电池电量转换参考

http://blog.csdn.net/yunfly163/article/details/9232031

 "code" class="cpp">"code" class="cpp">/**
  * Driver for batteries with DS2760 chips inside.
  *
  * Copyright © 2007 Anton Vorontsov
  *         2004-2007 Matt Reimer
  *         2004 Szabolcs Gyurko
  *
  * Use consistent with the GNU GPL is permitted,
  * provided that this copyright notice is
  * preserved in its entirety in all copies and derived works.
  *
  * Author:  Anton Vorontsov
  *      February 2007
  *
  *      Matt Reimer
  *      April 2004, 2005, 2007
  *
  *      Szabolcs Gyurko
  *      September 2004
  */

 #include
 #include
 #include
 #include
 #include
 #include
 #include
 #include

 #include "../w1/w1.h"
 #include "../w1/slaves/w1_ds2760.h"

 struct ds2760_device_info {
     struct device *dev;

     /** DS2760 data, valid after calling ds2760_battery_read_status() */
     unsigned long update_time;  /** jiffies when data read */
     char raw[DS2760_DATA_SIZE]; /** raw DS2760 data */
     int voltage_raw;        /** units of 4.88 mV */
     int voltage_uV;         /** units of µV */
     int current_raw;        /** units of 0.625 mA */
     int current_uA;         /** units of µA */
     int accum_current_raw;      /** units of 0.25 mAh */
     int accum_current_uAh;      /** units of µAh */
     int temp_raw;           /** units of 0.125 °C */
     int temp_C;         /** units of 0.1 °C */
     int rated_capacity;     /** units of µAh */
     int rem_capacity;       /** percentage */
     int full_active_uAh;        /** units of µAh */
     int empty_uAh;          /** units of µAh */
     int life_sec;           /** units of seconds */
     int charge_status;      /** POWER_SUPPLY_STATUS_* */

     int full_counter;
     struct power_supply bat;
     struct device *w1_dev;
     struct workqueue_struct *monitor_wqueue;
     struct delayed_work monitor_work;
     struct delayed_work set_charged_work;
 };

 static unsigned int cache_time = 1000;
 module_param(cache_time, uint, 0644);
 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");

 static unsigned int pmod_enabled;
 module_param(pmod_enabled, bool, 0644);
 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");

 static unsigned int rated_capacity;
 module_param(rated_capacity, uint, 0644);
 MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");

 static unsigned int current_accum;
 module_param(current_accum, uint, 0644);
 MODULE_PARM_DESC(current_accum, "current accumulator value");

 /** Some batteries have their rated capacity stored a N * 10 mAh, while
  * others use an index into this table. */
 static int rated_capacities[] = {
     0,
     920,    /** Samsung */
     920,    /** BYD */
     920,    /** Lishen */
     920,    /** NEC */
     1440,   /** Samsung */
     1440,   /** BYD */
     1440,   /** Lishen */
     1440,   /** NEC */
     2880,   /** Samsung */
     2880,   /** BYD */
     2880,   /** Lishen */
     2880    /** NEC */
 };

 /** array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
  * temp is in Celsius */
 static int battery_interpolate(int array[], int temp)
 {
     int index, dt;

     if (temp <= 0)
         return array[0];
     if (temp >= 40)
         return array[4];

     index = temp / 10;
     dt    = temp % 10;

     return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
 }

 static int ds2760_battery_read_status(struct ds2760_device_info *di)
 {
     int ret, i, start, count, scale[5];

     if (di->update_time && time_before(jiffies, di->update_time +
                        msecs_to_jiffies(cache_time)))
         return 0;

     /** The first time we read the entire contents of SRAM/EEPROM,
      * but after that we just read the interesting bits that change. */
     if (di->update_time == 0) {
         start = 0;
         count = DS2760_DATA_SIZE;
     } else {
         start = DS2760_VOLTAGE_MSB;
         count = DS2760_TEMP_LSB - start + 1;
     }

     ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
     if (ret != count) {
         dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
              di->w1_dev);
         return 1;
     }

     di->update_time = jiffies;

     /** DS2760 reports voltage in units of 4.88mV, but the battery class
      * reports in units of uV, so convert by multiplying by 4880. */
     di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
               (di->raw[DS2760_VOLTAGE_LSB] >> 5);
     di->voltage_uV = di->voltage_raw * 4880;

     /** DS2760 reports current in signed units of 0.625mA, but the battery
      * class reports in units of µA, so convert by multiplying by 625. */
     di->current_raw =
         (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
               (di->raw[DS2760_CURRENT_LSB] >> 3);
     di->current_uA = di->current_raw * 625;

     /** DS2760 reports accumulated current in signed units of 0.25mAh. */
     di->accum_current_raw =
         (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
                di->raw[DS2760_CURRENT_ACCUM_LSB];
     di->accum_current_uAh = di->accum_current_raw * 250;

     /** DS2760 reports temperature in signed units of 0.125°C, but the
      * battery class reports in units of 1/10 °C, so we convert by
      * multiplying by .125 * 10 = 1.25. */
     di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
                      (di->raw[DS2760_TEMP_LSB] >> 5);
     di->temp_C = di->temp_raw + (di->temp_raw / 4);

     /** At least some battery monitors (e.g. HP iPAQ) store the battery's
      * maximum rated capacity. */
     if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
         di->rated_capacity = rated_capacities[
             (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
     else
         di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;

     di->rated_capacity *= 1000; /** convert to µAh */

     /** Calculate the full level at the present temperature. */
     di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
                   di->raw[DS2760_ACTIVE_FULL + 1];

     /** If the full_active_uAh value is not given, fall back to the rated
      * capacity. This is likely to happen when chips are not part of the
      * battery pack and is therefore not bootstrapped. */
     if (di->full_active_uAh == 0)
         di->full_active_uAh = di->rated_capacity / 1000L;

     scale[0] = di->full_active_uAh;
     for (i = 1; i < 5; i++)
         scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];

     di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
     di->full_active_uAh *= 1000; /** convert to µAh */

     /** Calculate the empty level at the present temperature. */
     scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
     for (i = 3; i >= 0; i--)
         scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];

     di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
     di->empty_uAh *= 1000; /** convert to µAh */

     if (di->full_active_uAh == di->empty_uAh)
         di->rem_capacity = 0;
     else
         /** From Maxim Application Note 131: remaining capacity =
          * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
         di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
                     (di->full_active_uAh - di->empty_uAh);

     if (di->rem_capacity < 0)
         di->rem_capacity = 0;
     if (di->rem_capacity > 100)
         di->rem_capacity = 100;

     if (di->current_uA >= 100L)
         di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
                     / (di->current_uA / 100L);
     else
         di->life_sec = 0;

     return 0;
 }

 static void ds2760_battery_set_current_accum(struct ds2760_device_info *di,
                          unsigned int acr_val)
 {
     unsigned char acr[2];

     /** acr is in units of 0.25 mAh */
     acr_val *= 4L;
     acr_val /= 1000;

     acr[0] = acr_val >> 8;
     acr[1] = acr_val & 0xff;

     if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2)
         dev_warn(di->dev, "ACR write failed\n");
 }

 static void ds2760_battery_update_status(struct ds2760_device_info *di)
 {
     int old_charge_status = di->charge_status;

     ds2760_battery_read_status(di);

     if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
         di->full_counter = 0;

     if (power_supply_am_i_supplied(&di->bat)) {
         if (di->current_uA > 10000) {
             di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
             di->full_counter = 0;
         } else if (di->current_uA < -5000) {
             if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
                 dev_notice(di->dev, "not enough power to "
                        "charge\n");
             di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
             di->full_counter = 0;
         } else if (di->current_uA < 10000 &&
                 di->charge_status != POWER_SUPPLY_STATUS_FULL) {

             /** Don't consider the battery to be full unless
              * we've seen the current < 10 mA at least two
              * consecutive times. */

             di->full_counter++;

             if (di->full_counter < 2) {
                 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
             } else {
                 di->charge_status = POWER_SUPPLY_STATUS_FULL;
                 ds2760_battery_set_current_accum(di,
                         di->full_active_uAh);
             }
         }
     } else {
         di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
         di->full_counter = 0;
     }

     if (di->charge_status != old_charge_status)
         power_supply_changed(&di->bat);
 }

 static void ds2760_battery_write_status(struct ds2760_device_info *di,
                     char status)
 {
     if (status == di->raw[DS2760_STATUS_REG])
         return;

     w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
     w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
     w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 }

 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
                         unsigned char rated_capacity)
 {
     if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
         return;

     w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
     w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
     w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 }

 static void ds2760_battery_write_active_full(struct ds2760_device_info *di,
                          int active_full)
 {
     unsigned char tmp[2] = {
         active_full >> 8,
         active_full & 0xff
     };

     if (tmp[0] == di->raw[DS2760_ACTIVE_FULL] &&
         tmp[1] == di->raw[DS2760_ACTIVE_FULL + 1])
         return;

     w1_ds2760_write(di->w1_dev, tmp, DS2760_ACTIVE_FULL, sizeof(tmp));
     w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);
     w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);

     /** Write to the di->raw[] buffer directly - the DS2760_ACTIVE_FULL
      * values won't be read back by ds2760_battery_read_status() */
     di->raw[DS2760_ACTIVE_FULL] = tmp[0];
     di->raw[DS2760_ACTIVE_FULL + 1] = tmp[1];
 }

 static void ds2760_battery_work(struct work_struct *work)
 {
     struct ds2760_device_info *di = container_of(work,
         struct ds2760_device_info, monitor_work.work);
     const int interval = HZ * 60;

     dev_dbg(di->dev, "%s\n", __func__);

     ds2760_battery_update_status(di);
     queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
 }

 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
                           bat);

 static void ds2760_battery_external_power_changed(struct power_supply *psy)
 {
     struct ds2760_device_info *di = to_ds2760_device_info(psy);

     dev_dbg(di->dev, "%s\n", __func__);

     cancel_delayed_work(&di->monitor_work);
     queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
 }


 static void ds2760_battery_set_charged_work(struct work_struct *work)
 {
     char bias;
     struct ds2760_device_info *di = container_of(work,
         struct ds2760_device_info, set_charged_work.work);

     dev_dbg(di->dev, "%s\n", __func__);

     ds2760_battery_read_status(di);

     /** When we get notified by external circuitry that the battery is
      * considered fully charged now, we know that there is no current
      * flow any more. However, the ds2760's internal current meter is
      * too inaccurate to rely on - spec say something ~15% failure.
      * Hence, we use the current offset bias register to compensate
      * that error.
      */

     if (!power_supply_am_i_supplied(&di->bat))
         return;

     bias = (signed char) di->current_raw +
         (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS];

     dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias);

     w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1);
     w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
     w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);

     /** Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
      * value won't be read back by ds2760_battery_read_status() */
     di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias;
 }

 static void ds2760_battery_set_charged(struct power_supply *psy)
 {
     struct ds2760_device_info *di = to_ds2760_device_info(psy);

     /** postpone the actual work by 20 secs. This is for debouncing GPIO
      * signals and to let the current value settle. See AN4188. */
     cancel_delayed_work(&di->set_charged_work);
     queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
 }

 static int ds2760_battery_get_property(struct power_supply *psy,
                        enum power_supply_property psp,
                        union power_supply_propval *val)
 {
     struct ds2760_device_info *di = to_ds2760_device_info(psy);

     switch (psp) {
     case POWER_SUPPLY_PROP_STATUS:
         val->intval = di->charge_status;
         return 0;
     default:
         break;
     }

     ds2760_battery_read_status(di);

     switch (psp) {
     case POWER_SUPPLY_PROP_VOLTAGE_NOW:
         val->intval = di->voltage_uV;
         break;
     case POWER_SUPPLY_PROP_CURRENT_NOW:
         val->intval = di->current_uA;
         break;
     case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
         val->intval = di->rated_capacity;
         break;
     case POWER_SUPPLY_PROP_CHARGE_FULL:
         val->intval = di->full_active_uAh;
         break;
     case POWER_SUPPLY_PROP_CHARGE_EMPTY:
         val->intval = di->empty_uAh;
         break;
     case POWER_SUPPLY_PROP_CHARGE_NOW:
         val->intval = di->accum_current_uAh;
         break;
     case POWER_SUPPLY_PROP_TEMP:
         val->intval = di->temp_C;
         break;
     case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
         val->intval = di->life_sec;
         break;
     case POWER_SUPPLY_PROP_CAPACITY:
         val->intval = di->rem_capacity;
         break;
     default:
         return -EINVAL;
     }

     return 0;
 }

 static int ds2760_battery_set_property(struct power_supply *psy,
                        enum power_supply_property psp,
                        const union power_supply_propval *val)
 {
     struct ds2760_device_info *di = to_ds2760_device_info(psy);

     switch (psp) {
     case POWER_SUPPLY_PROP_CHARGE_FULL:
         /** the interface counts in uAh, convert the value */
         ds2760_battery_write_active_full(di, val->intval / 1000L);
         break;

     case POWER_SUPPLY_PROP_CHARGE_NOW:
         /** ds2760_battery_set_current_accum() does the conversion */
         ds2760_battery_set_current_accum(di, val->intval);
         break;

     default:
         return -EPERM;
     }

     return 0;
 }

 static int ds2760_battery_property_is_writeable(struct power_supply *psy,
                         enum power_supply_property psp)
 {
     switch (psp) {
     case POWER_SUPPLY_PROP_CHARGE_FULL:
     case POWER_SUPPLY_PROP_CHARGE_NOW:
         return 1;

     default:
         break;
     }

     return 0;
 }

 static enum power_supply_property ds2760_battery_props[] = {
     POWER_SUPPLY_PROP_STATUS,
     POWER_SUPPLY_PROP_VOLTAGE_NOW,
     POWER_SUPPLY_PROP_CURRENT_NOW,
     POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
     POWER_SUPPLY_PROP_CHARGE_FULL,
     POWER_SUPPLY_PROP_CHARGE_EMPTY,
     POWER_SUPPLY_PROP_CHARGE_NOW,
     POWER_SUPPLY_PROP_TEMP,
     POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
     POWER_SUPPLY_PROP_CAPACITY,
 };

 static int ds2760_battery_probe(struct platform_device *pdev)
 {
     char status;
     int retval = 0;
     struct ds2760_device_info *di;

     di = kzalloc(sizeof(*di), GFP_KERNEL);
     if (!di) {
         retval = -ENOMEM;
         goto di_alloc_failed;
     }

     platform_set_drvdata(pdev, di);

     di->dev          = &pdev->dev;
     di->w1_dev       = pdev->dev.parent;
     di->bat.name     = dev_name(&pdev->dev);
     di->bat.type     = POWER_SUPPLY_TYPE_BATTERY;
     di->bat.properties   = ds2760_battery_props;
     di->bat.num_properties   = ARRAY_SIZE(ds2760_battery_props);
     di->bat.get_property = ds2760_battery_get_property;
     di->bat.set_property = ds2760_battery_set_property;
     di->bat.property_is_writeable =
                   ds2760_battery_property_is_writeable;
     di->bat.set_charged  = ds2760_battery_set_charged;
     di->bat.external_power_changed =
                   ds2760_battery_external_power_changed;

     di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;

     /** enable sleep mode feature */
     ds2760_battery_read_status(di);
     status = di->raw[DS2760_STATUS_REG];
     if (pmod_enabled)
         status |= DS2760_STATUS_PMOD;
     else
         status &= ~DS2760_STATUS_PMOD;

     ds2760_battery_write_status(di, status);

     /** set rated capacity from module param */
     if (rated_capacity)
         ds2760_battery_write_rated_capacity(di, rated_capacity);

     /** set current accumulator if given as parameter.
      * this should only be done for bootstrapping the value */
     if (current_accum)
         ds2760_battery_set_current_accum(di, current_accum);

     retval = power_supply_register(&pdev->dev, &di->bat);
     if (retval) {
         dev_err(di->dev, "failed to register battery\n");
         goto batt_failed;
     }

     INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
     INIT_DELAYED_WORK(&di->set_charged_work,
               ds2760_battery_set_charged_work);
     di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
     if (!di->monitor_wqueue) {
         retval = -ESRCH;
         goto workqueue_failed;
     }
     queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);

     goto success;

 workqueue_failed:
     power_supply_unregister(&di->bat);
 batt_failed:
     kfree(di);
 di_alloc_failed:
 success:
     return retval;
 }

 static int ds2760_battery_remove(struct platform_device *pdev)
 {
     struct ds2760_device_info *di = platform_get_drvdata(pdev);

     cancel_rearming_delayed_workqueue(di->monitor_wqueue,
                       &di->monitor_work);
     cancel_rearming_delayed_workqueue(di->monitor_wqueue,
                       &di->set_charged_work);
     destroy_workqueue(di->monitor_wqueue);
     power_supply_unregister(&di->bat);
     kfree(di);

     return 0;
 }

 #ifdef CONFIG_PM

 static int ds2760_battery_suspend(struct platform_device *pdev,
                   pm_message_t state)
 {
     struct ds2760_device_info *di = platform_get_drvdata(pdev);

     di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;

     return 0;
 }

 static int ds2760_battery_resume(struct platform_device *pdev)
 {
     struct ds2760_device_info *di = platform_get_drvdata(pdev);

     di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
     power_supply_changed(&di->bat);

     cancel_delayed_work(&di->monitor_work);
     queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);

     return 0;
 }

 #else

 #define ds2760_battery_suspend NULL
 #define ds2760_battery_resume NULL

 #endif /** CONFIG_PM */

 MODULE_ALIAS("platform:ds2760-battery");

 static struct platform_driver ds2760_battery_driver = {
     .driver = {
         .name = "ds2760-battery",
     },
     .probe    = ds2760_battery_probe,
     .remove   = ds2760_battery_remove,
     .suspend  = ds2760_battery_suspend,
     .resume   = ds2760_battery_resume,
 };

 static int __init ds2760_battery_init(void)
 {
     return platform_driver_register(&ds2760_battery_driver);
 }

 static void __exit ds2760_battery_exit(void)
 {
     platform_driver_unregister(&ds2760_battery_driver);
 }

 module_init(ds2760_battery_init);
 module_exit(ds2760_battery_exit);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Szabolcs Gyurko , "
           "Matt Reimer , "
           "Anton Vorontsov ");
 MODULE_DESCRIPTION("ds2760 battery driver");

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