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

[Robin Gong]

> -----Original Message-----
> From: Oleksij Rempel [mailto:o.rempel@xxxxxxxxxxxxxx]
> Sent: 2018年7月26日 19:38
> To: Robin Gong <yibin.gong@xxxxxxx>; Shawn Guo <shawnguo@xxxxxxxxxx>;
> Mark Brown <broonie@xxxxxxxxxx>; Rafael J. Wysocki
> <rafael.j.wysocki@xxxxxxxxx>
> Cc: kernel@xxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-clk@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>;
> Liam Girdwood <lgirdwood@xxxxxxxxx>; Leonard Crestez
> <leonard.crestez@xxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; Mark
> Rutland <mark.rutland@xxxxxxx>; Michael Turquette
> <mturquette@xxxxxxxxxxxx>; Stephen Boyd <sboyd@xxxxxxxxxxxxxx>; Fabio
> Estevam <fabio.estevam@xxxxxxx>; Russell King <linux@xxxxxxxxxxxxxxx>;
> dl-linux-imx <linux-imx@xxxxxxx>; A.s. Dong <aisheng.dong@xxxxxxx>
> Subject: Re: [PATCH v8 1/6] ARM: imx6q: provide documentation for new
> fsl,pmic-stby-poweroff property
> 
> Hi,
> 
> On 26.07.2018 11:51, Robin Gong wrote:
> >
> >
> >> -----Original Message-----
> >> From: Oleksij Rempel [mailto:o.rempel@xxxxxxxxxxxxxx]
> >> Sent: 2018年7月26日 17:22
> >> To: Shawn Guo <shawnguo@xxxxxxxxxx>; Mark Brown
> <broonie@xxxxxxxxxx>;
> >> Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> >> Cc: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>; kernel@xxxxxxxxxxxxxx;
> >> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> >> linux-clk@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Andrew
> >> Morton <akpm@xxxxxxxxxxxxxxxxxxxx>; Liam Girdwood
> >> <lgirdwood@xxxxxxxxx>; Leonard Crestez <leonard.crestez@xxxxxxx>;
> Rob
> >> Herring <robh+dt@xxxxxxxxxx>; Mark Rutland <mark.rutland@xxxxxxx>;
> >> Michael Turquette <mturquette@xxxxxxxxxxxx>; Stephen Boyd
> >> <sboyd@xxxxxxxxxxxxxx>; Fabio Estevam <fabio.estevam@xxxxxxx>;
> >> Russell King <linux@xxxxxxxxxxxxxxx>; dl-linux-imx
> >> <linux-imx@xxxxxxx>; Robin Gong <yibin.gong@xxxxxxx>; A.s. Dong
> >> <aisheng.dong@xxxxxxx>
> >> Subject: [PATCH v8 1/6] ARM: imx6q: provide documentation for new
> >> fsl,pmic-stby-poweroff property
> >>
> >> Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> >> Acked-by: Rob Herring <robh@xxxxxxxxxx>
> >> ---
> >>  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.
> 
> > Don't understand
> > why not follow normal board design guide to power off pmic by
> PMIC_ON_REQ.
> > How to power on board again then?
> 
> Power cycle. Without this patch, power of is not real power off. So, power cycle,
> is expected behavior for user interaction. On usual PC, reset button will not
> enable PC as well.
Your board can't support wakeup by RTC alarm if not use PMIC_ON_REQ to power off.
Again, why your board not follow the design guide?