linux-kernel - Re: [PATCH v2 5/6] regulator: pfuze100-regulator: provide pm_power_off

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Message-ID: <c8457655-2e8b-7362-5e39-bebddbe5c502@rempel-privat.de>
Date:   Thu, 1 Jun 2017 08:19:39 +0200
From:   Oleksij Rempel <linux@...pel-privat.de>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Oleksij Rempel <o.rempel@...gutronix.de>
Cc:     kernel@...gutronix.de, linux-arm-kernel@...ts.infradead.org,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 5/6] regulator: pfuze100-regulator: provide
 pm_power_off_prepare handler

Am 31.05.2017 um 22:59 schrieb Andrew Morton:
> On Wed, 31 May 2017 08:14:56 +0200 Oleksij Rempel <o.rempel@...gutronix.de> wrote:
> 
>> On some boards the SoC can use one pin "PMIC_STBY_REQ" to notify th PMIC
>> about state changes. In this case internal state of PMIC must be
>> preconfigured for upcomming state change.
>> It works fine with the current regulator framework, except with the
>> power-off case.
>>
>> This patch is providing an optional pm_power_off_prepare handler
>> which will configure the PMIC_StandBy state to disable all power lines.
>>
>> In my power consumption test on RIoTBoard, I got the following results:
>> poweroff without this patch:	320 mA
>> poweroff with this patch:	2   mA
>> suspend to ram:			40  mA
>>
>> ...
>>
>> +static int pfuze_poweroff_pre_init(struct pfuze_chip *pfuze_chip)
>> +{
>> +	if (pfuze_chip->chip_id != PFUZE100) {
>> +		dev_warn(pfuze_chip->dev, "Requested pm_power_off_prepare handler for not supoorted chip\n");
>> +		return -ENODEV;
>> +	}
>> +
>> +	if (pm_power_off_prepare) {
>> +		dev_warn(pfuze_chip->dev, "pm_power_off_prepare is already registred.\n");
>> +		return -EBUSY;
>> +	}
>> +
>> +	syspm_pfuze_chip = pfuze_chip;
>> +	pm_power_off_prepare = pfuze_poweroff_pre;
>> +
>> +	return 0;
>> +}
>> +
> 
> Ah, there it is.
> 
> This looks a bit dodgy.  What happens after someone does rmmod on this
> driver?

ok, got it.

> (typo in comment: "supoorted")
> 
> (I wish we could get "poweroff" and "power_off" consistent)

Hm.. only in this case or in DT bindings too? Which variant should be
used? Driver: *_power_off_*; DT: *-power-off-* ?

-- 
Regards,
Oleksij



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