linux/drivers/power/supply/sbs-charger.c
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   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
  40struct 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
  48static 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
  96static 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
 111static 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
 121static 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
 131static 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
 138static bool sbs_readable_reg(struct device *dev, unsigned int reg)
 139{
 140        return reg >= SBS_CHARGER_REG_SPEC_INFO;
 141}
 142
 143static 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
 153static 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
 162static 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
 170static 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
 235static 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
 245static const struct of_device_id sbs_dt_ids[] = {
 246        { .compatible = "sbs,sbs-charger" },
 247        { },
 248};
 249MODULE_DEVICE_TABLE(of, sbs_dt_ids);
 250#endif
 251
 252static const struct i2c_device_id sbs_id[] = {
 253        { "sbs-charger", 0 },
 254        { }
 255};
 256MODULE_DEVICE_TABLE(i2c, sbs_id);
 257
 258static 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};
 267module_i2c_driver(sbs_driver);
 268
 269MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
 270MODULE_DESCRIPTION("SBS smart charger driver");
 271MODULE_LICENSE("GPL v2");
 272