Quelle  acer_a500_battery.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0+
/*
 * Battery driver for Acer Iconia Tab A500.
 *
 * Copyright 2020 GRATE-driver project.
 *
 * Based on downstream driver from Acer Inc.
 * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries.
 *
 * Copyright (c) 2010, NVIDIA Corporation.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/regmap.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#include <linux/property.h>

enum {
 REG_CAPACITY,
 REG_VOLTAGE,
 REG_CURRENT,
 REG_DESIGN_CAPACITY,
 REG_TEMPERATURE,
};

#define EC_DATA(_reg, _psp) {   \
 .psp = POWER_SUPPLY_PROP_ ## _psp, \
 .reg = _reg,    \
}

static const struct battery_register {
 enum power_supply_property psp;
 unsigned int reg;
} ec_data[] = {
 [REG_CAPACITY]  = EC_DATA(0x00, CAPACITY),
 [REG_VOLTAGE]  = EC_DATA(0x01, VOLTAGE_NOW),
 [REG_CURRENT]  = EC_DATA(0x03, CURRENT_NOW),
 [REG_DESIGN_CAPACITY] = EC_DATA(0x08, CHARGE_FULL_DESIGN),
 [REG_TEMPERATURE] = EC_DATA(0x0a, TEMP),
};

static const enum power_supply_property a500_battery_properties[] = {
 POWER_SUPPLY_PROP_CAPACITY,
 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 POWER_SUPPLY_PROP_CURRENT_NOW,
 POWER_SUPPLY_PROP_PRESENT,
 POWER_SUPPLY_PROP_STATUS,
 POWER_SUPPLY_PROP_TECHNOLOGY,
 POWER_SUPPLY_PROP_TEMP,
 POWER_SUPPLY_PROP_VOLTAGE_NOW,
};

struct a500_battery {
 struct delayed_work poll_work;
 struct power_supply *psy;
 struct regmap *regmap;
 unsigned int capacity;
};

static bool a500_battery_update_capacity(struct a500_battery *bat)
{
 unsigned int capacity;
 int err;

 err = regmap_read(bat->regmap, ec_data[REG_CAPACITY].reg, &capacity);
 if (err)
  return false;

 /* capacity can be >100% even if max value is 100% */
 capacity = min(capacity, 100u);

 if (bat->capacity != capacity) {
  bat->capacity = capacity;
  return true;
 }

 return false;
}

static int a500_battery_get_status(struct a500_battery *bat)
{
 if (bat->capacity < 100) {
  if (power_supply_am_i_supplied(bat->psy))
   return POWER_SUPPLY_STATUS_CHARGING;
  else
   return POWER_SUPPLY_STATUS_DISCHARGING;
 }

 return POWER_SUPPLY_STATUS_FULL;
}

static void a500_battery_unit_adjustment(struct device *dev,
      enum power_supply_property psp,
      union power_supply_propval *val)
{
 const unsigned int base_unit_conversion = 1000;
 const unsigned int temp_kelvin_to_celsius = 2731;

 switch (psp) {
 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 case POWER_SUPPLY_PROP_CURRENT_NOW:
 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  val->intval *= base_unit_conversion;
  break;

 case POWER_SUPPLY_PROP_TEMP:
  val->intval -= temp_kelvin_to_celsius;
  break;

 case POWER_SUPPLY_PROP_PRESENT:
  val->intval = !!val->intval;
  break;

 default:
  dev_dbg(dev,
   "%s: no need for unit conversion %d\n", __func__, psp);
 }
}

static int a500_battery_get_ec_data_index(struct device *dev,
       enum power_supply_property psp)
{
 unsigned int i;

 /*
 * DESIGN_CAPACITY register always returns a non-zero value if
 * battery is connected and zero if disconnected, hence we'll use
 * it for judging the battery presence.
 */
 if (psp == POWER_SUPPLY_PROP_PRESENT)
  psp = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;

 for (i = 0; i < ARRAY_SIZE(ec_data); i++)
  if (psp == ec_data[i].psp)
   return i;

 dev_dbg(dev, "%s: invalid property %u\n", __func__, psp);

 return -EINVAL;
}

static int a500_battery_get_property(struct power_supply *psy,
         enum power_supply_property psp,
         union power_supply_propval *val)
{
 struct a500_battery *bat = power_supply_get_drvdata(psy);
 struct device *dev = psy->dev.parent;
 int ret = 0;

 switch (psp) {
 case POWER_SUPPLY_PROP_STATUS:
  val->intval = a500_battery_get_status(bat);
  break;

 case POWER_SUPPLY_PROP_TECHNOLOGY:
  val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
  break;

 case POWER_SUPPLY_PROP_CAPACITY:
  a500_battery_update_capacity(bat);
  val->intval = bat->capacity;
  break;

 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 case POWER_SUPPLY_PROP_CURRENT_NOW:
 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 case POWER_SUPPLY_PROP_PRESENT:
 case POWER_SUPPLY_PROP_TEMP:
  ret = a500_battery_get_ec_data_index(dev, psp);
  if (ret < 0)
   break;

  ret = regmap_read(bat->regmap, ec_data[ret].reg, &val->intval);
  break;

 default:
  dev_err(dev, "%s: invalid property %u\n", __func__, psp);
  return -EINVAL;
 }

 if (!ret) {
  /* convert units to match requirements of power supply class */
  a500_battery_unit_adjustment(dev, psp, val);
 }

 dev_dbg(dev, "%s: property = %d, value = %x\n",
  __func__, psp, val->intval);

 /* return NODATA for properties if battery not presents */
 if (ret)
  return -ENODATA;

 return 0;
}

static void a500_battery_poll_work(struct work_struct *work)
{
 struct a500_battery *bat;
 bool capacity_changed;

 bat = container_of(work, struct a500_battery, poll_work.work);
 capacity_changed = a500_battery_update_capacity(bat);

 if (capacity_changed)
  power_supply_changed(bat->psy);

 /* continuously send uevent notification */
 schedule_delayed_work(&bat->poll_work, 30 * HZ);
}

static const struct power_supply_desc a500_battery_desc = {
 .name = "ec-battery",
 .type = POWER_SUPPLY_TYPE_BATTERY,
 .properties = a500_battery_properties,
 .get_property = a500_battery_get_property,
 .num_properties = ARRAY_SIZE(a500_battery_properties),
 .external_power_changed = power_supply_changed,
};

static int a500_battery_probe(struct platform_device *pdev)
{
 struct power_supply_config psy_cfg = {};
 struct a500_battery *bat;

 bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL);
 if (!bat)
  return -ENOMEM;

 platform_set_drvdata(pdev, bat);

 psy_cfg.fwnode = dev_fwnode(pdev->dev.parent);
 psy_cfg.drv_data = bat;
 psy_cfg.no_wakeup_source = true;

 bat->regmap = dev_get_regmap(pdev->dev.parent, "KB930");
 if (!bat->regmap)
  return -EINVAL;

 bat->psy = devm_power_supply_register(&pdev->dev,
           &a500_battery_desc,
           &psy_cfg);
 if (IS_ERR(bat->psy))
  return dev_err_probe(&pdev->dev, PTR_ERR(bat->psy),
         "failed to register battery\n");

 INIT_DELAYED_WORK(&bat->poll_work, a500_battery_poll_work);
 schedule_delayed_work(&bat->poll_work, HZ);

 return 0;
}

static void a500_battery_remove(struct platform_device *pdev)
{
 struct a500_battery *bat = dev_get_drvdata(&pdev->dev);

 cancel_delayed_work_sync(&bat->poll_work);
}

static int __maybe_unused a500_battery_suspend(struct device *dev)
{
 struct a500_battery *bat = dev_get_drvdata(dev);

 cancel_delayed_work_sync(&bat->poll_work);

 return 0;
}

static int __maybe_unused a500_battery_resume(struct device *dev)
{
 struct a500_battery *bat = dev_get_drvdata(dev);

 schedule_delayed_work(&bat->poll_work, HZ);

 return 0;
}

static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops,
    a500_battery_suspend, a500_battery_resume);

static struct platform_driver a500_battery_driver = {
 .driver = {
  .name = "acer-a500-iconia-battery",
  .pm = &a500_battery_pm_ops,
 },
 .probe = a500_battery_probe,
 .remove = a500_battery_remove,
};
module_platform_driver(a500_battery_driver);

MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500");
MODULE_AUTHOR("Dmitry Osipenko ");
MODULE_ALIAS("platform:acer-a500-iconia-battery");
MODULE_LICENSE("GPL");