Re: [PATCH v2 08/14] power: supply: Add power_supply_set_input_current_limit_from_supplier helper

[Sebastian Reichel <sebastian.reichel@collabora.co.uk>]

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Hi,

On Tue, Aug 15, 2017 at 10:04:56PM +0200, Hans de Goede wrote:
> On some devices the USB Type-C port power (USB PD 2.0) negotiation is
> done by a separate port-controller IC, while the current limit is
> controlled through another (charger) IC.
> 
> It has been decided to model this by modelling the external Type-C
> power brick (adapter/charger) as a power-supply class device which
> supplies the charger-IC, with its voltage-now and current-max representing
> the negotiated voltage and max current draw.
> 
> This commit adds a power_supply_set_input_current_limit_from_supplier
> helper function which charger power-supply drivers can call to get
> the max-current from their supplier and have this applied
> through their set_property call-back to their input-current-limit.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Thanks, queued.

-- Sebastian

>  drivers/power/supply/power_supply_core.c | 41 ++++++++++++++++++++++++++++++++
>  include/linux/power_supply.h             |  2 ++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
> index 0741fce..3f92574 100644
> --- a/drivers/power/supply/power_supply_core.c
> +++ b/drivers/power/supply/power_supply_core.c
> @@ -375,6 +375,47 @@ int power_supply_is_system_supplied(void)
>  }
>  EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);
>  
> +static int __power_supply_get_supplier_max_current(struct device *dev,
> +						   void *data)
> +{
> +	union power_supply_propval ret = {0,};
> +	struct power_supply *epsy = dev_get_drvdata(dev);
> +	struct power_supply *psy = data;
> +
> +	if (__power_supply_is_supplied_by(epsy, psy))
> +		if (!epsy->desc->get_property(epsy,
> +					      POWER_SUPPLY_PROP_CURRENT_MAX,
> +					      &ret))
> +			return ret.intval;
> +
> +	return 0;
> +}
> +
> +int power_supply_set_input_current_limit_from_supplier(struct power_supply *psy)
> +{
> +	union power_supply_propval val = {0,};
> +	int curr;
> +
> +	if (!psy->desc->set_property)
> +		return -EINVAL;
> +
> +	/*
> +	 * This function is not intended for use with a supply with multiple
> +	 * suppliers, we simply pick the first supply to report a non 0
> +	 * max-current.
> +	 */
> +	curr = class_for_each_device(power_supply_class, NULL, psy,
> +				      __power_supply_get_supplier_max_current);
> +	if (curr <= 0)
> +		return (curr == 0) ? -ENODEV : curr;
> +
> +	val.intval = curr;
> +
> +	return psy->desc->set_property(psy,
> +				POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT, &val);
> +}
> +EXPORT_SYMBOL_GPL(power_supply_set_input_current_limit_from_supplier);
> +
>  int power_supply_set_battery_charged(struct power_supply *psy)
>  {
>  	if (atomic_read(&psy->use_cnt) >= 0 &&
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index de89066..79e90b3 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -332,6 +332,8 @@ extern int power_supply_get_battery_info(struct power_supply *psy,
>  					 struct power_supply_battery_info *info);
>  extern void power_supply_changed(struct power_supply *psy);
>  extern int power_supply_am_i_supplied(struct power_supply *psy);
> +extern int power_supply_set_input_current_limit_from_supplier(
> +					 struct power_supply *psy);
>  extern int power_supply_set_battery_charged(struct power_supply *psy);
>  
>  #ifdef CONFIG_POWER_SUPPLY
> -- 
> 2.9.4
> 

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