netdev - Re: [PATCH net-next v3 4/6] net: phy: microchip_t1s: fix reset complete status handling

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Date: Fri, 26 May 2023 13:16:50 +0000
From: <Parthiban.Veerasooran@...rochip.com>
To: <ramon.nordin.rodriguez@...roamp.se>
CC: <andrew@...n.ch>, <hkallweit1@...il.com>, <linux@...linux.org.uk>,
	<davem@...emloft.net>, <edumazet@...gle.com>, <kuba@...nel.org>,
	<pabeni@...hat.com>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <Horatiu.Vultur@...rochip.com>,
	<Woojung.Huh@...rochip.com>, <Nicolas.Ferre@...rochip.com>,
	<Thorsten.Kummermehr@...rochip.com>
Subject: Re: [PATCH net-next v3 4/6] net: phy: microchip_t1s: fix reset
 complete status handling

Hi Ramon,

On 26/05/23 12:44 pm, Ramón Nordin Rodriguez wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Fri, May 26, 2023 at 06:00:08AM +0000, Parthiban.Veerasooran@...rochip.com wrote:
>> Hi Ramon,
>>>> +     /* Read STS2 register and check for the Reset Complete status to do the
>>>> +      * init configuration. If the Reset Complete is not set, wait for 5us
>>>> +      * and then read STS2 register again and check for Reset Complete status.
>>>> +      * Still if it is failed then declare PHY reset error or else proceed
>>>> +      * for the PHY initial register configuration.
>>>> +      */
>>>
>>> This comment explains exactly what the code does, which is also obvious
>>> from reading the code. A meaningful comment would be explaining why the
>>> state can change 5us later.
>>>
>> As per design, LAN867x reset to be completed by 3us. Just for a safer
>> side it is recommended to use 5us. With the assumption of more than 3us
>> completion, the first read checks for the Reset Complete. If the
>> config_init is more faster, then once again checks for it after 5us.
>>
>> As you mentioned, can we remove the existing block comment as it
>> explains the code and add the above comment to explain 5us delay.
>> What is your opinion on this proposal?
>>
>> Best Regards,
>> Parthiban V
>>
> 
> I'd suggest the following
> /*The chip completes a reset in 3us, we might get here earlier than that,
> as an added margin we'll conditionally sleep 5us*/
Ok I will use this proposal in the next version.

Best Regards,
Parthiban V