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
  22 #define SBS_CHARGER_REG_SPEC_INFO               0x11
  23 #define SBS_CHARGER_REG_STATUS                  0x13
  24 #define SBS_CHARGER_REG_ALARM_WARNING           0x16
  25
  26 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED     BIT(1)
  27 #define SBS_CHARGER_STATUS_RES_COLD             BIT(9)
  28 #define SBS_CHARGER_STATUS_RES_HOT              BIT(10)
  29 #define SBS_CHARGER_STATUS_BATTERY_PRESENT      BIT(14)
  30 #define SBS_CHARGER_STATUS_AC_PRESENT           BIT(15)
  31
  32 #define SBS_CHARGER_POLL_TIME                   500
  33
  34 struct sbs_info {
  35         struct i2c_client               *client;
  36         struct power_supply             *power_supply;
  37         struct regmap                   *regmap;
  38         struct delayed_work             work;
  39         unsigned int                    last_state;
  40 };
  41
  42 static int sbs_get_property(struct power_supply *psy,
  43                             enum power_supply_property psp,
  44                             union power_supply_propval *val)
  45 {
  46         struct sbs_info *chip = power_supply_get_drvdata(psy);
  47         unsigned int reg;
  48
  49         reg = chip->last_state;
  50
  51         switch (psp) {
  52         case POWER_SUPPLY_PROP_PRESENT:
  53                 val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
  54                 break;
  55
  56         case POWER_SUPPLY_PROP_ONLINE:
  57                 val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
  58                 break;
  59
  60         case POWER_SUPPLY_PROP_STATUS:
  61                 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
  62
  63                 if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
  64                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  65                 else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
  66                          !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
  67                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  68                 else
  69                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  70
  71                 break;
  72
  73         case POWER_SUPPLY_PROP_HEALTH:
  74                 if (reg & SBS_CHARGER_STATUS_RES_COLD)
  75                         val->intval = POWER_SUPPLY_HEALTH_COLD;
  76                 if (reg & SBS_CHARGER_STATUS_RES_HOT)
  77                         val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  78                 else
  79                         val->intval = POWER_SUPPLY_HEALTH_GOOD;
  80
  81                 break;
  82
  83         default:
  84                 return -EINVAL;
  85         }
  86
  87         return 0;
  88 }
  89
  90 static int sbs_check_state(struct sbs_info *chip)
  91 {
  92         unsigned int reg;
  93         int ret;
  94
  95         ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &reg);
  96         if (!ret && reg != chip->last_state) {
  97                 chip->last_state = reg;
  98                 power_supply_changed(chip->power_supply);
  99                 return 1;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static void sbs_delayed_work(struct work_struct *work)
 106 {
 107         struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
 108
 109         sbs_check_state(chip);
 110
 111         schedule_delayed_work(&chip->work,
 112                               msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 113 }
 114
 115 static irqreturn_t sbs_irq_thread(int irq, void *data)
 116 {
 117         struct sbs_info *chip = data;
 118         int ret;
 119
 120         ret = sbs_check_state(chip);
 121
 122         return ret ? IRQ_HANDLED : IRQ_NONE;
 123 }
 124
 125 static enum power_supply_property sbs_properties[] = {
 126         POWER_SUPPLY_PROP_STATUS,
 127         POWER_SUPPLY_PROP_PRESENT,
 128         POWER_SUPPLY_PROP_ONLINE,
 129         POWER_SUPPLY_PROP_HEALTH,
 130 };
 131
 132 static bool sbs_readable_reg(struct device *dev, unsigned int reg)
 133 {
 134         return reg >= SBS_CHARGER_REG_SPEC_INFO;
 135 }
 136
 137 static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
 138 {
 139         switch (reg) {
 140         case SBS_CHARGER_REG_STATUS:
 141                 return true;
 142         }
 143
 144         return false;
 145 }
 146
 147 static const struct regmap_config sbs_regmap = {
 148         .reg_bits       = 8,
 149         .val_bits       = 16,
 150         .max_register   = SBS_CHARGER_REG_ALARM_WARNING,
 151         .readable_reg   = sbs_readable_reg,
 152         .volatile_reg   = sbs_volatile_reg,
 153         .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
 154 };
 155
 156 static const struct power_supply_desc sbs_desc = {
 157         .name = "sbs-charger",
 158         .type = POWER_SUPPLY_TYPE_MAINS,
 159         .properties = sbs_properties,
 160         .num_properties = ARRAY_SIZE(sbs_properties),
 161         .get_property = sbs_get_property,
 162 };
 163
 164 static int sbs_probe(struct i2c_client *client,
 165                      const struct i2c_device_id *id)
 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                 INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
 213                 schedule_delayed_work(&chip->work,
 214                                       msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 215         }
 216
 217         dev_info(&client->dev,
 218                  "%s: smart charger device registered\n", client->name);
 219
 220         return 0;
 221 }
 222
 223 static int sbs_remove(struct i2c_client *client)
 224 {
 225         struct sbs_info *chip = i2c_get_clientdata(client);
 226
 227         cancel_delayed_work_sync(&chip->work);
 228
 229         return 0;
 230 }
 231
 232 #ifdef CONFIG_OF
 233 static const struct of_device_id sbs_dt_ids[] = {
 234         { .compatible = "sbs,sbs-charger" },
 235         { },
 236 };
 237 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
 238 #endif
 239
 240 static const struct i2c_device_id sbs_id[] = {
 241         { "sbs-charger", 0 },
 242         { }
 243 };
 244 MODULE_DEVICE_TABLE(i2c, sbs_id);
 245
 246 static struct i2c_driver sbs_driver = {
 247         .probe          = sbs_probe,
 248         .remove         = sbs_remove,
 249         .id_table       = sbs_id,
 250         .driver = {
 251                 .name   = "sbs-charger",
 252                 .of_match_table = of_match_ptr(sbs_dt_ids),
 253         },
 254 };
 255 module_i2c_driver(sbs_driver);
 256
 257 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
 258 MODULE_DESCRIPTION("SBS smart charger driver");
 259 MODULE_LICENSE("GPL v2");