Re: [PATCH net-next v2 2/3] dt-bindings: net: add T-HEAD dwmac support

[Jisheng Zhang <jszhang@kernel.org>]

On Mon, Aug 28, 2023 at 04:13:00PM +0300, Serge Semin wrote:
> On Sun, Aug 27, 2023 at 05:17:09PM +0800, Jisheng Zhang wrote:
> > Add documentation to describe T-HEAD dwmac.
> > 
> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> >  .../devicetree/bindings/net/snps,dwmac.yaml   |  1 +
> >  .../devicetree/bindings/net/thead,dwmac.yaml  | 77 +++++++++++++++++++
> >  2 files changed, 78 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/net/thead,dwmac.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/net/snps,dwmac.yaml b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > index b196c5de2061..73821f86a609 100644
> > --- a/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > +++ b/Documentation/devicetree/bindings/net/snps,dwmac.yaml
> > @@ -96,6 +96,7 @@ properties:
> >          - snps,dwxgmac
> >          - snps,dwxgmac-2.10
> >          - starfive,jh7110-dwmac
> > +        - thead,th1520-dwmac
> >  
> >    reg:
> >      minItems: 1
> > diff --git a/Documentation/devicetree/bindings/net/thead,dwmac.yaml b/Documentation/devicetree/bindings/net/thead,dwmac.yaml
> > new file mode 100644
> > index 000000000000..bf8ec8ca2753
> > --- /dev/null
> 
> > +++ b/Documentation/devicetree/bindings/net/thead,dwmac.yaml
> 
> see further regarding using dwmac in the names here.
> 
> > @@ -0,0 +1,77 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/net/thead,dwmac.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> 
> > +title: T-HEAD DWMAC Ethernet controller
> 
> Additionally would be nice to have a brief controller "description:"
> having the next info: the SoCs the controllers can be found on, the DW
> (G)MAC IP-core version the ethernet controller is based on and some
> data about the synthesize parameters: SMA (MDIO-bus), Tx/Rx COE, DMA
> FIFOs size, perfect and hash MAC-filters size, L3L4 frame filters
> availability, VLAN hash filter, SA/VLAN-tag insertion, ARP offload
> engine, PHY interfaces (MII, RMII, RGMII, etc), EEE support, IEEE
> 1588(-2008) Timestamping support, PMT and Wake-up frame support, MAC
> Management counters (MMC). In addition to that for DW QoS
> ETH/XGMAC/XLGMAC the next info would be useful: number of MTL Queues
> and DMA channels, MTL queues capabilities (QoS-related), TSO
> availability, SPO availability.
> 
> Note DMA FIFO sizes can be also constrained in the properties
> "rx-fifo-depth" and "tx-fifo-depth"; perfect and hash MAC-filter sizes -
> in "snps,perfect-filter-entries" and "snps,multicast-filter-bins".

Hi Serge,

Thank you for your code review. I have different views here: If we
only support the gmac controller in one specific SoC, these detailed
information is nice to have, but what about if the driver/dt-binding
supports the gmac controller in different SoCs? These detailed
information will be outdated.

what's more, I think the purpose of dt-binding is different from
the one of documentation.

So I prefer to put these GMAC IP related detailed information into
the SoC's dtsi commit msg rather than polluting the dt-binding.
> 
> > +
> > +maintainers:
> > +  - Jisheng Zhang <jszhang@kernel.org>
> > +
> > +select:
> > +  properties:
> > +    compatible:
> > +      contains:
> > +        enum:
> 
> > +          - thead,th1520-dwmac
> 
> Referring to the DW IP-core in the compatible string isn't very
> much useful especially seeing you have a generic fallback compatible.
> Name like "thead,th1520-gmac" looks more informative indicating its
> speed capability.

This is just to follow the common style as those dwmac-* does.
I'm not sure which is better, but personally, I'd like to keep current
common style.