linux-kernel - Re: [PATCH 8/9] net: mdio: ipq4019: add qca8084 configurations

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Message-ID: <c1233090-b77d-43b7-9419-74f904cfae07@quicinc.com>
Date:   Fri, 17 Nov 2023 18:15:39 +0800
From:   Jie Luo <quic_luoj@...cinc.com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <davem@...emloft.net>,
        <edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
        <robh+dt@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>,
        <conor+dt@...nel.org>, <hkallweit1@...il.com>,
        <linux@...linux.org.uk>, <robert.marko@...tura.hr>,
        <linux-arm-msm@...r.kernel.org>, <netdev@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_srichara@...cinc.com>
Subject: Re: [PATCH 8/9] net: mdio: ipq4019: add qca8084 configurations



On 11/17/2023 1:12 AM, Andrew Lunn wrote:
> On Thu, Nov 16, 2023 at 06:47:08PM +0800, Jie Luo wrote:
>>
>>
>> On 11/16/2023 12:20 AM, Andrew Lunn wrote:
>>> On Wed, Nov 15, 2023 at 11:25:14AM +0800, Luo Jie wrote:
>>>> The PHY & PCS clocks need to be enabled and the reset
>>>> sequence needs to be completed to make qca8084 PHY
>>>> probeable by MDIO bus.
>>>
>>> Is all this guaranteed to be the same between different boards? Can
>>> the board be wired differently and need a different configuration?
>>>
>>>       Andrew
>>
>> Hi Andrew,
>> This configuration sequence is specified to the qca8084 chip,
>> not related with the platform(such as ipq5332).
>>
>> All these configured registers are located in qca8084 chip, we need
>> to complete these configurations to make MDIO bus being able to
>> scan the qca8084 PHY(PHY registers can be accessed).
> 
> So nothing here has anything to do with the actual PHYs on the bus?
> The only clock exposed here is MDC, and that runs at the standard
> 2.5MHz? All the clock tree configuration is completely internal to the
> SOC?
> 
> What we don't want is some hard coded configuration which only works
> for one specific reference design.
> 
> 	Andrew

These configured registers are related with PHYs, which is located in
the qca8084 PHY chip, qca8084 PHY chip includes the GCC register that
is not from the SOC(ipq5332), is a internal part of qca8084 PHY.

qca8084 PHY works on 6.25MHZ and other clock rates below 6.25MHZ.

will move these clock configurations using the clock APIs into the PHY
probe function in the next patch set, since it is the internal configs
of qca8084 PHY.