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Groups > linux.kernel > #1470537 > unrolled thread

Re: [PATCH] net: phy: micrel: remove suspend/resume

Started byFlorian Fainelli <f.fainelli@gmail.com>
First post2016-08-26 06:40 +0200
Last post2016-08-26 08:30 +0200
Articles 2 — 2 participants

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  Re: [PATCH] net: phy: micrel: remove suspend/resume Florian Fainelli <f.fainelli@gmail.com> - 2016-08-26 06:40 +0200
    Re: [PATCH] net: phy: micrel: remove suspend/resume Christophe Leroy <christophe.leroy@c-s.fr> - 2016-08-26 08:30 +0200

#1470537 — Re: [PATCH] net: phy: micrel: remove suspend/resume

FromFlorian Fainelli <f.fainelli@gmail.com>
Date2016-08-26 06:40 +0200
SubjectRe: [PATCH] net: phy: micrel: remove suspend/resume
Message-ID<sah5U-2g4-1@gated-at.bofh.it>
Le 24/08/2016 à 07:14, Christophe Leroy a écrit :
> 
> 
> Le 23/08/2016 à 21:03, Florian Fainelli a écrit :
>> +others,
>>
>> On 08/23/2016 04:13 AM, Christophe Leroy wrote:
>>> In ERRATA DS80000700A dated 05 May 2016, Microship recommends to
>>> not use software power down mode on KSZ8041 family.
>>
>> s/Microship/Microchip/
>>
>>> They say they have no plan to fix this ERRATA in future releases.
>>
>> The errata applies to specific revisions, is this revision present in
>> the lower 4 bits of the MII_PHYSID2 register such that it could be used
>> to key the disabling of the power down?
> 
> It doesn't seem clear to me how this could/should be handled.
> 
> According to the documentation, all variants have the same ID 0x0022151x
> with revision x. A3 has ID 0x00221512 and A4 has 0x00221513.
> According to the doc, the KSZ8041RNLI should has same ID. But according
> to micrel driver, it has ID 0x00221537. And the buggy revision of that
> one is rev A. Is it what the 7 means ?

Humm the revision is typically stored on 4 bits, so 0x7 could mean
anything here, it really depends if how they are allocating their revision.

0b0000 -> A0
0b0001 -> A1
...
0b0110 -> A6
0b0111 -> A7?

Who knows.

> 
> The ERRATA applies to KSZ8041NL revision A4 and to KSZ8041NL-AM revision
> A3. My understanding it that both variants have ID 0x0022151x, ie
> KSZ8041NL-AM revision A3 has ID 0x00221512 and KSZ8041NL revision A4 has
> ID 0x00221513. But KSZ8041NL revision A3 also has ID 0x00221512 and the
> ERRATA doesn't apply to it.
> 
> So what can be done really ? Only apply the fix to ID 0x00221513 (which
> is what I need as I have KSZ8041NL revision A4 on my boards) ? Or apply
> it for all KSZ8041 and KSZ8041RNLI to be on the safe side ?

I would apply it to just the KSZ8041NL rev. A4 for now, ideally we would
want to track down the users of the KSZ8041RNLI and see if somebody
could test that, realistically, we won't be able to, so I would err on
the side of caution at the expense of slightly increased power
consumption for that particular PHY and have a broader match of all the
KSZ8041RNLI potentially affected.

Does that make sense?
-- 
Florian

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#1470560

FromChristophe Leroy <christophe.leroy@c-s.fr>
Date2016-08-26 08:30 +0200
Message-ID<saiOl-3mM-3@gated-at.bofh.it>
In reply to#1470537

Le 26/08/2016 à 06:35, Florian Fainelli a écrit :
> Le 24/08/2016 à 07:14, Christophe Leroy a écrit :
>>
>>
>> Le 23/08/2016 à 21:03, Florian Fainelli a écrit :
>>> +others,
>>>
>>> On 08/23/2016 04:13 AM, Christophe Leroy wrote:
>>>> In ERRATA DS80000700A dated 05 May 2016, Microship recommends to
>>>> not use software power down mode on KSZ8041 family.
>>>
>>> s/Microship/Microchip/
>>>
>>>> They say they have no plan to fix this ERRATA in future releases.
>>>
>>> The errata applies to specific revisions, is this revision present in
>>> the lower 4 bits of the MII_PHYSID2 register such that it could be used
>>> to key the disabling of the power down?
>>
>> It doesn't seem clear to me how this could/should be handled.
>>
>> According to the documentation, all variants have the same ID 0x0022151x
>> with revision x. A3 has ID 0x00221512 and A4 has 0x00221513.
>> According to the doc, the KSZ8041RNLI should has same ID. But according
>> to micrel driver, it has ID 0x00221537. And the buggy revision of that
>> one is rev A. Is it what the 7 means ?
>
> Humm the revision is typically stored on 4 bits, so 0x7 could mean
> anything here, it really depends if how they are allocating their revision.
>
> 0b0000 -> A0
> 0b0001 -> A1
> ...
> 0b0110 -> A6
> 0b0111 -> A7?
>
> Who knows.
>
>>
>> The ERRATA applies to KSZ8041NL revision A4 and to KSZ8041NL-AM revision
>> A3. My understanding it that both variants have ID 0x0022151x, ie
>> KSZ8041NL-AM revision A3 has ID 0x00221512 and KSZ8041NL revision A4 has
>> ID 0x00221513. But KSZ8041NL revision A3 also has ID 0x00221512 and the
>> ERRATA doesn't apply to it.
>>
>> So what can be done really ? Only apply the fix to ID 0x00221513 (which
>> is what I need as I have KSZ8041NL revision A4 on my boards) ? Or apply
>> it for all KSZ8041 and KSZ8041RNLI to be on the safe side ?
>
> I would apply it to just the KSZ8041NL rev. A4 for now, ideally we would
> want to track down the users of the KSZ8041RNLI and see if somebody
> could test that, realistically, we won't be able to, so I would err on
> the side of caution at the expense of slightly increased power
> consumption for that particular PHY and have a broader match of all the
> KSZ8041RNLI potentially affected.
>
> Does that make sense?
>

What about the KSZ8041NL-AM revision A3, which has the same PHY ID as 
the KSZ8041NL revision A3 ?
Shouldn't we also have a broader match on this one in order to cover all 
cases and also be on the side of caution ?

Christophe

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