Quelle  power_supply_sysfs.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Sysfs interface for the universal power supply monitor class
 *
 *  Copyright © 2007  David Woodhouse <dwmw2@infradead.org>
 *  Copyright © 2007  Anton Vorontsov <cbou@mail.ru>
 *  Copyright © 2004  Szabolcs Gyurko
 *  Copyright © 2003  Ian Molton <spyro@f2s.com>
 *
 *  Modified: 2004, Oct     Szabolcs Gyurko
 */

#include <linux/ctype.h>
#include <linux/device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/string_helpers.h>

#include "power_supply.h"

#define MAX_PROP_NAME_LEN 30

struct power_supply_attr {
 const char *prop_name;
 char attr_name[MAX_PROP_NAME_LEN + 1];
 struct device_attribute dev_attr;
 const char * const *text_values;
 int text_values_len;
};

#define _POWER_SUPPLY_ATTR(_name, _text, _len) \
[POWER_SUPPLY_PROP_ ## _name] =   \
{      \
 .prop_name = #_name,   \
 .attr_name = #_name,   \
 .text_values = _text,   \
 .text_values_len = _len,  \
}

#define POWER_SUPPLY_ATTR(_name) _POWER_SUPPLY_ATTR(_name, NULL, 0)
#define _POWER_SUPPLY_ENUM_ATTR(_name, _text) \
 _POWER_SUPPLY_ATTR(_name, _text, ARRAY_SIZE(_text))
#define POWER_SUPPLY_ENUM_ATTR(_name) \
 _POWER_SUPPLY_ENUM_ATTR(_name, POWER_SUPPLY_ ## _name ## _TEXT)

static const char * const POWER_SUPPLY_TYPE_TEXT[] = {
 [POWER_SUPPLY_TYPE_UNKNOWN]  = "Unknown",
 [POWER_SUPPLY_TYPE_BATTERY]  = "Battery",
 [POWER_SUPPLY_TYPE_UPS]   = "UPS",
 [POWER_SUPPLY_TYPE_MAINS]  = "Mains",
 [POWER_SUPPLY_TYPE_USB]   = "USB",
 [POWER_SUPPLY_TYPE_USB_DCP]  = "USB_DCP",
 [POWER_SUPPLY_TYPE_USB_CDP]  = "USB_CDP",
 [POWER_SUPPLY_TYPE_USB_ACA]  = "USB_ACA",
 [POWER_SUPPLY_TYPE_USB_TYPE_C]  = "USB_C",
 [POWER_SUPPLY_TYPE_USB_PD]  = "USB_PD",
 [POWER_SUPPLY_TYPE_USB_PD_DRP]  = "USB_PD_DRP",
 [POWER_SUPPLY_TYPE_APPLE_BRICK_ID] = "BrickID",
 [POWER_SUPPLY_TYPE_WIRELESS]  = "Wireless",
};

static const char * const POWER_SUPPLY_USB_TYPE_TEXT[] = {
 [POWER_SUPPLY_USB_TYPE_UNKNOWN]  = "Unknown",
 [POWER_SUPPLY_USB_TYPE_SDP]  = "SDP",
 [POWER_SUPPLY_USB_TYPE_DCP]  = "DCP",
 [POWER_SUPPLY_USB_TYPE_CDP]  = "CDP",
 [POWER_SUPPLY_USB_TYPE_ACA]  = "ACA",
 [POWER_SUPPLY_USB_TYPE_C]  = "C",
 [POWER_SUPPLY_USB_TYPE_PD]  = "PD",
 [POWER_SUPPLY_USB_TYPE_PD_DRP]  = "PD_DRP",
 [POWER_SUPPLY_USB_TYPE_PD_PPS]  = "PD_PPS",
 [POWER_SUPPLY_USB_TYPE_APPLE_BRICK_ID] = "BrickID",
};

static const char * const POWER_SUPPLY_STATUS_TEXT[] = {
 [POWER_SUPPLY_STATUS_UNKNOWN]  = "Unknown",
 [POWER_SUPPLY_STATUS_CHARGING]  = "Charging",
 [POWER_SUPPLY_STATUS_DISCHARGING] = "Discharging",
 [POWER_SUPPLY_STATUS_NOT_CHARGING] = "Not charging",
 [POWER_SUPPLY_STATUS_FULL]  = "Full",
};

static const char * const POWER_SUPPLY_CHARGE_TYPE_TEXT[] = {
 [POWER_SUPPLY_CHARGE_TYPE_UNKNOWN] = "Unknown",
 [POWER_SUPPLY_CHARGE_TYPE_NONE]  = "N/A",
 [POWER_SUPPLY_CHARGE_TYPE_TRICKLE] = "Trickle",
 [POWER_SUPPLY_CHARGE_TYPE_FAST]  = "Fast",
 [POWER_SUPPLY_CHARGE_TYPE_STANDARD] = "Standard",
 [POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE] = "Adaptive",
 [POWER_SUPPLY_CHARGE_TYPE_CUSTOM] = "Custom",
 [POWER_SUPPLY_CHARGE_TYPE_LONGLIFE] = "Long Life",
 [POWER_SUPPLY_CHARGE_TYPE_BYPASS] = "Bypass",
};

static const char * const POWER_SUPPLY_HEALTH_TEXT[] = {
 [POWER_SUPPLY_HEALTH_UNKNOWN]      = "Unknown",
 [POWER_SUPPLY_HEALTH_GOOD]      = "Good",
 [POWER_SUPPLY_HEALTH_OVERHEAT]      = "Overheat",
 [POWER_SUPPLY_HEALTH_DEAD]      = "Dead",
 [POWER_SUPPLY_HEALTH_OVERVOLTAGE]     = "Over voltage",
 [POWER_SUPPLY_HEALTH_UNDERVOLTAGE]     = "Under voltage",
 [POWER_SUPPLY_HEALTH_UNSPEC_FAILURE]     = "Unspecified failure",
 [POWER_SUPPLY_HEALTH_COLD]      = "Cold",
 [POWER_SUPPLY_HEALTH_WATCHDOG_TIMER_EXPIRE] = "Watchdog timer expire",
 [POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE]   = "Safety timer expire",
 [POWER_SUPPLY_HEALTH_OVERCURRENT]     = "Over current",
 [POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED]  = "Calibration required",
 [POWER_SUPPLY_HEALTH_WARM]      = "Warm",
 [POWER_SUPPLY_HEALTH_COOL]      = "Cool",
 [POWER_SUPPLY_HEALTH_HOT]      = "Hot",
 [POWER_SUPPLY_HEALTH_NO_BATTERY]     = "No battery",
 [POWER_SUPPLY_HEALTH_BLOWN_FUSE]     = "Blown fuse",
 [POWER_SUPPLY_HEALTH_CELL_IMBALANCE]     = "Cell imbalance",
};

static const char * const POWER_SUPPLY_TECHNOLOGY_TEXT[] = {
 [POWER_SUPPLY_TECHNOLOGY_UNKNOWN] = "Unknown",
 [POWER_SUPPLY_TECHNOLOGY_NiMH]  = "NiMH",
 [POWER_SUPPLY_TECHNOLOGY_LION]  = "Li-ion",
 [POWER_SUPPLY_TECHNOLOGY_LIPO]  = "Li-poly",
 [POWER_SUPPLY_TECHNOLOGY_LiFe]  = "LiFe",
 [POWER_SUPPLY_TECHNOLOGY_NiCd]  = "NiCd",
 [POWER_SUPPLY_TECHNOLOGY_LiMn]  = "LiMn",
};

static const char * const POWER_SUPPLY_CAPACITY_LEVEL_TEXT[] = {
 [POWER_SUPPLY_CAPACITY_LEVEL_UNKNOWN] = "Unknown",
 [POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL] = "Critical",
 [POWER_SUPPLY_CAPACITY_LEVEL_LOW] = "Low",
 [POWER_SUPPLY_CAPACITY_LEVEL_NORMAL] = "Normal",
 [POWER_SUPPLY_CAPACITY_LEVEL_HIGH] = "High",
 [POWER_SUPPLY_CAPACITY_LEVEL_FULL] = "Full",
};

static const char * const POWER_SUPPLY_SCOPE_TEXT[] = {
 [POWER_SUPPLY_SCOPE_UNKNOWN] = "Unknown",
 [POWER_SUPPLY_SCOPE_SYSTEM] = "System",
 [POWER_SUPPLY_SCOPE_DEVICE] = "Device",
};

static const char * const POWER_SUPPLY_CHARGE_BEHAVIOUR_TEXT[] = {
 [POWER_SUPPLY_CHARGE_BEHAVIOUR_AUTO]   = "auto",
 [POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE]  = "inhibit-charge",
 [POWER_SUPPLY_CHARGE_BEHAVIOUR_INHIBIT_CHARGE_AWAKE] = "inhibit-charge-awake",
 [POWER_SUPPLY_CHARGE_BEHAVIOUR_FORCE_DISCHARGE]  = "force-discharge",
};

static struct power_supply_attr power_supply_attrs[] __ro_after_init = {
 /* Properties of type `int' */
 POWER_SUPPLY_ENUM_ATTR(STATUS),
 POWER_SUPPLY_ENUM_ATTR(CHARGE_TYPE),
 POWER_SUPPLY_ENUM_ATTR(HEALTH),
 POWER_SUPPLY_ATTR(PRESENT),
 POWER_SUPPLY_ATTR(ONLINE),
 POWER_SUPPLY_ATTR(AUTHENTIC),
 POWER_SUPPLY_ENUM_ATTR(TECHNOLOGY),
 POWER_SUPPLY_ATTR(CYCLE_COUNT),
 POWER_SUPPLY_ATTR(VOLTAGE_MAX),
 POWER_SUPPLY_ATTR(VOLTAGE_MIN),
 POWER_SUPPLY_ATTR(VOLTAGE_MAX_DESIGN),
 POWER_SUPPLY_ATTR(VOLTAGE_MIN_DESIGN),
 POWER_SUPPLY_ATTR(VOLTAGE_NOW),
 POWER_SUPPLY_ATTR(VOLTAGE_AVG),
 POWER_SUPPLY_ATTR(VOLTAGE_OCV),
 POWER_SUPPLY_ATTR(VOLTAGE_BOOT),
 POWER_SUPPLY_ATTR(CURRENT_MAX),
 POWER_SUPPLY_ATTR(CURRENT_NOW),
 POWER_SUPPLY_ATTR(CURRENT_AVG),
 POWER_SUPPLY_ATTR(CURRENT_BOOT),
 POWER_SUPPLY_ATTR(POWER_NOW),
 POWER_SUPPLY_ATTR(POWER_AVG),
 POWER_SUPPLY_ATTR(CHARGE_FULL_DESIGN),
 POWER_SUPPLY_ATTR(CHARGE_EMPTY_DESIGN),
 POWER_SUPPLY_ATTR(CHARGE_FULL),
 POWER_SUPPLY_ATTR(CHARGE_EMPTY),
 POWER_SUPPLY_ATTR(CHARGE_NOW),
 POWER_SUPPLY_ATTR(CHARGE_AVG),
 POWER_SUPPLY_ATTR(CHARGE_COUNTER),
 POWER_SUPPLY_ATTR(CONSTANT_CHARGE_CURRENT),
 POWER_SUPPLY_ATTR(CONSTANT_CHARGE_CURRENT_MAX),
 POWER_SUPPLY_ATTR(CONSTANT_CHARGE_VOLTAGE),
 POWER_SUPPLY_ATTR(CONSTANT_CHARGE_VOLTAGE_MAX),
 POWER_SUPPLY_ATTR(CHARGE_CONTROL_LIMIT),
 POWER_SUPPLY_ATTR(CHARGE_CONTROL_LIMIT_MAX),
 POWER_SUPPLY_ATTR(CHARGE_CONTROL_START_THRESHOLD),
 POWER_SUPPLY_ATTR(CHARGE_CONTROL_END_THRESHOLD),
 POWER_SUPPLY_ENUM_ATTR(CHARGE_BEHAVIOUR),
 /* Same enum value texts as "charge_type" without the 's' at the end */
 _POWER_SUPPLY_ENUM_ATTR(CHARGE_TYPES, POWER_SUPPLY_CHARGE_TYPE_TEXT),
 POWER_SUPPLY_ATTR(INPUT_CURRENT_LIMIT),
 POWER_SUPPLY_ATTR(INPUT_VOLTAGE_LIMIT),
 POWER_SUPPLY_ATTR(INPUT_POWER_LIMIT),
 POWER_SUPPLY_ATTR(ENERGY_FULL_DESIGN),
 POWER_SUPPLY_ATTR(ENERGY_EMPTY_DESIGN),
 POWER_SUPPLY_ATTR(ENERGY_FULL),
 POWER_SUPPLY_ATTR(ENERGY_EMPTY),
 POWER_SUPPLY_ATTR(ENERGY_NOW),
 POWER_SUPPLY_ATTR(ENERGY_AVG),
 POWER_SUPPLY_ATTR(CAPACITY),
 POWER_SUPPLY_ATTR(CAPACITY_ALERT_MIN),
 POWER_SUPPLY_ATTR(CAPACITY_ALERT_MAX),
 POWER_SUPPLY_ATTR(CAPACITY_ERROR_MARGIN),
 POWER_SUPPLY_ENUM_ATTR(CAPACITY_LEVEL),
 POWER_SUPPLY_ATTR(TEMP),
 POWER_SUPPLY_ATTR(TEMP_MAX),
 POWER_SUPPLY_ATTR(TEMP_MIN),
 POWER_SUPPLY_ATTR(TEMP_ALERT_MIN),
 POWER_SUPPLY_ATTR(TEMP_ALERT_MAX),
 POWER_SUPPLY_ATTR(TEMP_AMBIENT),
 POWER_SUPPLY_ATTR(TEMP_AMBIENT_ALERT_MIN),
 POWER_SUPPLY_ATTR(TEMP_AMBIENT_ALERT_MAX),
 POWER_SUPPLY_ATTR(TIME_TO_EMPTY_NOW),
 POWER_SUPPLY_ATTR(TIME_TO_EMPTY_AVG),
 POWER_SUPPLY_ATTR(TIME_TO_FULL_NOW),
 POWER_SUPPLY_ATTR(TIME_TO_FULL_AVG),
 POWER_SUPPLY_ENUM_ATTR(TYPE),
 POWER_SUPPLY_ENUM_ATTR(USB_TYPE),
 POWER_SUPPLY_ENUM_ATTR(SCOPE),
 POWER_SUPPLY_ATTR(PRECHARGE_CURRENT),
 POWER_SUPPLY_ATTR(CHARGE_TERM_CURRENT),
 POWER_SUPPLY_ATTR(CALIBRATE),
 POWER_SUPPLY_ATTR(MANUFACTURE_YEAR),
 POWER_SUPPLY_ATTR(MANUFACTURE_MONTH),
 POWER_SUPPLY_ATTR(MANUFACTURE_DAY),
 /* Properties of type `const char *' */
 POWER_SUPPLY_ATTR(MODEL_NAME),
 POWER_SUPPLY_ATTR(MANUFACTURER),
 POWER_SUPPLY_ATTR(SERIAL_NUMBER),
};
#define POWER_SUPPLY_ATTR_CNT ARRAY_SIZE(power_supply_attrs)

static struct attribute *
__power_supply_attrs[POWER_SUPPLY_ATTR_CNT + 1] __ro_after_init;

static const struct power_supply_attr *to_ps_attr(struct device_attribute *attr)
{
 return container_of(attr, struct power_supply_attr, dev_attr);
}

static enum power_supply_property dev_attr_psp(struct device_attribute *attr)
{
 return  to_ps_attr(attr) - power_supply_attrs;
}

static void power_supply_escape_spaces(const char *str, char *buf, size_t bufsize)
{
 strscpy(buf, str, bufsize);
 strreplace(buf, ' ', '_');
}

static int power_supply_match_string(const char * const *array, size_t n, const char *s)
{
 int ret;

 /* First try an exact match */
 ret = __sysfs_match_string(array, n, s);
 if (ret >= 0)
  return ret;

 /* Second round, try matching with spaces replaced by '_' */
 for (size_t i = 0; i < n; i++) {
  char buf[32];

  power_supply_escape_spaces(array[i], buf, sizeof(buf));
  if (sysfs_streq(buf, s))
   return i;
 }

 return -EINVAL;
}

static ssize_t power_supply_show_enum_with_available(
   struct device *dev, const char * const labels[], int label_count,
   unsigned int available_values, int value, char *buf)
{
 bool match = false, available, active;
 char escaped_label[32];
 ssize_t count = 0;
 int i;

 for (i = 0; i < label_count; i++) {
  available = available_values & BIT(i);
  active = i == value;
  power_supply_escape_spaces(labels[i], escaped_label, sizeof(escaped_label));

  if (available && active) {
   count += sysfs_emit_at(buf, count, "[%s] ", escaped_label);
   match = true;
  } else if (available) {
   count += sysfs_emit_at(buf, count, "%s ", escaped_label);
  }
 }

 if (!match) {
  dev_warn(dev, "driver reporting unavailable enum value %d\n", value);
  return -EINVAL;
 }

 if (count)
  buf[count - 1] = '\n';

 return count;
}

static ssize_t power_supply_show_charge_behaviour(struct device *dev,
        struct power_supply *psy,
        union power_supply_propval *value,
        char *buf)
{
 struct power_supply_ext_registration *reg;

 scoped_guard(rwsem_read, &psy->extensions_sem) {
  power_supply_for_each_extension(reg, psy) {
   if (power_supply_ext_has_property(reg->ext,
         POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR))
    return power_supply_charge_behaviour_show(dev,
      reg->ext->charge_behaviours,
      value->intval, buf);
  }
 }

 return power_supply_charge_behaviour_show(dev, psy->desc->charge_behaviours,
        value->intval, buf);
}

static ssize_t power_supply_show_charge_types(struct device *dev,
           struct power_supply *psy,
           enum power_supply_charge_type current_type,
           char *buf)
{
 struct power_supply_ext_registration *reg;

 scoped_guard(rwsem_read, &psy->extensions_sem) {
  power_supply_for_each_extension(reg, psy) {
   if (power_supply_ext_has_property(reg->ext,
         POWER_SUPPLY_PROP_CHARGE_TYPES))
    return power_supply_charge_types_show(dev,
      reg->ext->charge_types,
      current_type, buf);
  }
 }

 return power_supply_charge_types_show(dev, psy->desc->charge_types,
        current_type, buf);
}

static ssize_t power_supply_format_property(struct device *dev,
         bool uevent,
         struct device_attribute *attr,
         char *buf)
{
 ssize_t ret;
 struct power_supply *psy = dev_to_psy(dev);
 const struct power_supply_attr *ps_attr = to_ps_attr(attr);
 enum power_supply_property psp = dev_attr_psp(attr);
 union power_supply_propval value;

 if (psp == POWER_SUPPLY_PROP_TYPE) {
  value.intval = psy->desc->type;
 } else {
  ret = power_supply_get_property(psy, psp, &value);

  if (ret < 0) {
   if (ret == -ENODATA)
    dev_dbg_ratelimited(dev,
     "driver has no data for `%s' property\n",
     attr->attr.name);
   else if (ret != -ENODEV && ret != -EAGAIN && ret != -EINVAL)
    dev_err_ratelimited(dev,
     "driver failed to report `%s' property: %zd\n",
     attr->attr.name, ret);
   return ret;
  }
 }

 switch (psp) {
 case POWER_SUPPLY_PROP_USB_TYPE:
  ret = power_supply_show_enum_with_available(
    dev, POWER_SUPPLY_USB_TYPE_TEXT,
    ARRAY_SIZE(POWER_SUPPLY_USB_TYPE_TEXT),
    psy->desc->usb_types, value.intval, buf);
  break;
 case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
  if (uevent) /* no possible values in uevents */
   goto default_format;
  ret = power_supply_show_charge_behaviour(dev, psy, &value, buf);
  break;
 case POWER_SUPPLY_PROP_CHARGE_TYPES:
  if (uevent) /* no possible values in uevents */
   goto default_format;
  ret = power_supply_show_charge_types(dev, psy,
           value.intval, buf);
  break;
 case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
  ret = sysfs_emit(buf, "%s\n", value.strval);
  break;
 default:
default_format:
  if (ps_attr->text_values_len > 0 &&
    value.intval < ps_attr->text_values_len && value.intval >= 0) {
   ret = sysfs_emit(buf, "%s\n", ps_attr->text_values[value.intval]);
  } else {
   ret = sysfs_emit(buf, "%d\n", value.intval);
  }
 }

 return ret;
}

static ssize_t power_supply_show_property(struct device *dev,
       struct device_attribute *attr,
       char *buf)
{
 return power_supply_format_property(dev, false, attr, buf);
}

static ssize_t power_supply_store_property(struct device *dev,
        struct device_attribute *attr,
        const char *buf, size_t count) {
 ssize_t ret;
 struct power_supply *psy = dev_to_psy(dev);
 const struct power_supply_attr *ps_attr = to_ps_attr(attr);
 enum power_supply_property psp = dev_attr_psp(attr);
 union power_supply_propval value;

 ret = -EINVAL;
 if (ps_attr->text_values_len > 0) {
  ret = power_supply_match_string(ps_attr->text_values,
      ps_attr->text_values_len, buf);
 }

 /*
 * If no match was found, then check to see if it is an integer.
 * Integer values are valid for enums in addition to the text value.
 */
 if (ret < 0) {
  long long_val;

  ret = kstrtol(buf, 10, &long_val);
  if (ret < 0)
   return ret;

  ret = long_val;
 }

 value.intval = ret;

 ret = power_supply_set_property(psy, psp, &value);
 if (ret < 0)
  return ret;

 return count;
}

static umode_t power_supply_attr_is_visible(struct kobject *kobj,
        struct attribute *attr,
        int attrno)
{
 struct device *dev = kobj_to_dev(kobj);
 struct power_supply *psy = dev_to_psy(dev);
 umode_t mode = S_IRUSR | S_IRGRP | S_IROTH;

 if (!power_supply_attrs[attrno].prop_name)
  return 0;

 if (attrno == POWER_SUPPLY_PROP_TYPE)
  return mode;

 guard(rwsem_read)(&psy->extensions_sem);

 if (power_supply_has_property(psy, attrno)) {
  if (power_supply_property_is_writeable(psy, attrno) > 0)
   mode |= S_IWUSR;
  return mode;
 }

 return 0;
}

static const struct attribute_group power_supply_attr_group = {
 .attrs = __power_supply_attrs,
 .is_visible = power_supply_attr_is_visible,
};

static struct attribute *power_supply_extension_attrs[] = {
 NULL
};

static const struct attribute_group power_supply_extension_group = {
 .name = "extensions",
 .attrs = power_supply_extension_attrs,
};

const struct attribute_group *power_supply_attr_groups[] = {
 &power_supply_attr_group,
 &power_supply_extension_group,
 NULL
};

void __init power_supply_init_attrs(void)
{
 int i;

 for (i = 0; i < ARRAY_SIZE(power_supply_attrs); i++) {
  struct device_attribute *attr;

  if (!power_supply_attrs[i].prop_name) {
   pr_warn("%s: Property %d skipped because it is missing from power_supply_attrs\n",
    __func__, i);
   sprintf(power_supply_attrs[i].attr_name, "_err_%d", i);
  } else {
   string_lower(power_supply_attrs[i].attr_name,
         power_supply_attrs[i].attr_name);
  }

  attr = &power_supply_attrs[i].dev_attr;

  attr->attr.name = power_supply_attrs[i].attr_name;
  attr->show = power_supply_show_property;
  attr->store = power_supply_store_property;
  __power_supply_attrs[i] = &attr->attr;
 }
}

static int add_prop_uevent(const struct device *dev, struct kobj_uevent_env *env,
      enum power_supply_property prop, char *prop_buf)
{
 int ret = 0;
 struct power_supply_attr *pwr_attr;
 struct device_attribute *dev_attr;
 char *line;

 pwr_attr = &power_supply_attrs[prop];
 dev_attr = &pwr_attr->dev_attr;

 ret = power_supply_format_property((struct device *)dev, true, dev_attr, prop_buf);
 if (ret == -ENODEV || ret == -ENODATA || ret == -EINVAL) {
  /*
 * When a battery is absent, we expect -ENODEV. Don't abort;
 * send the uevent with at least the PRESENT=0 property
 */
  return 0;
 }

 if (ret < 0)
  return ret;

 line = strchr(prop_buf, '\n');
 if (line)
  *line = 0;

 return add_uevent_var(env, "POWER_SUPPLY_%s=%s",
         pwr_attr->prop_name, prop_buf);
}

int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env)
{
 const struct power_supply *psy = dev_to_psy(dev);
 int ret = 0, j;
 char *prop_buf;

 if (!psy || !psy->desc) {
  dev_dbg(dev, "No power supply yet\n");
  return ret;
 }

 ret = add_uevent_var(env, "POWER_SUPPLY_NAME=%s", psy->desc->name);
 if (ret)
  return ret;

 /*
 * Kernel generates KOBJ_REMOVE uevent in device removal path, after
 * resources have been freed. Exit early to avoid use-after-free.
 */
 if (psy->removing)
  return 0;

 prop_buf = (char *)get_zeroed_page(GFP_KERNEL);
 if (!prop_buf)
  return -ENOMEM;

 ret = add_prop_uevent(dev, env, POWER_SUPPLY_PROP_TYPE, prop_buf);
 if (ret)
  goto out;

 for (j = 0; j < POWER_SUPPLY_ATTR_CNT; j++) {
  ret = add_prop_uevent(dev, env, j, prop_buf);
  if (ret)
   goto out;
 }

out:
 free_page((unsigned long)prop_buf);

 return ret;
}

ssize_t power_supply_charge_behaviour_show(struct device *dev,
        unsigned int available_behaviours,
        enum power_supply_charge_behaviour current_behaviour,
        char *buf)
{
 return power_supply_show_enum_with_available(
    dev, POWER_SUPPLY_CHARGE_BEHAVIOUR_TEXT,
    ARRAY_SIZE(POWER_SUPPLY_CHARGE_BEHAVIOUR_TEXT),
    available_behaviours, current_behaviour, buf);
}
EXPORT_SYMBOL_GPL(power_supply_charge_behaviour_show);

int power_supply_charge_behaviour_parse(unsigned int available_behaviours, const char *buf)
{
 int i = sysfs_match_string(POWER_SUPPLY_CHARGE_BEHAVIOUR_TEXT, buf);

 if (i < 0)
  return i;

 if (available_behaviours & BIT(i))
  return i;

 return -EINVAL;
}
EXPORT_SYMBOL_GPL(power_supply_charge_behaviour_parse);

ssize_t power_supply_charge_types_show(struct device *dev,
           unsigned int available_types,
           enum power_supply_charge_type current_type,
           char *buf)
{
 return power_supply_show_enum_with_available(
    dev, POWER_SUPPLY_CHARGE_TYPE_TEXT,
    ARRAY_SIZE(POWER_SUPPLY_CHARGE_TYPE_TEXT),
    available_types, current_type, buf);
}
EXPORT_SYMBOL_GPL(power_supply_charge_types_show);

int power_supply_charge_types_parse(unsigned int available_types, const char *buf)
{
 int i = power_supply_match_string(POWER_SUPPLY_CHARGE_TYPE_TEXT,
       ARRAY_SIZE(POWER_SUPPLY_CHARGE_TYPE_TEXT),
       buf);

 if (i < 0)
  return i;

 if (available_types & BIT(i))
  return i;

 return -EINVAL;
}
EXPORT_SYMBOL_GPL(power_supply_charge_types_parse);

int power_supply_sysfs_add_extension(struct power_supply *psy, const struct power_supply_ext *ext,
         struct device *dev)
{
 return sysfs_add_link_to_group(&psy->dev.kobj, power_supply_extension_group.name,
           &dev->kobj, ext->name);
}

void power_supply_sysfs_remove_extension(struct power_supply *psy,
      const struct power_supply_ext *ext)
{
 sysfs_remove_link_from_group(&psy->dev.kobj, power_supply_extension_group.name, ext->name);
}