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Re: [PATCH v5 2/6] ARM: imx6: register pm_power_off handler if "fsl,pmic-stby-poweroff" is set

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  Re: [PATCH v5 2/6] ARM: imx6: register pm_power_off handler if  "fsl,pmic-stby-poweroff" is set Oleksij Rempel <ore@pengutronix.de> - 2017-06-20 07:00 +0200
    Re: [PATCH v5 2/6] ARM: imx6: register pm_power_off handler if  "fsl,pmic-stby-poweroff" is set Oleksij Rempel <ore@pengutronix.de> - 2017-06-20 17:30 +0200

#1670268 — Re: [PATCH v5 2/6] ARM: imx6: register pm_power_off handler if "fsl,pmic-stby-poweroff" is set

Hi Leonard,

On 19.06.2017 13:35, Leonard Crestez wrote:
> On Mon, 2017-06-19 at 07:02 +0200, Oleksij Rempel wrote:
>> One of the Freescale recommended sequences for power off with
>> external
>> PMIC is the following:
>> ...
>> 3.  SoC is programming PMIC for power off when standby is asserted.
>> 4.  In CCM STOP mode, Standby is asserted, PMIC gates SoC supplies.
>>
>> See:
>> https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww
>> .nxp.com%2Fassets%2Fdocuments%2Fdata%2Fen%2Freference-
>> manuals%2FIMX6DQRM.pdf&data=01%7C01%7Cleonard.crestez%40nxp.com%7C32c
>> df19d0ab44ed8e24d08d4b6d097f4%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0&
>> sdata=CWDpnEGikPGmSTM3dQH8IMxQCVzcIvHL69nu962d8M0%3D&reserved=0
>> page 5083
>>
>> This patch implements step 4. of this sequence.
>>
>> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
>> ---
>>  arch/arm/mach-imx/pm-imx6.c | 25 +++++++++++++++++++++++++
>>  1 file changed, 25 insertions(+)
>>
>> diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-
>> imx6.c
>> index e61b1d1027e1..cb76832935f0 100644
>> --- a/arch/arm/mach-imx/pm-imx6.c
>> +++ b/arch/arm/mach-imx/pm-imx6.c
>> @@ -602,6 +602,28 @@ static void __init imx6_pm_common_init(const
>> struct imx6_pm_socdata
>>  				   IMX6Q_GPR1_GINT);
>>  }
>>
>> +static void imx6_pm_poweroff(void)
>> +{
>> +	imx6_set_lpm(STOP_POWER_OFF);
>> +	cpu_suspend(0, imx6q_suspend_finish);
>
> It's a bit strange that you're using parts of the suspend code for
> this. Perhaps you could just write your bits to CLPCR and then execute
> a WFI?

Well, every thing in this patch set, yell about using standby/suspend 
path in HW for power off. Even iMX code use STOP_POWER_OFF for 
configuring this regs. How can it be more strange? :) Should i really 
duplicate code to hide this?

> It would also be nice to rename this to something like
> imx6_pm_stby_poweroff to make it clear that it's only for a certain
> power off path.

ok.

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#1670875

On Tue, Jun 20, 2017 at 05:32:16PM +0300, Leonard Crestez wrote:
> On Tue, 2017-06-20 at 06:55 +0200, Oleksij Rempel wrote:
> > On 19.06.2017 13:35, Leonard Crestez wrote:
> > > On Mon, 2017-06-19 at 07:02 +0200, Oleksij Rempel wrote:
> > > > 
> > > > One of the Freescale recommended sequences for power off with
> > > > external
> > > > PMIC is the following:
> > > > ...
> > > > 3.  SoC is programming PMIC for power off when standby is asserted.
> > > > 4.  In CCM STOP mode, Standby is asserted, PMIC gates SoC supplies.
> > > > 
> > > > This patch implements step 4. of this sequence.
> > > > 
> > > > Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> > > > ---
> > > >  arch/arm/mach-imx/pm-imx6.c | 25 +++++++++++++++++++++++++
> > > >  1 file changed, 25 insertions(+)
> > > > 
> > > > diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-
> > > > imx6.c
> > > > index e61b1d1027e1..cb76832935f0 100644
> > > > --- a/arch/arm/mach-imx/pm-imx6.c
> > > > +++ b/arch/arm/mach-imx/pm-imx6.c
> > > > @@ -602,6 +602,28 @@ static void __init imx6_pm_common_init(const
> > > > struct imx6_pm_socdata
> > > >  				   IMX6Q_GPR1_GINT);
> > > >  }
> > > > 
> > > > +static void imx6_pm_poweroff(void)
> > > > +{
> > > > +	imx6_set_lpm(STOP_POWER_OFF);
> > > > +	cpu_suspend(0, imx6q_suspend_finish);
> > > It's a bit strange that you're using parts of the suspend code for
> > > this. Perhaps you could just write your bits to CLPCR and then execute
> > > a WFI?
> > Well, every thing in this patch set, yell about using standby/suspend 
> > path in HW for power off. Even iMX code use STOP_POWER_OFF for 
> > configuring this regs. How can it be more strange? :) Should i really 
> > duplicate code to hide this?
> > 
> This code is used to set the power state the soc enters on WFI. These
> function try to ensure that it is possible to come back up when woken
> by an interrupt later. That part you don't want, right?
> 
> However I can't think of any obvious way this could misbehave so I
> guess it's fine.

ok, thx.

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