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From: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org,
	linux-pm@vger.kernel.org
Subject: Re: [PATCH v4 2/4] power: supply: core: add input voltage/current measurements
Date: Sun, 3 May 2020 00:45:26 +0200	[thread overview]
Message-ID: <20200502224526.GA25127@qmqm.qmqm.pl> (raw)
In-Reply-To: <20200502222349.tfa72nr5zunybpla@earth.universe>

On Sun, May 03, 2020 at 12:23:49AM +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Fri, May 01, 2020 at 05:11:18PM +0200, Michał Mirosław wrote:
> > Introduce input voltage and current limits and measurements.
> > This makes room for e.g. VBUS measurements in USB chargers.
> We already have properties for charger input voltage/current.
> Unfortunately the naming is not as straight forward, as it
> could be. Basically the properties have been added over time
> and are ABI now. Things are documented in
> 
> Documentation/ABI/testing/sysfs-class-power
> 
> I provided the relevant properties below.

Hmm. Looks like there is no battery current/voltage properties then?
This is different from IBUS (input current), as IBUS = charging
current + system load. Documentation/power/power_supply_class.rst is
missing descriptions for the properties you mention.

[...]
> > --- a/include/linux/power_supply.h
> > +++ b/include/linux/power_supply.h
> > @@ -127,7 +127,9 @@ enum power_supply_property {
> >  	POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX,
> >  	POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD, /* in percents! */
> >  	POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD, /* in percents! */
> > +	POWER_SUPPLY_PROP_INPUT_CURRENT_NOW,
> 
> What:           /sys/class/power_supply/<supply_name>/current_avg    
> Date:           May 2007
> Contact:        linux-pm@vger.kernel.org                          
> Description:                  
>                 Reports an average IBUS current reading over a fixed period.   
>                 Normally devices will provide a fixed interval in which they   
>                 average readings to smooth out the reported value.             
>                                                                                 
>                 Access: Read    
>                 Valid values: Represented in microamps
> 

There are two entries for /sys/class/power_supply/<supply_name>/current_avg
in the file, the other one mentions IBAT instead. "voltage_now" has the
same problem. There seems to be a split-personality disorder present in
the kernel ABI. ;-)

Best Regards,
Michał Mirosław

  reply	other threads:[~2020-05-02 22:45 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-01 15:11 [PATCH v4 0/4] power: supply: core: extend with new properties Michał Mirosław
2020-05-01 15:11 ` [PATCH v4 1/4] power: supply: core: tabularize HWMON temperature labels Michał Mirosław
2020-05-02 22:24   ` Sebastian Reichel
2020-05-01 15:11 ` [PATCH v4 2/4] power: supply: core: add input voltage/current measurements Michał Mirosław
2020-05-02 22:23   ` Sebastian Reichel
2020-05-02 22:45     ` Michał Mirosław [this message]
2020-05-02 23:11       ` Michał Mirosław
2020-05-03  0:09         ` Sebastian Reichel
2020-05-01 15:11 ` [PATCH v4 4/4] power: supply: core: document measurement points Michał Mirosław
2020-05-01 15:11 ` [PATCH v4 3/4] power: supply: core: add output voltage measurements Michał Mirosław

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