power/supply/sbs-charger.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright (c) 2016, Prodys S.L.
0004  *
0005  * This adds support for sbs-charger compilant chips as defined here:
0006  * http://sbs-forum.org/specs/sbc110.pdf
0007  *
0008  * Implemetation based on sbs-battery.c
0009  */
0010
0011 #include <linux/init.h>
0012 #include <linux/module.h>
0013 #include <linux/kernel.h>
0014 #include <linux/err.h>
0015 #include <linux/power_supply.h>
0016 #include <linux/i2c.h>
0017 #include <linux/slab.h>
0018 #include <linux/interrupt.h>
0019 #include <linux/regmap.h>
0020 #include <linux/bitops.h>
0021 #include <linux/devm-helpers.h>
0022
0023 #define SBS_CHARGER_REG_SPEC_INFO       0x11
0024 #define SBS_CHARGER_REG_STATUS          0x13
0025 #define SBS_CHARGER_REG_ALARM_WARNING       0x16
0026
0027 #define SBS_CHARGER_STATUS_CHARGE_INHIBITED BIT(1)
0028 #define SBS_CHARGER_STATUS_RES_COLD     BIT(9)
0029 #define SBS_CHARGER_STATUS_RES_HOT      BIT(10)
0030 #define SBS_CHARGER_STATUS_BATTERY_PRESENT  BIT(14)
0031 #define SBS_CHARGER_STATUS_AC_PRESENT       BIT(15)
0032
0033 #define SBS_CHARGER_POLL_TIME           500
0034
0035 struct sbs_info {
0036     struct i2c_client       *client;
0037     struct power_supply     *power_supply;
0038     struct regmap           *regmap;
0039     struct delayed_work     work;
0040     unsigned int            last_state;
0041 };
0042
0043 static int sbs_get_property(struct power_supply *psy,
0044                 enum power_supply_property psp,
0045                 union power_supply_propval *val)
0046 {
0047     struct sbs_info *chip = power_supply_get_drvdata(psy);
0048     unsigned int reg;
0049
0050     reg = chip->last_state;
0051
0052     switch (psp) {
0053     case POWER_SUPPLY_PROP_PRESENT:
0054         val->intval = !!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT);
0055         break;
0056
0057     case POWER_SUPPLY_PROP_ONLINE:
0058         val->intval = !!(reg & SBS_CHARGER_STATUS_AC_PRESENT);
0059         break;
0060
0061     case POWER_SUPPLY_PROP_STATUS:
0062         val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
0063
0064         if (!(reg & SBS_CHARGER_STATUS_BATTERY_PRESENT))
0065             val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
0066         else if (reg & SBS_CHARGER_STATUS_AC_PRESENT &&
0067              !(reg & SBS_CHARGER_STATUS_CHARGE_INHIBITED))
0068             val->intval = POWER_SUPPLY_STATUS_CHARGING;
0069         else
0070             val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
0071
0072         break;
0073
0074     case POWER_SUPPLY_PROP_HEALTH:
0075         if (reg & SBS_CHARGER_STATUS_RES_COLD)
0076             val->intval = POWER_SUPPLY_HEALTH_COLD;
0077         if (reg & SBS_CHARGER_STATUS_RES_HOT)
0078             val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
0079         else
0080             val->intval = POWER_SUPPLY_HEALTH_GOOD;
0081
0082         break;
0083
0084     default:
0085         return -EINVAL;
0086     }
0087
0088     return 0;
0089 }
0090
0091 static int sbs_check_state(struct sbs_info *chip)
0092 {
0093     unsigned int reg;
0094     int ret;
0095
0096     ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &reg);
0097     if (!ret && reg != chip->last_state) {
0098         chip->last_state = reg;
0099         power_supply_changed(chip->power_supply);
0100         return 1;
0101     }
0102
0103     return 0;
0104 }
0105
0106 static void sbs_delayed_work(struct work_struct *work)
0107 {
0108     struct sbs_info *chip = container_of(work, struct sbs_info, work.work);
0109
0110     sbs_check_state(chip);
0111
0112     schedule_delayed_work(&chip->work,
0113                   msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
0114 }
0115
0116 static irqreturn_t sbs_irq_thread(int irq, void *data)
0117 {
0118     struct sbs_info *chip = data;
0119     int ret;
0120
0121     ret = sbs_check_state(chip);
0122
0123     return ret ? IRQ_HANDLED : IRQ_NONE;
0124 }
0125
0126 static enum power_supply_property sbs_properties[] = {
0127     POWER_SUPPLY_PROP_STATUS,
0128     POWER_SUPPLY_PROP_PRESENT,
0129     POWER_SUPPLY_PROP_ONLINE,
0130     POWER_SUPPLY_PROP_HEALTH,
0131 };
0132
0133 static bool sbs_readable_reg(struct device *dev, unsigned int reg)
0134 {
0135     return reg >= SBS_CHARGER_REG_SPEC_INFO;
0136 }
0137
0138 static bool sbs_volatile_reg(struct device *dev, unsigned int reg)
0139 {
0140     switch (reg) {
0141     case SBS_CHARGER_REG_STATUS:
0142         return true;
0143     }
0144
0145     return false;
0146 }
0147
0148 static const struct regmap_config sbs_regmap = {
0149     .reg_bits   = 8,
0150     .val_bits   = 16,
0151     .max_register   = SBS_CHARGER_REG_ALARM_WARNING,
0152     .readable_reg   = sbs_readable_reg,
0153     .volatile_reg   = sbs_volatile_reg,
0154     .val_format_endian = REGMAP_ENDIAN_LITTLE, /* since based on SMBus */
0155 };
0156
0157 static const struct power_supply_desc sbs_desc = {
0158     .name = "sbs-charger",
0159     .type = POWER_SUPPLY_TYPE_MAINS,
0160     .properties = sbs_properties,
0161     .num_properties = ARRAY_SIZE(sbs_properties),
0162     .get_property = sbs_get_property,
0163 };
0164
0165 static int sbs_probe(struct i2c_client *client,
0166              const struct i2c_device_id *id)
0167 {
0168     struct power_supply_config psy_cfg = {};
0169     struct sbs_info *chip;
0170     int ret, val;
0171
0172     chip = devm_kzalloc(&client->dev, sizeof(struct sbs_info), GFP_KERNEL);
0173     if (!chip)
0174         return -ENOMEM;
0175
0176     chip->client = client;
0177     psy_cfg.of_node = client->dev.of_node;
0178     psy_cfg.drv_data = chip;
0179
0180     i2c_set_clientdata(client, chip);
0181
0182     chip->regmap = devm_regmap_init_i2c(client, &sbs_regmap);
0183     if (IS_ERR(chip->regmap))
0184         return PTR_ERR(chip->regmap);
0185
0186     /*
0187      * Before we register, we need to make sure we can actually talk
0188      * to the battery.
0189      */
0190     ret = regmap_read(chip->regmap, SBS_CHARGER_REG_STATUS, &val);
0191     if (ret)
0192         return dev_err_probe(&client->dev, ret, "Failed to get device status\n");
0193     chip->last_state = val;
0194
0195     chip->power_supply = devm_power_supply_register(&client->dev, &sbs_desc, &psy_cfg);
0196     if (IS_ERR(chip->power_supply))
0197         return dev_err_probe(&client->dev, PTR_ERR(chip->power_supply),
0198                      "Failed to register power supply\n");
0199
0200     /*
0201      * The sbs-charger spec doesn't impose the use of an interrupt. So in
0202      * the case it wasn't provided we use polling in order get the charger's
0203      * status.
0204      */
0205     if (client->irq) {
0206         ret = devm_request_threaded_irq(&client->dev, client->irq,
0207                     NULL, sbs_irq_thread,
0208                     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
0209                     dev_name(&client->dev), chip);
0210         if (ret)
0211             return dev_err_probe(&client->dev, ret, "Failed to request irq\n");
0212     } else {
0213         ret = devm_delayed_work_autocancel(&client->dev, &chip->work,
0214                            sbs_delayed_work);
0215         if (ret)
0216             return dev_err_probe(&client->dev, ret,
0217                          "Failed to init work for polling\n");
0218
0219         schedule_delayed_work(&chip->work,
0220                       msecs_to_jiffies(SBS_CHARGER_POLL_TIME));
0221     }
0222
0223     dev_info(&client->dev,
0224          "%s: smart charger device registered\n", client->name);
0225
0226     return 0;
0227 }
0228
0229 #ifdef CONFIG_OF
0230 static const struct of_device_id sbs_dt_ids[] = {
0231     { .compatible = "sbs,sbs-charger" },
0232     { },
0233 };
0234 MODULE_DEVICE_TABLE(of, sbs_dt_ids);
0235 #endif
0236
0237 static const struct i2c_device_id sbs_id[] = {
0238     { "sbs-charger", 0 },
0239     { }
0240 };
0241 MODULE_DEVICE_TABLE(i2c, sbs_id);
0242
0243 static struct i2c_driver sbs_driver = {
0244     .probe      = sbs_probe,
0245     .id_table   = sbs_id,
0246     .driver = {
0247         .name   = "sbs-charger",
0248         .of_match_table = of_match_ptr(sbs_dt_ids),
0249     },
0250 };
0251 module_i2c_driver(sbs_driver);
0252
0253 MODULE_AUTHOR("Nicolas Saenz Julienne <nicolassaenzj@gmail.com>");
0254 MODULE_DESCRIPTION("SBS smart charger driver");
0255 MODULE_LICENSE("GPL v2");