drivers/power/supply/sbs-charger.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (c) 2016, Prodys S.L.
   4  *
   5  * This adds support for sbs-charger compilant chips as defined here:
   6  * http://sbs-forum.org/specs/sbc110.pdf
   7  *
   8  * Implemetation based on sbs-battery.c
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/err.h>
  15 #include <linux/power_supply.h>
  16 #include <linux/i2c.h>
  17 #include <linux/slab.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/regmap.h>
  20 #include <linux/bitops.h>
  21 #include <linux/devm-helpers.h>
  22
  23 #define SBS_CHARGER_REG_SPEC_INFO               0x11
  24 #define SBS_CHARGER_REG_STATUS                  0x13
  25 #define SBS_CHARGER_REG_ALARM_WARNING           0x16
  26
  27 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED     BIT(0)
  28 #define SBS_CHARGER_STATUS_RES_COLD             BIT(9)
  29 #define SBS_CHARGER_STATUS_RES_HOT              BIT(10)
  30 #define SBS_CHARGER_STATUS_BATTERY_PRESENT      BIT(14)
  31 #define SBS_CHARGER_STATUS_AC_PRESENT           BIT(15)
  32
  33 #define SBS_CHARGER_POLL_TIME                   500
  34
  35 struct sbs_info {
  36         struct i2c_client               *client;
  37         struct power_supply             *power_supply;
  38         struct regmap                   *regmap;
  39         struct delayed_work             work;
  40         unsigned int                    last_state;
  41 };
  42
  43 static int sbs_get_property(struct power_supply *psy,
  44                             enum power_supply_property psp,
  45                             union power_supply_propval *val)
  46 {
  47         struct sbs_info *chip = power_supply_get_drvdata(psy);
  48         unsigned int reg;
  49
  50         reg = chip->last_state;
  51
  52         switch (psp) {
  53         case POWER_SUPPLY_PROP_PRESENT:
  54                 val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
  55                 break;
  56
  57         case POWER_SUPPLY_PROP_ONLINE:
  58                 val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
  59                 break;
  60
  61         case POWER_SUPPLY_PROP_STATUS:
  62                 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
  63
  64                 if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
  65                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  66                 else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
  67                          !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
  68                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  69                 else
  70                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  71
  72                 break;
  73
  74         case POWER_SUPPLY_PROP_HEALTH:
  75                 if (reg & SBS_CHARGER_STATUS_RES_COLD)
  76                         val->intval = POWER_SUPPLY_HEALTH_COLD;
  77                 if (reg & SBS_CHARGER_STATUS_RES_HOT)
  78                         val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  79                 else
  80                         val->intval = POWER_SUPPLY_HEALTH_GOOD;
  81
  82                 break;
  83
  84         default:
  85                 return -EINVAL;
  86         }
  87
  88         return 0;
  89 }
  90
  91 static int sbs_check_state(struct sbs_info *chip)
  92 {
  93         unsigned int reg;
  94         int ret;
  95
  96         ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &reg);
  97         if (!ret && reg != chip->last_state) {
  98                 chip->last_state = reg;
  99                 power_supply_changed(chip->power_supply);
 100                 return 1;
 101         }
 102
 103         return 0;
 104 }
 105
 106 static void sbs_delayed_work(struct work_struct *work)
 107 {
 108         struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
 109
 110         sbs_check_state(chip);
 111
 112         schedule_delayed_work(&chip->work,
 113                               msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 114 }
 115
 116 static irqreturn_t sbs_irq_thread(int irq, void *data)
 117 {
 118         struct sbs_info *chip = data;
 119         int ret;
 120
 121         ret = sbs_check_state(chip);
 122
 123         return ret ? IRQ_HANDLED : IRQ_NONE;
 124 }
 125
 126 static enum power_supply_property sbs_properties[] = {
 127         POWER_SUPPLY_PROP_STATUS,
 128         POWER_SUPPLY_PROP_PRESENT,
 129         POWER_SUPPLY_PROP_ONLINE,
 130         POWER_SUPPLY_PROP_HEALTH,
 131 };
 132
 133 static bool sbs_readable_reg(struct device *dev, unsigned int reg)
 134 {
 135         return reg >= SBS_CHARGER_REG_SPEC_INFO;
 136 }
 137
 138 static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
 139 {
 140         switch (reg) {
 141         case SBS_CHARGER_REG_STATUS:
 142                 return true;
 143         }
 144
 145         return false;
 146 }
 147
 148 static const struct regmap_config sbs_regmap = {
 149         .reg_bits       = 8,
 150         .val_bits       = 16,
 151         .max_register   = SBS_CHARGER_REG_ALARM_WARNING,
 152         .readable_reg   = sbs_readable_reg,
 153         .volatile_reg   = sbs_volatile_reg,
 154         .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
 155 };
 156
 157 static const struct power_supply_desc sbs_desc = {
 158         .name = "sbs-charger",
 159         .type = POWER_SUPPLY_TYPE_MAINS,
 160         .properties = sbs_properties,
 161         .num_properties = ARRAY_SIZE(sbs_properties),
 162         .get_property = sbs_get_property,
 163 };
 164
 165 static int sbs_probe(struct i2c_client *client)
 166 {
 167         struct power_supply_config psy_cfg = {};
 168         struct sbs_info *chip;
 169         int ret, val;
 170
 171         chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
 172         if (!chip)
 173                 return -ENOMEM;
 174
 175         chip->client = client;
 176         psy_cfg.of_node = client->dev.of_node;
 177         psy_cfg.drv_data = chip;
 178
 179         i2c_set_clientdata(client, chip);
 180
 181         chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
 182         if (IS_ERR(chip->regmap))
 183                 return PTR_ERR(chip->regmap);
 184
 185         /*
 186          * Before we register, we need to make sure we can actually talk
 187          * to the battery.
 188          */
 189         ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
 190         if (ret)
 191                 return dev_err_probe(&client->dev, ret, "Failed to get device status\n");
 192         chip->last_state = val;
 193
 194         chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc, &psy_cfg);
 195         if (IS_ERR(chip->power_supply))
 196                 return dev_err_probe(&client->dev, PTR_ERR(chip->power_supply),
 197                                      "Failed to register power supply\n");
 198
 199         /*
 200          * The sbs-charger spec doesn't impose the use of an interrupt. So in
 201          * the case it wasn't provided we use polling in order get the charger's
 202          * status.
 203          */
 204         if (client->irq) {
 205                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 206                                         NULL, sbs_irq_thread,
 207                                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 208                                         dev_name(&client->dev), chip);
 209                 if (ret)
 210                         return dev_err_probe(&client->dev, ret, "Failed to request irq\n");
 211         } else {
 212                 ret = devm_delayed_work_autocancel(&client->dev, &chip->work,
 213                                                    sbs_delayed_work);
 214                 if (ret)
 215                         return dev_err_probe(&client->dev, ret,
 216                                              "Failed to init work for polling\n");
 217
 218                 schedule_delayed_work(&chip->work,
 219                                       msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 220         }
 221
 222         dev_info(&client->dev,
 223                  "%s: smart charger device registered\n", client->name);
 224
 225         return 0;
 226 }
 227
 228 #ifdef CONFIG_OF
 229 static const struct of_device_id sbs_dt_ids[] = {
 230         { .compatible = "sbs,sbs-charger" },
 231         { },
 232 };
 233 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
 234 #endif
 235
 236 static const struct i2c_device_id sbs_id[] = {
 237         { "sbs-charger", 0 },
 238         { }
 239 };
 240 MODULE_DEVICE_TABLE(i2c, sbs_id);
 241
 242 static struct i2c_driver sbs_driver = {
 243         .probe          = sbs_probe,
 244         .id_table       = sbs_id,
 245         .driver = {
 246                 .name   = "sbs-charger",
 247                 .of_match_table = of_match_ptr(sbs_dt_ids),
 248         },
 249 };
 250 module_i2c_driver(sbs_driver);
 251
 252 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
 253 MODULE_DESCRIPTION("SBS smart charger driver");
 254 MODULE_LICENSE("GPL v2");