| Message ID | 20210322195001.28036-2-kabel@kernel.org (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [RFC,net-next,1/2] dt-bindings: ethernet-controller: create a type for PHY interface modes | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Clearly marked for net-next |
| netdev/subject_prefix | success | Link |
| netdev/cc_maintainers | warning | 3 maintainers not CCed: robh+dt@kernel.org linux@armlinux.org.uk kuba@kernel.org |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 26 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
On Mon, Mar 22, 2021 at 08:49:59PM +0100, Marek Behún wrote: > diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml > index 2766fe45bb98..4c5b8fabbec3 100644 > --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml > +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml > @@ -136,6 +136,20 @@ properties: > used. The absence of this property indicates the muxers > should be configured so that the external PHY is used. > > + unsupported-mac-connection-types: > + $ref: "ethernet-controller.yaml#/$defs/phy-connection-type-array" > + description: > + The PHY device may support different interface types for > + connecting the Ethernet MAC device to the PHY device (i.e. > + rgmii, sgmii, xaui, ...), but not all of these interface > + types must necessarily be supported for a specific board > + (either not all of them are wired, or there is a known bug > + for a specific mode). > + This property specifies a list of interface modes are not > + supported on the board. I think this needs to be clearer. "This property specifies a list of interface modes supported by the PHY hardware but are not supported on the board." I would also suggest having a think about a PHY that supports some interface types that we don't have support in the kernel for, but which also are not part of the board. Should these be listed somehow as well? If not, how do we deal with the kernel later gaining support for those interface modes, potentially the PHY driver as well, and then having a load of boards not listing this? My feeling is that listing negative properties presents something of a problem, and we ought to stick with boards specifying what they support, rather than what they don't.
On Mon, 22 Mar 2021 19:56:05 +0000 Russell King - ARM Linux admin <linux@armlinux.org.uk> wrote: > On Mon, Mar 22, 2021 at 08:49:59PM +0100, Marek Behún wrote: > > diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml > > index 2766fe45bb98..4c5b8fabbec3 100644 > > --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml > > +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml > > @@ -136,6 +136,20 @@ properties: > > used. The absence of this property indicates the muxers > > should be configured so that the external PHY is used. > > > > + unsupported-mac-connection-types: > > + $ref: "ethernet-controller.yaml#/$defs/phy-connection-type-array" > > + description: > > + The PHY device may support different interface types for > > + connecting the Ethernet MAC device to the PHY device (i.e. > > + rgmii, sgmii, xaui, ...), but not all of these interface > > + types must necessarily be supported for a specific board > > + (either not all of them are wired, or there is a known bug > > + for a specific mode). > > + This property specifies a list of interface modes are not > > + supported on the board. > > I think this needs to be clearer. "This property specifies a list > of interface modes supported by the PHY hardware but are not > supported on the board." > > I would also suggest having a think about a PHY that supports some > interface types that we don't have support in the kernel for, but > which also are not part of the board. Should these be listed > somehow as well? If not, how do we deal with the kernel later gaining > support for those interface modes, potentially the PHY driver as well, > and then having a load of boards not listing this? > > My feeling is that listing negative properties presents something of > a problem, and we ought to stick with boards specifying what they > support, rather than what they don't. That is a good point. And if this alternative `supported-modes` property is missing, we can just assume that all modes are supported, in order to be backward compatible.
diff --git a/Documentation/devicetree/bindings/net/ethernet-phy.yaml b/Documentation/devicetree/bindings/net/ethernet-phy.yaml index 2766fe45bb98..4c5b8fabbec3 100644 --- a/Documentation/devicetree/bindings/net/ethernet-phy.yaml +++ b/Documentation/devicetree/bindings/net/ethernet-phy.yaml @@ -136,6 +136,20 @@ properties: used. The absence of this property indicates the muxers should be configured so that the external PHY is used. + unsupported-mac-connection-types: + $ref: "ethernet-controller.yaml#/$defs/phy-connection-type-array" + description: + The PHY device may support different interface types for + connecting the Ethernet MAC device to the PHY device (i.e. + rgmii, sgmii, xaui, ...), but not all of these interface + types must necessarily be supported for a specific board + (either not all of them are wired, or there is a known bug + for a specific mode). + This property specifies a list of interface modes are not + supported on the board. + minItems: 1 + maxItems: 128 + resets: maxItems: 1 @@ -196,5 +210,6 @@ examples: reset-gpios = <&gpio1 4 1>; reset-assert-us = <1000>; reset-deassert-us = <2000>; + unsupported-mac-connection-types = "xaui", "rxaui"; }; };
An ethernet PHY may support PHY interface modes that are not wired on a specific board (or are broken for some other reason). In order for the kernel to know that these modes should not be used, we need to specify this in device tree. Define a new ethernet PHY property `unsupported-mac-connection-types`, which lists these unsupported modes. Signed-off-by: Marek Behún <kabel@kernel.org> --- As in the previous patch: we allow both `phy-connection-type` and `phy-mode` to define PHY interface mode. Should we call this new property as it is proposed by this patch, or something different, like `unsupported-mac-phy-modes`? Also, some PHYs (marvell10g for example) also multiple units (host unit for connecting to the MAC, fiber unit for connecting for example via a SFP). Should we also add `unsupported-fiber-connection-types` property? Moreover should this property be a member of PHY's node, or the ethernet controller's node? Were it a member of ethernet controller's node, we wouldn't need to $ref a definition from another file's $defs (which Rob Herring says that so far is done only in withing single file). On the other hand `unsupported-fiber-connection-types` property should be a member of PHY's node, if we will add this in the future. --- .../devicetree/bindings/net/ethernet-phy.yaml | 15 +++++++++++++++ 1 file changed, 15 insertions(+)