[U-Boot] [PATCH] net/phy: Fix phy_connect() for phy addr 0

[Marek Vasut]

On 12/17/19 5:25 PM, Joe Hershberger wrote:
> Hi Marek,

Hi Joe,

> On Tue, Dec 17, 2019 at 1:39 AM Marek Vasut <marex at denx.de> wrote:
>>
>> On 11/7/19 9:04 PM, Joe Hershberger wrote:
>>> On Thu, Nov 7, 2019 at 1:16 PM Tom Rini <trini at konsulko.com> wrote:
>>>>
>>>> On Tue, Nov 05, 2019 at 04:05:11AM +0000, Priyanka Jain wrote:
>>>>
>>>>> Fix 'mask' calculation in phy_connect() for phy addr '0'.
>>>>> 'mask' is getting set to '0xffffffff' for phy addr '0'
>>>>> in phy_connect() whereas expected value is '0'.
>>>>>
>>>>>
>>>>> Signed-off-by: Priyanka Jain <priyanka.jain at nxp.com>
>>>>
>>>> Reported-by: tetsu-aoki via github
>>>
>>> Acked-by: Joe Hershberger <joe.hershberger at ni.com>
>>
>> Sadly, this breaks systems where a PHY is at address 0.
>> I have such an STM32MP1 system with LAN8720 PHY and since this patch, I
>> cannot use ethernet. Please revert.
> 
> It seems like a case that shouldn't have worked before.

Eh? PHY at address 0 definitely did work before and must work now.

> What about
> this board requires the mask to be all 'f's, other than specifying the
> wrong phy address? It seems that in your case the phy address is not
> actually 0 (or the computed mask would find it), but your board dts
> may be setting it to 0 as an "unknown" value, but the correct unknown
> value should be "-1". It seems the issue is with these boards.

Nope, the address is actually configured to 0 in hardware.