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Subject: Re: [PATCH net-next v2 4/8] net: usb: asix: ax88772: add phylib
 support
From:   Marek Szyprowski <m.szyprowski@samsung.com>
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, Andrew Lunn <andrew@lunn.ch>,
        Heiner Kallweit <hkallweit1@gmail.com>,
        Russell King <linux@armlinux.org.uk>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
        netdev@vger.kernel.org
Message-ID: <b3b990b5-d2f6-3e93-effd-44e10c5dfb5e@samsung.com>
Date:   Fri, 18 Jun 2021 12:57:13 +0200
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References: <20210607082727.26045-1-o.rempel@pengutronix.de>
        <20210607082727.26045-5-o.rempel@pengutronix.de>
        <CGME20210618083914eucas1p240f88e7064a7bf15b68370b7506d24a9@eucas1p2.samsung.com>
        <15e1bb24-7d67-9d45-54c1-c1c1a0fe444a@samsung.com>
        <20210618101317.55fr5vl5akmtgcf6@pengutronix.de>
        <460f971e-fbae-8d3d-ae8e-ed90bbebda4d@samsung.com>
Precedence: bulk

On 18.06.2021 12:45, Marek Szyprowski wrote:
> On 18.06.2021 12:13, Oleksij Rempel wrote:
>> thank you for your feedback.
>>
>> On Fri, Jun 18, 2021 at 10:39:12AM +0200, Marek Szyprowski wrote:
>>> On 07.06.2021 10:27, Oleksij Rempel wrote:
>>>> To be able to use ax88772 with external PHYs and use advantage of
>>>> existing PHY drivers, we need to port at least ax88772 part of asix
>>>> driver to the phylib framework.
>>>>
>>>> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
>>> I found one more issue with this patch. On one of my test boards
>>> (Samsung Exynos5250 SoC based Arndale) system fails to establish 
>>> network
>>> connection just after starting the kernel when the driver is build-in.
>>>
>>> --->8---
>>> # dmesg | grep asix
>>> [    2.761928] usbcore: registered new interface driver asix
>>> [    5.003110] asix 1-3.2.4:1.0 (unnamed net_device) (uninitialized):
>>> invalid hw address, using random
>>> [    6.065400] asix 1-3.2.4:1.0 eth0: register 'asix' at
>>> usb-12110000.usb-3.2.4, ASIX AX88772 USB 2.0 Ethernet, 
>>> 7a:9b:9a:f2:94:8e
>>> [   14.043868] asix 1-3.2.4:1.0 eth0: Link is Up - 100Mbps/Full - flow
>>> control off
>>> # ping -c2  host
>>> PING host (192.168.100.1) 56(84) bytes of data.
>>>   From 192.168.100.20 icmp_seq=1 Destination Host Unreachable
>>>   From 192.168.100.20 icmp_seq=2 Destination Host Unreachable
>>>
>>> --- host ping statistics ---
>>> 2 packets transmitted, 0 received, +2 errors, 100% packet loss, time 
>>> 59ms
>>> --->8---
>> Hm... it looks like different chip variant. My is registered as
>> "ASIX AX88772B USB", yours is "ASIX AX88772 USB 2.0" - "B" is the
>> difference. Can you please tell me more about this adapter and if 
>> possible open
>> tell the real part name.
> Well, currently I have only remote access to that board. The network 
> chip is soldered on board. Maybe you can read something from the photo 
> on the wiki page: https://en.wikipedia.org/wiki/Arndale_Board
>> I can imagine that this adapter may using generic PHY driver.
>> Can you please confirm it by dmesg | grep PHY?
>> In my case i'll get:
>> Asix Electronics AX88772C usb-001:003:10: attached PHY driver 
>> (mii_bus:phy_addr=usb-001:003:10, irq=POLL)
> # dmesg | grep PHY
> [    5.700274] Asix Electronics AX88772A usb-001:004:10: attached PHY 
> driver (mii_bus:phy_addr=usb-001:004:10, irq=POLL)
>> If you have a different PHY, can you please send me the PHY id:
>> cat /sys/bus/mdio_bus/devices/usb-001\:003\:10/phy_id
>>
>> Your usb path will probably be different.
>
> # cat /sys/bus/mdio_bus/devices/usb-001\:004\:10/phy_id
> 0x003b1861
>
> > ...

Just for the record, I also have a board with external USB Ethernet 
dongle based on ASIX chip, which works fine with this patch, both when 
driver is built-in or as a module. Here is the log:

# dmesg | grep -i Asix
[    1.718349] usbcore: registered new interface driver asix
[    2.608596] usb 3-1: Manufacturer: ASIX Elec. Corp.
[    3.876279] libphy: Asix MDIO Bus: probed
[    3.958105] Asix Electronics AX88772C usb-003:002:10: attached PHY 
driver (mii_bus:phy_addr=usb-003:002:10, irq=POLL)
[    3.962728] asix 3-1:1.0 eth0: register 'asix' at 
usb-xhci-hcd.6.auto-1, ASIX AX88772B USB 2.0 Ethernet, 00:50:b6:18:92:f0
[   17.488532] asix 3-1:1.0 eth0: Link is Down
[   19.557233] asix 3-1:1.0 eth0: Link is Up - 100Mbps/Full - flow 
control off

# cat /sys/bus/mdio_bus/devices/usb-003\:002\:10/phy_id
0x003b1881


Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland