diff mbox series

[net-next,v5,10/17] net: pse-pd: Add support for PSE PIs

Message ID 20240227-feature_poe-v5-10-28f0aa48246d@bootlin.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series net: Add support for Power over Ethernet (PoE) | expand

Checks

Context Check Description
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netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; GEN HAS DIFF 2 files changed, 96 insertions(+), 39 deletions(-);
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 942 this patch: 942
netdev/build_tools success Errors and warnings before: 0 this patch: 0
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netdev/build_clang success Errors and warnings before: 958 this patch: 958
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 959 this patch: 959
netdev/checkpatch warning WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
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netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-27--21-00 (tests: 1362)

Commit Message

Kory Maincent Feb. 27, 2024, 2:42 p.m. UTC
Add support for getting the PSE controller node through PSE PI device
subnode.
This supports adds a way to get the PSE PI id from the pse_pi devicetree
subnode of a PSE controller node simply by reading the reg property.

This patch is sponsored by Dent Project <dentproject@linuxfoundation.org>.

Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
---

Changes in v3:
- New patch.

Changes in v4:
- Add PSE PI documentation.

Changes in v5:
- Update PSE PI documentation.
---
 Documentation/networking/pse-pd/index.rst  |   1 +
 Documentation/networking/pse-pd/pse-pi.rst | 302 +++++++++++++++++++++++++++++
 drivers/net/pse-pd/pse_core.c              | 223 +++++++++++++++++----
 include/linux/pse-pd/pse.h                 |  38 +++-
 4 files changed, 520 insertions(+), 44 deletions(-)

Comments

Oleksij Rempel March 1, 2024, 2:24 p.m. UTC | #1
Hi Kory,

On Tue, Feb 27, 2024 at 03:42:52PM +0100, Kory Maincent wrote:
....

> diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
> index fed006cbc185..9124eb3d6492 100644
> --- a/drivers/net/pse-pd/pse_core.c
> +++ b/drivers/net/pse-pd/pse_core.c
> @@ -27,38 +27,137 @@ struct pse_control {
>  	struct kref refcnt;
>  };
>  
> -/**
> - * of_pse_zero_xlate - dummy function for controllers with one only control
> - * @pcdev: a pointer to the PSE controller device
> - * @pse_spec: PSE line specifier as found in the device tree
> - *
> - * This static translation function is used by default if of_xlate in
> - * :c:type:`pse_controller_dev` is not set. It is useful for all PSE
> - * controllers with #pse-cells = <0>.
> - */

Please replace documentation

> -static int of_pse_zero_xlate(struct pse_controller_dev *pcdev,
> -			     const struct of_phandle_args *pse_spec)
> +static int of_load_pse_pi_pairsets(struct device_node *node,
> +				   struct pse_pi *pi,
> +				   int npairsets)
>  {
> -	return 0;
> +	struct device_node *pairset_np;
> +	const char *name;
> +	int i, ret;
> +
> +	for (i = 0; i < npairsets; i++) {

please move this scope to a separate function.

> +		ret = of_property_read_string_index(node,
> +						    "pairset-names",
> +						     i, &name);
> +		if (ret)
> +			break;
> +
> +		if (strcmp(name, "alternative-a")) {

strcmp returns 0 if it matching

		if (!strcmp(name, "alternative-a")) {


> +			pi->pairset[i].pinout = ALTERNATIVE_A;
> +		} else if (strcmp(name, "alternative-b")) {

		if (!strcmp(name, "alternative-a")) {

> +			pi->pairset[i].pinout = ALTERNATIVE_B;
> +		} else {
> +			pr_err("pse: wrong pairset-names value %s\n", name);
> +			ret = -EINVAL;
> +			break;
> +		}
> +
> +		pairset_np = of_parse_phandle(node, "pairsets", i);
> +		if (!pairset_np) {
> +			ret = -ENODEV;
> +			break;
> +		}
> +
> +		pi->pairset[i].np = pairset_np;
> +	}
> +
> +	if (i == 2 && pi->pairset[0].pinout == pi->pairset[1].pinout) {
> +		pr_err("pse: two PI pairsets can not have identical pinout");
> +		ret = -EINVAL;
> +	}
> +
> +	/* If an error appears on the second pairset load, release the first
> +	 * pairset device node kref
> +	 */
> +	if (ret) {
> +		of_node_put(pi->pairset[0].np);
> +		pi->pairset[0].np = NULL;
> +		of_node_put(pi->pairset[1].np);
> +		pi->pairset[1].np = NULL;
> +	}
> +
> +	return ret;
>  }
>  
> -/**
> - * of_pse_simple_xlate - translate pse_spec to the PSE line number
> - * @pcdev: a pointer to the PSE controller device
> - * @pse_spec: PSE line specifier as found in the device tree
> - *
> - * This static translation function is used by default if of_xlate in
> - * :c:type:`pse_controller_dev` is not set. It is useful for all PSE
> - * controllers with 1:1 mapping, where PSE lines can be indexed by number
> - * without gaps.
> - */

Please replace documentation

> -static int of_pse_simple_xlate(struct pse_controller_dev *pcdev,
> -			       const struct of_phandle_args *pse_spec)
> +static int of_load_pse_pis(struct pse_controller_dev *pcdev)
>  {
> -	if (pse_spec->args[0] >= pcdev->nr_lines)
> -		return -EINVAL;
> +	struct device_node *np = pcdev->dev->of_node;
> +	struct device_node *node, *pis;
> +	int ret, i;
>  
> -	return pse_spec->args[0];
> +	if (!np)
> +		return -ENODEV;
> +
> +	pcdev->pi = kcalloc(pcdev->nr_lines, sizeof(*pcdev->pi), GFP_KERNEL);
> +	if (!pcdev->pi)
> +		return -ENOMEM;
> +
> +	pis = of_get_child_by_name(np, "pse-pis");
> +	if (!pis) {

Do we need to allocate pcdev->pi if there are no pse-pis?

> +		/* Legacy OF description of PSE PIs */
> +		pcdev->of_legacy = true;

It is not "legacy" :) PoDL do not providing definition of PSE PI since there
is only one pair. May be: single_pair, no_pse_pi or any other idea.

> +		return 0;
> +	}
> +
> +	for_each_child_of_node(pis, node) {

please move this scope to a separate function.

> +		struct pse_pi pi = {0};
> +		int npairsets;
> +		u32 id;
> +
> +		if (!of_node_name_eq(node, "pse-pi"))
> +			continue;
> +
> +		ret = of_property_read_u32(node, "reg", &id);
> +		if (ret)

error: can't get "reg" property for node "%s"

> +			goto out;
> +
> +		if (id >= pcdev->nr_lines || pcdev->pi[id].np) {

Here two different kind of errors:
- (id >= pcdev->nr_lines) reg value is out of range. print value and max
  range.
- (pcdev->pi[id].np) other node with same reg value was already
  registered... print both node names.

> +			dev_err(pcdev->dev, "wrong id of pse pi: %u\n",
> +				id);
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		ret = of_property_count_strings(node, "pairset-names");
> +		if (ret <= 0)

if (ret < 0)
   error: can't get "pairset-names" property: %pe
if (ret < 1 || ret > 2)
   error: wrong number of pairset-names. Should be 1 or 2, got %i

> +			goto out;
> +		npairsets = ret;
> +
> +		ret = of_count_phandle_with_args(node, "pairsets", NULL);
> +		if (ret <= 0)

same as for pairset-names

> +			goto out;
> +
> +		/* npairsets is limited to value one or two */
> +		if (ret != npairsets || ret > 2) {

(ret > 2) will be handled by previous checks
(ret != npairsets) amount of pairsets and pairset-names is not equal %i
!= %i

> +			dev_err(pcdev->dev,
> +				"wrong number of pairsets or pairset-names for pse pi %d\n",
> +				id);
> +			ret = -EINVAL;
> +			goto out;
> +		}
> +
> +		ret = of_load_pse_pi_pairsets(node, &pi, npairsets);
> +		if (ret)
> +			goto out;
> +
> +		of_node_get(node);
> +		pi.np = node;
> +		memcpy(&pcdev->pi[id], &pi, sizeof(pi));
> +	}
> +
> +	of_node_put(pis);
> +	return 0;
> +
> +out:
> +	for (i = 0; i <= pcdev->nr_lines; i++) {
> +		of_node_put(pcdev->pi[i].pairset[0].np);
> +		of_node_put(pcdev->pi[i].pairset[1].np);
> +		of_node_put(pcdev->pi[i].np);
> +	}
> +	of_node_put(node);
> +	of_node_put(pis);
> +	kfree(pcdev->pi);
> +	return ret;
>  }
>  
>  /**
> @@ -67,16 +166,18 @@ static int of_pse_simple_xlate(struct pse_controller_dev *pcdev,
>   */
>  int pse_controller_register(struct pse_controller_dev *pcdev)
>  {
> -	if (!pcdev->of_xlate) {
> -		if (pcdev->of_pse_n_cells == 0)
> -			pcdev->of_xlate = of_pse_zero_xlate;
> -		else if (pcdev->of_pse_n_cells == 1)
> -			pcdev->of_xlate = of_pse_simple_xlate;
> -	}
> +	int ret;
>  
>  	mutex_init(&pcdev->lock);
>  	INIT_LIST_HEAD(&pcdev->pse_control_head);
>  
> +	if (!pcdev->nr_lines)
> +		pcdev->nr_lines = 1;
> +
> +	ret = of_load_pse_pis(pcdev);
> +	if (ret)
> +		return ret;
> +
>  	mutex_lock(&pse_list_mutex);
>  	list_add(&pcdev->list, &pse_controller_list);
>  	mutex_unlock(&pse_list_mutex);
> @@ -91,6 +192,14 @@ EXPORT_SYMBOL_GPL(pse_controller_register);
>   */
>  void pse_controller_unregister(struct pse_controller_dev *pcdev)
>  {
> +	int i;
> +
> +	for (i = 0; i <= pcdev->nr_lines; i++) {
> +		of_node_put(pcdev->pi[i].pairset[0].np);
> +		of_node_put(pcdev->pi[i].pairset[1].np);
> +		of_node_put(pcdev->pi[i].np);
> +	}
> +	kfree(pcdev->pi);

Same pattern was already used. It is better to move it to a separate
function.

>  	mutex_lock(&pse_list_mutex);
>  	list_del(&pcdev->list);
>  	mutex_unlock(&pse_list_mutex);
> @@ -203,8 +312,33 @@ pse_control_get_internal(struct pse_controller_dev *pcdev, unsigned int index)
>  	return psec;
>  }
>  
> -struct pse_control *
> -of_pse_control_get(struct device_node *node)
> +static int of_pse_match_pi(struct pse_controller_dev *pcdev,
> +			   struct device_node *np)
> +{
> +	int i;
> +
> +	for (i = 0; i <= pcdev->nr_lines; i++) {
> +		if (pcdev->pi[i].np == np)
> +			return i;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int psec_id_legacy_xlate(struct pse_controller_dev *pcdev,
> +				const struct of_phandle_args *pse_spec)

rename legacy to some other name in all places.

> +{
> +	if (!pcdev->of_pse_n_cells)
> +		return 0;
> +
> +	if (pcdev->of_pse_n_cells > 1 ||
> +	    pse_spec->args[0] >= pcdev->nr_lines)
> +		return -EINVAL;
> +
> +	return pse_spec->args[0];
> +}
> +
> +struct pse_control *of_pse_control_get(struct device_node *node)
>  {
>  	struct pse_controller_dev *r, *pcdev;
>  	struct of_phandle_args args;
> @@ -222,7 +356,14 @@ of_pse_control_get(struct device_node *node)
>  	mutex_lock(&pse_list_mutex);
>  	pcdev = NULL;
>  	list_for_each_entry(r, &pse_controller_list, list) {
> -		if (args.np == r->dev->of_node) {
> +		if (!r->of_legacy) {
> +			ret = of_pse_match_pi(r, args.np);
> +			if (ret >= 0) {
> +				pcdev = r;
> +				psec_id = ret;
> +				break;
> +			}
> +		} else if (args.np == r->dev->of_node) {
>  			pcdev = r;
>  			break;
>  		}
> @@ -238,10 +379,12 @@ of_pse_control_get(struct device_node *node)
>  		goto out;
>  	}
>  
> -	psec_id = pcdev->of_xlate(pcdev, &args);
> -	if (psec_id < 0) {
> -		psec = ERR_PTR(psec_id);
> -		goto out;
> +	if (pcdev->of_legacy) {
> +		psec_id = psec_id_legacy_xlate(pcdev, &args);
> +		if (psec_id < 0) {
> +			psec = ERR_PTR(psec_id);
> +			goto out;
> +		}
>  	}
>  
>  	/* pse_list_mutex also protects the pcdev's pse_control list */
> diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
> index 19589571157f..01b3b9adfe2a 100644
> --- a/include/linux/pse-pd/pse.h
> +++ b/include/linux/pse-pd/pse.h
> @@ -64,6 +64,36 @@ struct device_node;
>  struct of_phandle_args;
>  struct pse_control;
>  
> +/* PSE PI pairset pinout can either be Alternative A or Alternative B */
> +enum pse_pi_pairset_pinout {
> +	ALTERNATIVE_A,
> +	ALTERNATIVE_B,
> +};
> +
> +/**
> + * struct pse_pi_pairset - PSE PI pairset entity describing the pinout
> + *			   alternative ant its phandle
> + *
> + * @pinout: description of the pinout alternative
> + * @np: device node pointer describing the pairset phandle
> + */
> +struct pse_pi_pairset {
> +	enum pse_pi_pairset_pinout pinout;
> +	struct device_node *np;
> +};
> +
> +/**
> + * struct pse_pi - PSE PI (Power Interface) entity as described in
> + *		   IEEE 802.3-2022 145.2.4
> + *
> + * @pairset: table of the PSE PI pinout alternative for the two pairset
> + * @np: device node pointer of the PSE PI node
> + */
> +struct pse_pi {
> +	struct pse_pi_pairset pairset[2];
> +	struct device_node *np;
> +};
> +
>  /**
>   * struct pse_controller_dev - PSE controller entity that might
>   *                             provide multiple PSE controls
> @@ -73,11 +103,11 @@ struct pse_control;
>   * @pse_control_head: head of internal list of requested PSE controls
>   * @dev: corresponding driver model device struct
>   * @of_pse_n_cells: number of cells in PSE line specifiers
> - * @of_xlate: translation function to translate from specifier as found in the
> - *            device tree to id as given to the PSE control ops
>   * @nr_lines: number of PSE controls in this controller device
>   * @lock: Mutex for serialization access to the PSE controller
>   * @types: types of the PSE controller
> + * @pi: table of PSE PIs described in this controller device
> + * @of_legacy: flag set if the pse_pis devicetree node is not used
>   */
>  struct pse_controller_dev {
>  	const struct pse_controller_ops *ops;
> @@ -86,11 +116,11 @@ struct pse_controller_dev {
>  	struct list_head pse_control_head;
>  	struct device *dev;
>  	int of_pse_n_cells;
> -	int (*of_xlate)(struct pse_controller_dev *pcdev,
> -			const struct of_phandle_args *pse_spec);
>  	unsigned int nr_lines;
>  	struct mutex lock;
>  	enum ethtool_pse_types types;
> +	struct pse_pi *pi;
> +	bool of_legacy;
>  };
>  
>  #if IS_ENABLED(CONFIG_PSE_CONTROLLER)

Regards,
Oleksij
Kory Maincent March 1, 2024, 4:10 p.m. UTC | #2
Hello Oleskij,

Thanks you for the review.

On Fri, 1 Mar 2024 15:24:07 +0100
Oleksij Rempel <o.rempel@pengutronix.de> wrote:

> > -static int of_pse_simple_xlate(struct pse_controller_dev *pcdev,
> > -			       const struct of_phandle_args *pse_spec)
> > +static int of_load_pse_pis(struct pse_controller_dev *pcdev)
> >  {
> > -	if (pse_spec->args[0] >= pcdev->nr_lines)
> > -		return -EINVAL;
> > +	struct device_node *np = pcdev->dev->of_node;
> > +	struct device_node *node, *pis;
> > +	int ret, i;
> >  
> > -	return pse_spec->args[0];
> > +	if (!np)
> > +		return -ENODEV;
> > +
> > +	pcdev->pi = kcalloc(pcdev->nr_lines, sizeof(*pcdev->pi),
> > GFP_KERNEL);
> > +	if (!pcdev->pi)
> > +		return -ENOMEM;
> > +
> > +	pis = of_get_child_by_name(np, "pse-pis");
> > +	if (!pis) {  
> 
> Do we need to allocate pcdev->pi if there are no pse-pis?

In fact it is not needed in this patch but in the patch 13 which use regulator
framework, as the regulator is described on each pi structure.

I will update them accordingly.

> > +		/* Legacy OF description of PSE PIs */
> > +		pcdev->of_legacy = true;  
> 
> It is not "legacy" :) PoDL do not providing definition of PSE PI since there
> is only one pair. May be: single_pair, no_pse_pi or any other idea.

You right it is not needed for PoDL. Maybe no_pse_pi is better according to the
following thoughts.

Just wondering, how a pse controller that support PoE and PoDL simultaneously
would be exposed in the binding. In that case I suppose all the PIs (PoE and
PoDL) need to use the pse-pi subnode. Then the "alternative pinout" and
"polarity" parameter would not be requested for PoDL PIs.

> > +			dev_err(pcdev->dev, "wrong id of pse pi: %u\n",
> > +				id);
> > +			ret = -EINVAL;
> > +			goto out;
> > +		}
> > +
> > +		ret = of_property_count_strings(node, "pairset-names");
> > +		if (ret <= 0)  
> 
> if (ret < 0)
>    error: can't get "pairset-names" property: %pe
> if (ret < 1 || ret > 2)
>    error: wrong number of pairset-names. Should be 1 or 2, got %i

Need to modify this to be able to have PoDL PIs without pairset description.

Regards,
Oleksij Rempel March 1, 2024, 4:48 p.m. UTC | #3
Hay Köry,

On Fri, Mar 01, 2024 at 05:10:05PM +0100, Köry Maincent wrote:
> Hello Oleskij,
> 
> Thanks you for the review.

I'll try to review more at weekend.

> > > +		/* Legacy OF description of PSE PIs */
> > > +		pcdev->of_legacy = true;  
> > 
> > It is not "legacy" :) PoDL do not providing definition of PSE PI since there
> > is only one pair. May be: single_pair, no_pse_pi or any other idea.
> 
> You right it is not needed for PoDL. Maybe no_pse_pi is better according to the
> following thoughts.
> 
> Just wondering, how a pse controller that support PoE and PoDL simultaneously
> would be exposed in the binding. In that case I suppose all the PIs (PoE and
> PoDL) need to use the pse-pi subnode. Then the "alternative pinout" and
> "polarity" parameter would not be requested for PoDL PIs.

In case of hybrid device I would expect that we will have an 4 pair
connector where only one pair will be used. In this case we will need to
know what pair and polarity is supported or can be configured for PoDL.
It will be full blown PSE PI node with PoDL specific extras.

Don't worry about it right now.

Regards,
Oleksij
diff mbox series

Patch

diff --git a/Documentation/networking/pse-pd/index.rst b/Documentation/networking/pse-pd/index.rst
index 18197bc7303d..de28a5aee316 100644
--- a/Documentation/networking/pse-pd/index.rst
+++ b/Documentation/networking/pse-pd/index.rst
@@ -7,3 +7,4 @@  Power Sourcing Equipment (PSE) Documentation
    :maxdepth: 2
 
    introduction
+   pse-pi
diff --git a/Documentation/networking/pse-pd/pse-pi.rst b/Documentation/networking/pse-pd/pse-pi.rst
new file mode 100644
index 000000000000..c4a50c670d9c
--- /dev/null
+++ b/Documentation/networking/pse-pd/pse-pi.rst
@@ -0,0 +1,302 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+PSE Power Interface (PSE PI) Documentation
+==========================================
+
+The Power Sourcing Equipment Power Interface (PSE PI) plays a pivotal role in
+the architecture of Power over Ethernet (PoE) systems. It is essentially a
+blueprint that outlines how one or multiple power sources are connected to the
+eight-pin modular jack, commonly known as the Ethernet RJ45 port. This
+connection scheme is crucial for enabling the delivery of power alongside data
+over Ethernet cables.
+
+Documentation and Standards
+---------------------------
+
+The IEEE 802.3 standard provides detailed documentation on the PSE PI.
+Specifically:
+
+- Section "33.2.3 PI pin assignments" covers the pin assignments for PoE
+  systems that utilize two pairs for power delivery.
+- Section "145.2.4 PSE PI" addresses the configuration for PoE systems that
+  deliver power over all four pairs of an Ethernet cable.
+
+PSE PI and Single Pair Ethernet
+-------------------------------
+
+Single Pair Ethernet (SPE) represents a different approach to Ethernet
+connectivity, utilizing just one pair of conductors for both data and power
+transmission. Unlike the configurations detailed in the PSE PI for standard
+Ethernet, which can involve multiple power sourcing arrangements across four or
+two pairs of wires, SPE operates on a simpler model due to its single-pair
+design. As a result, the complexities of choosing between alternative pin
+assignments for power delivery, as described in the PSE PI for multi-pair
+Ethernet, are not applicable to SPE.
+
+Understanding PSE PI
+--------------------
+
+The Power Sourcing Equipment Power Interface (PSE PI) is a framework defining
+how Power Sourcing Equipment (PSE) delivers power to Powered Devices (PDs) over
+Ethernet cables. It details two main configurations for power delivery, known
+as Alternative A and Alternative B, which are distinguished not only by their
+method of power transmission but also by the implications for polarity and data
+transmission direction.
+
+Alternative A and B Overview
+----------------------------
+
+- **Alternative A:** Utilizes RJ45 conductors 1, 2, 3 and 6. In either case of
+  networks 10/100BaseT or 1G/2G/5G/10GBaseT, the pairs used are carrying data.
+  The power delivery's polarity in this alternative can vary based on the MDI
+  (Medium Dependent Interface) or MDI-X (Medium Dependent Interface Crossover)
+  configuration.
+
+- **Alternative B:** Utilizes RJ45 conductors 4, 5, 7 and 8. In case of
+  10/100BaseT network the pairs used are spare pairs without data and are less
+  influenced by data transmission direction. This is not the case for
+  1G/2G/5G/10GBaseT network. Alternative B includes two configurations with
+  different polarities, known as variant X and variant S, to accommodate
+  different network requirements and device specifications.
+
+Table 145–3—PSE Pinout Alternatives
+-----------------------------------
+
+The following table outlines the pin configurations for both Alternative A and
+Alternative B.
+
++------------+-------------------+-----------------+-----------------+-----------------+
+| Conductor  | Alternative A     | Alternative A   | Alternative B   | Alternative B   |
+|            |    (MDI-X)        |      (MDI)      |        (X)      |        (S)      |
++============+===================+=================+=================+=================+
+| 1          | Negative V        | Positive V      | -               | -               |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 2          | Negative V        | Positive V      | -               | -               |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 3          | Positive V        | Negative V      | -               | -               |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 4          | -                 | -               | Negative V      | Positive V      |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 5          | -                 | -               | Negative V      | Positive V      |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 6          | Positive V        | Negative V      | -               | -               |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 7          | -                 | -               | Positive V      | Negative V      |
++------------+-------------------+-----------------+-----------------+-----------------+
+| 8          | -                 | -               | Positive V      | Negative V      |
++------------+-------------------+-----------------+-----------------+-----------------+
+
+.. note::
+    - "Positive V" and "Negative V" indicate the voltage polarity for each pin.
+    - "-" indicates that the pin is not used for power delivery in that
+      specific configuration.
+
+PSE PI compatibilities
+----------------------
+
+The following table outlines the compatibility between the pinout alternative
+and the 1000/2.5G/5G/10GBaseT in the PSE 2 pairs connection.
+
++---------+---------------+---------------------+-----------------------+
+| Variant | Alternative   | Power Feeding Type  | Compatibility with    |
+|         | (A/B)         | (Direct/Phantom)    | 1000/2.5G/5G/10GBaseT |
++=========+===============+=====================+=======================+
+| 1       | A             | Phantom             | Yes                   |
++---------+---------------+---------------------+-----------------------+
+| 2       | B             | Phantom             | Yes                   |
++---------+---------------+---------------------+-----------------------+
+| 3       | B             | Direct              | No                    |
++---------+---------------+---------------------+-----------------------+
+
+.. note::
+    - "Direct" indicate a variant where the power is injected directly to pairs
+       without using magnetics in case of spare pairs.
+    - "Phantom" indicate power path over coils/magnetics as it is done for
+       Alternative A variant.
+
+In case of PSE 4 pairs, a PSE supporting only 10/100BaseT (which mean Direct
+Power on pinout Alternative B) is not compatible with a 4 pairs
+1000/2.5G/5G/10GBaseT.
+
+PSE Power Interface (PSE PI) Connection Diagram
+-----------------------------------------------
+
+The diagram below illustrates the connection architecture between the RJ45
+port, the Ethernet PHY (Physical Layer), and the PSE PI (Power Sourcing
+Equipment Power Interface), demonstrating how power and data are delivered
+simultaneously through an Ethernet cable. The RJ45 port serves as the physical
+interface for these connections, with each of its eight pins connected to both
+the Ethernet PHY for data transmission and the PSE PI for power delivery.
+
+.. code-block::
+
+    +--------------------------+
+    |                          |
+    |          RJ45 Port       |
+    |                          |
+    +--+--+--+--+--+--+--+--+--+                +-------------+
+      1| 2| 3| 4| 5| 6| 7| 8|                   |             |
+       |  |  |  |  |  |  |  o-------------------+             |
+       |  |  |  |  |  |  o--|-------------------+             +<--- PSE 1
+       |  |  |  |  |  o--|--|-------------------+             |
+       |  |  |  |  o--|--|--|-------------------+             |
+       |  |  |  o--|--|--|--|-------------------+  PSE PI     |
+       |  |  o--|--|--|--|--|-------------------+             |
+       |  o--|--|--|--|--|--|-------------------+             +<--- PSE 2 (optional)
+       o--|--|--|--|--|--|--|-------------------+             |
+       |  |  |  |  |  |  |  |                   |             |
+    +--+--+--+--+--+--+--+--+--+                +-------------+
+    |                          |
+    |       Ethernet PHY       |
+    |                          |
+    +--------------------------+
+
+Simple PSE PI Configuration for Alternative A
+---------------------------------------------
+
+The diagram below illustrates a straightforward PSE PI (Power Sourcing
+Equipment Power Interface) configuration designed to support the Alternative A
+setup for Power over Ethernet (PoE). This implementation is tailored to provide
+power delivery through the data-carrying pairs of an Ethernet cable, suitable
+for either MDI or MDI-X configurations, albeit supporting one variation at a
+time.
+
+.. code-block::
+
+         +-------------+
+         |    PSE PI   |
+ 8  -----+                             +-------------+
+ 7  -----+                    Rail 1   |
+ 6  -----+------+----------------------+
+ 5  -----+      |                      |
+ 4  -----+     /              Rail 2   |  PSE 1
+ 3  -----+----´          +-------------+
+ 2  -----+----+---------´              |
+ 1  -----+---´                         +-------------+
+         |
+         +-------------+
+
+In this configuration:
+
+- Pins 1 and 2, as well as pins 3 and 6, are utilized for power delivery in
+  addition to data transmission. This aligns with the standard wiring for
+  10/100BaseT Ethernet networks where these pairs are used for data.
+- Rail 1 and Rail 2 represent the positive and negative voltage rails, with
+  Rail 1 connected to pins 1 and 2, and Rail 2 connected to pins 3 and 6.
+  More advanced PSE PI configurations may include integrated or external
+  switches to change the polarity of the voltage rails, allowing for
+  compatibility with both MDI and MDI-X configurations.
+
+More complex PSE PI configurations may include additional components, to support
+Alternative B, or to provide additional features such as power management, or
+additional power delivery capabilities such as 2-pair or 4-pair power delivery.
+
+.. code-block::
+
+         +-------------+
+         |    PSE PI   |
+         |        +---+
+ 8  -----+--------+   |                 +-------------+
+ 7  -----+--------+   |       Rail 1   |
+ 6  -----+--------+   +-----------------+
+ 5  -----+--------+   |                |
+ 4  -----+--------+   |       Rail 2   |  PSE 1
+ 3  -----+--------+   +----------------+
+ 2  -----+--------+   |                |
+ 1  -----+--------+   |                 +-------------+
+         |        +---+
+         +-------------+
+
+Device Tree Configuration: Describing PSE PI Configurations
+-----------------------------------------------------------
+
+The necessity for a separate PSE PI node in the device tree is influenced by
+the intricacy of the Power over Ethernet (PoE) system's setup. Here are
+descriptions of both simple and complex PSE PI configurations to illustrate
+this decision-making process:
+
+**Simple PSE PI Configuration:**
+In a straightforward scenario, the PSE PI setup involves a direct, one-to-one
+connection between a single PSE controller and an Ethernet port. This setup
+typically supports basic PoE functionality without the need for dynamic
+configuration or management of multiple power delivery modes. For such simple
+configurations, detailing the PSE PI within the existing PSE controller's node
+may suffice, as the system does not encompass additional complexity that
+warrants a separate node. The primary focus here is on the clear and direct
+association of power delivery to a specific Ethernet port.
+
+**Complex PSE PI Configuration:**
+Contrastingly, a complex PSE PI setup may encompass multiple PSE controllers or
+auxiliary circuits that collectively manage power delivery to one Ethernet
+port. Such configurations might support a range of PoE standards and require
+the capability to dynamically configure power delivery based on the operational
+mode (e.g., PoE2 versus PoE4) or specific requirements of connected devices. In
+these instances, a dedicated PSE PI node becomes essential for accurately
+documenting the system architecture. This node would serve to detail the
+interactions between different PSE controllers, the support for various PoE
+modes, and any additional logic required to coordinate power delivery across
+the network infrastructure.
+
+**Guidance:**
+
+For simple PSE setups, including PSE PI information in the PSE controller node
+might suffice due to the straightforward nature of these systems. However,
+complex configurations, involving multiple components or advanced PoE features,
+benefit from a dedicated PSE PI node. This method adheres to IEEE 802.3
+specifications, improving documentation clarity and ensuring accurate
+representation of the PoE system's complexity.
+
+PSE PI Node: Essential Information
+----------------------------------
+
+The PSE PI (Power Sourcing Equipment Power Interface) node in a device tree can
+include several key pieces of information critical for defining the power
+delivery capabilities and configurations of a PoE (Power over Ethernet) system.
+Below is a list of such information, along with explanations for their
+necessity and reasons why they might not be found within a PSE controller node:
+
+1. **Powered Pairs Configuration**
+
+   - *Description:* Identifies the pairs used for power delivery in the
+     Ethernet cable.
+   - *Necessity:* Essential to ensure the correct pairs are powered according
+     to the board's design.
+   - *PSE Controller Node:* Typically lacks details on physical pair usage,
+     focusing on power regulation.
+
+2. **Polarity of Powered Pairs**
+
+   - *Description:* Specifies the polarity (positive or negative) for each
+     powered pair.
+   - *Necessity:* Critical for safe and effective power transmission to PDs.
+   - *PSE Controller Node:* Polarity management may exceed the standard
+     functionalities of PSE controllers.
+
+3. **PSE Cells Association**
+
+   - *Description:* Details the association of PSE cells with Ethernet ports or
+     pairs in multi-cell configurations.
+   - *Necessity:* Allows for optimized power resource allocation in complex
+     systems.
+   - *PSE Controller Node:* Controllers may not manage cell associations
+     directly, focusing instead on power flow regulation.
+
+4. **Support for PoE Standards**
+
+   - *Description:* Lists the PoE standards and configurations supported by the
+     system.
+   - *Necessity:* Ensures system compatibility with various PDs and adherence
+     to industry standards.
+   - *PSE Controller Node:* Specific capabilities may depend on the overall PSE
+     PI design rather than the controller alone. Multiple PSE cells per PI
+     do not necessarily imply support for multiple PoE standards.
+
+5. **Protection Mechanisms**
+
+   - *Description:* Outlines additional protection mechanisms, such as
+     overcurrent protection and thermal management.
+   - *Necessity:* Provides extra safety and stability, complementing PSE
+     controller protections.
+   - *PSE Controller Node:* Some protections may be implemented via
+     board-specific hardware or algorithms external to the controller.
+
diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index fed006cbc185..9124eb3d6492 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -27,38 +27,137 @@  struct pse_control {
 	struct kref refcnt;
 };
 
-/**
- * of_pse_zero_xlate - dummy function for controllers with one only control
- * @pcdev: a pointer to the PSE controller device
- * @pse_spec: PSE line specifier as found in the device tree
- *
- * This static translation function is used by default if of_xlate in
- * :c:type:`pse_controller_dev` is not set. It is useful for all PSE
- * controllers with #pse-cells = <0>.
- */
-static int of_pse_zero_xlate(struct pse_controller_dev *pcdev,
-			     const struct of_phandle_args *pse_spec)
+static int of_load_pse_pi_pairsets(struct device_node *node,
+				   struct pse_pi *pi,
+				   int npairsets)
 {
-	return 0;
+	struct device_node *pairset_np;
+	const char *name;
+	int i, ret;
+
+	for (i = 0; i < npairsets; i++) {
+		ret = of_property_read_string_index(node,
+						    "pairset-names",
+						     i, &name);
+		if (ret)
+			break;
+
+		if (strcmp(name, "alternative-a")) {
+			pi->pairset[i].pinout = ALTERNATIVE_A;
+		} else if (strcmp(name, "alternative-b")) {
+			pi->pairset[i].pinout = ALTERNATIVE_B;
+		} else {
+			pr_err("pse: wrong pairset-names value %s\n", name);
+			ret = -EINVAL;
+			break;
+		}
+
+		pairset_np = of_parse_phandle(node, "pairsets", i);
+		if (!pairset_np) {
+			ret = -ENODEV;
+			break;
+		}
+
+		pi->pairset[i].np = pairset_np;
+	}
+
+	if (i == 2 && pi->pairset[0].pinout == pi->pairset[1].pinout) {
+		pr_err("pse: two PI pairsets can not have identical pinout");
+		ret = -EINVAL;
+	}
+
+	/* If an error appears on the second pairset load, release the first
+	 * pairset device node kref
+	 */
+	if (ret) {
+		of_node_put(pi->pairset[0].np);
+		pi->pairset[0].np = NULL;
+		of_node_put(pi->pairset[1].np);
+		pi->pairset[1].np = NULL;
+	}
+
+	return ret;
 }
 
-/**
- * of_pse_simple_xlate - translate pse_spec to the PSE line number
- * @pcdev: a pointer to the PSE controller device
- * @pse_spec: PSE line specifier as found in the device tree
- *
- * This static translation function is used by default if of_xlate in
- * :c:type:`pse_controller_dev` is not set. It is useful for all PSE
- * controllers with 1:1 mapping, where PSE lines can be indexed by number
- * without gaps.
- */
-static int of_pse_simple_xlate(struct pse_controller_dev *pcdev,
-			       const struct of_phandle_args *pse_spec)
+static int of_load_pse_pis(struct pse_controller_dev *pcdev)
 {
-	if (pse_spec->args[0] >= pcdev->nr_lines)
-		return -EINVAL;
+	struct device_node *np = pcdev->dev->of_node;
+	struct device_node *node, *pis;
+	int ret, i;
 
-	return pse_spec->args[0];
+	if (!np)
+		return -ENODEV;
+
+	pcdev->pi = kcalloc(pcdev->nr_lines, sizeof(*pcdev->pi), GFP_KERNEL);
+	if (!pcdev->pi)
+		return -ENOMEM;
+
+	pis = of_get_child_by_name(np, "pse-pis");
+	if (!pis) {
+		/* Legacy OF description of PSE PIs */
+		pcdev->of_legacy = true;
+		return 0;
+	}
+
+	for_each_child_of_node(pis, node) {
+		struct pse_pi pi = {0};
+		int npairsets;
+		u32 id;
+
+		if (!of_node_name_eq(node, "pse-pi"))
+			continue;
+
+		ret = of_property_read_u32(node, "reg", &id);
+		if (ret)
+			goto out;
+
+		if (id >= pcdev->nr_lines || pcdev->pi[id].np) {
+			dev_err(pcdev->dev, "wrong id of pse pi: %u\n",
+				id);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = of_property_count_strings(node, "pairset-names");
+		if (ret <= 0)
+			goto out;
+		npairsets = ret;
+
+		ret = of_count_phandle_with_args(node, "pairsets", NULL);
+		if (ret <= 0)
+			goto out;
+
+		/* npairsets is limited to value one or two */
+		if (ret != npairsets || ret > 2) {
+			dev_err(pcdev->dev,
+				"wrong number of pairsets or pairset-names for pse pi %d\n",
+				id);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		ret = of_load_pse_pi_pairsets(node, &pi, npairsets);
+		if (ret)
+			goto out;
+
+		of_node_get(node);
+		pi.np = node;
+		memcpy(&pcdev->pi[id], &pi, sizeof(pi));
+	}
+
+	of_node_put(pis);
+	return 0;
+
+out:
+	for (i = 0; i <= pcdev->nr_lines; i++) {
+		of_node_put(pcdev->pi[i].pairset[0].np);
+		of_node_put(pcdev->pi[i].pairset[1].np);
+		of_node_put(pcdev->pi[i].np);
+	}
+	of_node_put(node);
+	of_node_put(pis);
+	kfree(pcdev->pi);
+	return ret;
 }
 
 /**
@@ -67,16 +166,18 @@  static int of_pse_simple_xlate(struct pse_controller_dev *pcdev,
  */
 int pse_controller_register(struct pse_controller_dev *pcdev)
 {
-	if (!pcdev->of_xlate) {
-		if (pcdev->of_pse_n_cells == 0)
-			pcdev->of_xlate = of_pse_zero_xlate;
-		else if (pcdev->of_pse_n_cells == 1)
-			pcdev->of_xlate = of_pse_simple_xlate;
-	}
+	int ret;
 
 	mutex_init(&pcdev->lock);
 	INIT_LIST_HEAD(&pcdev->pse_control_head);
 
+	if (!pcdev->nr_lines)
+		pcdev->nr_lines = 1;
+
+	ret = of_load_pse_pis(pcdev);
+	if (ret)
+		return ret;
+
 	mutex_lock(&pse_list_mutex);
 	list_add(&pcdev->list, &pse_controller_list);
 	mutex_unlock(&pse_list_mutex);
@@ -91,6 +192,14 @@  EXPORT_SYMBOL_GPL(pse_controller_register);
  */
 void pse_controller_unregister(struct pse_controller_dev *pcdev)
 {
+	int i;
+
+	for (i = 0; i <= pcdev->nr_lines; i++) {
+		of_node_put(pcdev->pi[i].pairset[0].np);
+		of_node_put(pcdev->pi[i].pairset[1].np);
+		of_node_put(pcdev->pi[i].np);
+	}
+	kfree(pcdev->pi);
 	mutex_lock(&pse_list_mutex);
 	list_del(&pcdev->list);
 	mutex_unlock(&pse_list_mutex);
@@ -203,8 +312,33 @@  pse_control_get_internal(struct pse_controller_dev *pcdev, unsigned int index)
 	return psec;
 }
 
-struct pse_control *
-of_pse_control_get(struct device_node *node)
+static int of_pse_match_pi(struct pse_controller_dev *pcdev,
+			   struct device_node *np)
+{
+	int i;
+
+	for (i = 0; i <= pcdev->nr_lines; i++) {
+		if (pcdev->pi[i].np == np)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int psec_id_legacy_xlate(struct pse_controller_dev *pcdev,
+				const struct of_phandle_args *pse_spec)
+{
+	if (!pcdev->of_pse_n_cells)
+		return 0;
+
+	if (pcdev->of_pse_n_cells > 1 ||
+	    pse_spec->args[0] >= pcdev->nr_lines)
+		return -EINVAL;
+
+	return pse_spec->args[0];
+}
+
+struct pse_control *of_pse_control_get(struct device_node *node)
 {
 	struct pse_controller_dev *r, *pcdev;
 	struct of_phandle_args args;
@@ -222,7 +356,14 @@  of_pse_control_get(struct device_node *node)
 	mutex_lock(&pse_list_mutex);
 	pcdev = NULL;
 	list_for_each_entry(r, &pse_controller_list, list) {
-		if (args.np == r->dev->of_node) {
+		if (!r->of_legacy) {
+			ret = of_pse_match_pi(r, args.np);
+			if (ret >= 0) {
+				pcdev = r;
+				psec_id = ret;
+				break;
+			}
+		} else if (args.np == r->dev->of_node) {
 			pcdev = r;
 			break;
 		}
@@ -238,10 +379,12 @@  of_pse_control_get(struct device_node *node)
 		goto out;
 	}
 
-	psec_id = pcdev->of_xlate(pcdev, &args);
-	if (psec_id < 0) {
-		psec = ERR_PTR(psec_id);
-		goto out;
+	if (pcdev->of_legacy) {
+		psec_id = psec_id_legacy_xlate(pcdev, &args);
+		if (psec_id < 0) {
+			psec = ERR_PTR(psec_id);
+			goto out;
+		}
 	}
 
 	/* pse_list_mutex also protects the pcdev's pse_control list */
diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
index 19589571157f..01b3b9adfe2a 100644
--- a/include/linux/pse-pd/pse.h
+++ b/include/linux/pse-pd/pse.h
@@ -64,6 +64,36 @@  struct device_node;
 struct of_phandle_args;
 struct pse_control;
 
+/* PSE PI pairset pinout can either be Alternative A or Alternative B */
+enum pse_pi_pairset_pinout {
+	ALTERNATIVE_A,
+	ALTERNATIVE_B,
+};
+
+/**
+ * struct pse_pi_pairset - PSE PI pairset entity describing the pinout
+ *			   alternative ant its phandle
+ *
+ * @pinout: description of the pinout alternative
+ * @np: device node pointer describing the pairset phandle
+ */
+struct pse_pi_pairset {
+	enum pse_pi_pairset_pinout pinout;
+	struct device_node *np;
+};
+
+/**
+ * struct pse_pi - PSE PI (Power Interface) entity as described in
+ *		   IEEE 802.3-2022 145.2.4
+ *
+ * @pairset: table of the PSE PI pinout alternative for the two pairset
+ * @np: device node pointer of the PSE PI node
+ */
+struct pse_pi {
+	struct pse_pi_pairset pairset[2];
+	struct device_node *np;
+};
+
 /**
  * struct pse_controller_dev - PSE controller entity that might
  *                             provide multiple PSE controls
@@ -73,11 +103,11 @@  struct pse_control;
  * @pse_control_head: head of internal list of requested PSE controls
  * @dev: corresponding driver model device struct
  * @of_pse_n_cells: number of cells in PSE line specifiers
- * @of_xlate: translation function to translate from specifier as found in the
- *            device tree to id as given to the PSE control ops
  * @nr_lines: number of PSE controls in this controller device
  * @lock: Mutex for serialization access to the PSE controller
  * @types: types of the PSE controller
+ * @pi: table of PSE PIs described in this controller device
+ * @of_legacy: flag set if the pse_pis devicetree node is not used
  */
 struct pse_controller_dev {
 	const struct pse_controller_ops *ops;
@@ -86,11 +116,11 @@  struct pse_controller_dev {
 	struct list_head pse_control_head;
 	struct device *dev;
 	int of_pse_n_cells;
-	int (*of_xlate)(struct pse_controller_dev *pcdev,
-			const struct of_phandle_args *pse_spec);
 	unsigned int nr_lines;
 	struct mutex lock;
 	enum ethtool_pse_types types;
+	struct pse_pi *pi;
+	bool of_legacy;
 };
 
 #if IS_ENABLED(CONFIG_PSE_CONTROLLER)