Quelle  ingenic-battery.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Battery driver for the Ingenic JZ47xx SoCs
 * Copyright (c) 2019 Artur Rojek <contact@artur-rojek.eu>
 *
 * based on drivers/power/supply/jz4740-battery.c
 */

#include <linux/iio/consumer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/property.h>

struct ingenic_battery {
 struct device *dev;
 struct iio_channel *channel;
 struct power_supply_desc desc;
 struct power_supply *battery;
 struct power_supply_battery_info *info;
};

static int ingenic_battery_get_property(struct power_supply *psy,
     enum power_supply_property psp,
     union power_supply_propval *val)
{
 struct ingenic_battery *bat = power_supply_get_drvdata(psy);
 struct power_supply_battery_info *info = bat->info;
 int ret;

 switch (psp) {
 case POWER_SUPPLY_PROP_HEALTH:
  ret = iio_read_channel_processed_scale(bat->channel,
             &val->intval,
             1000);
  if (val->intval < info->voltage_min_design_uv)
   val->intval = POWER_SUPPLY_HEALTH_DEAD;
  else if (val->intval > info->voltage_max_design_uv)
   val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
  else
   val->intval = POWER_SUPPLY_HEALTH_GOOD;
  return ret;
 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
  ret = iio_read_channel_processed_scale(bat->channel,
             &val->intval,
             1000);
  return ret;
 case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
  val->intval = info->voltage_min_design_uv;
  return 0;
 case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
  val->intval = info->voltage_max_design_uv;
  return 0;
 default:
  return -EINVAL;
 }
}

/* Set the most appropriate IIO channel voltage reference scale
 * based on the battery's max voltage.
 */
static int ingenic_battery_set_scale(struct ingenic_battery *bat)
{
 const int *scale_raw;
 int scale_len, scale_type, best_idx = -1, best_mV, max_raw, i, ret;
 u64 max_mV;

 ret = iio_read_max_channel_raw(bat->channel, &max_raw);
 if (ret) {
  dev_err(bat->dev, "Unable to read max raw channel value\n");
  return ret;
 }

 ret = iio_read_avail_channel_attribute(bat->channel, &scale_raw,
            &scale_type, &scale_len,
            IIO_CHAN_INFO_SCALE);
 if (ret < 0) {
  dev_err(bat->dev, "Unable to read channel avail scale\n");
  return ret;
 }
 if (ret != IIO_AVAIL_LIST || scale_type != IIO_VAL_FRACTIONAL_LOG2)
  return -EINVAL;

 max_mV = bat->info->voltage_max_design_uv / 1000;

 for (i = 0; i < scale_len; i += 2) {
  u64 scale_mV = (max_raw * scale_raw[i]) >> scale_raw[i + 1];

  if (scale_mV < max_mV)
   continue;

  if (best_idx >= 0 && scale_mV > best_mV)
   continue;

  best_mV = scale_mV;
  best_idx = i;
 }

 if (best_idx < 0) {
  dev_err(bat->dev, "Unable to find matching voltage scale\n");
  return -EINVAL;
 }

 /* Only set scale if there is more than one (fractional) entry */
 if (scale_len > 2) {
  ret = iio_write_channel_attribute(bat->channel,
        scale_raw[best_idx],
        scale_raw[best_idx + 1],
        IIO_CHAN_INFO_SCALE);
  if (ret)
   return ret;
 }

 return 0;
}

static enum power_supply_property ingenic_battery_properties[] = {
 POWER_SUPPLY_PROP_HEALTH,
 POWER_SUPPLY_PROP_VOLTAGE_NOW,
 POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
 POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
};

static int ingenic_battery_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 struct ingenic_battery *bat;
 struct power_supply_config psy_cfg = {};
 struct power_supply_desc *desc;
 int ret;

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

 bat->dev = dev;
 bat->channel = devm_iio_channel_get(dev, "battery");
 if (IS_ERR(bat->channel))
  return PTR_ERR(bat->channel);

 desc = &bat->desc;
 desc->name = "jz-battery";
 desc->type = POWER_SUPPLY_TYPE_BATTERY;
 desc->properties = ingenic_battery_properties;
 desc->num_properties = ARRAY_SIZE(ingenic_battery_properties);
 desc->get_property = ingenic_battery_get_property;
 psy_cfg.drv_data = bat;
 psy_cfg.fwnode = dev_fwnode(dev);

 bat->battery = devm_power_supply_register(dev, desc, &psy_cfg);
 if (IS_ERR(bat->battery))
  return dev_err_probe(dev, PTR_ERR(bat->battery),
         "Unable to register battery\n");

 ret = power_supply_get_battery_info(bat->battery, &bat->info);
 if (ret) {
  dev_err(dev, "Unable to get battery info: %d\n", ret);
  return ret;
 }
 if (bat->info->voltage_min_design_uv < 0) {
  dev_err(dev, "Unable to get voltage min design\n");
  return bat->info->voltage_min_design_uv;
 }
 if (bat->info->voltage_max_design_uv < 0) {
  dev_err(dev, "Unable to get voltage max design\n");
  return bat->info->voltage_max_design_uv;
 }

 return ingenic_battery_set_scale(bat);
}

#ifdef CONFIG_OF
static const struct of_device_id ingenic_battery_of_match[] = {
 { .compatible = "ingenic,jz4740-battery", },
 { },
};
MODULE_DEVICE_TABLE(of, ingenic_battery_of_match);
#endif

static struct platform_driver ingenic_battery_driver = {
 .driver = {
  .name = "ingenic-battery",
  .of_match_table = of_match_ptr(ingenic_battery_of_match),
 },
 .probe = ingenic_battery_probe,
};
module_platform_driver(ingenic_battery_driver);

MODULE_DESCRIPTION("Battery driver for Ingenic JZ47xx SoCs");
MODULE_AUTHOR("Artur Rojek ");
MODULE_LICENSE("GPL");