470 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC4 *5 * Copyright (C) 2009 Bluewater Systems Ltd6 *7 * Author: Ryan Mallon8 *9 * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>10 *11 * UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru>12 */13 14#include <linux/kernel.h>15#include <linux/module.h>16#include <linux/types.h>17#include <linux/errno.h>18#include <linux/swab.h>19#include <linux/i2c.h>20#include <linux/delay.h>21#include <linux/idr.h>22#include <linux/power_supply.h>23#include <linux/slab.h>24#include <linux/ds2782_battery.h>25 26#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */27 28#define DS278x_REG_VOLT_MSB 0x0c29#define DS278x_REG_TEMP_MSB 0x0a30#define DS278x_REG_CURRENT_MSB 0x0e31 32/* EEPROM Block */33#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */34 35/* Current unit measurement in uA for a 1 milli-ohm sense resistor */36#define DS2782_CURRENT_UNITS 156337 38#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */39 40#define DS2786_CURRENT_UNITS 2541 42#define DS278x_DELAY 100043 44struct ds278x_info;45 46struct ds278x_battery_ops {47 int (*get_battery_current)(struct ds278x_info *info, int *current_uA);48 int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);49 int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);50};51 52#define to_ds278x_info(x) power_supply_get_drvdata(x)53 54struct ds278x_info {55 struct i2c_client *client;56 struct power_supply *battery;57 struct power_supply_desc battery_desc;58 const struct ds278x_battery_ops *ops;59 struct delayed_work bat_work;60 int id;61 int rsns;62 int capacity;63 int status; /* State Of Charge */64};65 66static DEFINE_IDR(battery_id);67static DEFINE_MUTEX(battery_lock);68 69static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)70{71 int ret;72 73 ret = i2c_smbus_read_byte_data(info->client, reg);74 if (ret < 0) {75 dev_err(&info->client->dev, "register read failed\n");76 return ret;77 }78 79 *val = ret;80 return 0;81}82 83static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,84 s16 *val)85{86 int ret;87 88 ret = i2c_smbus_read_word_data(info->client, reg_msb);89 if (ret < 0) {90 dev_err(&info->client->dev, "register read failed\n");91 return ret;92 }93 94 *val = swab16(ret);95 return 0;96}97 98static int ds278x_get_temp(struct ds278x_info *info, int *temp)99{100 s16 raw;101 int err;102 103 /*104 * Temperature is measured in units of 0.125 degrees celcius, the105 * power_supply class measures temperature in tenths of degrees106 * celsius. The temperature value is stored as a 10 bit number, plus107 * sign in the upper bits of a 16 bit register.108 */109 err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);110 if (err)111 return err;112 *temp = ((raw / 32) * 125) / 100;113 return 0;114}115 116static int ds2782_get_current(struct ds278x_info *info, int *current_uA)117{118 int sense_res;119 int err;120 u8 sense_res_raw;121 s16 raw;122 123 /*124 * The units of measurement for current are dependent on the value of125 * the sense resistor.126 */127 err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);128 if (err)129 return err;130 if (sense_res_raw == 0) {131 dev_err(&info->client->dev, "sense resistor value is 0\n");132 return -ENXIO;133 }134 sense_res = 1000 / sense_res_raw;135 136 dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",137 sense_res);138 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);139 if (err)140 return err;141 *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);142 return 0;143}144 145static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)146{147 s16 raw;148 int err;149 150 /*151 * Voltage is measured in units of 4.88mV. The voltage is stored as152 * a 10-bit number plus sign, in the upper bits of a 16-bit register153 */154 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);155 if (err)156 return err;157 *voltage_uV = (raw / 32) * 4800;158 return 0;159}160 161static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)162{163 int err;164 u8 raw;165 166 err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);167 if (err)168 return err;169 *capacity = raw;170 return 0;171}172 173static int ds2786_get_current(struct ds278x_info *info, int *current_uA)174{175 int err;176 s16 raw;177 178 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);179 if (err)180 return err;181 *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);182 return 0;183}184 185static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)186{187 s16 raw;188 int err;189 190 /*191 * Voltage is measured in units of 1.22mV. The voltage is stored as192 * a 12-bit number plus sign, in the upper bits of a 16-bit register193 */194 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);195 if (err)196 return err;197 *voltage_uV = (raw / 8) * 1220;198 return 0;199}200 201static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)202{203 int err;204 u8 raw;205 206 err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);207 if (err)208 return err;209 /* Relative capacity is displayed with resolution 0.5 % */210 *capacity = raw/2 ;211 return 0;212}213 214static int ds278x_get_status(struct ds278x_info *info, int *status)215{216 int err;217 int current_uA;218 int capacity;219 220 err = info->ops->get_battery_current(info, ¤t_uA);221 if (err)222 return err;223 224 err = info->ops->get_battery_capacity(info, &capacity);225 if (err)226 return err;227 228 info->capacity = capacity;229 230 if (capacity == 100)231 *status = POWER_SUPPLY_STATUS_FULL;232 else if (current_uA == 0)233 *status = POWER_SUPPLY_STATUS_NOT_CHARGING;234 else if (current_uA < 0)235 *status = POWER_SUPPLY_STATUS_DISCHARGING;236 else237 *status = POWER_SUPPLY_STATUS_CHARGING;238 239 return 0;240}241 242static int ds278x_battery_get_property(struct power_supply *psy,243 enum power_supply_property prop,244 union power_supply_propval *val)245{246 struct ds278x_info *info = to_ds278x_info(psy);247 int ret;248 249 switch (prop) {250 case POWER_SUPPLY_PROP_STATUS:251 ret = ds278x_get_status(info, &val->intval);252 break;253 254 case POWER_SUPPLY_PROP_CAPACITY:255 ret = info->ops->get_battery_capacity(info, &val->intval);256 break;257 258 case POWER_SUPPLY_PROP_VOLTAGE_NOW:259 ret = info->ops->get_battery_voltage(info, &val->intval);260 break;261 262 case POWER_SUPPLY_PROP_CURRENT_NOW:263 ret = info->ops->get_battery_current(info, &val->intval);264 break;265 266 case POWER_SUPPLY_PROP_TEMP:267 ret = ds278x_get_temp(info, &val->intval);268 break;269 270 default:271 ret = -EINVAL;272 }273 274 return ret;275}276 277static void ds278x_bat_update(struct ds278x_info *info)278{279 int old_status = info->status;280 int old_capacity = info->capacity;281 282 ds278x_get_status(info, &info->status);283 284 if ((old_status != info->status) || (old_capacity != info->capacity))285 power_supply_changed(info->battery);286}287 288static void ds278x_bat_work(struct work_struct *work)289{290 struct ds278x_info *info;291 292 info = container_of(work, struct ds278x_info, bat_work.work);293 ds278x_bat_update(info);294 295 schedule_delayed_work(&info->bat_work, DS278x_DELAY);296}297 298static enum power_supply_property ds278x_battery_props[] = {299 POWER_SUPPLY_PROP_STATUS,300 POWER_SUPPLY_PROP_CAPACITY,301 POWER_SUPPLY_PROP_VOLTAGE_NOW,302 POWER_SUPPLY_PROP_CURRENT_NOW,303 POWER_SUPPLY_PROP_TEMP,304};305 306static void ds278x_power_supply_init(struct power_supply_desc *battery)307{308 battery->type = POWER_SUPPLY_TYPE_BATTERY;309 battery->properties = ds278x_battery_props;310 battery->num_properties = ARRAY_SIZE(ds278x_battery_props);311 battery->get_property = ds278x_battery_get_property;312 battery->external_power_changed = NULL;313}314 315static void ds278x_battery_remove(struct i2c_client *client)316{317 struct ds278x_info *info = i2c_get_clientdata(client);318 int id = info->id;319 320 power_supply_unregister(info->battery);321 cancel_delayed_work_sync(&info->bat_work);322 kfree(info->battery_desc.name);323 kfree(info);324 325 mutex_lock(&battery_lock);326 idr_remove(&battery_id, id);327 mutex_unlock(&battery_lock);328}329 330#ifdef CONFIG_PM_SLEEP331 332static int ds278x_suspend(struct device *dev)333{334 struct i2c_client *client = to_i2c_client(dev);335 struct ds278x_info *info = i2c_get_clientdata(client);336 337 cancel_delayed_work(&info->bat_work);338 return 0;339}340 341static int ds278x_resume(struct device *dev)342{343 struct i2c_client *client = to_i2c_client(dev);344 struct ds278x_info *info = i2c_get_clientdata(client);345 346 schedule_delayed_work(&info->bat_work, DS278x_DELAY);347 return 0;348}349#endif /* CONFIG_PM_SLEEP */350 351static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);352 353enum ds278x_num_id {354 DS2782 = 0,355 DS2786,356};357 358static const struct ds278x_battery_ops ds278x_ops[] = {359 [DS2782] = {360 .get_battery_current = ds2782_get_current,361 .get_battery_voltage = ds2782_get_voltage,362 .get_battery_capacity = ds2782_get_capacity,363 },364 [DS2786] = {365 .get_battery_current = ds2786_get_current,366 .get_battery_voltage = ds2786_get_voltage,367 .get_battery_capacity = ds2786_get_capacity,368 }369};370 371static int ds278x_battery_probe(struct i2c_client *client)372{373 const struct i2c_device_id *id = i2c_client_get_device_id(client);374 struct ds278x_platform_data *pdata = client->dev.platform_data;375 struct power_supply_config psy_cfg = {};376 struct ds278x_info *info;377 int ret;378 int num;379 380 /*381 * ds2786 should have the sense resistor value set382 * in the platform data383 */384 if (id->driver_data == DS2786 && !pdata) {385 dev_err(&client->dev, "missing platform data for ds2786\n");386 return -EINVAL;387 }388 389 /* Get an ID for this battery */390 mutex_lock(&battery_lock);391 ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL);392 mutex_unlock(&battery_lock);393 if (ret < 0)394 goto fail_id;395 num = ret;396 397 info = kzalloc(sizeof(*info), GFP_KERNEL);398 if (!info) {399 ret = -ENOMEM;400 goto fail_info;401 }402 403 info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d",404 client->name, num);405 if (!info->battery_desc.name) {406 ret = -ENOMEM;407 goto fail_name;408 }409 410 if (id->driver_data == DS2786)411 info->rsns = pdata->rsns;412 413 i2c_set_clientdata(client, info);414 info->client = client;415 info->id = num;416 info->ops = &ds278x_ops[id->driver_data];417 ds278x_power_supply_init(&info->battery_desc);418 psy_cfg.drv_data = info;419 420 info->capacity = 100;421 info->status = POWER_SUPPLY_STATUS_FULL;422 423 INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work);424 425 info->battery = power_supply_register(&client->dev,426 &info->battery_desc, &psy_cfg);427 if (IS_ERR(info->battery)) {428 dev_err(&client->dev, "failed to register battery\n");429 ret = PTR_ERR(info->battery);430 goto fail_register;431 } else {432 schedule_delayed_work(&info->bat_work, DS278x_DELAY);433 }434 435 return 0;436 437fail_register:438 kfree(info->battery_desc.name);439fail_name:440 kfree(info);441fail_info:442 mutex_lock(&battery_lock);443 idr_remove(&battery_id, num);444 mutex_unlock(&battery_lock);445fail_id:446 return ret;447}448 449static const struct i2c_device_id ds278x_id[] = {450 {"ds2782", DS2782},451 {"ds2786", DS2786},452 {},453};454MODULE_DEVICE_TABLE(i2c, ds278x_id);455 456static struct i2c_driver ds278x_battery_driver = {457 .driver = {458 .name = "ds2782-battery",459 .pm = &ds278x_battery_pm_ops,460 },461 .probe = ds278x_battery_probe,462 .remove = ds278x_battery_remove,463 .id_table = ds278x_id,464};465module_i2c_driver(ds278x_battery_driver);466 467MODULE_AUTHOR("Ryan Mallon");468MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC driver");469MODULE_LICENSE("GPL");470