power_supply_core.c

Go to the documentation of this file.

/*
 *  Universal power supply monitor class
 *
 *  Copyright © 2007  Anton Vorontsov <[email protected]>
 *  Copyright © 2004  Szabolcs Gyurko
 *  Copyright © 2003  Ian Molton <[email protected]>
 *
 *  Modified: 2004, Oct     Szabolcs Gyurko
 *
 *  You may use this code as per GPL version 2
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/power_supply.h>
#include <linux/thermal.h>
#include "power_supply.h"

/* exported for the APM Power driver, APM emulation */
struct class *power_supply_class;
EXPORT_SYMBOL_GPL(power_supply_class);

static struct device_type power_supply_dev_type;

static int __power_supply_changed_work(struct device *dev, void *data)
{
    struct power_supply *psy = (struct power_supply *)data;
    struct power_supply *pst = dev_get_drvdata(dev);
    int i;

    for (i = 0; i < psy->num_supplicants; i++)
        if (!strcmp(psy->supplied_to[i], pst->name)) {
            if (pst->external_power_changed)
                pst->external_power_changed(pst);
        }
    return 0;
}

static void power_supply_changed_work(struct work_struct *work)
{
    struct power_supply *psy = container_of(work, struct power_supply,
                        changed_work);

    dev_dbg(psy->dev, "%s\n", __func__);

    class_for_each_device(power_supply_class, NULL, psy,
                  __power_supply_changed_work);

    power_supply_update_leds(psy);

    kobject_uevent(&psy->dev->kobj, KOBJ_CHANGE);
}

void power_supply_changed(struct power_supply *psy)
{
    dev_dbg(psy->dev, "%s\n", __func__);

    schedule_work(&psy->changed_work);
}
EXPORT_SYMBOL_GPL(power_supply_changed);

static int __power_supply_am_i_supplied(struct device *dev, void *data)
{
    union power_supply_propval ret = {0,};
    struct power_supply *psy = (struct power_supply *)data;
    struct power_supply *epsy = dev_get_drvdata(dev);
    int i;

    for (i = 0; i < epsy->num_supplicants; i++) {
        if (!strcmp(epsy->supplied_to[i], psy->name)) {
            if (epsy->get_property(epsy,
                  POWER_SUPPLY_PROP_ONLINE, &ret))
                continue;
            if (ret.intval)
                return ret.intval;
        }
    }
    return 0;
}

int power_supply_am_i_supplied(struct power_supply *psy)
{
    int error;

    error = class_for_each_device(power_supply_class, NULL, psy,
                      __power_supply_am_i_supplied);

    dev_dbg(psy->dev, "%s %d\n", __func__, error);

    return error;
}
EXPORT_SYMBOL_GPL(power_supply_am_i_supplied);

static int __power_supply_is_system_supplied(struct device *dev, void *data)
{
    union power_supply_propval ret = {0,};
    struct power_supply *psy = dev_get_drvdata(dev);
    unsigned int *count = data;

    (*count)++;
    if (psy->type != POWER_SUPPLY_TYPE_BATTERY) {
        if (psy->get_property(psy, POWER_SUPPLY_PROP_ONLINE, &ret))
            return 0;
        if (ret.intval)
            return ret.intval;
    }
    return 0;
}

int power_supply_is_system_supplied(void)
{
    int error;
    unsigned int count = 0;

    error = class_for_each_device(power_supply_class, NULL, &count,
                      __power_supply_is_system_supplied);

    /*
     * If no power class device was found at all, most probably we are
     * running on a desktop system, so assume we are on mains power.
     */
    if (count == 0)
        return 1;

    return error;
}
EXPORT_SYMBOL_GPL(power_supply_is_system_supplied);

int power_supply_set_battery_charged(struct power_supply *psy)
{
    if (psy->type == POWER_SUPPLY_TYPE_BATTERY && psy->set_charged) {
        psy->set_charged(psy);
        return 0;
    }

    return -EINVAL;
}
EXPORT_SYMBOL_GPL(power_supply_set_battery_charged);

static int power_supply_match_device_by_name(struct device *dev, void *data)
{
    const char *name = data;
    struct power_supply *psy = dev_get_drvdata(dev);

    return strcmp(psy->name, name) == 0;
}

struct power_supply *power_supply_get_by_name(char *name)
{
    struct device *dev = class_find_device(power_supply_class, NULL, name,
                    power_supply_match_device_by_name);

    return dev ? dev_get_drvdata(dev) : NULL;
}
EXPORT_SYMBOL_GPL(power_supply_get_by_name);

int power_supply_powers(struct power_supply *psy, struct device *dev)
{
    return sysfs_create_link(&psy->dev->kobj, &dev->kobj, "powers");
}
EXPORT_SYMBOL_GPL(power_supply_powers);

static void power_supply_dev_release(struct device *dev)
{
    pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
    kfree(dev);
}

#ifdef CONFIG_THERMAL
static int power_supply_read_temp(struct thermal_zone_device *tzd,
        unsigned long *temp)
{
    struct power_supply *psy;
    union power_supply_propval val;
    int ret;

    WARN_ON(tzd == NULL);
    psy = tzd->devdata;
    ret = psy->get_property(psy, POWER_SUPPLY_PROP_TEMP, &val);

    /* Convert tenths of degree Celsius to milli degree Celsius. */
    if (!ret)
        *temp = val.intval * 100;

    return ret;
}

static struct thermal_zone_device_ops psy_tzd_ops = {
    .get_temp = power_supply_read_temp,
};

static int psy_register_thermal(struct power_supply *psy)
{
    int i;

    /* Register battery zone device psy reports temperature */
    for (i = 0; i < psy->num_properties; i++) {
        if (psy->properties[i] == POWER_SUPPLY_PROP_TEMP) {
            psy->tzd = thermal_zone_device_register(psy->name, 0, 0,
                    psy, &psy_tzd_ops, 0, 0);
            if (IS_ERR(psy->tzd))
                return PTR_ERR(psy->tzd);
            break;
        }
    }
    return 0;
}

static void psy_unregister_thermal(struct power_supply *psy)
{
    if (IS_ERR_OR_NULL(psy->tzd))
        return;
    thermal_zone_device_unregister(psy->tzd);
}
#else
static int psy_register_thermal(struct power_supply *psy)
{
    return 0;
}

static void psy_unregister_thermal(struct power_supply *psy)
{
}
#endif

int power_supply_register(struct device *parent, struct power_supply *psy)
{
    struct device *dev;
    int rc;

    dev = kzalloc(sizeof(*dev), GFP_KERNEL);
    if (!dev)
        return -ENOMEM;

    device_initialize(dev);

    dev->class = power_supply_class;
    dev->type = &power_supply_dev_type;
    dev->parent = parent;
    dev->release = power_supply_dev_release;
    dev_set_drvdata(dev, psy);
    psy->dev = dev;

    INIT_WORK(&psy->changed_work, power_supply_changed_work);

    rc = kobject_set_name(&dev->kobj, "%s", psy->name);
    if (rc)
        goto kobject_set_name_failed;

    rc = device_add(dev);
    if (rc)
        goto device_add_failed;

    rc = psy_register_thermal(psy);
    if (rc)
        goto register_thermal_failed;

    rc = power_supply_create_triggers(psy);
    if (rc)
        goto create_triggers_failed;

    power_supply_changed(psy);

    goto success;

create_triggers_failed:
    psy_unregister_thermal(psy);
register_thermal_failed:
    device_del(dev);
kobject_set_name_failed:
device_add_failed:
    put_device(dev);
success:
    return rc;
}
EXPORT_SYMBOL_GPL(power_supply_register);

void power_supply_unregister(struct power_supply *psy)
{
    cancel_work_sync(&psy->changed_work);
    sysfs_remove_link(&psy->dev->kobj, "powers");
    power_supply_remove_triggers(psy);
    psy_unregister_thermal(psy);
    device_unregister(psy->dev);
}
EXPORT_SYMBOL_GPL(power_supply_unregister);

static int __init power_supply_class_init(void)
{
    power_supply_class = class_create(THIS_MODULE, "power_supply");

    if (IS_ERR(power_supply_class))
        return PTR_ERR(power_supply_class);

    power_supply_class->dev_uevent = power_supply_uevent;
    power_supply_init_attrs(&power_supply_dev_type);

    return 0;
}

static void __exit power_supply_class_exit(void)
{
    class_destroy(power_supply_class);
}

subsys_initcall(power_supply_class_init);
module_exit(power_supply_class_exit);

MODULE_DESCRIPTION("Universal power supply monitor class");
MODULE_AUTHOR("Ian Molton <[email protected]>, "
          "Szabolcs Gyurko, "
          "Anton Vorontsov <[email protected]>");
MODULE_LICENSE("GPL");