Re: [PATCH net-next v1 1/7] dt-bindings: net: pse-dt: add bindings for generic PSE controller

On Mon, Aug 22, 2022 at 01:41:12PM -0500, Rob Herring wrote:

On Fri, Aug 19, 2022 at 02:01:03PM +0200, Oleksij Rempel wrote:

quoted

Add binding for generic Ethernet PSE controller.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
---
 .../bindings/net/pse-pd/generic-pse.yaml      | 40 +++++++++++++++++++
 1 file changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/pse-pd/generic-pse.yaml

diff --git a/Documentation/devicetree/bindings/net/pse-pd/generic-pse.yaml b/Documentation/devicetree/bindings/net/pse-pd/generic-pse.yaml
new file mode 100644
index 0000000000000..64f91efa79a56
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/pse-pd/generic-pse.yaml

@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/pse-pd/generic-pse.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Generic Power Sourcing Equipment
+
+maintainers:
+  - Oleksij Rempel <o.rempel@pengutronix.de>
+
+description: |
+  Generic PSE controller. The device must be referenced by the PHY node
+  to control power injection to the Ethernet cable.

Isn't this separate from the PHY other than you need to associate 
supplies with ethernet ports?

Is there a controller here? Or it is just a regulator consumer 
associated with an ethernet port?

Current version has only regulator. It will be extended with IEEE 802.3
specific power source classification information, wich will be overkill for the
regulator framework. I can add it to the v2 version.

quoted

+properties:
+  compatible:
+    const: ieee802.3-podl-pse-generic

Is this for 802.3bu only (which is where PoDL comes from) or all the 
flavors? If all, do they need to be distinguished?

yes. ieee802.3 defines type and class with different enumeration and
meanings for PSE and PoDL PSE. 

So far we have two different modes:
 - 802.3bu (PoDL PSE). Has own types and classes
 - 802.3af  is extended by 802.3at, and the extended by 802.3bt
   all of them are named as PSE and has own types and classes as well.

I worry more about the fact is some one will implement HW supporting both
modes. IMO, it is possible to take usual ethernet PHY, configure to
10Bit half-duplex and run over single pair. In this case it is possible
to use only PoDL PSE mode.

In this case I need single generic compatible but different properties
to describe supported PSE and PoDL PSE modes.

'generic' is redundant.

ok

quoted

+
+  '#pse-cells':

What's this for? You don't have a consumer.

the consumer is PHY.

quoted

+    const: 0
+
+  ieee802.3-podl-pse-supply:

Seems a bit long

ok. Reduce it to pse-supply ?

quoted

+    description: |

Don't need '|' if no formatting to maintain.

ok

quoted

+      Power supply for the PSE controller
+
+additionalProperties: false
+
+required:
+  - compatible
+  - '#pse-cells'
+  - ieee802.3-podl-pse-supply
+
+examples:
+  - |
+    ethernet-pse-1 {
+      compatible = "ieee802.3-podl-pse-generic";
+      ieee802.3-podl-pse-supply = <&reg_t1l1>;
+      #pse-cells = <0>;
+    };
-- 
2.30.2

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