drivers/power/supply/sbs-manager.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for SBS compliant Smart Battery System Managers
   4  *
   5  * The device communicates via i2c at address 0x0a and multiplexes access to up
   6  * to four smart batteries at address 0x0b.
   7  *
   8  * Via sysfs interface the online state and charge type are presented.
   9  *
  10  * Datasheet SBSM:    http://sbs-forum.org/specs/sbsm100b.pdf
  11  * Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf
  12  *
  13  * Karl-Heinz Schneider <karl-heinz@schneider-inet.de>
  14  */
  15
  16 #include <linux/gpio.h>
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/i2c-mux.h>
  20 #include <linux/power_supply.h>
  21 #include <linux/property.h>
  22
  23 #define SBSM_MAX_BATS  4
  24 #define SBSM_RETRY_CNT 3
  25
  26 /* registers addresses */
  27 #define SBSM_CMD_BATSYSSTATE     0x01
  28 #define SBSM_CMD_BATSYSSTATECONT 0x02
  29 #define SBSM_CMD_BATSYSINFO      0x04
  30 #define SBSM_CMD_LTC             0x3c
  31
  32 #define SBSM_MASK_BAT_SUPPORTED  GENMASK(3, 0)
  33 #define SBSM_MASK_CHARGE_BAT     GENMASK(7, 4)
  34 #define SBSM_BIT_AC_PRESENT      BIT(0)
  35 #define SBSM_BIT_TURBO           BIT(7)
  36
  37 #define SBSM_SMB_BAT_OFFSET      11
  38 struct sbsm_data {
  39         struct i2c_client *client;
  40         struct i2c_mux_core *muxc;
  41
  42         struct power_supply *psy;
  43
  44         u8 cur_chan;          /* currently selected channel */
  45         struct gpio_chip chip;
  46         bool is_ltc1760;      /* special capabilities */
  47
  48         unsigned int supported_bats;
  49         unsigned int last_state;
  50         unsigned int last_state_cont;
  51 };
  52
  53 static enum power_supply_property sbsm_props[] = {
  54         POWER_SUPPLY_PROP_ONLINE,
  55         POWER_SUPPLY_PROP_CHARGE_TYPE,
  56 };
  57
  58 static int sbsm_read_word(struct i2c_client *client, u8 address)
  59 {
  60         int reg, retries;
  61
  62         for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
  63                 reg = i2c_smbus_read_word_data(client, address);
  64                 if (reg >= 0)
  65                         break;
  66         }
  67
  68         if (reg < 0) {
  69                 dev_err(&client->dev, "failed to read register 0x%02x\n",
  70                         address);
  71         }
  72
  73         return reg;
  74 }
  75
  76 static int sbsm_write_word(struct i2c_client *client, u8 address, u16 word)
  77 {
  78         int ret, retries;
  79
  80         for (retries = SBSM_RETRY_CNT; retries > 0; retries--) {
  81                 ret = i2c_smbus_write_word_data(client, address, word);
  82                 if (ret >= 0)
  83                         break;
  84         }
  85         if (ret < 0)
  86                 dev_err(&client->dev, "failed to write to register 0x%02x\n",
  87                         address);
  88
  89         return ret;
  90 }
  91
  92 static int sbsm_get_property(struct power_supply *psy,
  93                              enum power_supply_property psp,
  94                              union power_supply_propval *val)
  95 {
  96         struct sbsm_data *data = power_supply_get_drvdata(psy);
  97         int regval = 0;
  98
  99         switch (psp) {
 100         case POWER_SUPPLY_PROP_ONLINE:
 101                 regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATECONT);
 102                 if (regval < 0)
 103                         return regval;
 104                 val->intval = !!(regval & SBSM_BIT_AC_PRESENT);
 105                 break;
 106
 107         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 108                 regval = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
 109                 if (regval < 0)
 110                         return regval;
 111
 112                 if ((regval & SBSM_MASK_CHARGE_BAT) == 0) {
 113                         val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
 114                         return 0;
 115                 }
 116                 val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
 117
 118                 if (data->is_ltc1760) {
 119                         /* charge mode fast if turbo is active */
 120                         regval = sbsm_read_word(data->client, SBSM_CMD_LTC);
 121                         if (regval < 0)
 122                                 return regval;
 123                         else if (regval & SBSM_BIT_TURBO)
 124                                 val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
 125                 }
 126                 break;
 127
 128         default:
 129                 return -EINVAL;
 130         }
 131
 132         return 0;
 133 }
 134
 135 static int sbsm_prop_is_writeable(struct power_supply *psy,
 136                                   enum power_supply_property psp)
 137 {
 138         struct sbsm_data *data = power_supply_get_drvdata(psy);
 139
 140         return (psp == POWER_SUPPLY_PROP_CHARGE_TYPE) && data->is_ltc1760;
 141 }
 142
 143 static int sbsm_set_property(struct power_supply *psy,
 144                              enum power_supply_property psp,
 145                              const union power_supply_propval *val)
 146 {
 147         struct sbsm_data *data = power_supply_get_drvdata(psy);
 148         int ret = -EINVAL;
 149         u16 regval;
 150
 151         switch (psp) {
 152         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 153                 /* write 1 to TURBO if type fast is given */
 154                 if (!data->is_ltc1760)
 155                         break;
 156                 regval = val->intval ==
 157                          POWER_SUPPLY_CHARGE_TYPE_FAST ? SBSM_BIT_TURBO : 0;
 158                 ret = sbsm_write_word(data->client, SBSM_CMD_LTC, regval);
 159                 break;
 160
 161         default:
 162                 break;
 163         }
 164
 165         return ret;
 166 }
 167
 168 /*
 169  * Switch to battery
 170  * Parameter chan is directly the content of SMB_BAT* nibble
 171  */
 172 static int sbsm_select(struct i2c_mux_core *muxc, u32 chan)
 173 {
 174         struct sbsm_data *data = i2c_mux_priv(muxc);
 175         struct device *dev = &data->client->dev;
 176         int ret = 0;
 177         u16 reg;
 178
 179         if (data->cur_chan == chan)
 180                 return ret;
 181
 182         /* chan goes from 1 ... 4 */
 183         reg = BIT(SBSM_SMB_BAT_OFFSET + chan);
 184         ret = sbsm_write_word(data->client, SBSM_CMD_BATSYSSTATE, reg);
 185         if (ret)
 186                 dev_err(dev, "Failed to select channel %i\n", chan);
 187         else
 188                 data->cur_chan = chan;
 189
 190         return ret;
 191 }
 192
 193 static int sbsm_gpio_get_value(struct gpio_chip *gc, unsigned int off)
 194 {
 195         struct sbsm_data *data = gpiochip_get_data(gc);
 196         int ret;
 197
 198         ret = sbsm_read_word(data->client, SBSM_CMD_BATSYSSTATE);
 199         if (ret < 0)
 200                 return ret;
 201
 202         return ret & BIT(off);
 203 }
 204
 205 /*
 206  * This needs to be defined or the GPIO lib fails to register the pin.
 207  * But the 'gpio' is always an input.
 208  */
 209 static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
 210 {
 211         return 0;
 212 }
 213
 214 static int sbsm_do_alert(struct device *dev, void *d)
 215 {
 216         struct i2c_client *client = i2c_verify_client(dev);
 217         struct i2c_driver *driver;
 218
 219         if (!client || client->addr != 0x0b)
 220                 return 0;
 221
 222         device_lock(dev);
 223         if (client->dev.driver) {
 224                 driver = to_i2c_driver(client->dev.driver);
 225                 if (driver->alert)
 226                         driver->alert(client, I2C_PROTOCOL_SMBUS_ALERT, 0);
 227                 else
 228                         dev_warn(&client->dev, "no driver alert()!\n");
 229         } else {
 230                 dev_dbg(&client->dev, "alert with no driver\n");
 231         }
 232         device_unlock(dev);
 233
 234         return -EBUSY;
 235 }
 236
 237 static void sbsm_alert(struct i2c_client *client, enum i2c_alert_protocol prot,
 238                        unsigned int d)
 239 {
 240         struct sbsm_data *sbsm = i2c_get_clientdata(client);
 241
 242         int ret, i, irq_bat = 0, state = 0;
 243
 244         ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATE);
 245         if (ret >= 0) {
 246                 irq_bat = ret ^ sbsm->last_state;
 247                 sbsm->last_state = ret;
 248                 state = ret;
 249         }
 250
 251         ret = sbsm_read_word(sbsm->client, SBSM_CMD_BATSYSSTATECONT);
 252         if ((ret >= 0) &&
 253             ((ret ^ sbsm->last_state_cont) & SBSM_BIT_AC_PRESENT)) {
 254                 irq_bat |= sbsm->supported_bats & state;
 255                 power_supply_changed(sbsm->psy);
 256         }
 257         sbsm->last_state_cont = ret;
 258
 259         for (i = 0; i < SBSM_MAX_BATS; i++) {
 260                 if (irq_bat & BIT(i)) {
 261                         device_for_each_child(&sbsm->muxc->adapter[i]->dev,
 262                                               NULL, sbsm_do_alert);
 263                 }
 264         }
 265 }
 266
 267 static int sbsm_gpio_setup(struct sbsm_data *data)
 268 {
 269         struct gpio_chip *gc = &data->chip;
 270         struct i2c_client *client = data->client;
 271         struct device *dev = &client->dev;
 272         int ret;
 273
 274         if (!device_property_present(dev, "gpio-controller"))
 275                 return 0;
 276
 277         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATE);
 278         if (ret < 0)
 279                 return ret;
 280         data->last_state = ret;
 281
 282         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSSTATECONT);
 283         if (ret < 0)
 284                 return ret;
 285         data->last_state_cont = ret;
 286
 287         gc->get = sbsm_gpio_get_value;
 288         gc->direction_input  = sbsm_gpio_direction_input;
 289         gc->can_sleep = true;
 290         gc->base = -1;
 291         gc->ngpio = SBSM_MAX_BATS;
 292         gc->label = client->name;
 293         gc->parent = dev;
 294         gc->owner = THIS_MODULE;
 295
 296         ret = devm_gpiochip_add_data(dev, gc, data);
 297         if (ret) {
 298                 dev_err(dev, "devm_gpiochip_add_data failed: %d\n", ret);
 299                 return ret;
 300         }
 301
 302         return ret;
 303 }
 304
 305 static const struct power_supply_desc sbsm_default_psy_desc = {
 306         .type = POWER_SUPPLY_TYPE_MAINS,
 307         .properties = sbsm_props,
 308         .num_properties = ARRAY_SIZE(sbsm_props),
 309         .get_property = &sbsm_get_property,
 310         .set_property = &sbsm_set_property,
 311         .property_is_writeable = &sbsm_prop_is_writeable,
 312 };
 313
 314 static int sbsm_probe(struct i2c_client *client,
 315                       const struct i2c_device_id *id)
 316 {
 317         struct i2c_adapter *adapter = client->adapter;
 318         struct sbsm_data *data;
 319         struct device *dev = &client->dev;
 320         struct power_supply_desc *psy_desc;
 321         struct power_supply_config psy_cfg = {};
 322         int ret = 0, i;
 323
 324         /* Device listens only at address 0x0a */
 325         if (client->addr != 0x0a)
 326                 return -EINVAL;
 327
 328         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
 329                 return -EPFNOSUPPORT;
 330
 331         data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 332         if (!data)
 333                 return -ENOMEM;
 334
 335         i2c_set_clientdata(client, data);
 336
 337         data->client = client;
 338         data->is_ltc1760 = !!strstr(id->name, "ltc1760");
 339
 340         ret  = sbsm_read_word(client, SBSM_CMD_BATSYSINFO);
 341         if (ret < 0)
 342                 return ret;
 343         data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED;
 344         data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0,
 345                                    I2C_MUX_LOCKED, &sbsm_select, NULL);
 346         if (!data->muxc) {
 347                 dev_err(dev, "failed to alloc i2c mux\n");
 348                 ret = -ENOMEM;
 349                 goto err_mux_alloc;
 350         }
 351         data->muxc->priv = data;
 352
 353         /* register muxed i2c channels. One for each supported battery */
 354         for (i = 0; i < SBSM_MAX_BATS; ++i) {
 355                 if (data->supported_bats & BIT(i)) {
 356                         ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0);
 357                         if (ret)
 358                                 break;
 359                 }
 360         }
 361         if (ret) {
 362                 dev_err(dev, "failed to register i2c mux channel %d\n", i + 1);
 363                 goto err_mux_register;
 364         }
 365
 366         psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc,
 367                                 sizeof(struct power_supply_desc),
 368                                 GFP_KERNEL);
 369         if (!psy_desc) {
 370                 ret = -ENOMEM;
 371                 goto err_psy;
 372         }
 373
 374         psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s",
 375                                         dev_name(&client->dev));
 376         if (!psy_desc->name) {
 377                 ret = -ENOMEM;
 378                 goto err_psy;
 379         }
 380         ret = sbsm_gpio_setup(data);
 381         if (ret < 0)
 382                 goto err_psy;
 383
 384         psy_cfg.drv_data = data;
 385         psy_cfg.of_node = dev->of_node;
 386         data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg);
 387         if (IS_ERR(data->psy)) {
 388                 ret = PTR_ERR(data->psy);
 389                 dev_err(dev, "failed to register power supply %s\n",
 390                         psy_desc->name);
 391                 goto err_psy;
 392         }
 393
 394         return 0;
 395
 396 err_psy:
 397 err_mux_register:
 398         i2c_mux_del_adapters(data->muxc);
 399
 400 err_mux_alloc:
 401         return ret;
 402 }
 403
 404 static int sbsm_remove(struct i2c_client *client)
 405 {
 406         struct sbsm_data *data = i2c_get_clientdata(client);
 407
 408         i2c_mux_del_adapters(data->muxc);
 409         return 0;
 410 }
 411
 412 static const struct i2c_device_id sbsm_ids[] = {
 413         { "sbs-manager", 0 },
 414         { "ltc1760",     0 },
 415         { }
 416 };
 417 MODULE_DEVICE_TABLE(i2c, sbsm_ids);
 418
 419 #ifdef CONFIG_OF
 420 static const struct of_device_id sbsm_dt_ids[] = {
 421         { .compatible = "sbs,sbs-manager" },
 422         { .compatible = "lltc,ltc1760" },
 423         { }
 424 };
 425 MODULE_DEVICE_TABLE(of, sbsm_dt_ids);
 426 #endif
 427
 428 static struct i2c_driver sbsm_driver = {
 429         .driver = {
 430                 .name = "sbsm",
 431                 .of_match_table = of_match_ptr(sbsm_dt_ids),
 432         },
 433         .probe          = sbsm_probe,
 434         .remove         = sbsm_remove,
 435         .alert          = sbsm_alert,
 436         .id_table       = sbsm_ids
 437 };
 438 module_i2c_driver(sbsm_driver);
 439
 440 MODULE_LICENSE("GPL");
 441 MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");
 442 MODULE_DESCRIPTION("SBSM Smart Battery System Manager");