Quelle  wilco-charger.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Charging control driver for the Wilco EC
 *
 * Copyright 2019 Google LLC
 *
 * See Documentation/ABI/testing/sysfs-class-power and
 * Documentation/ABI/testing/sysfs-class-power-wilco for userspace interface
 * and other info.
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/platform_data/wilco-ec.h>
#include <linux/power_supply.h>

#define DRV_NAME "wilco-charger"

/* Property IDs and related EC constants */
#define PID_CHARGE_MODE  0x0710
#define PID_CHARGE_LOWER_LIMIT 0x0711
#define PID_CHARGE_UPPER_LIMIT 0x0712

enum charge_mode {
 CHARGE_MODE_STD = 1, /* Used for Standard */
 CHARGE_MODE_EXP = 2, /* Express Charge, used for Fast */
 CHARGE_MODE_AC = 3, /* Mostly AC use, used for Trickle */
 CHARGE_MODE_AUTO = 4, /* Used for Adaptive */
 CHARGE_MODE_CUSTOM = 5, /* Used for Custom */
 CHARGE_MODE_LONGLIFE = 6, /* Used for Long Life */
};

#define CHARGE_LOWER_LIMIT_MIN 50
#define CHARGE_LOWER_LIMIT_MAX 95
#define CHARGE_UPPER_LIMIT_MIN 55
#define CHARGE_UPPER_LIMIT_MAX 100

/* Convert from POWER_SUPPLY_PROP_CHARGE_TYPE value to the EC's charge mode */
static int psp_val_to_charge_mode(int psp_val)
{
 switch (psp_val) {
 case POWER_SUPPLY_CHARGE_TYPE_TRICKLE:
  return CHARGE_MODE_AC;
 case POWER_SUPPLY_CHARGE_TYPE_FAST:
  return CHARGE_MODE_EXP;
 case POWER_SUPPLY_CHARGE_TYPE_STANDARD:
  return CHARGE_MODE_STD;
 case POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE:
  return CHARGE_MODE_AUTO;
 case POWER_SUPPLY_CHARGE_TYPE_CUSTOM:
  return CHARGE_MODE_CUSTOM;
 case POWER_SUPPLY_CHARGE_TYPE_LONGLIFE:
  return CHARGE_MODE_LONGLIFE;
 default:
  return -EINVAL;
 }
}

/* Convert from EC's charge mode to POWER_SUPPLY_PROP_CHARGE_TYPE value */
static int charge_mode_to_psp_val(enum charge_mode mode)
{
 switch (mode) {
 case CHARGE_MODE_AC:
  return POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
 case CHARGE_MODE_EXP:
  return POWER_SUPPLY_CHARGE_TYPE_FAST;
 case CHARGE_MODE_STD:
  return POWER_SUPPLY_CHARGE_TYPE_STANDARD;
 case CHARGE_MODE_AUTO:
  return POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE;
 case CHARGE_MODE_CUSTOM:
  return POWER_SUPPLY_CHARGE_TYPE_CUSTOM;
 case CHARGE_MODE_LONGLIFE:
  return POWER_SUPPLY_CHARGE_TYPE_LONGLIFE;
 default:
  return -EINVAL;
 }
}

static enum power_supply_property wilco_charge_props[] = {
 POWER_SUPPLY_PROP_CHARGE_TYPE,
 POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD,
 POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD,
};

static int wilco_charge_get_property(struct power_supply *psy,
         enum power_supply_property psp,
         union power_supply_propval *val)
{
 struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
 u32 property_id;
 int ret;
 u8 raw;

 switch (psp) {
 case POWER_SUPPLY_PROP_CHARGE_TYPE:
  property_id = PID_CHARGE_MODE;
  break;
 case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
  property_id = PID_CHARGE_LOWER_LIMIT;
  break;
 case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
  property_id = PID_CHARGE_UPPER_LIMIT;
  break;
 default:
  return -EINVAL;
 }

 ret = wilco_ec_get_byte_property(ec, property_id, &raw);
 if (ret < 0)
  return ret;
 if (property_id == PID_CHARGE_MODE) {
  ret = charge_mode_to_psp_val(raw);
  if (ret < 0)
   return -EBADMSG;
  raw = ret;
 }
 val->intval = raw;

 return 0;
}

static int wilco_charge_set_property(struct power_supply *psy,
         enum power_supply_property psp,
         const union power_supply_propval *val)
{
 struct wilco_ec_device *ec = power_supply_get_drvdata(psy);
 int mode;

 switch (psp) {
 case POWER_SUPPLY_PROP_CHARGE_TYPE:
  mode = psp_val_to_charge_mode(val->intval);
  if (mode < 0)
   return -EINVAL;
  return wilco_ec_set_byte_property(ec, PID_CHARGE_MODE, mode);
 case POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD:
  if (val->intval < CHARGE_LOWER_LIMIT_MIN ||
      val->intval > CHARGE_LOWER_LIMIT_MAX)
   return -EINVAL;
  return wilco_ec_set_byte_property(ec, PID_CHARGE_LOWER_LIMIT,
        val->intval);
 case POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD:
  if (val->intval < CHARGE_UPPER_LIMIT_MIN ||
      val->intval > CHARGE_UPPER_LIMIT_MAX)
   return -EINVAL;
  return wilco_ec_set_byte_property(ec, PID_CHARGE_UPPER_LIMIT,
        val->intval);
 default:
  return -EINVAL;
 }
}

static int wilco_charge_property_is_writeable(struct power_supply *psy,
           enum power_supply_property psp)
{
 return 1;
}

static const struct power_supply_desc wilco_ps_desc = {
 .properties  = wilco_charge_props,
 .num_properties  = ARRAY_SIZE(wilco_charge_props),
 .get_property  = wilco_charge_get_property,
 .set_property  = wilco_charge_set_property,
 .property_is_writeable = wilco_charge_property_is_writeable,
 .name   = DRV_NAME,
 .type   = POWER_SUPPLY_TYPE_MAINS,
};

static int wilco_charge_probe(struct platform_device *pdev)
{
 struct wilco_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 struct power_supply_config psy_cfg = {};
 struct power_supply *psy;

 psy_cfg.drv_data = ec;
 psy = devm_power_supply_register(&pdev->dev, &wilco_ps_desc, &psy_cfg);

 return PTR_ERR_OR_ZERO(psy);
}

static struct platform_driver wilco_charge_driver = {
 .probe = wilco_charge_probe,
 .driver = {
  .name = DRV_NAME,
 }
};
module_platform_driver(wilco_charge_driver);

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_AUTHOR("Nick Crews ");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Wilco EC charge control driver");