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/driver.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 return dev_err_probe(dev, ret, "devm_gpiochip_add_data failed\n"); 299 300 return ret; 301 } 302 303 static const struct power_supply_desc sbsm_default_psy_desc = { 304 .type = POWER_SUPPLY_TYPE_MAINS, 305 .properties = sbsm_props, 306 .num_properties = ARRAY_SIZE(sbsm_props), 307 .get_property = &sbsm_get_property, 308 .set_property = &sbsm_set_property, 309 .property_is_writeable = &sbsm_prop_is_writeable, 310 }; 311 312 static void sbsm_del_mux_adapter(void *data) 313 { 314 struct sbsm_data *sbsm = data; 315 i2c_mux_del_adapters(sbsm->muxc); 316 } 317 318 static int sbsm_probe(struct i2c_client *client) 319 { 320 const struct i2c_device_id *id = i2c_client_get_device_id(client); 321 struct i2c_adapter *adapter = client->adapter; 322 struct sbsm_data *data; 323 struct device *dev = &client->dev; 324 struct power_supply_desc *psy_desc; 325 struct power_supply_config psy_cfg = {}; 326 int ret = 0, i; 327 328 /* Device listens only at address 0x0a */ 329 if (client->addr != 0x0a) 330 return -EINVAL; 331 332 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) 333 return -EPFNOSUPPORT; 334 335 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 336 if (!data) 337 return -ENOMEM; 338 339 i2c_set_clientdata(client, data); 340 341 data->client = client; 342 data->is_ltc1760 = !!strstr(id->name, "ltc1760"); 343 344 ret = sbsm_read_word(client, SBSM_CMD_BATSYSINFO); 345 if (ret < 0) 346 return ret; 347 data->supported_bats = ret & SBSM_MASK_BAT_SUPPORTED; 348 data->muxc = i2c_mux_alloc(adapter, dev, SBSM_MAX_BATS, 0, 349 I2C_MUX_LOCKED, &sbsm_select, NULL); 350 if (!data->muxc) 351 return dev_err_probe(dev, -ENOMEM, "failed to alloc i2c mux\n"); 352 data->muxc->priv = data; 353 354 ret = devm_add_action_or_reset(dev, sbsm_del_mux_adapter, data); 355 if (ret) 356 return ret; 357 358 /* register muxed i2c channels. One for each supported battery */ 359 for (i = 0; i < SBSM_MAX_BATS; ++i) { 360 if (data->supported_bats & BIT(i)) { 361 ret = i2c_mux_add_adapter(data->muxc, 0, i + 1, 0); 362 if (ret) 363 break; 364 } 365 } 366 if (ret) 367 return dev_err_probe(dev, ret, "failed to register i2c mux channel %d\n", i + 1); 368 369 psy_desc = devm_kmemdup(dev, &sbsm_default_psy_desc, sizeof(*psy_desc), GFP_KERNEL); 370 if (!psy_desc) 371 return -ENOMEM; 372 373 psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, "sbsm-%s", dev_name(&client->dev)); 374 if (!psy_desc->name) 375 return -ENOMEM; 376 377 ret = sbsm_gpio_setup(data); 378 if (ret < 0) 379 return ret; 380 381 psy_cfg.drv_data = data; 382 psy_cfg.of_node = dev->of_node; 383 data->psy = devm_power_supply_register(dev, psy_desc, &psy_cfg); 384 if (IS_ERR(data->psy)) 385 return dev_err_probe(dev, PTR_ERR(data->psy), 386 "failed to register power supply %s\n", psy_desc->name); 387 388 return 0; 389 } 390 391 static const struct i2c_device_id sbsm_ids[] = { 392 { "sbs-manager", 0 }, 393 { "ltc1760", 0 }, 394 { } 395 }; 396 MODULE_DEVICE_TABLE(i2c, sbsm_ids); 397 398 #ifdef CONFIG_OF 399 static const struct of_device_id sbsm_dt_ids[] = { 400 { .compatible = "sbs,sbs-manager" }, 401 { .compatible = "lltc,ltc1760" }, 402 { } 403 }; 404 MODULE_DEVICE_TABLE(of, sbsm_dt_ids); 405 #endif 406 407 static struct i2c_driver sbsm_driver = { 408 .driver = { 409 .name = "sbsm", 410 .of_match_table = of_match_ptr(sbsm_dt_ids), 411 }, 412 .probe = sbsm_probe, 413 .alert = sbsm_alert, 414 .id_table = sbsm_ids 415 }; 416 module_i2c_driver(sbsm_driver); 417 418 MODULE_LICENSE("GPL"); 419 MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>"); 420 MODULE_DESCRIPTION("SBSM Smart Battery System Manager"); 421