linux-kernel - Re: [PATCH v8 1/6] ARM: imx6q: provide documentation for new fsl,pmic-stby-poweroff property

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Message-ID: <02f4b642-14a8-f2db-ea23-c42a4f6f1652@pengutronix.de>
Date:   Mon, 30 Jul 2018 10:03:29 +0200
From:   Oleksij Rempel <o.rempel@...gutronix.de>
To:     Robin Gong <yibin.gong@....com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Mark Brown <broonie@...nel.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Cc:     Mark Rutland <mark.rutland@....com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        dl-linux-imx <linux-imx@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "A.s. Dong" <aisheng.dong@....com>,
        Fabio Estevam <fabio.estevam@....com>,
        Russell King <linux@...linux.org.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Leonard Crestez <leonard.crestez@....com>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v8 1/6] ARM: imx6q: provide documentation for new
 fsl,pmic-stby-poweroff property



On 27.07.2018 10:58, Robin Gong wrote:
> 
> 
>> -----Original Message-----
>> From: Lucas Stach [mailto:l.stach@...gutronix.de]
>> Sent: 2018年7月27日 16:30
>> To: Robin Gong <yibin.gong@....com>; Oleksij Rempel
>> <o.rempel@...gutronix.de>; Shawn Guo <shawnguo@...nel.org>; Mark
>> Brown <broonie@...nel.org>; Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> Cc: Mark Rutland <mark.rutland@....com>; devicetree@...r.kernel.org;
>> Michael Turquette <mturquette@...libre.com>; Stephen Boyd
>> <sboyd@...eaurora.org>; linux-kernel@...r.kernel.org; Liam Girdwood
>> <lgirdwood@...il.com>; Rob Herring <robh+dt@...nel.org>; dl-linux-imx
>> <linux-imx@....com>; kernel@...gutronix.de; A.s. Dong
>> <aisheng.dong@....com>; Fabio Estevam <fabio.estevam@....com>; Russell
>> King <linux@...linux.org.uk>; Andrew Morton <akpm@...ux-foundation.org>;
>> Leonard Crestez <leonard.crestez@....com>; linux-clk@...r.kernel.org;
>> linux-arm-kernel@...ts.infradead.org
>> Subject: Re: [PATCH v8 1/6] ARM: imx6q: provide documentation for new
>> fsl,pmic-stby-poweroff property
>>
>> Hi Robin,
>>
>> Am Freitag, den 27.07.2018, 01:51 +0000 schrieb Robin Gong:
>> [...]
>>>>>> ---
>>>>>>  Documentation/devicetree/bindings/clock/imx6q-clock.txt | 8
>>>>>> ++++++++
>>>>>>  1 file changed, 8 insertions(+)
>>>>>>
>>>>>> diff --git
>>>>>> a/Documentation/devicetree/bindings/clock/imx6q-clock.txt
>>>>>> b/Documentation/devicetree/bindings/clock/imx6q-clock.txt
>>>>>> index a45ca67a9d5f..e1308346e00d 100644
>>>>>> --- a/Documentation/devicetree/bindings/clock/imx6q-clock.txt
>>>>>> +++ b/Documentation/devicetree/bindings/clock/imx6q-clock.txt
>>>>>> @@ -6,6 +6,14 @@ Required properties:
>>>>>>  - interrupts: Should contain CCM interrupt
>>>>>>  - #clock-cells: Should be <1>
>>>>>>
>>>>>> +Optional properties:
>>>>>> +- fsl,pmic-stby-poweroff: Configure CCM to assert PMIC_STBY_REQ
>>>>>> +signal
>>>>>> +  on power off.
>>>>>> +  Use this property if the SoC should be powered off by
>>>>>> +external power
>>>>>> +  management IC (PMIC) triggered via PMIC_STBY_REQ signal.
>>>>>
>>>>> PMIC_ON_REQ didn't connect to any pin of PMIC in your case?
>>>>
>>>> No. First, it was only one customer specific issue. After some
>>>> research I found even publicly available boards (for example
>>>> RioTboard) which has same/similar design. After seeing this in imx6
>>>> documentation as valid power off way, I have no doubts - there should be
>> even more devices doin this in the wild.
>>>
>>> Not sure why the customer didn't follow reference design, since
>>> PMIC_ON_REQ can provide power off/on feature by pressing ONOFF key
>>> which connected ONOFF pin of i.mx6(ONOFF will toggle PMIC_ON_REQ to
>>> power off/on PMIC). The official power off/on way (PMIC_ON_REQ) can
>>> also power off all power rails of PFUZE except snvs as your patch did
>>> on PMIC_STBY_REQ.  PMIC_STBY_REQ is used to notify pmic switch power
>>> mode (PFM/APS) or decrease voltage to save power in kernel suspend, not
>> power off....I am not sure if we need this patchset to 'workaround' the board
>> issue.
>>>
>> Not all boards follow the reference design, that's a fact of life.
>>
>> Please look at the i.MX6Q reference manual. The sequence implemented in this
>> patchset can be found as a valid way to power off the system in
>> "60.4.3 Power mode transitions" "Normal ON to OFF with external PMIC", so
>> there is hardly any way to argue that this is a board specific quirk. This is one of
>> the Freescale/NXP recommended sequences to turn off the system.

> Okay, but could you add one more comment for this solution? RTC alarm and ONOFF
> Button wakeup feature can't be support in this case.

Enough to add it in to changelog? or should it go to the binding
documentation?



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