Re: [PATCH v2 1/8] power: supply: core: Add resistance power supply property

[Fenglin Wu]

On 6/22/2025 9:26 AM, Sebastian Reichel wrote:
> Hi,
>
> On Fri, May 30, 2025 at 03:35:06PM +0800, Fenglin Wu via B4 Relay wrote:
> > From: Fenglin Wu <fenglin.wu@xxxxxxxxxxxxxxxx>
> >
> > Some battery drivers provide the ability to export resistance as a
> > parameter. Add resistance power supply property for that purpose.
> This is missing some information and the naming is bad.
>
> Which resistance (I suppose battery internal resistance)?
>
> That is heavily dependent on the battery temperature. So this needs
> to document if this is for the current temperature or for some
> specific one.
>
> -- Sebastian

This is battery internal resistance calculated by battery management 
system, using the real-time temperature measured by the thermistor 
inside the battery pack.

I can update the name to something like "rt_internal_resistance" and 
update the description accordingly.

> > Signed-off-by: Fenglin Wu <fenglin.wu@xxxxxxxxxxxxxxxx>
> > ---
> >   Documentation/ABI/testing/sysfs-class-power | 10 ++++++++++
> >   drivers/power/supply/power_supply_sysfs.c   |  1 +
> >   include/linux/power_supply.h                |  1 +
> >   3 files changed, 12 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
> > index 560124cc31770cde03bcdbbba0d85a5bd78b15a0..22a565a6a1c509461b8c483e12975295765121d6 100644
> > --- a/Documentation/ABI/testing/sysfs-class-power
> > +++ b/Documentation/ABI/testing/sysfs-class-power
> > @@ -552,6 +552,16 @@ Description:
> >   			Integer > 0: representing full cycles
> >   			Integer = 0: cycle_count info is not available
> >   
> > +What:		/sys/class/power_supply/<supply_name>/resistance
> > +Date:		May 2025
> > +Contact:	linux-arm-msm@xxxxxxxxxxxxxxx
> > +Description:
> > +		Reports the resistance of the battery power supply.
> > +
> > +		Access: Read
> > +
> > +		Valid values: Represented in microohms
> > +
> >   **USB Properties**
> >   
> >   What:		/sys/class/power_supply/<supply_name>/input_current_limit
> > diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
> > index a438f7983d4f6a832e9d479184c7c35453e1757c..dd829148eb6fda5dcd7eab53fc70f99081763714 100644
> > --- a/drivers/power/supply/power_supply_sysfs.c
> > +++ b/drivers/power/supply/power_supply_sysfs.c
> > @@ -220,6 +220,7 @@ static struct power_supply_attr power_supply_attrs[] __ro_after_init = {
> >   	POWER_SUPPLY_ATTR(MANUFACTURE_YEAR),
> >   	POWER_SUPPLY_ATTR(MANUFACTURE_MONTH),
> >   	POWER_SUPPLY_ATTR(MANUFACTURE_DAY),
> > +	POWER_SUPPLY_ATTR(RESISTANCE),
> >   	/* Properties of type `const char *' */
> >   	POWER_SUPPLY_ATTR(MODEL_NAME),
> >   	POWER_SUPPLY_ATTR(MANUFACTURER),
> > diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> > index c4cb854971f53a244ba7742a15ce7a5515da6199..de3e88810e322546470b21258913abc7707c86a7 100644
> > --- a/include/linux/power_supply.h
> > +++ b/include/linux/power_supply.h
> > @@ -174,6 +174,7 @@ enum power_supply_property {
> >   	POWER_SUPPLY_PROP_MANUFACTURE_YEAR,
> >   	POWER_SUPPLY_PROP_MANUFACTURE_MONTH,
> >   	POWER_SUPPLY_PROP_MANUFACTURE_DAY,
> > +	POWER_SUPPLY_PROP_RESISTANCE,
> >   	/* Properties of type `const char *' */
> >   	POWER_SUPPLY_PROP_MODEL_NAME,
> >   	POWER_SUPPLY_PROP_MANUFACTURER,
> >
> > --
> > 2.34.1