linux-kernel - Re: [PATCH] regulator: s2mps11: Added shutdown function to poweroff Odroid-XU3

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Date:	Sat, 11 Jul 2015 16:57:21 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Anand Moon <linux.amoon@...il.com>
CC:	Sangbeom Kim <sbkim73@...sung.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH] regulator: s2mps11: Added shutdown function to poweroff
 Odroid-XU3

+CC Marek


W dniu 11.07.2015 o 16:12, Anand Moon pisze:
> Hi Krzysztof,
> 
> On 24 June 2015 at 16:27, Krzysztof Kozlowski <k.kozlowski@...sung.com> wrote:
>> 2015-06-24 19:32 GMT+09:00 Anand Moon <linux.amoon@...il.com>:
>>> Hi Krzysztof,
>>>
>>> On 24 June 2015 at 13:27, Krzysztof Kozlowski <k.kozlowski@...sung.com> wrote:
>>>> 2015-06-24 16:16 GMT+09:00 Anand Moon <linux.amoon@...il.com>:
>>>>> Added .shutdown function to s2mps11 to help poweroff the board succefully.
>>>>
>>>> s/succefully/successfully/
>>>>
>>>>> The device drivers set the register to turn off the PMIC.
>>>>
>>>> Driver or drivers?
>>>>
>>>>>
>>>>> Signed-off-by: Anand Moon <linux.amoon@...il.com>
>>>>> ---
>>>>> Changes fixes the poweroff
>>>>> root@...oidxu3:~# poweroff
>>>>>
>>>>> Broadcast message from root@...oidxu3
>>>>>         (/dev/ttySAC2) at 13:08 ...
>>>>>
>>>>> The system is going down for power off NOW!
>>>>> root@...oidxu3:~# wait-for-state stop/waiting
>>>>>  * Stopping rsync daemon rsync                                           [ OK ]
>>>>>  * Stopping RDP Session manager                                          [ OK ]
>>>>>  * Stopping NTP server ntpd                                              [ OK ]
>>>>>  * Asking all remaining processes to terminate...                        [ OK ]
>>>>>  * All processes ended within 1 seconds...                               [ OK ]
>>>>> nm-dispatcher.action: Caught signal 15, shutting down...
>>>>> ModemManager[2134]: <warn>  Could not acquire the 'org.freedesktop.ModemManager1' service name
>>>>>
>>>>> ModemManager[2134]: <info>  ModemManager is shut down
>>>>>
>>>>>  * Unmounting temporary filesystems...                                   [ OK ]
>>>>>  * Deactivating swap...                                                  [ OK ]
>>>>>  * Unmounting local filesystems...                                       [ OK ]
>>>>>  * Will now halt
>>>>> [  209.020280] reboot: Power down
>>>>> [  209.122039] Power down failed, please power off system manually.
>>>>> ---
>>>>>  drivers/regulator/s2mps11.c | 8 ++++++++
>>>>>  1 file changed, 8 insertions(+)
>>>>>
>>>>> diff --git a/drivers/regulator/s2mps11.c b/drivers/regulator/s2mps11.c
>>>>> index ff82811..871f7b8 100644
>>>>> --- a/drivers/regulator/s2mps11.c
>>>>> +++ b/drivers/regulator/s2mps11.c
>>>>> @@ -1060,6 +1060,13 @@ out:
>>>>>         return ret;
>>>>>  }
>>>>>
>>>>> +static void s2mps11_pmic_shutdown(struct platform_device *pdev)
>>>>> +{
>>>>> +       struct sec_pmic_dev *iodev = dev_get_drvdata(pdev->dev.parent);
>>>>> +
>>>>> +       regmap_update_bits(iodev->regmap_pmic, S2MPS11_REG_CTRL1, 0xff, 0x00);
>>>>
>>>> This looks odd to me and interesting in the same time...
>>>> 1. Why clearing all of the fields from the register? Don't you want to
>>>> clear only one of it?
>>>
>>> I have followed what the hardkernel source code point at this point.
>>> I will look into which bit need to clear/set to power off successful.
>>
>> Following other tree is not enough, even when it solves some one
>> problem. Drivers could be used on different boards, where hardkernel
>> patches were not tested. This driver is used on many boards so please
>> explain exactly what is the cause of problem, what have to be done and
>> how patch achieves this. Such explanation helps understanding impact
>> on other boards.
>>
>>>
>>>> 2. What exactly you want to do here? What is expected behaviour?
>>>
>>> When you power off the board dose not power off cleanly.
>>> [  209.122039] Power down failed, please power off system manually.
>>>
>>> After this changes Its power off the board. Leaving the board with
>>> solid red led blowing.
>>
>> You described observable issue, which is nice, but I am asking for
>> technical details. What exactly do you want to achieve here?
>> Technically. What is expected behaviour. In technical details, not
>> only observable. I am asking for these technical details not only
>> because they are important but also because I do not know them.
>>
>>>
>>>> 3. How this relates to PWRHOLD coming from AP to the PMIC?
>>>
>>> No Idea right now about this right now. but will update you it I have
>>> some thing.
>>
>> The PMIC receives two signals - PWREN and PWRHOLD. It seems strange
>> that PMIC must override PWRHOLD... maybe there is an issue in
>> mach-exynos code?
>>
>>>
>>>> 4. Why this is needed only for this driver and only for this board (Odroid XU3)?
>>>
>>> Yes It could be generic not specific for the Odroid XU3 will correct
>>> in next patch.
>>
>> Thanks,
>> Best regards,
>> Krzysztof
> 
> I don't have much technical knowlegde on the arch side PMIC.
> 
> Problem that I am trying to addressed is unclean shutdown. i.e. CPU is
> still running in busy loop.
> which leads external HDD not able to clean umount or power-off of the board.
> 
> [   27.427485] reboot: Power down
> [   27.529236] Power down failed, please power off system manually.
> 
> My investigation lead to the following.
> Reading the control register S2MPS11_REG_CTRL1 of s2mps11-pmic shown below.
> 
> [   27.411231] s2mps11-pmic s2mps11-pmic: reg value
> 16:00000000000000000000000000010000

This means the PWRHOLD bit is high.

> 
> clearing the bit of the control register S2MPS11_REG_CTRL1 which lead
> to proper shutdown of board.
> 
> Please share you thought on this.

The power off should be initiated from application processor, not PMIC.
The AP should set PWRHOLD pin (XPSHOLD on AP) to low which will turn off
the power.

This works for other Exynos SoCs.

Power off should not be performed by driver's shutdown callback because
there is no guarantee that this is the last shutdown callback. Maybe
other shutdowns would be executed after it?

The power should go off from exynos_power_off() method in pmu.c. Please
start with that. Why disabling PS_HOLD does not turn off the power?


Marek (cc-ed), do you have any ideas why Odroid XU3 fails to power down?


Best regards,
Krzysztof
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