linux-kernel - Re: [PATCH net-next v5 4/4] net: dp83869: Add RGMII internal delay configuration

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Message-ID: <f92f70b2-6e42-5bdb-187d-ecd8533b06a6@ti.com>
Date:   Tue, 2 Jun 2020 18:18:04 -0500
From:   Dan Murphy <dmurphy@...com>
To:     Florian Fainelli <f.fainelli@...il.com>, <andrew@...n.ch>,
        <hkallweit1@...il.com>, <davem@...emloft.net>, <robh@...nel.org>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <devicetree@...r.kernel.org>
Subject: Re: [PATCH net-next v5 4/4] net: dp83869: Add RGMII internal delay
 configuration

Florian

On 6/2/20 6:13 PM, Florian Fainelli wrote:
>
> On 6/2/2020 4:10 PM, Dan Murphy wrote:
>> Florian
>>
>> On 6/2/20 5:33 PM, Florian Fainelli wrote:
>>> On 6/2/2020 9:45 AM, Dan Murphy wrote:
>>>> Add RGMII internal delay configuration for Rx and Tx.
>>>>
>>>> Signed-off-by: Dan Murphy <dmurphy@...com>
>>>> ---
>>> [snip]
>>>
>>>> +
>>>>    enum {
>>>>        DP83869_PORT_MIRRORING_KEEP,
>>>>        DP83869_PORT_MIRRORING_EN,
>>>> @@ -108,6 +113,8 @@ enum {
>>>>    struct dp83869_private {
>>>>        int tx_fifo_depth;
>>>>        int rx_fifo_depth;
>>>> +    s32 rx_id_delay;
>>>> +    s32 tx_id_delay;
>>>>        int io_impedance;
>>>>        int port_mirroring;
>>>>        bool rxctrl_strap_quirk;
>>>> @@ -232,6 +239,22 @@ static int dp83869_of_init(struct phy_device
>>>> *phydev)
>>>>                     &dp83869->tx_fifo_depth))
>>>>            dp83869->tx_fifo_depth = DP83869_PHYCR_FIFO_DEPTH_4_B_NIB;
>>>>    +    ret = of_property_read_u32(of_node, "rx-internal-delay-ps",
>>>> +                   &dp83869->rx_id_delay);
>>>> +    if (ret) {
>>>> +        dp83869->rx_id_delay =
>>>> +                dp83869_internal_delay[DP83869_CLK_DELAY_DEF];
>>>> +        ret = 0;
>>>> +    }
>>>> +
>>>> +    ret = of_property_read_u32(of_node, "tx-internal-delay-ps",
>>>> +                   &dp83869->tx_id_delay);
>>>> +    if (ret) {
>>>> +        dp83869->tx_id_delay =
>>>> +                dp83869_internal_delay[DP83869_CLK_DELAY_DEF];
>>>> +        ret = 0;
>>>> +    }
>>> It is still not clear to me why is not the parsing being done by the PHY
>>> library helper directly?
>> Why would we do that for these properties and not any other?
> Those properties have a standard name, which makes them suitable for
> parsing by the core PHY library.
>> Unless there is a new precedence being set here by having the PHY
>> framework do all the dt node parsing for common properties.
> You could parse the vendor properties through the driver, let the PHY
> library parse the standard properties, and resolve any ordering
> precedence within the driver. In general, I would favor standard
> properties over vendor properties.
>
> Does this help?

Ok so new precedence then.

Because there are common properties like tx-fifo-depth, rx-fifo-depth, 
enet-phy-lane-swap and max_speed that the PHY framework should parse as 
well.

Dan