power/supply/acer_a500_battery.c

0001 // SPDX-License-Identifier: GPL-2.0+
0002 /*
0003  * Battery driver for Acer Iconia Tab A500.
0004  *
0005  * Copyright 2020 GRATE-driver project.
0006  *
0007  * Based on downstream driver from Acer Inc.
0008  * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries.
0009  *
0010  * Copyright (c) 2010, NVIDIA Corporation.
0011  */
0012
0013 #include <linux/module.h>
0014 #include <linux/platform_device.h>
0015 #include <linux/power_supply.h>
0016 #include <linux/regmap.h>
0017 #include <linux/sched.h>
0018 #include <linux/slab.h>
0019 #include <linux/workqueue.h>
0020
0021 enum {
0022     REG_CAPACITY,
0023     REG_VOLTAGE,
0024     REG_CURRENT,
0025     REG_DESIGN_CAPACITY,
0026     REG_TEMPERATURE,
0027 };
0028
0029 #define EC_DATA(_reg, _psp) {           \
0030     .psp = POWER_SUPPLY_PROP_ ## _psp,  \
0031     .reg = _reg,                \
0032 }
0033
0034 static const struct battery_register {
0035     enum power_supply_property psp;
0036     unsigned int reg;
0037 } ec_data[] = {
0038     [REG_CAPACITY]      = EC_DATA(0x00, CAPACITY),
0039     [REG_VOLTAGE]       = EC_DATA(0x01, VOLTAGE_NOW),
0040     [REG_CURRENT]       = EC_DATA(0x03, CURRENT_NOW),
0041     [REG_DESIGN_CAPACITY]   = EC_DATA(0x08, CHARGE_FULL_DESIGN),
0042     [REG_TEMPERATURE]   = EC_DATA(0x0a, TEMP),
0043 };
0044
0045 static const enum power_supply_property a500_battery_properties[] = {
0046     POWER_SUPPLY_PROP_CAPACITY,
0047     POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
0048     POWER_SUPPLY_PROP_CURRENT_NOW,
0049     POWER_SUPPLY_PROP_PRESENT,
0050     POWER_SUPPLY_PROP_STATUS,
0051     POWER_SUPPLY_PROP_TECHNOLOGY,
0052     POWER_SUPPLY_PROP_TEMP,
0053     POWER_SUPPLY_PROP_VOLTAGE_NOW,
0054 };
0055
0056 struct a500_battery {
0057     struct delayed_work poll_work;
0058     struct power_supply *psy;
0059     struct regmap *regmap;
0060     unsigned int capacity;
0061 };
0062
0063 static bool a500_battery_update_capacity(struct a500_battery *bat)
0064 {
0065     unsigned int capacity;
0066     int err;
0067
0068     err = regmap_read(bat->regmap, ec_data[REG_CAPACITY].reg, &capacity);
0069     if (err)
0070         return false;
0071
0072     /* capacity can be >100% even if max value is 100% */
0073     capacity = min(capacity, 100u);
0074
0075     if (bat->capacity != capacity) {
0076         bat->capacity = capacity;
0077         return true;
0078     }
0079
0080     return false;
0081 }
0082
0083 static int a500_battery_get_status(struct a500_battery *bat)
0084 {
0085     if (bat->capacity < 100) {
0086         if (power_supply_am_i_supplied(bat->psy))
0087             return POWER_SUPPLY_STATUS_CHARGING;
0088         else
0089             return POWER_SUPPLY_STATUS_DISCHARGING;
0090     }
0091
0092     return POWER_SUPPLY_STATUS_FULL;
0093 }
0094
0095 static void a500_battery_unit_adjustment(struct device *dev,
0096                      enum power_supply_property psp,
0097                      union power_supply_propval *val)
0098 {
0099     const unsigned int base_unit_conversion = 1000;
0100     const unsigned int temp_kelvin_to_celsius = 2731;
0101
0102     switch (psp) {
0103     case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
0104     case POWER_SUPPLY_PROP_CURRENT_NOW:
0105     case POWER_SUPPLY_PROP_VOLTAGE_NOW:
0106         val->intval *= base_unit_conversion;
0107         break;
0108
0109     case POWER_SUPPLY_PROP_TEMP:
0110         val->intval -= temp_kelvin_to_celsius;
0111         break;
0112
0113     case POWER_SUPPLY_PROP_PRESENT:
0114         val->intval = !!val->intval;
0115         break;
0116
0117     default:
0118         dev_dbg(dev,
0119             "%s: no need for unit conversion %d\n", __func__, psp);
0120     }
0121 }
0122
0123 static int a500_battery_get_ec_data_index(struct device *dev,
0124                       enum power_supply_property psp)
0125 {
0126     unsigned int i;
0127
0128     /*
0129      * DESIGN_CAPACITY register always returns a non-zero value if
0130      * battery is connected and zero if disconnected, hence we'll use
0131      * it for judging the battery presence.
0132      */
0133     if (psp == POWER_SUPPLY_PROP_PRESENT)
0134         psp = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
0135
0136     for (i = 0; i < ARRAY_SIZE(ec_data); i++)
0137         if (psp == ec_data[i].psp)
0138             return i;
0139
0140     dev_dbg(dev, "%s: invalid property %u\n", __func__, psp);
0141
0142     return -EINVAL;
0143 }
0144
0145 static int a500_battery_get_property(struct power_supply *psy,
0146                      enum power_supply_property psp,
0147                      union power_supply_propval *val)
0148 {
0149     struct a500_battery *bat = power_supply_get_drvdata(psy);
0150     struct device *dev = psy->dev.parent;
0151     int ret = 0;
0152
0153     switch (psp) {
0154     case POWER_SUPPLY_PROP_STATUS:
0155         val->intval = a500_battery_get_status(bat);
0156         break;
0157
0158     case POWER_SUPPLY_PROP_TECHNOLOGY:
0159         val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
0160         break;
0161
0162     case POWER_SUPPLY_PROP_CAPACITY:
0163         a500_battery_update_capacity(bat);
0164         val->intval = bat->capacity;
0165         break;
0166
0167     case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
0168     case POWER_SUPPLY_PROP_CURRENT_NOW:
0169     case POWER_SUPPLY_PROP_VOLTAGE_NOW:
0170     case POWER_SUPPLY_PROP_PRESENT:
0171     case POWER_SUPPLY_PROP_TEMP:
0172         ret = a500_battery_get_ec_data_index(dev, psp);
0173         if (ret < 0)
0174             break;
0175
0176         ret = regmap_read(bat->regmap, ec_data[ret].reg, &val->intval);
0177         break;
0178
0179     default:
0180         dev_err(dev, "%s: invalid property %u\n", __func__, psp);
0181         return -EINVAL;
0182     }
0183
0184     if (!ret) {
0185         /* convert units to match requirements of power supply class */
0186         a500_battery_unit_adjustment(dev, psp, val);
0187     }
0188
0189     dev_dbg(dev, "%s: property = %d, value = %x\n",
0190         __func__, psp, val->intval);
0191
0192     /* return NODATA for properties if battery not presents */
0193     if (ret)
0194         return -ENODATA;
0195
0196     return 0;
0197 }
0198
0199 static void a500_battery_poll_work(struct work_struct *work)
0200 {
0201     struct a500_battery *bat;
0202     bool capacity_changed;
0203
0204     bat = container_of(work, struct a500_battery, poll_work.work);
0205     capacity_changed = a500_battery_update_capacity(bat);
0206
0207     if (capacity_changed)
0208         power_supply_changed(bat->psy);
0209
0210     /* continuously send uevent notification */
0211     schedule_delayed_work(&bat->poll_work, 30 * HZ);
0212 }
0213
0214 static const struct power_supply_desc a500_battery_desc = {
0215     .name = "ec-battery",
0216     .type = POWER_SUPPLY_TYPE_BATTERY,
0217     .properties = a500_battery_properties,
0218     .get_property = a500_battery_get_property,
0219     .num_properties = ARRAY_SIZE(a500_battery_properties),
0220     .external_power_changed = power_supply_changed,
0221 };
0222
0223 static int a500_battery_probe(struct platform_device *pdev)
0224 {
0225     struct power_supply_config psy_cfg = {};
0226     struct a500_battery *bat;
0227
0228     bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL);
0229     if (!bat)
0230         return -ENOMEM;
0231
0232     platform_set_drvdata(pdev, bat);
0233
0234     psy_cfg.of_node = pdev->dev.parent->of_node;
0235     psy_cfg.drv_data = bat;
0236
0237     bat->regmap = dev_get_regmap(pdev->dev.parent, "KB930");
0238     if (!bat->regmap)
0239         return -EINVAL;
0240
0241     bat->psy = devm_power_supply_register_no_ws(&pdev->dev,
0242                             &a500_battery_desc,
0243                             &psy_cfg);
0244     if (IS_ERR(bat->psy))
0245         return dev_err_probe(&pdev->dev, PTR_ERR(bat->psy),
0246                      "failed to register battery\n");
0247
0248     INIT_DELAYED_WORK(&bat->poll_work, a500_battery_poll_work);
0249     schedule_delayed_work(&bat->poll_work, HZ);
0250
0251     return 0;
0252 }
0253
0254 static int a500_battery_remove(struct platform_device *pdev)
0255 {
0256     struct a500_battery *bat = dev_get_drvdata(&pdev->dev);
0257
0258     cancel_delayed_work_sync(&bat->poll_work);
0259
0260     return 0;
0261 }
0262
0263 static int __maybe_unused a500_battery_suspend(struct device *dev)
0264 {
0265     struct a500_battery *bat = dev_get_drvdata(dev);
0266
0267     cancel_delayed_work_sync(&bat->poll_work);
0268
0269     return 0;
0270 }
0271
0272 static int __maybe_unused a500_battery_resume(struct device *dev)
0273 {
0274     struct a500_battery *bat = dev_get_drvdata(dev);
0275
0276     schedule_delayed_work(&bat->poll_work, HZ);
0277
0278     return 0;
0279 }
0280
0281 static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops,
0282              a500_battery_suspend, a500_battery_resume);
0283
0284 static struct platform_driver a500_battery_driver = {
0285     .driver = {
0286         .name = "acer-a500-iconia-battery",
0287         .pm = &a500_battery_pm_ops,
0288     },
0289     .probe = a500_battery_probe,
0290     .remove = a500_battery_remove,
0291 };
0292 module_platform_driver(a500_battery_driver);
0293
0294 MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500");
0295 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
0296 MODULE_ALIAS("platform:acer-a500-iconia-battery");
0297 MODULE_LICENSE("GPL");