Date:   Fri, 17 Dec 2021 10:05:58 +0800
From:   Biao Huang <biao.huang@...iatek.com>
To:     Rob Herring <robh@...nel.org>
CC:     <srv_heupstream@...iatek.com>,
        <linux-arm-kernel@...ts.infradead.org>, <davem@...emloft.net>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <angelogioacchino.delregno@...labora.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        <linux-mediatek@...ts.infradead.org>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        Jose Abreu <joabreu@...opsys.com>, <netdev@...r.kernel.org>,
        <dkirjanov@...e.de>, <linux-kernel@...r.kernel.org>,
        <macpaul.lin@...iatek.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        <devicetree@...r.kernel.org>, Jakub Kicinski <kuba@...nel.org>,
        Rob Herring <robh+dt@...nel.org>
Subject: Re: [PATCH net-next v10 6/6] net: dt-bindings: dwmac: add support
 for mt8195

Dear Rob,
  Thanks for your comments~

  For mt8195, the eth device node will look like:
  eth: ethernet@...21000 {
    compatible = "mediatek,mt8195-gmac", "snps,dwmac-5.10a";
    ...
    clock-names = "axi",
                  "apb",
                  "mac_cg",
                  "mac_main",
                  "ptp_ref",
                  "rmii_internal";
    clocks = <&pericfg_ao CLK_PERI_AO_ETHERNET>,
             <&pericfg_ao CLK_PERI_AO_ETHERNET_BUS>,
             <&pericfg_ao CLK_PERI_AO_ETHERNET_MAC>,
             <&topckgen CLK_TOP_SNPS_ETH_250M>,
             <&topckgen CLK_TOP_SNPS_ETH_62P4M_PTP>,
             <&topckgen CLK_TOP_SNPS_ETH_50M_RMII>;
    ...
  }

1. "rmii_internal" is a special clock only required for
   RMII phy interface, dwmac-mediatek.c will enable clocks
   invoking clk_bulk_prepare_enable(xx, 6) for RMII,
   and clk_bulk_prepare_enable(xx, 5) for other phy interfaces.
   so, mt2712/mt8195 all put "rmii_internal" clock to the
   end of clock list to simplify clock handling.

   If I put mac_cg as described above, a if condition is required
for clocks description in dt-binding, just like what I do in v7 send:
  - if:
      properties:
        compatible:
          contains:
            enum:
              - mediatek,mt2712-gmac

    then:
      properties:
        clocks:
          minItems: 5
          items:
            - description: AXI clock
            - description: APB clock
            - description: MAC Main clock
            - description: PTP clock
            - description: RMII reference clock provided by MAC

        clock-names:
          minItems: 5
          items:
            - const: axi
            - const: apb
            - const: mac_main
            - const: ptp_ref
            - const: rmii_internal

  - if:
      properties:
        compatible:
          contains:
            enum:
              - mediatek,mt8195-gmac

    then:
      properties:
        clocks:
          minItems: 6
          items:
            - description: AXI clock
            - description: APB clock
            - description: MAC clock gate
            - description: MAC Main clock
            - description: PTP clock
            - description: RMII reference clock provided by MAC

   This introduces some duplicated description.

2. If I put "mac_cg" to the end of clock list,
   the dt-binding file can be simple just like
   what we do in this v10 patch(need fix warnings reported by "make
DT_CHECKER_FLAGS=-m dt_binding_check").

   But for mt8195:
     the eth node in dts should be modified,
     and eth driver clock handling will be complex;

We prefer 1(duplicated description one).
Can we just descirbe clocks/clocks-names for mt2712/mt8195 seperately?
Please kindly comment about this issue.
Thanks in advance.

On Thu, 2021-12-16 at 07:53 -0600, Rob Herring wrote:
> On Thu, 16 Dec 2021 13:53:28 +0800, Biao Huang wrote:
> > Add binding document for the ethernet on mt8195.
> > 
> > Signed-off-by: Biao Huang <biao.huang@...iatek.com>
> > ---
> >  .../bindings/net/mediatek-dwmac.yaml          | 29
> > ++++++++++++++++---
> >  1 file changed, 25 insertions(+), 4 deletions(-)
> > 
> 
> My bot found errors running 'make DT_CHECKER_FLAGS=-m
> dt_binding_check'
> on your patch (DT_CHECKER_FLAGS is new in v5.13):
> 
> yamllint warnings/errors:
> 
> dtschema/dtc warnings/errors:
> /builds/robherring/linux-dt-
> review/Documentation/devicetree/bindings/net/mediatek-dwmac.yaml:
> properties:clock-names: {'minItems': 5, 'maxItems': 6, 'items':
> [{'const': 'axi'}, {'const': 'apb'}, {'const': 'mac_main'}, {'const':
> 'ptp_ref'}, {'const': 'rmii_internal'}, {'const': 'mac_cg'}]} should
> not be valid under {'required': ['maxItems']}
> 	hint: "maxItems" is not needed with an "items" list
> 	from schema $id: http://devicetree.org/meta-schemas/items.yaml#
> /builds/robherring/linux-dt-
> review/Documentation/devicetree/bindings/net/mediatek-dwmac.yaml:
> ignoring, error in schema: properties: clock-names
> warning: no schema found in file:
> ./Documentation/devicetree/bindings/net/mediatek-dwmac.yaml
> Documentation/devicetree/bindings/net/mediatek-
> dwmac.example.dt.yaml:0:0: /example-0/ethernet@...1c000: failed to
> match any schema with compatible: ['mediatek,mt2712-gmac',
> 'snps,dwmac-4.20a']
> 
> doc reference errors (make refcheckdocs):
> 
> See https://patchwork.ozlabs.org/patch/1568902
> 
> This check can fail if there are any dependencies. The base for a
> patch
> series is generally the most recent rc1.
> 
> If you already ran 'make dt_binding_check' and didn't see the above
> error(s), then make sure 'yamllint' is installed and dt-schema is up
> to
> date:
> 
> pip3 install dtschema --upgrade
> 
> Please check and re-submit.
> 

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