power/supply/sbs-manager.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Driver for SBS compliant Smart Battery System Managers
0004  *
0005  * The device communicates via i2c at address 0x0a and multiplexes access to up
0006  * to four smart batteries at address 0x0b.
0007  *
0008  * Via sysfs interface the online state and charge type are presented.
0009  *
0010  * Datasheet SBSM:    http://sbs-forum.org/specs/sbsm100b.pdf
0011  * Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf
0012  *
0013  * Karl-Heinz Schneider <karl-heinz@schneider-inet.de>
0014  */
0015
0016 #include <linux/gpio/driver.h>
0017 #include <linux/module.h>
0018 #include <linux/i2c.h>
0019 #include <linux/i2c-mux.h>
0020 #include <linux/power_supply.h>
0021 #include <linux/property.h>
0022
0023 #define SBSM_MAX_BATS  4
0024 #define SBSM_RETRY_CNT 3
0025
0026 /* registers addresses */
0027 #define SBSM_CMD_BATSYSSTATE     0x01
0028 #define SBSM_CMD_BATSYSSTATECONT 0x02
0029 #define SBSM_CMD_BATSYSINFO      0x04
0030 #define SBSM_CMD_LTC             0x3c
0031
0032 #define SBSM_MASK_BAT_SUPPORTED  GENMASK(3, 0)
0033 #define SBSM_MASK_CHARGE_BAT     GENMASK(7, 4)
0034 #define SBSM_BIT_AC_PRESENT      BIT(0)
0035 #define SBSM_BIT_TURBO           BIT(7)
0036
0037 #define SBSM_SMB_BAT_OFFSET      11
0038 struct sbsm_data {
0039     struct i2c_client *client;
0040     struct i2c_mux_core *muxc;
0041
0042     struct power_supply *psy;
0043
0044     u8 cur_chan;          /* currently selected channel */
0045     struct gpio_chip chip;
0046     bool is_ltc1760;      /* special capabilities */
0047
0048     unsigned int supported_bats;
0049     unsigned int last_state;
0050     unsigned int last_state_cont;
0051 };
0052
0053 static enum power_supply_property sbsm_props[] = {
0054     POWER_SUPPLY_PROP_ONLINE,
0055     POWER_SUPPLY_PROP_CHARGE_TYPE,
0056 };
0057
0058 static int sbsm_read_word(struct i2c_client *client, u8 address)
0059 {
0060     int reg, retries;
0061
0062     for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
0063         reg = i2c_smbus_read_word_data(client, address);
0064         if (reg >= 0)
0065             break;
0066     }
0067
0068     if (reg < 0) {
0069         dev_err(&client->dev, "failed to read register 0x%02x\n",
0070             address);
0071     }
0072
0073     return reg;
0074 }
0075
0076 static int sbsm_write_word(struct i2c_client *client, u8 address, u16 word)
0077 {
0078     int ret, retries;
0079
0080     for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
0081         ret = i2c_smbus_write_word_data(client, address, word);
0082         if (ret >= 0)
0083             break;
0084     }
0085     if (ret < 0)
0086         dev_err(&client->dev, "failed to write to register 0x%02x\n",
0087             address);
0088
0089     return ret;
0090 }
0091
0092 static int sbsm_get_property(struct power_supply *psy,
0093                  enum power_supply_property psp,
0094                  union power_supply_propval *val)
0095 {
0096     struct sbsm_data *data = power_supply_get_drvdata(psy);
0097     int regval = 0;
0098
0099     switch (psp) {
0100     case POWER_SUPPLY_PROP_ONLINE:
0101         regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATECONT);
0102         if (regval < 0)
0103             return regval;
0104         val->intval = !!(regval & SBSM_BIT_AC_PRESENT);
0105         break;
0106
0107     case POWER_SUPPLY_PROP_CHARGE_TYPE:
0108         regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
0109         if (regval < 0)
0110             return regval;
0111
0112         if ((regval & SBSM_MASK_CHARGE_BAT) == 0) {
0113             val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
0114             return 0;
0115         }
0116         val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
0117
0118         if (data->is_ltc1760) {
0119             /* charge mode fast if turbo is active */
0120             regval = sbsm_read_word(data->client, SBSM_CMD_LTC);
0121             if (regval < 0)
0122                 return regval;
0123             else if (regval & SBSM_BIT_TURBO)
0124                 val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
0125         }
0126         break;
0127
0128     default:
0129         return -EINVAL;
0130     }
0131
0132     return 0;
0133 }
0134
0135 static int sbsm_prop_is_writeable(struct power_supply *psy,
0136                   enum power_supply_property psp)
0137 {
0138     struct sbsm_data *data = power_supply_get_drvdata(psy);
0139
0140     return (psp == POWER_SUPPLY_PROP_CHARGE_TYPE) && data->is_ltc1760;
0141 }
0142
0143 static int sbsm_set_property(struct power_supply *psy,
0144                  enum power_supply_property psp,
0145                  const union power_supply_propval *val)
0146 {
0147     struct sbsm_data *data = power_supply_get_drvdata(psy);
0148     int ret = -EINVAL;
0149     u16 regval;
0150
0151     switch (psp) {
0152     case POWER_SUPPLY_PROP_CHARGE_TYPE:
0153         /* write 1 to TURBO if type fast is given */
0154         if (!data->is_ltc1760)
0155             break;
0156         regval = val->intval ==
0157              POWER_SUPPLY_CHARGE_TYPE_FAST ? SBSM_BIT_TURBO : 0;
0158         ret = sbsm_write_word(data->client, SBSM_CMD_LTC, regval);
0159         break;
0160
0161     default:
0162         break;
0163     }
0164
0165     return ret;
0166 }
0167
0168 /*
0169  * Switch to battery
0170  * Parameter chan is directly the content of SMB_BAT* nibble
0171  */
0172 static int sbsm_select(struct i2c_mux_core *muxc, u32 chan)
0173 {
0174     struct sbsm_data *data = i2c_mux_priv(muxc);
0175     struct device *dev = &data->client->dev;
0176     int ret = 0;
0177     u16 reg;
0178
0179     if (data->cur_chan == chan)
0180         return ret;
0181
0182     /* chan goes from 1 ... 4 */
0183     reg = BIT(SBSM_SMB_BAT_OFFSET + chan);
0184     ret = sbsm_write_word(data->client, SBSM_CMD_BATSYSSTATE, reg);
0185     if (ret)
0186         dev_err(dev, "Failed to select channel %i\n", chan);
0187     else
0188         data->cur_chan = chan;
0189
0190     return ret;
0191 }
0192
0193 static int sbsm_gpio_get_value(struct gpio_chip *gc, unsigned int off)
0194 {
0195     struct sbsm_data *data = gpiochip_get_data(gc);
0196     int ret;
0197
0198     ret = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
0199     if (ret < 0)
0200         return ret;
0201
0202     return ret & BIT(off);
0203 }
0204
0205 /*
0206  * This needs to be defined or the GPIO lib fails to register the pin.
0207  * But the 'gpio' is always an input.
0208  */
0209 static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
0210 {
0211     return 0;
0212 }
0213
0214 static int sbsm_do_alert(struct device *dev, void *d)
0215 {
0216     struct i2c_client *client = i2c_verify_client(dev);
0217     struct i2c_driver *driver;
0218
0219     if (!client || client->addr != 0x0b)
0220         return 0;
0221
0222     device_lock(dev);
0223     if (client->dev.driver) {
0224         driver = to_i2c_driver(client->dev.driver);
0225         if (driver->alert)
0226             driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, 0);
0227         else
0228             dev_warn(&client->dev, "no driver alert()!\n");
0229     } else {
0230         dev_dbg(&client->dev, "alert with no driver\n");
0231     }
0232     device_unlock(dev);
0233
0234     return -EBUSY;
0235 }
0236
0237 static void sbsm_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
0238                unsigned int d)
0239 {
0240     struct sbsm_data *sbsm = i2c_get_clientdata(client);
0241
0242     int ret, i, irq_bat = 0, state = 0;
0243
0244     ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATE);
0245     if (ret >= 0) {
0246         irq_bat = ret ^ sbsm->last_state;
0247         sbsm->last_state = ret;
0248         state = ret;
0249     }
0250
0251     ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATECONT);
0252     if ((ret >= 0) &&
0253         ((ret ^ sbsm->last_state_cont) & SBSM_BIT_AC_PRESENT)) {
0254         irq_bat |= sbsm->supported_bats & state;
0255         power_supply_changed(sbsm->psy);
0256     }
0257     sbsm->last_state_cont = ret;
0258
0259     for (i = 0; i < SBSM_MAX_BATS; i++) {
0260         if (irq_bat & BIT(i)) {
0261             device_for_each_child(&sbsm->muxc->adapter[i]->dev,
0262                           NULL, sbsm_do_alert);
0263         }
0264     }
0265 }
0266
0267 static int sbsm_gpio_setup(struct sbsm_data *data)
0268 {
0269     struct gpio_chip *gc = &data->chip;
0270     struct i2c_client *client = data->client;
0271     struct device *dev = &client->dev;
0272     int ret;
0273
0274     if (!device_property_present(dev, "gpio-controller"))
0275         return 0;
0276
0277     ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATE);
0278     if (ret < 0)
0279         return ret;
0280     data->last_state = ret;
0281
0282     ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATECONT);
0283     if (ret < 0)
0284         return ret;
0285     data->last_state_cont = ret;
0286
0287     gc->get = sbsm_gpio_get_value;
0288     gc->direction_input  = sbsm_gpio_direction_input;
0289     gc->can_sleep = true;
0290     gc->base = -1;
0291     gc->ngpio = SBSM_MAX_BATS;
0292     gc->label = client->name;
0293     gc->parent = dev;
0294     gc->owner = THIS_MODULE;
0295
0296     ret = devm_gpiochip_add_data(dev, gc, data);
0297     if (ret)
0298         return dev_err_probe(dev, ret, "devm_gpiochip_add_data failed\n");
0299
0300     return ret;
0301 }
0302
0303 static const struct power_supply_desc sbsm_default_psy_desc = {
0304     .type = POWER_SUPPLY_TYPE_MAINS,
0305     .properties = sbsm_props,
0306     .num_properties = ARRAY_SIZE(sbsm_props),
0307     .get_property = &sbsm_get_property,
0308     .set_property = &sbsm_set_property,
0309     .property_is_writeable = &sbsm_prop_is_writeable,
0310 };
0311
0312 static void sbsm_del_mux_adapter(void *data)
0313 {
0314     struct sbsm_data *sbsm = data;
0315     i2c_mux_del_adapters(sbsm->muxc);
0316 }
0317
0318 static int sbsm_probe(struct i2c_client *client,
0319               const struct i2c_device_id *id)
0320 {
0321     struct i2c_adapter *adapter = client->adapter;
0322     struct sbsm_data *data;
0323     struct device *dev = &client->dev;
0324     struct power_supply_desc *psy_desc;
0325     struct power_supply_config psy_cfg = {};
0326     int ret = 0, i;
0327
0328     /* Device listens only at address 0x0a */
0329     if (client->addr != 0x0a)
0330         return -EINVAL;
0331
0332     if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
0333         return -EPFNOSUPPORT;
0334
0335     data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
0336     if (!data)
0337         return -ENOMEM;
0338
0339     i2c_set_clientdata(client, data);
0340
0341     data->client = client;
0342     data->is_ltc1760 = !!strstr(id->name, "ltc1760");
0343
0344     ret  = sbsm_read_word(client, SBSM_CMD_BATSYSINFO);
0345     if (ret < 0)
0346         return ret;
0347     data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED;
0348     data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0,
0349                    I2C_MUX_LOCKED, &sbsm_select, NULL);
0350     if (!data->muxc)
0351         return dev_err_probe(dev, -ENOMEM, "failed to alloc i2c mux\n");
0352     data->muxc->priv = data;
0353
0354     ret = devm_add_action_or_reset(dev, sbsm_del_mux_adapter, data);
0355     if (ret)
0356         return ret;
0357
0358     /* register muxed i2c channels. One for each supported battery */
0359     for (i = 0; i < SBSM_MAX_BATS; ++i) {
0360         if (data->supported_bats & BIT(i)) {
0361             ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0);
0362             if (ret)
0363                 break;
0364         }
0365     }
0366     if (ret)
0367         return dev_err_probe(dev, ret, "failed to register i2c mux channel %d\n", i + 1);
0368
0369     psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc, sizeof(*psy_desc), GFP_KERNEL);
0370     if (!psy_desc)
0371         return -ENOMEM;
0372
0373     psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s", dev_name(&client->dev));
0374     if (!psy_desc->name)
0375         return -ENOMEM;
0376
0377     ret = sbsm_gpio_setup(data);
0378     if (ret < 0)
0379         return ret;
0380
0381     psy_cfg.drv_data = data;
0382     psy_cfg.of_node = dev->of_node;
0383     data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg);
0384     if (IS_ERR(data->psy))
0385         return dev_err_probe(dev, PTR_ERR(data->psy),
0386                      "failed to register power supply %s\n", psy_desc->name);
0387
0388     return 0;
0389 }
0390
0391 static const struct i2c_device_id sbsm_ids[] = {
0392     { "sbs-manager", 0 },
0393     { "ltc1760",     0 },
0394     { }
0395 };
0396 MODULE_DEVICE_TABLE(i2c, sbsm_ids);
0397
0398 #ifdef CONFIG_OF
0399 static const struct of_device_id sbsm_dt_ids[] = {
0400     { .compatible = "sbs,sbs-manager" },
0401     { .compatible = "lltc,ltc1760" },
0402     { }
0403 };
0404 MODULE_DEVICE_TABLE(of, sbsm_dt_ids);
0405 #endif
0406
0407 static struct i2c_driver sbsm_driver = {
0408     .driver = {
0409         .name = "sbsm",
0410         .of_match_table = of_match_ptr(sbsm_dt_ids),
0411     },
0412     .probe      = sbsm_probe,
0413     .alert      = sbsm_alert,
0414     .id_table   = sbsm_ids
0415 };
0416 module_i2c_driver(sbsm_driver);
0417
0418 MODULE_LICENSE("GPL");
0419 MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");
0420 MODULE_DESCRIPTION("SBSM Smart Battery System Manager");