539b109-72ad-470a-9dae-9f53de4f64ec@lunn.ch/
> 
> Sponsored-by: Dent Project <dentproject@linuxfoundation.org>
> Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
> ---
> 
> Changes in v2:
> - Rename all the PoE variables and enum with a c33 prefix.
> - Add documentation, thanks to Oleksij for having written one.
> ---
>  Documentation/networking/pse-pd/introduction.rst | 73 ++++++++++++++++++++++++
>  include/linux/pse-pd/pse.h                       |  9 +++
>  include/uapi/linux/ethtool.h                     | 43 ++++++++++++++
>  include/uapi/linux/ethtool_netlink.h             |  3 +
>  4 files changed, 128 insertions(+)
> 
> diff --git a/Documentation/networking/pse-pd/introduction.rst b/Documentation/networking/pse-pd/introduction.rst
> new file mode 100644
> index 000000000000..e213083b9aff
> --- /dev/null
> +++ 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.

I get many htmldocs warnings:

```
Documentation/networking/pse-pd/introduction.rst:56: WARNING: Title underline too short.

Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI)
-------------------------------------------------------------------------------------------
Documentation/networking/pse-pd/introduction.rst:56: WARNING: Title underline too short.

Summary of Clause 33: Data Terminal Equipment (DTE) Power via Media Dependent Interface (MDI)
-------------------------------------------------------------------------------------------
Documentation/networking/pse-pd/introduction.rst:65: WARNING: Title underline too short.

Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet
-------------------------------------------------------------------------------------------
Documentation/networking/pse-pd/introduction.rst:65: WARNING: Title underline too short.

Summary of Clause 104: Power over Data Lines (PoDL) of Single Balanced Twisted-Pair Ethernet
-------------------------------------------------------------------------------------------
looking for now-outdated files... none found
pickling environment... done
checking consistency... Documentation/networking/pse-pd/introduction.rst: WARNING: document isn't included in any toctree
```

I have to fix them up:

---- >8 ----
diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst
index 683eb42309cc5b..3900c6885cfc7d 100644
--- a/Documentation/networking/index.rst
+++ b/Documentation/networking/index.rst
@@ -88,6 +88,7 @@ Contents:
    phonet
    pktgen
    plip
+   pse-pd/index
    ppp_generic
    proc_net_tcp
    radiotap-headers
diff --git a/Documentation/networking/pse-pd/index.rst b/Documentation/networking/pse-pd/index.rst
new file mode 100644
index 00000000000000..18197bc7303dc9
--- /dev/null
+++ b/Documentation/networking/pse-pd/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Power Sourcing Equipment (PSE) Documentation
+============================================
+
+.. toctree::
+   :maxdepth: 2
+
+   introduction
diff --git a/Documentation/networking/pse-pd/introduction.rst b/Documentation/networking/pse-pd/introduction.rst
index e213083b9aff2d..e3d3faaef717f2 100644
--- a/Documentation/networking/pse-pd/introduction.rst
+++ b/Documentation/networking/pse-pd/introduction.rst
@@ -24,7 +24,7 @@ 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:
@@ -53,7 +53,7 @@ following naming conventions are recommended:
   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).
@@ -62,7 +62,7 @@ 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

Thanks.

-- 
An old man doll... just what I always wanted! - Clara

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