Quelle  sbs-charger.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2016, Prodys S.L.
 *
 * This adds support for sbs-charger compilant chips as defined here:
 * http://sbs-forum.org/specs/sbc110.pdf
 *
 * Implemetation based on sbs-battery.c
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/power_supply.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/regmap.h>
#include <linux/bitops.h>
#include <linux/devm-helpers.h>

#define SBS_CHARGER_REG_SPEC_INFO  0x11
#define SBS_CHARGER_REG_STATUS   0x13
#define SBS_CHARGER_REG_ALARM_WARNING  0x16

#define SBS_CHARGER_STATUS_CHARGE_INHIBITED BIT(0)
#define SBS_CHARGER_STATUS_RES_COLD  BIT(9)
#define SBS_CHARGER_STATUS_RES_HOT  BIT(10)
#define SBS_CHARGER_STATUS_BATTERY_PRESENT BIT(14)
#define SBS_CHARGER_STATUS_AC_PRESENT  BIT(15)

#define SBS_CHARGER_POLL_TIME   500

struct sbs_info {
 struct i2c_client  *client;
 struct power_supply  *power_supply;
 struct regmap   *regmap;
 struct delayed_work  work;
 unsigned int   last_state;
};

static int sbs_get_property(struct power_supply *psy,
       enum power_supply_property psp,
       union power_supply_propval *val)
{
 struct sbs_info *chip = power_supply_get_drvdata(psy);
 unsigned int reg;

 reg = chip->last_state;

 switch (psp) {
 case POWER_SUPPLY_PROP_PRESENT:
  val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
  break;

 case POWER_SUPPLY_PROP_ONLINE:
  val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
  break;

 case POWER_SUPPLY_PROP_STATUS:
  val->intval = POWER_SUPPLY_STATUS_UNKNOWN;

  if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
   val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
    !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
   val->intval = POWER_SUPPLY_STATUS_CHARGING;
  else
   val->intval = POWER_SUPPLY_STATUS_DISCHARGING;

  break;

 case POWER_SUPPLY_PROP_HEALTH:
  if (reg & SBS_CHARGER_STATUS_RES_COLD)
   val->intval = POWER_SUPPLY_HEALTH_COLD;
  if (reg & SBS_CHARGER_STATUS_RES_HOT)
   val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  else
   val->intval = POWER_SUPPLY_HEALTH_GOOD;

  break;

 default:
  return -EINVAL;
 }

 return 0;
}

static int sbs_check_state(struct sbs_info *chip)
{
 unsigned int reg;
 int ret;

 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, ®);
 if (!ret && reg != chip->last_state) {
  chip->last_state = reg;
  power_supply_changed(chip->power_supply);
  return 1;
 }

 return 0;
}

static void sbs_delayed_work(struct work_struct *work)
{
 struct sbs_info *chip = container_of(work, struct sbs_info, work.work);

 sbs_check_state(chip);

 schedule_delayed_work(&chip->work,
         msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
}

static irqreturn_t sbs_irq_thread(int irq, void *data)
{
 struct sbs_info *chip = data;
 int ret;

 ret = sbs_check_state(chip);

 return ret ? IRQ_HANDLED : IRQ_NONE;
}

static enum power_supply_property sbs_properties[] = {
 POWER_SUPPLY_PROP_STATUS,
 POWER_SUPPLY_PROP_PRESENT,
 POWER_SUPPLY_PROP_ONLINE,
 POWER_SUPPLY_PROP_HEALTH,
};

static bool sbs_readable_reg(struct device *dev, unsigned int reg)
{
 return reg >= SBS_CHARGER_REG_SPEC_INFO;
}

static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
{
 switch (reg) {
 case SBS_CHARGER_REG_STATUS:
  return true;
 }

 return false;
}

static const struct regmap_config sbs_regmap = {
 .reg_bits = 8,
 .val_bits = 16,
 .max_register = SBS_CHARGER_REG_ALARM_WARNING,
 .readable_reg = sbs_readable_reg,
 .volatile_reg = sbs_volatile_reg,
 .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
};

static const struct power_supply_desc sbs_default_desc = {
 .type = POWER_SUPPLY_TYPE_MAINS,
 .properties = sbs_properties,
 .num_properties = ARRAY_SIZE(sbs_properties),
 .get_property = sbs_get_property,
};

static int sbs_probe(struct i2c_client *client)
{
 struct power_supply_config psy_cfg = {};
 struct power_supply_desc *sbs_desc;
 struct sbs_info *chip;
 int ret, val;

 sbs_desc = devm_kmemdup(&client->dev, &sbs_default_desc,
    sizeof(*sbs_desc), GFP_KERNEL);
 if (!sbs_desc)
  return -ENOMEM;

 sbs_desc->name = devm_kasprintf(&client->dev, GFP_KERNEL, "sbs-%s",
     dev_name(&client->dev));
 if (!sbs_desc->name)
  return -ENOMEM;

 chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
 if (!chip)
  return -ENOMEM;

 chip->client = client;
 psy_cfg.fwnode = dev_fwnode(&client->dev);
 psy_cfg.drv_data = chip;

 i2c_set_clientdata(client, chip);

 chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
 if (IS_ERR(chip->regmap))
  return PTR_ERR(chip->regmap);

 /*
 * Before we register, we need to make sure we can actually talk
 * to the battery.
 */
 ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
 if (ret)
  return dev_err_probe(&client->dev, ret, "Failed to get device status\n");
 chip->last_state = val;

 chip->power_supply = devm_power_supply_register(&client->dev, sbs_desc, &psy_cfg);
 if (IS_ERR(chip->power_supply))
  return dev_err_probe(&client->dev, PTR_ERR(chip->power_supply),
         "Failed to register power supply\n");

 /*
 * The sbs-charger spec doesn't impose the use of an interrupt. So in
 * the case it wasn't provided we use polling in order get the charger's
 * status.
 */
 if (client->irq) {
  ret = devm_request_threaded_irq(&client->dev, client->irq,
     NULL, sbs_irq_thread,
     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
     dev_name(&client->dev), chip);
  if (ret)
   return dev_err_probe(&client->dev, ret, "Failed to request irq\n");
 } else {
  ret = devm_delayed_work_autocancel(&client->dev, &chip->work,
         sbs_delayed_work);
  if (ret)
   return dev_err_probe(&client->dev, ret,
          "Failed to init work for polling\n");

  schedule_delayed_work(&chip->work,
          msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 }

 dev_info(&client->dev,
   "%s: smart charger device registered\n", client->name);

 return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id sbs_dt_ids[] = {
 { .compatible = "sbs,sbs-charger" },
 { },
};
MODULE_DEVICE_TABLE(of, sbs_dt_ids);
#endif

static const struct i2c_device_id sbs_id[] = {
 { "sbs-charger" },
 { }
};
MODULE_DEVICE_TABLE(i2c, sbs_id);

static struct i2c_driver sbs_driver = {
 .probe  = sbs_probe,
 .id_table = sbs_id,
 .driver = {
  .name = "sbs-charger",
  .of_match_table = of_match_ptr(sbs_dt_ids),
 },
};
module_i2c_driver(sbs_driver);

MODULE_AUTHOR("Nicolas Saenz Julienne ");
MODULE_DESCRIPTION("SBS smart charger driver");
MODULE_LICENSE("GPL v2");