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Subject: Re: [PATCH net-next v3 4/4] net: phy: dp83td510: Add support for the
 DP83TD510 Ethernet PHY
To:     Dan Murphy <dmurphy@ti.com>, Andrew Lunn <andrew@lunn.ch>
Cc:     davem@davemloft.net, hkallweit1@gmail.com, robh@kernel.org,
        devicetree@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20201030172950.12767-1-dmurphy@ti.com>
 <20201030172950.12767-5-dmurphy@ti.com> <20201030201515.GE1042051@lunn.ch>
 <202b6626-b7bf-3159-f474-56f6fa0c8247@ti.com>
 <20201103171838.GN1042051@lunn.ch>
 <f44af428-acd9-daef-3609-4d6ea24cd436@ti.com>
From:   Florian Fainelli <f.fainelli@gmail.com>
Message-ID: <2513627e-42d4-88d5-c8fe-f4b90b1b56b5@gmail.com>
Date:   Wed, 4 Nov 2020 19:03:15 -0800
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On 11/3/2020 9:35 AM, Dan Murphy wrote:
> Andrew
> 
> On 11/3/20 11:18 AM, Andrew Lunn wrote:
>> On Tue, Nov 03, 2020 at 11:07:00AM -0600, Dan Murphy wrote:
>>> Andrew
>>>
>>> On 10/30/20 3:15 PM, Andrew Lunn wrote:
>>>>> +static int dp83td510_config_init(struct phy_device *phydev)
>>>>> +{
>>>>> +    struct dp83td510_private *dp83td510 = phydev->priv;
>>>>> +    int mst_slave_cfg;
>>>>> +    int ret = 0;
>>>>> +
>>>>> +    if (phy_interface_is_rgmii(phydev)) {
>>>>> +        if (dp83td510->rgmii_delay) {
>>>>> +            ret = phy_set_bits_mmd(phydev, DP83TD510_DEVADDR,
>>>>> +                           DP83TD510_MAC_CFG_1,
>>>>> dp83td510->rgmii_delay);
>>>>> +            if (ret)
>>>>> +                return ret;
>>>>> +        }
>>>>> +    }
>>>> Hi Dan
>>>>
>>>> I'm getting a bit paranoid about RGMII delays...
>>> Not sure what this means.
>> See the discussion and breakage around the realtek PHY. It wrongly
>> implemented RGMII delays. When it was fixed, lots of board broke
>> because the bug in the PHY driver hid bugs in the DT.
>>
> I will have to go find that thread. Do you have a link?

That would be the thread:

https://lore.kernel.org/netdev/CAMj1kXEEF_Un-4NTaD5iUN0NoZYaJQn-rPediX0S6oRiuVuW-A@mail.gmail.com/
-- 
Florian