Re: [PATCH RESEND net] net: phy: xgmiitorgmii: Support generic PHY status read

From: Michal Simek <michal.simek@xilinx.com>
To: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
	Michal Simek <michal.simek@xilinx.com>,
	Andrew Lunn <andrew@lunn.ch>
Cc: Florian Fainelli <f.fainelli@gmail.com>, <netdev@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Heiner Kallweit <hkallweit1@gmail.com>
Subject: Re: [PATCH RESEND net] net: phy: xgmiitorgmii: Support generic PHY status read
Date: Thu, 21 Feb 2019 12:03:44 +0100	[thread overview]
Message-ID: <9cb2f7a8-a8cf-ef80-d260-cc67c072b5c5@xilinx.com> (raw)
In-Reply-To: <adbb183836e22dfc4558beaa818677c24bacf3a8.camel@bootlin.com>

On 21. 02. 19 11:24, Paul Kocialkowski wrote:
> Hi,
> 
> On Wed, 2019-02-20 at 07:58 +0100, Michal Simek wrote:
>> Hi,
>>
>> On 19. 02. 19 18:25, Andrew Lunn wrote:
>>>> Thanks for the suggestion! So I had a closer look at that driver to try
>>>> and see what could go wrong and it looks like I found a few things
>>>> there.
>>>
>>> Hi Paul
>>>
>>> Yes, this driver has issues. If i remember correctly, it got merged
>>> while i was on vacation. I pointed out a few issues, but the authors
>>> never responded. Feel free to fix it up.
>>
>> Will be good to know who was that person.
>>
>> I can't do much this week with this because responsible person for this
>> driver is out of office this week. That's why please give us some time
>> to get back to this.
> 
> Understood. I think we need to start a discussion about how the general
> design of this driver can be improved.
> 
> In particular, I wonder if it could work better to make this driver a
> PHY driver that just redirects all its ops to the actual PHY driver,
> except for read_status where it should also add some code.

I didn't take a look at Linux driver but it should work in a way that it
checks description (more below) and then wait for attached phy to do its
work and on the way back just setup this bridge based on that.

> Maybe we could also manage to expose a RGMII PHY mode to the actual PHY
> this way. Currently, the PHY mode has to be set to GMII for the MAC to
> be configured correctly, but the PHY also gets this information while
> it should be told that RGMII is in use. This doesn't seem to play a big
> role in PHY configuration though, but it's still inadequate.
> 
> What do you think?

I stop the driver to be applied to u-boot because exactly this
gmii/rgmii configuration. There is a need that mac is configured to gmii
and this needs to be checked but to phy rgmii needs to be exposed.
I was trying to find out hardware design and board where I can do some
experiments but didn't find out. That's why I need to wait for
colleagues to point me to that.

Thanks,
Michal