linux-kernel - RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life charging mode

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Date:   Tue, 23 Jun 2020 18:59:00 +0000
From:   <Mario.Limonciello@...l.com>
To:     <Crag.Wang@...l.com>, <crag0715@...il.com>, <sre@...nel.org>
CC:     <mathewk@...omium.org>, <linux-pm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life
 charging mode

> -----Original Message-----
> From: Wang, Crag <Crag_Wang@...l.com>
> Sent: Tuesday, June 23, 2020 10:51 AM
> To: Limonciello, Mario; Crag Wang; Sebastian Reichel
> Cc: mathewk@...omium.org; linux-pm@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life
> charging mode
> 
> > -----Original Message-----
> > From: Limonciello, Mario <Mario_Limonciello@...l.com>
> > Sent: Tuesday, June 23, 2020 9:48 PM
> > To: Crag Wang; Sebastian Reichel
> > Cc: mathewk@...omium.org; Wang, Crag; linux-pm@...r.kernel.org; linux-
> > kernel@...r.kernel.org
> > Subject: RE: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life
> > charging mode
> >
> > > -----Original Message-----
> > > From: Crag Wang <crag0715@...il.com>
> > > Sent: Tuesday, June 23, 2020 3:20 AM
> > > To: Sebastian Reichel
> > > Cc: mathewk@...omium.org; Limonciello, Mario; Wang, Crag; linux-
> > > pm@...r.kernel.org; linux-kernel@...r.kernel.org
> > > Subject: [PATCH 1/1] power_supply: wilco_ec: Add permanent long life
> > > charging mode
> > >
> > >
> > > [EXTERNAL EMAIL]
> > >
> > > This is a long life mode for extended warranty battery, switching to a
> > > differnt mode selection is unavailable. The power charging rate is
> > > customized so that battery at work last longer.
> > >
> > > Signed-off-by: Crag Wang <crag_wang@...l.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-class-power-wilco | 3 +++
> > >  drivers/power/supply/power_supply_sysfs.c         | 1 +
> > >  drivers/power/supply/wilco-charger.c              | 5 +++++
> > >  include/linux/power_supply.h                      | 1 +
> > >  4 files changed, 10 insertions(+)
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-class-power-wilco
> > > b/Documentation/ABI/testing/sysfs-class-power-wilco
> > > index da1d6ffe5e3c..1c91b17b6fd4 100644
> > > --- a/Documentation/ABI/testing/sysfs-class-power-wilco
> > > +++ b/Documentation/ABI/testing/sysfs-class-power-wilco
> > > @@ -14,6 +14,9 @@ Description:
> > >  			Charging begins when level drops below
> > >  			charge_control_start_threshold, and ceases when
> > >  			level is above charge_control_end_threshold.
> > > +		Permanent Long Life: Last longer battery life, this mode
> > > +			is programmed once in the factory. Switching to a
> > > +			different mode is unavailable.
> > >
> > >  What:		/sys/class/power_supply/wilco-
> > > charger/charge_control_start_threshold
> > >  Date:		April 2019
> > > diff --git a/drivers/power/supply/power_supply_sysfs.c
> > > b/drivers/power/supply/power_supply_sysfs.c
> > > index bc79560229b5..af3884015ad8 100644
> > > --- a/drivers/power/supply/power_supply_sysfs.c
> > > +++ b/drivers/power/supply/power_supply_sysfs.c
> > > @@ -87,6 +87,7 @@ static const char * const
> > > POWER_SUPPLY_CHARGE_TYPE_TEXT[] = {
> > >  	[POWER_SUPPLY_CHARGE_TYPE_STANDARD]	= "Standard",
> > >  	[POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE]	= "Adaptive",
> > >  	[POWER_SUPPLY_CHARGE_TYPE_CUSTOM]	= "Custom",
> > > +	[POWER_SUPPLY_CHARGE_TYPE_LONGLIFE]	= "Permanent Long
> > Life",
> > >  };
> > >
> > >  static const char * const POWER_SUPPLY_HEALTH_TEXT[] = { diff --git
> > > a/drivers/power/supply/wilco-charger.c
> > > b/drivers/power/supply/wilco-charger.c
> > > index b3c6d7cdd731..713c3018652f 100644
> > > --- a/drivers/power/supply/wilco-charger.c
> > > +++ b/drivers/power/supply/wilco-charger.c
> > > @@ -27,6 +27,7 @@ enum charge_mode {
> > >  	CHARGE_MODE_AC = 3,	/* Mostly AC use, used for Trickle */
> > >  	CHARGE_MODE_AUTO = 4,	/* Used for Adaptive */
> > >  	CHARGE_MODE_CUSTOM = 5,	/* Used for Custom */
> > > +	CHARGE_MODE_LONGLIFE = 6, /* Used for Permanent Long Life */
> >
> > Since this is normally only done in the factory context, can you please
> > confirm does something need to be artificially done to block userland from
> > trying to set the battery charging to this mode?  Or will the EC already
> handle
> > blocking it directly?
> 
> This is a feature of the battery, when the EC receives this setting it will be
> sent
> to the battery and stored there. Afterwards any attempt to change this mode
> will return a failure.

Sorry this still isn't clear to me.  You're saying that if EC receives longlife setting
it will be able to do this in the field?  If so, then I think this patch will need
to block that setting to not allow field conversions into longlife mode.

> 
> It's even better to block mode selection in the userland if long life mode
> already
> in use.

Yes, I agree.  This sounds like a good follow up to me too.

> 
> >
> > >  };
> > >
> > >  #define CHARGE_LOWER_LIMIT_MIN	50
> > > @@ -48,6 +49,8 @@ static int psp_val_to_charge_mode(int psp_val)
> > >  		return CHARGE_MODE_AUTO;
> > >  	case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
> > >  		return CHARGE_MODE_CUSTOM;
> > > +	case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
> > > +		return CHARGE_MODE_LONGLIFE;
> > >  	default:
> > >  		return -EINVAL;
> > >  	}
> > > @@ -67,6 +70,8 @@ static int charge_mode_to_psp_val(enum
> > charge_mode mode)
> > >  		return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
> > >  	case CHARGE_MODE_CUSTOM:
> > >  		return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
> > > +	case CHARGE_MODE_LONGLIFE:
> > > +		return POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
> > >  	default:
> > >  		return -EINVAL;
> > >  	}
> > > diff --git a/include/linux/power_supply.h
> > > b/include/linux/power_supply.h index ac1345a48ad0..528a3eaa2320
> > 100644
> > > --- a/include/linux/power_supply.h
> > > +++ b/include/linux/power_supply.h
> > > @@ -48,6 +48,7 @@ enum {
> > >  	POWER_SUPPLY_CHARGE_TYPE_STANDARD,	/* normal speed */
> > >  	POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE,	/* dynamically
> > adjusted speed */
> > >  	POWER_SUPPLY_CHARGE_TYPE_CUSTOM,	/* use
> > CHARGE_CONTROL_* props */
> > > +	POWER_SUPPLY_CHARGE_TYPE_LONGLIFE,	/* slow speed, longer
> > life */
> > >  };
> > >
> > >  enum {
> > > --
> > > 2.20.1