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Commit c08b1f45 authored by Liam Breck's avatar Liam Breck Committed by Sebastian Reichel
Browse files

power: supply: core: Add power_supply_battery_info and API 



power_supply_get_battery_info() reads battery data from devicetree.
struct power_supply_battery_info provides battery data to drivers.
Its fields correspond to elements in enum power_supply_property.
Drivers may surface battery data in sysfs via corresponding
POWER_SUPPLY_PROP_* fields.

Signed-off-by: default avatarMatt Ranostay <matt@ranostay.consulting>
Signed-off-by: default avatarLiam Breck <kernel@networkimprov.net>
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.co.uk>
parent 23067047

Documentation/power/power_supply_class.txt

+12 −0
Original line number Diff line number Diff line
@@ -174,6 +174,18 @@ issued by external power supply will notify supplicants via 
external_power_changed callback.





Devicetree battery characteristics

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Drivers should call power_supply_get_battery_info() to obtain battery

characteristics from a devicetree battery node, defined in

Documentation/devicetree/bindings/power/supply/battery.txt. This is

implemented in drivers/power/supply/bq27xxx_battery.c.



Properties in struct power_supply_battery_info and their counterparts in the

battery node have names corresponding to elements in enum power_supply_property,

for naming consistency between sysfs attributes and battery node properties.





QA

~~

Q: Where is POWER_SUPPLY_PROP_XYZ attribute?

drivers/power/supply/power_supply_core.c

+57 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
#include <linux/device.h>

#include <linux/notifier.h>

#include <linux/err.h>

#include <linux/of.h>

#include <linux/power_supply.h>

#include <linux/thermal.h>

#include "power_supply.h"
@@ -519,6 +520,62 @@ struct power_supply *devm_power_supply_get_by_phandle(struct device *dev, 
EXPORT_SYMBOL_GPL(devm_power_supply_get_by_phandle);

#endif /* CONFIG_OF */



int power_supply_get_battery_info(struct power_supply *psy,

				  struct power_supply_battery_info *info)

{

	struct device_node *battery_np;

	const char *value;

	int err;



	info->energy_full_design_uwh         = -EINVAL;

	info->charge_full_design_uah         = -EINVAL;

	info->voltage_min_design_uv          = -EINVAL;

	info->precharge_current_ua           = -EINVAL;

	info->charge_term_current_ua         = -EINVAL;

	info->constant_charge_current_max_ua = -EINVAL;

	info->constant_charge_voltage_max_uv = -EINVAL;



	if (!psy->of_node) {

		dev_warn(&psy->dev, "%s currently only supports devicetree\n",

			 __func__);

		return -ENXIO;

	}



	battery_np = of_parse_phandle(psy->of_node, "monitored-battery", 0);

	if (!battery_np)

		return -ENODEV;



	err = of_property_read_string(battery_np, "compatible", &value);

	if (err)

		return err;



	if (strcmp("simple-battery", value))

		return -ENODEV;



	/* The property and field names below must correspond to elements

	 * in enum power_supply_property. For reasoning, see

	 * Documentation/power/power_supply_class.txt.

	 */



	of_property_read_u32(battery_np, "energy-full-design-microwatt-hours",

			     &info->energy_full_design_uwh);

	of_property_read_u32(battery_np, "charge-full-design-microamp-hours",

			     &info->charge_full_design_uah);

	of_property_read_u32(battery_np, "voltage-min-design-microvolt",

			     &info->voltage_min_design_uv);

	of_property_read_u32(battery_np, "precharge-current-microamp",

			     &info->precharge_current_ua);

	of_property_read_u32(battery_np, "charge-term-current-microamp",

			     &info->charge_term_current_ua);

	of_property_read_u32(battery_np, "constant_charge_current_max_microamp",

			     &info->constant_charge_current_max_ua);

	of_property_read_u32(battery_np, "constant_charge_voltage_max_microvolt",

			     &info->constant_charge_voltage_max_uv);



	return 0;

}

EXPORT_SYMBOL_GPL(power_supply_get_battery_info);



int power_supply_get_property(struct power_supply *psy,

			    enum power_supply_property psp,

			    union power_supply_propval *val)

include/linux/power_supply.h

+22 −0
Original line number Diff line number Diff line
@@ -289,6 +289,25 @@ struct power_supply_info { 
	int use_for_apm;

};



/*

 * This is the recommended struct to manage static battery parameters,

 * populated by power_supply_get_battery_info(). Most platform drivers should

 * use these for consistency.

 * Its field names must correspond to elements in enum power_supply_property.

 * The default field value is -EINVAL.

 * Power supply class itself doesn't use this.

 */



struct power_supply_battery_info {

	int energy_full_design_uwh;	    /* microWatt-hours */

	int charge_full_design_uah;	    /* microAmp-hours */

	int voltage_min_design_uv;	    /* microVolts */

	int precharge_current_ua;	    /* microAmps */

	int charge_term_current_ua;	    /* microAmps */

	int constant_charge_current_max_ua; /* microAmps */

	int constant_charge_voltage_max_uv; /* microVolts */

};



extern struct atomic_notifier_head power_supply_notifier;

extern int power_supply_reg_notifier(struct notifier_block *nb);

extern void power_supply_unreg_notifier(struct notifier_block *nb);
@@ -307,6 +326,9 @@ static inline struct power_supply * 
devm_power_supply_get_by_phandle(struct device *dev, const char *property)

{ return NULL; }

#endif /* CONFIG_OF */



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_battery_charged(struct power_supply *psy);