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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Driver for SBS compliant Smart Battery System Managers4 *5 * The device communicates via i2c at address 0x0a and multiplexes access to up6 * 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.pdf11 * Datasheet LTC1760: http://cds.linear.com/docs/en/datasheet/1760fb.pdf12 *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 424#define SBSM_RETRY_CNT 325 26/* registers addresses */27#define SBSM_CMD_BATSYSSTATE 0x0128#define SBSM_CMD_BATSYSSTATECONT 0x0229#define SBSM_CMD_BATSYSINFO 0x0430#define SBSM_CMD_LTC 0x3c31 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 1138struct 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 53static enum power_supply_property sbsm_props[] = {54 POWER_SUPPLY_PROP_ONLINE,55 POWER_SUPPLY_PROP_CHARGE_TYPE,56};57 58static 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 76static 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 92static 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 135static 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 143static 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 battery170 * Parameter chan is directly the content of SMB_BAT* nibble171 */172static 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 else188 data->cur_chan = chan;189 190 return ret;191}192 193static 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 */209static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)210{211 return 0;212}213 214static 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 else228 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 237static 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 267static 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 303static 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 312static void sbsm_del_mux_adapter(void *data)313{314 struct sbsm_data *sbsm = data;315 i2c_mux_del_adapters(sbsm->muxc);316}317 318static 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);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 391static const struct i2c_device_id sbsm_ids[] = {392 { "sbs-manager" },393 { "ltc1760" },394 { }395};396MODULE_DEVICE_TABLE(i2c, sbsm_ids);397 398#ifdef CONFIG_OF399static const struct of_device_id sbsm_dt_ids[] = {400 { .compatible = "sbs,sbs-manager" },401 { .compatible = "lltc,ltc1760" },402 { }403};404MODULE_DEVICE_TABLE(of, sbsm_dt_ids);405#endif406 407static 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_ids415};416module_i2c_driver(sbsm_driver);417 418MODULE_LICENSE("GPL");419MODULE_AUTHOR("Karl-Heinz Schneider <karl-heinz@schneider-inet.de>");420MODULE_DESCRIPTION("SBSM Smart Battery System Manager");421