Re: [PATCH v4 2/4] power: supply: core: add input voltage/current measurements

From: Sebastian Reichel
Date: Sat May 02 2020 - 18:23:56 EST


Hi,

On Fri, May 01, 2020 at 05:11:18PM +0200, MichaÅ MirosÅaw 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.

> Signed-off-by: MichaÅ MirosÅaw <mirq-linux@xxxxxxxxxxxx>

[...]

> --- a/drivers/power/supply/power_supply_sysfs.c
> +++ b/drivers/power/supply/power_supply_sysfs.c
> @@ -273,7 +273,9 @@ static struct device_attribute power_supply_attrs[] = {
> POWER_SUPPLY_ATTR(charge_control_limit_max),
> POWER_SUPPLY_ATTR(charge_control_start_threshold),
> POWER_SUPPLY_ATTR(charge_control_end_threshold),
> + POWER_SUPPLY_ATTR(input_current_now),
> POWER_SUPPLY_ATTR(input_current_limit),
> + POWER_SUPPLY_ATTR(input_voltage_now),
> POWER_SUPPLY_ATTR(input_voltage_limit),
> POWER_SUPPLY_ATTR(input_power_limit),
> POWER_SUPPLY_ATTR(energy_full_design),
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index 6a34df65d4d1..5313d1284aad 100644
> --- 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@xxxxxxxxxxxxxxx
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

> POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
> + POWER_SUPPLY_PROP_INPUT_VOLTAGE_NOW,

What: /sys/class/power_supply/<supply_name>/voltage_now
Date: May 2007
Contact: linux-pm@xxxxxxxxxxxxxxx
Description:
Reports the VBUS voltage supplied now. This value is generally
read-only reporting, unless the 'online' state of the supply
is set to be programmable, in which case this value can be set
within the reported min/max range.

Access: Read, Write
Valid values: Represented in microvolts

> POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT,
> POWER_SUPPLY_PROP_INPUT_POWER_LIMIT,
> POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,

-- Sebastian

Attachment: signature.asc
Description: PGP signature