drivers/power/supply/sbs-charger.c

   1 /*
   2  * Copyright (c) 2016, Prodys S.L.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This adds support for sbs-charger compilant chips as defined here:
  10  * http://sbs-forum.org/specs/sbc110.pdf
  11  *
  12  * Implemetation based on sbs-battery.c
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/module.h>
  17 #include <linux/kernel.h>
  18 #include <linux/err.h>
  19 #include <linux/power_supply.h>
  20 #include <linux/i2c.h>
  21 #include <linux/slab.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/gpio.h>
  24 #include <linux/regmap.h>
  25 #include <linux/of_gpio.h>
  26 #include <linux/bitops.h>
  27
  28 #define SBS_CHARGER_REG_SPEC_INFO               0x11
  29 #define SBS_CHARGER_REG_STATUS                  0x13
  30 #define SBS_CHARGER_REG_ALARM_WARNING           0x16
  31
  32 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED     BIT(1)
  33 #define SBS_CHARGER_STATUS_RES_COLD             BIT(9)
  34 #define SBS_CHARGER_STATUS_RES_HOT              BIT(10)
  35 #define SBS_CHARGER_STATUS_BATTERY_PRESENT      BIT(14)
  36 #define SBS_CHARGER_STATUS_AC_PRESENT           BIT(15)
  37
  38 #define SBS_CHARGER_POLL_TIME                   500
  39
  40 struct sbs_info {
  41         struct i2c_client               *client;
  42         struct power_supply             *power_supply;
  43         struct regmap                   *regmap;
  44         struct delayed_work             work;
  45         unsigned int                    last_state;
  46 };
  47
  48 static int sbs_get_property(struct power_supply *psy,
  49                             enum power_supply_property psp,
  50                             union power_supply_propval *val)
  51 {
  52         struct sbs_info *chip = power_supply_get_drvdata(psy);
  53         unsigned int reg;
  54
  55         reg = chip->last_state;
  56
  57         switch (psp) {
  58         case POWER_SUPPLY_PROP_PRESENT:
  59                 val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
  60                 break;
  61
  62         case POWER_SUPPLY_PROP_ONLINE:
  63                 val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
  64                 break;
  65
  66         case POWER_SUPPLY_PROP_STATUS:
  67                 val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
  68
  69                 if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
  70                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
  71                 else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
  72                          !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
  73                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  74                 else
  75                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  76
  77                 break;
  78
  79         case POWER_SUPPLY_PROP_HEALTH:
  80                 if (reg & SBS_CHARGER_STATUS_RES_COLD)
  81                         val->intval = POWER_SUPPLY_HEALTH_COLD;
  82                 if (reg & SBS_CHARGER_STATUS_RES_HOT)
  83                         val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
  84                 else
  85                         val->intval = POWER_SUPPLY_HEALTH_GOOD;
  86
  87                 break;
  88
  89         default:
  90                 return -EINVAL;
  91         }
  92
  93         return 0;
  94 }
  95
  96 static int sbs_check_state(struct sbs_info *chip)
  97 {
  98         unsigned int reg;
  99         int ret;
 100
 101         ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &reg);
 102         if (!ret && reg != chip->last_state) {
 103                 chip->last_state = reg;
 104                 power_supply_changed(chip->power_supply);
 105                 return 1;
 106         }
 107
 108         return 0;
 109 }
 110
 111 static void sbs_delayed_work(struct work_struct *work)
 112 {
 113         struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
 114
 115         sbs_check_state(chip);
 116
 117         schedule_delayed_work(&chip->work,
 118                               msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 119 }
 120
 121 static irqreturn_t sbs_irq_thread(int irq, void *data)
 122 {
 123         struct sbs_info *chip = data;
 124         int ret;
 125
 126         ret = sbs_check_state(chip);
 127
 128         return ret ? IRQ_HANDLED : IRQ_NONE;
 129 }
 130
 131 static enum power_supply_property sbs_properties[] = {
 132         POWER_SUPPLY_PROP_STATUS,
 133         POWER_SUPPLY_PROP_PRESENT,
 134         POWER_SUPPLY_PROP_ONLINE,
 135         POWER_SUPPLY_PROP_HEALTH,
 136 };
 137
 138 static bool sbs_readable_reg(struct device *dev, unsigned int reg)
 139 {
 140         return reg >= SBS_CHARGER_REG_SPEC_INFO;
 141 }
 142
 143 static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
 144 {
 145         switch (reg) {
 146         case SBS_CHARGER_REG_STATUS:
 147                 return true;
 148         }
 149
 150         return false;
 151 }
 152
 153 static const struct regmap_config sbs_regmap = {
 154         .reg_bits       = 8,
 155         .val_bits       = 16,
 156         .max_register   = SBS_CHARGER_REG_ALARM_WARNING,
 157         .readable_reg   = sbs_readable_reg,
 158         .volatile_reg   = sbs_volatile_reg,
 159         .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
 160 };
 161
 162 static const struct power_supply_desc sbs_desc = {
 163         .name = "sbs-charger",
 164         .type = POWER_SUPPLY_TYPE_MAINS,
 165         .properties = sbs_properties,
 166         .num_properties = ARRAY_SIZE(sbs_properties),
 167         .get_property = sbs_get_property,
 168 };
 169
 170 static int sbs_probe(struct i2c_client *client,
 171                      const struct i2c_device_id *id)
 172 {
 173         struct power_supply_config psy_cfg = {};
 174         struct sbs_info *chip;
 175         int ret, val;
 176
 177         chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
 178         if (!chip)
 179                 return -ENOMEM;
 180
 181         chip->client = client;
 182         psy_cfg.of_node = client->dev.of_node;
 183         psy_cfg.drv_data = chip;
 184
 185         i2c_set_clientdata(client, chip);
 186
 187         chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
 188         if (IS_ERR(chip->regmap))
 189                 return PTR_ERR(chip->regmap);
 190
 191         /*
 192          * Before we register, we need to make sure we can actually talk
 193          * to the battery.
 194          */
 195         ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
 196         if (ret) {
 197                 dev_err(&client->dev, "Failed to get device status\n");
 198                 return ret;
 199         }
 200         chip->last_state = val;
 201
 202         chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc,
 203                                                         &psy_cfg);
 204         if (IS_ERR(chip->power_supply)) {
 205                 dev_err(&client->dev, "Failed to register power supply\n");
 206                 return PTR_ERR(chip->power_supply);
 207         }
 208
 209         /*
 210          * The sbs-charger spec doesn't impose the use of an interrupt. So in
 211          * the case it wasn't provided we use polling in order get the charger's
 212          * status.
 213          */
 214         if (client->irq) {
 215                 ret = devm_request_threaded_irq(&client->dev, client->irq,
 216                                         NULL, sbs_irq_thread,
 217                                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 218                                         dev_name(&client->dev), chip);
 219                 if (ret) {
 220                         dev_err(&client->dev, "Failed to request irq, %d\n", ret);
 221                         return ret;
 222                 }
 223         } else {
 224                 INIT_DELAYED_WORK(&chip->work, sbs_delayed_work);
 225                 schedule_delayed_work(&chip->work,
 226                                       msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
 227         }
 228
 229         dev_info(&client->dev,
 230                  "%s: smart charger device registered\n", client->name);
 231
 232         return 0;
 233 }
 234
 235 static int sbs_remove(struct i2c_client *client)
 236 {
 237         struct sbs_info *chip = i2c_get_clientdata(client);
 238
 239         cancel_delayed_work_sync(&chip->work);
 240
 241         return 0;
 242 }
 243
 244 #ifdef CONFIG_OF
 245 static const struct of_device_id sbs_dt_ids[] = {
 246         { .compatible = "sbs,sbs-charger" },
 247         { },
 248 };
 249 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
 250 #endif
 251
 252 static const struct i2c_device_id sbs_id[] = {
 253         { "sbs-charger", 0 },
 254         { }
 255 };
 256 MODULE_DEVICE_TABLE(i2c, sbs_id);
 257
 258 static struct i2c_driver sbs_driver = {
 259         .probe          = sbs_probe,
 260         .remove         = sbs_remove,
 261         .id_table       = sbs_id,
 262         .driver = {
 263                 .name   = "sbs-charger",
 264                 .of_match_table = of_match_ptr(sbs_dt_ids),
 265         },
 266 };
 267 module_i2c_driver(sbs_driver);
 268
 269 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
 270 MODULE_DESCRIPTION("SBS smart charger driver");
 271 MODULE_LICENSE("GPL v2");