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
38struct 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, command: 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, command: address, value: 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(client: 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(client: 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(client: 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(client: data->client, SBSM_CMD_LTC, word: 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 */
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(client: data->client, SBSM_CMD_BATSYSSTATE, word: 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
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(client: 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 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
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(client: 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(client: 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(psy: 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(parent: &sbsm->muxc->adapter[i]->dev,
262 NULL, fn: 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, propname: "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, err: ret, fmt: "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(muxc: 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(adap: adapter, I2C_FUNC_SMBUS_WORD_DATA))
333 return -EPFNOSUPPORT;
334
335 data = devm_kzalloc(dev, size: 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(parent: adapter, dev, SBSM_MAX_BATS, sizeof_priv: 0,
349 I2C_MUX_LOCKED, select: &sbsm_select, NULL);
350 if (!data->muxc)
351 return -ENOMEM;
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(muxc: data->muxc, force_nr: 0, chan_id: i + 1);
362 if (ret)
363 break;
364 }
365 }
366 if (ret)
367 return dev_err_probe(dev, err: ret, fmt: "failed to register i2c mux channel %d\n", i + 1);
368
369 psy_desc = devm_kmemdup(dev, src: &sbsm_default_psy_desc, len: sizeof(*psy_desc), GFP_KERNEL);
370 if (!psy_desc)
371 return -ENOMEM;
372
373 psy_desc->name = devm_kasprintf(dev, GFP_KERNEL, fmt: "sbsm-%s", dev_name(dev: &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.fwnode = dev_fwnode(dev);
383 data->psy = devm_power_supply_register(parent: dev, desc: psy_desc, cfg: &psy_cfg);
384 if (IS_ERR(ptr: data->psy))
385 return dev_err_probe(dev, err: PTR_ERR(ptr: data->psy),
386 fmt: "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_OF
399static 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#endif
406
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_ids
415};
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

source code of linux/drivers/power/supply/sbs-manager.c