Message-ID: <CAGb2v66ZG3Ct1aFBOXQd8vkMCF-UNk7bN-vsXasbe_j5FexENw@mail.gmail.com>
Date:   Thu, 10 Aug 2017 10:40:10 +0800
From:   Chen-Yu Tsai <wens@...e.org>
To:     "David.Wu" <david.wu@...k-chips.com>
Cc:     Corentin Labbe <clabbe.montjoie@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        David Miller <davem@...emloft.net>,
        Heiko Stübner <heiko@...ech.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Olof Johansson <olof@...om.net>,
        Russell King <linux@...linux.org.uk>,
        Arnd Bergmann <arnd@...db.de>,
        Tao Huang <huangtao@...k-chips.com>, hwg@...k-chips.com,
        alexandre.torgue@...com, devicetree <devicetree@...r.kernel.org>,
        netdev <netdev@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        Giuseppe Cavallaro <peppe.cavallaro@...com>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        Chen-Yu Tsai <wens@...e.org>
Subject: Re: [PATCH v3 05/11] net: stmmac: dwmac-rk: Add internal phy support

Hi David,

On Wed, Aug 9, 2017 at 5:38 PM, David.Wu <david.wu@...k-chips.com> wrote:
> Hello Corentin, Chen-Yu
>
>
> 在 2017/8/9 16:45, Corentin Labbe 写道:
>>
>> On Thu, Aug 03, 2017 at 07:06:33PM +0800, Chen-Yu Tsai wrote:
>>>
>>> On Thu, Aug 3, 2017 at 1:38 AM, Florian Fainelli <f.fainelli@...il.com>
>>> wrote:
>>>>
>>>> On 08/01/2017 11:21 PM, David Wu wrote:
>>>>>
>>>>> To make internal phy work, need to configure the phy_clock,
>>>>> phy cru_reset and related registers.
>>>>>
>>>>> Signed-off-by: David Wu <david.wu@...k-chips.com>
>>>>> ---
>>>>>   .../devicetree/bindings/net/rockchip-dwmac.txt     |  6 +-
>>>>>   drivers/net/ethernet/stmicro/stmmac/dwmac-rk.c     | 81
>>>>> ++++++++++++++++++++++
>>>>>   2 files changed, 86 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/net/rockchip-dwmac.txt
>>>>> b/Documentation/devicetree/bindings/net/rockchip-dwmac.txt
>>>>> index 8f42755..ec39b31 100644
>>>>> --- a/Documentation/devicetree/bindings/net/rockchip-dwmac.txt
>>>>> +++ b/Documentation/devicetree/bindings/net/rockchip-dwmac.txt
>>>>> @@ -25,7 +25,8 @@ Required properties:
>>>>>    - clock-names: One name for each entry in the clocks property.
>>>>>    - phy-mode: See ethernet.txt file in the same directory.
>>>>>    - pinctrl-names: Names corresponding to the numbered pinctrl states.
>>>>> - - pinctrl-0: pin-control mode. can be <&rgmii_pins> or <&rmii_pins>.
>>>>> + - pinctrl-0: pin-control mode. can be <&rgmii_pins>, <&rmii_pins> or
>>>>> led pins
>>>>> +   for internal phy mode.
>>>>>    - clock_in_out: For RGMII, it must be "input", means main
>>>>> clock(125MHz)
>>>>>      is not sourced from SoC's PLL, but input from PHY; For RMII,
>>>>> "input" means
>>>>>      PHY provides the reference clock(50MHz), "output" means GMAC
>>>>> provides the
>>>>> @@ -40,6 +41,9 @@ Optional properties:
>>>>>    - tx_delay: Delay value for TXD timing. Range value is 0~0x7F, 0x30
>>>>> as default.
>>>>>    - rx_delay: Delay value for RXD timing. Range value is 0~0x7F, 0x10
>>>>> as default.
>>>>>    - phy-supply: phandle to a regulator if the PHY needs one
>>>>> + - clocks: <&cru MAC_PHY>: Clock selector for internal macphy
>>>>> + - phy-is-internal: A boolean property allows us to know that MAC will
>>>>> connect to
>>>>> +   internal phy.
>>>>
>>>>
>>>> This is incorrect in two ways:
>>>>
>>>> - this is a property of the PHY, so it should be documented as such in
>>>> Documentation/devicetree/bindings/net/phy.txt so other bindings can
>>>> re-use it
>>>>
>>>> - if it was specific to your MAC you would expect a vendor prefix to
>>>> this property, which is not there
>>>>
>>>> An alternative way to implement the external/internal logic selection
>>>> would be mandate that your Ethernet PHY node have a compatible string
>>>> like this:
>>>>
>>>> phy@0 {
>>>>          compatible = "ethernet-phy-id1234.d400",
>>>> "ethernet-phy-802.3-c22";
>>>> };
>>>>
>>>> Then you don't need this phy-is-internal property, because you can
>>>> locate the PHY node by the phy-handle (see more about that in a reply to
>>>> patch 10) and you can determine ahead of time whether this PHY is
>>>> internal or not based on its compatible string.
>>>
>>>
>>> This doesn't really work for us (sunxi). The "internal" PHY of the H3
>>> is also available in the X-Powers AC200 combo chip, which would be
>>> external. Same ID. So if someone were to be stupid and put the two
>>> together, you wouldn't know which one it actually is. Generically
>>> it doesn't make sense to match against the ID either. The PHY is
>>> only integrated or inlined into the SoC, meaning it could be moved
>>> elsewhere or even be a discreet part.
>>>
>>> The way I see it is more like a reversed pinmux. The system should
>>> select either the internal set or external set of xMII pins to use.
>>>
>>> A phy-is-internal property in the PHY node would work for us. We
>>> already need a PHY node to describe its clocks and resets.
>>>
>>> A side note to this solution is that, since the internal PHY is defined
>>> at the .dtsi level, any external PHYs at the same address would need to
>>> make sure to delete the property, which is kind of counterintuitive, but
>>> it is how device tree works. One would want to put the internal PHY's
>>> address, assuming it is configurable, on something that is rarely used.
>>>
>>
>> Hello David, Florian, Andrew
>>
>> Could someone ack this ? or nack if you think that the chance for having
>> two PHY id both internal and external is too low.
>> Anyway, we need a choice.
>>
>
> I think we should be specific to the situation, for us we have the
> possibility that the Mac only picks up internal PHY, so this can be fixed at
> the. DTSi level, also possible INTERNL PHY's Mac can also be used to connect
> external PHY, while cutting off the connection with the internal PHY, so we
> should define the internal PHY at the DTS level, so I think Florian's
> approach is acceptable.

So it looks like you have the clock for the internal/integrated PHY at the
MAC level. I think this lets you define/add the PHY at the board level more
easily without a lot of duplication?

Sunxi has the clock and reset in the PHY node, which is defined in the dtsi
file. (This part is already done.)

ChenYu

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