drivers/power/supply/acer_a500_battery.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Battery driver for Acer Iconia Tab A500.
   4  *
   5  * Copyright 2020 GRATE-driver project.
   6  *
   7  * Based on downstream driver from Acer Inc.
   8  * Based on NVIDIA Gas Gauge driver for SBS Compliant Batteries.
   9  *
  10  * Copyright (c) 2010, NVIDIA Corporation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/power_supply.h>
  16 #include <linux/regmap.h>
  17 #include <linux/sched.h>
  18 #include <linux/slab.h>
  19 #include <linux/workqueue.h>
  20
  21 enum {
  22         REG_CAPACITY,
  23         REG_VOLTAGE,
  24         REG_CURRENT,
  25         REG_DESIGN_CAPACITY,
  26         REG_TEMPERATURE,
  27 };
  28
  29 #define EC_DATA(_reg, _psp) {                   \
  30         .psp = POWER_SUPPLY_PROP_ ## _psp,      \
  31         .reg = _reg,                            \
  32 }
  33
  34 static const struct battery_register {
  35         enum power_supply_property psp;
  36         unsigned int reg;
  37 } ec_data[] = {
  38         [REG_CAPACITY]          = EC_DATA(0x00, CAPACITY),
  39         [REG_VOLTAGE]           = EC_DATA(0x01, VOLTAGE_NOW),
  40         [REG_CURRENT]           = EC_DATA(0x03, CURRENT_NOW),
  41         [REG_DESIGN_CAPACITY]   = EC_DATA(0x08, CHARGE_FULL_DESIGN),
  42         [REG_TEMPERATURE]       = EC_DATA(0x0a, TEMP),
  43 };
  44
  45 static const enum power_supply_property a500_battery_properties[] = {
  46         POWER_SUPPLY_PROP_CAPACITY,
  47         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
  48         POWER_SUPPLY_PROP_CURRENT_NOW,
  49         POWER_SUPPLY_PROP_PRESENT,
  50         POWER_SUPPLY_PROP_STATUS,
  51         POWER_SUPPLY_PROP_TECHNOLOGY,
  52         POWER_SUPPLY_PROP_TEMP,
  53         POWER_SUPPLY_PROP_VOLTAGE_NOW,
  54 };
  55
  56 struct a500_battery {
  57         struct delayed_work poll_work;
  58         struct power_supply *psy;
  59         struct regmap *regmap;
  60         unsigned int capacity;
  61 };
  62
  63 static bool a500_battery_update_capacity(struct a500_battery *bat)
  64 {
  65         unsigned int capacity;
  66         int err;
  67
  68         err = regmap_read(bat->regmap, ec_data[REG_CAPACITY].reg, &capacity);
  69         if (err)
  70                 return false;
  71
  72         /* capacity can be >100% even if max value is 100% */
  73         capacity = min(capacity, 100u);
  74
  75         if (bat->capacity != capacity) {
  76                 bat->capacity = capacity;
  77                 return true;
  78         }
  79
  80         return false;
  81 }
  82
  83 static int a500_battery_get_status(struct a500_battery *bat)
  84 {
  85         if (bat->capacity < 100) {
  86                 if (power_supply_am_i_supplied(bat->psy))
  87                         return POWER_SUPPLY_STATUS_CHARGING;
  88                 else
  89                         return POWER_SUPPLY_STATUS_DISCHARGING;
  90         }
  91
  92         return POWER_SUPPLY_STATUS_FULL;
  93 }
  94
  95 static void a500_battery_unit_adjustment(struct device *dev,
  96                                          enum power_supply_property psp,
  97                                          union power_supply_propval *val)
  98 {
  99         const unsigned int base_unit_conversion = 1000;
 100         const unsigned int temp_kelvin_to_celsius = 2731;
 101
 102         switch (psp) {
 103         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 104         case POWER_SUPPLY_PROP_CURRENT_NOW:
 105         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 106                 val->intval *= base_unit_conversion;
 107                 break;
 108
 109         case POWER_SUPPLY_PROP_TEMP:
 110                 val->intval -= temp_kelvin_to_celsius;
 111                 break;
 112
 113         case POWER_SUPPLY_PROP_PRESENT:
 114                 val->intval = !!val->intval;
 115                 break;
 116
 117         default:
 118                 dev_dbg(dev,
 119                         "%s: no need for unit conversion %d\n", __func__, psp);
 120         }
 121 }
 122
 123 static int a500_battery_get_ec_data_index(struct device *dev,
 124                                           enum power_supply_property psp)
 125 {
 126         unsigned int i;
 127
 128         /*
 129          * DESIGN_CAPACITY register always returns a non-zero value if
 130          * battery is connected and zero if disconnected, hence we'll use
 131          * it for judging the battery presence.
 132          */
 133         if (psp == POWER_SUPPLY_PROP_PRESENT)
 134                 psp = POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN;
 135
 136         for (i = 0; i < ARRAY_SIZE(ec_data); i++)
 137                 if (psp == ec_data[i].psp)
 138                         return i;
 139
 140         dev_dbg(dev, "%s: invalid property %u\n", __func__, psp);
 141
 142         return -EINVAL;
 143 }
 144
 145 static int a500_battery_get_property(struct power_supply *psy,
 146                                      enum power_supply_property psp,
 147                                      union power_supply_propval *val)
 148 {
 149         struct a500_battery *bat = power_supply_get_drvdata(psy);
 150         struct device *dev = psy->dev.parent;
 151         int ret = 0;
 152
 153         switch (psp) {
 154         case POWER_SUPPLY_PROP_STATUS:
 155                 val->intval = a500_battery_get_status(bat);
 156                 break;
 157
 158         case POWER_SUPPLY_PROP_TECHNOLOGY:
 159                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 160                 break;
 161
 162         case POWER_SUPPLY_PROP_CAPACITY:
 163                 a500_battery_update_capacity(bat);
 164                 val->intval = bat->capacity;
 165                 break;
 166
 167         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 168         case POWER_SUPPLY_PROP_CURRENT_NOW:
 169         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 170         case POWER_SUPPLY_PROP_PRESENT:
 171         case POWER_SUPPLY_PROP_TEMP:
 172                 ret = a500_battery_get_ec_data_index(dev, psp);
 173                 if (ret < 0)
 174                         break;
 175
 176                 ret = regmap_read(bat->regmap, ec_data[ret].reg, &val->intval);
 177                 break;
 178
 179         default:
 180                 dev_err(dev, "%s: invalid property %u\n", __func__, psp);
 181                 return -EINVAL;
 182         }
 183
 184         if (!ret) {
 185                 /* convert units to match requirements of power supply class */
 186                 a500_battery_unit_adjustment(dev, psp, val);
 187         }
 188
 189         dev_dbg(dev, "%s: property = %d, value = %x\n",
 190                 __func__, psp, val->intval);
 191
 192         /* return NODATA for properties if battery not presents */
 193         if (ret)
 194                 return -ENODATA;
 195
 196         return 0;
 197 }
 198
 199 static void a500_battery_poll_work(struct work_struct *work)
 200 {
 201         struct a500_battery *bat;
 202         bool capacity_changed;
 203
 204         bat = container_of(work, struct a500_battery, poll_work.work);
 205         capacity_changed = a500_battery_update_capacity(bat);
 206
 207         if (capacity_changed)
 208                 power_supply_changed(bat->psy);
 209
 210         /* continuously send uevent notification */
 211         schedule_delayed_work(&bat->poll_work, 30 * HZ);
 212 }
 213
 214 static const struct power_supply_desc a500_battery_desc = {
 215         .name = "ec-battery",
 216         .type = POWER_SUPPLY_TYPE_BATTERY,
 217         .properties = a500_battery_properties,
 218         .get_property = a500_battery_get_property,
 219         .num_properties = ARRAY_SIZE(a500_battery_properties),
 220         .external_power_changed = power_supply_changed,
 221 };
 222
 223 static int a500_battery_probe(struct platform_device *pdev)
 224 {
 225         struct power_supply_config psy_cfg = {};
 226         struct a500_battery *bat;
 227
 228         bat = devm_kzalloc(&pdev->dev, sizeof(*bat), GFP_KERNEL);
 229         if (!bat)
 230                 return -ENOMEM;
 231
 232         platform_set_drvdata(pdev, bat);
 233
 234         psy_cfg.of_node = pdev->dev.parent->of_node;
 235         psy_cfg.drv_data = bat;
 236
 237         bat->regmap = dev_get_regmap(pdev->dev.parent, "KB930");
 238         if (!bat->regmap)
 239                 return -EINVAL;
 240
 241         bat->psy = devm_power_supply_register_no_ws(&pdev->dev,
 242                                                     &a500_battery_desc,
 243                                                     &psy_cfg);
 244         if (IS_ERR(bat->psy))
 245                 return dev_err_probe(&pdev->dev, PTR_ERR(bat->psy),
 246                                      "failed to register battery\n");
 247
 248         INIT_DELAYED_WORK(&bat->poll_work, a500_battery_poll_work);
 249         schedule_delayed_work(&bat->poll_work, HZ);
 250
 251         return 0;
 252 }
 253
 254 static int a500_battery_remove(struct platform_device *pdev)
 255 {
 256         struct a500_battery *bat = dev_get_drvdata(&pdev->dev);
 257
 258         cancel_delayed_work_sync(&bat->poll_work);
 259
 260         return 0;
 261 }
 262
 263 static int __maybe_unused a500_battery_suspend(struct device *dev)
 264 {
 265         struct a500_battery *bat = dev_get_drvdata(dev);
 266
 267         cancel_delayed_work_sync(&bat->poll_work);
 268
 269         return 0;
 270 }
 271
 272 static int __maybe_unused a500_battery_resume(struct device *dev)
 273 {
 274         struct a500_battery *bat = dev_get_drvdata(dev);
 275
 276         schedule_delayed_work(&bat->poll_work, HZ);
 277
 278         return 0;
 279 }
 280
 281 static SIMPLE_DEV_PM_OPS(a500_battery_pm_ops,
 282                          a500_battery_suspend, a500_battery_resume);
 283
 284 static struct platform_driver a500_battery_driver = {
 285         .driver = {
 286                 .name = "acer-a500-iconia-battery",
 287                 .pm = &a500_battery_pm_ops,
 288         },
 289         .probe = a500_battery_probe,
 290         .remove = a500_battery_remove,
 291 };
 292 module_platform_driver(a500_battery_driver);
 293
 294 MODULE_DESCRIPTION("Battery gauge driver for Acer Iconia Tab A500");
 295 MODULE_AUTHOR("Dmitry Osipenko <digetx@gmail.com>");
 296 MODULE_ALIAS("platform:acer-a500-iconia-battery");
 297 MODULE_LICENSE("GPL");