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
sbsm_read_word(struct i2c_client * client,u8 address)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
sbsm_write_word(struct i2c_client * client,u8 address,u16 word)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
sbsm_get_property(struct power_supply * psy,enum power_supply_property psp,union power_supply_propval * val)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
sbsm_prop_is_writeable(struct power_supply * psy,enum power_supply_property psp)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
sbsm_set_property(struct power_supply * psy,enum power_supply_property psp,const union power_supply_propval * val)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 */
sbsm_select(struct i2c_mux_core * muxc,u32 chan)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
sbsm_gpio_get_value(struct gpio_chip * gc,unsigned int off)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 */
sbsm_gpio_direction_input(struct gpio_chip * gc,unsigned int off)209 static int sbsm_gpio_direction_input(struct gpio_chip *gc, unsigned int off)
210 {
211 return 0;
212 }
213
sbsm_do_alert(struct device * dev,void * d)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
sbsm_alert(struct i2c_client * client,enum i2c_alert_protocol prot,unsigned int d)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
sbsm_gpio_setup(struct sbsm_data * data)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
sbsm_del_mux_adapter(void * data)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
sbsm_probe(struct i2c_client * client)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