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Message-ID: <a324b7d4-5265-4766-814a-36c53a84f732@quicinc.com>
Date:   Tue, 28 Nov 2023 17:50:41 +0800
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Subject: Re: [PATCH v6 3/6] net: phy: at803x: add QCA8084 ethernet phy support
To:     "Russell King (Oracle)" <linux@armlinux.org.uk>
CC:     Andrew Lunn <andrew@lunn.ch>, <davem@davemloft.net>,
        <edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
        <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <conor+dt@kernel.org>, <hkallweit1@gmail.com>, <corbet@lwn.net>,
        <netdev@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>
References: <20231126060732.31764-1-quic_luoj@quicinc.com>
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From:   Jie Luo <quic_luoj@quicinc.com>
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On 11/28/2023 5:00 PM, Russell King (Oracle) wrote:
> On Tue, Nov 28, 2023 at 03:16:45PM +0800, Jie Luo wrote:
>>>> The interface mode is passed in the .config_init, which is configured
>>>> by the PCS driver, the hardware register is located in the PCS, this
>>>> driver will be pushed later.
>>>
>>> Is this the same as how the syqca807x works? Can the PCS driver be
>>> shared by these two drivers?
>>
>> I am not sure syqca807x, would you point me the code path of this driver?
>>
>>>
>>> What i don't like at the moment is that we have two driver
>>> developments going on at once for hardware which seems very similar,
>>> but no apparent cooperation?
>>>
>>> 	Andrew
>>
>> The PCS of qca8084 is the PHY PCS, which should be new PCS driver,
>> in the previous chips, we don't have this kind of PHY PCS.
> 
> No. PCS drivers are for MAC-side PCS drivers, not PHY-side PCS drivers.
> 
>                       +-------------
> 		     |     PHY
> MAC---PCS --- link --- PCS --- ...
>         ^             |  ^
>         |	     +--|----------
>    For this PCS          |
>                    Not for this PCS
> 

The PCS drivers in drivers/net/pcs/ should be in PHY side, such as
pcs-lynx.c and pcs-xpcs.c, they are configuring the MDIO device
registers.