On Mon, 20 Nov 2023 19:00:03 +0100
Andrew Lunn [off-list ref] wrote:

quoted

Official name for "PoE" is "Power via Media Dependent Interface". PoE is
not used in the IEEE 802.3-2018. Using names not used in the specification,
make development even harder :)
Especially since there are even more marketing names (names not used in the
specification) for different PoE variants:
- 802.3af (802.3at Type 1), PoE
- 802.3at Type 2, PoE+
- 802.3bt Type 3, 4PPoE or PoE++
- 802.3bt Type 4, 4PPoE or PoE++  

From the 2018 standard:

  1.4.407 Power Sourcing Equipment (PSE): A DTE or midspan device that
  provides the power to a single link section. PSEs are defined for
  use with two different types of balanced twisted-pair PHYs. When
  used with 2 or 4 pair balanced twisted-pair (BASE-T) PHYs, (see IEEE
  Std 802.3, Clause 33), DTE powering is intended to provide a single
  10BASE-T, 100BASE-TX, or 1000BASE-T device with a unified interface
  for both the data it requires and the power to process these
  data. When used with single balanced twisted-pair (BASE-T1) PHYs
  (see IEEE Std 802.3, Clause 104), DTE powering is intended to
  provide a single 100BASE-T1 or 1000BASE-T1 device with a unified
  interface for both the data it requires and the power to process
  these data. A PSE used with balanced single twisted-pair PHYs is
  also referred to as a PoDL PSE.

So it seems like, anything not PoDL PSE does not have a name :-(

However, everything not PoDL PSE seems to be clause 33. So how about:

	enum ethtool_podl_pse_admin_state podl_admin_control;
	enum ethtool_c33_pse_admin_state c33_admin_control;  

At least inside the kernel we use c22, c45, c37 etc. I'm not sure they
are visible to userspace, but if we don't have a better name, maybe we
have to use c33 in userspace as well.

I do think naming like this makes it clear we are talking about two
parallel technologies, not a generic layer and then extensions for
podl.

What do you think?

If we decide to add a prefix, "c33" is precise but less easily understandable,
why not using simply "poe" prefix?
Maybe as POE were originally PMDI you prefer to use c33 which won't change over
time? 

Should I also modify the content of the enum?
ETHTOOL_PSE_ADMIN_STATE_* to ETHTOOL_C33_PSE_ADMIN_*
ETHTOOL_PSE_PW_D_STATUS_* to ETHTOOL_C33_PSE_PW_D_STATUS_*


-- 
Köry Maincent, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com