1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Driver for Linear Technology LTC2945 I2C Power Monitor
4 *
5 * Copyright (c) 2014 Guenter Roeck
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/err.h>
11 #include <linux/slab.h>
12 #include <linux/i2c.h>
13 #include <linux/hwmon.h>
14 #include <linux/hwmon-sysfs.h>
15 #include <linux/jiffies.h>
16 #include <linux/regmap.h>
17
18 /* chip registers */
19 #define LTC2945_CONTROL 0x00
20 #define LTC2945_ALERT 0x01
21 #define LTC2945_STATUS 0x02
22 #define LTC2945_FAULT 0x03
23 #define LTC2945_POWER_H 0x05
24 #define LTC2945_MAX_POWER_H 0x08
25 #define LTC2945_MIN_POWER_H 0x0b
26 #define LTC2945_MAX_POWER_THRES_H 0x0e
27 #define LTC2945_MIN_POWER_THRES_H 0x11
28 #define LTC2945_SENSE_H 0x14
29 #define LTC2945_MAX_SENSE_H 0x16
30 #define LTC2945_MIN_SENSE_H 0x18
31 #define LTC2945_MAX_SENSE_THRES_H 0x1a
32 #define LTC2945_MIN_SENSE_THRES_H 0x1c
33 #define LTC2945_VIN_H 0x1e
34 #define LTC2945_MAX_VIN_H 0x20
35 #define LTC2945_MIN_VIN_H 0x22
36 #define LTC2945_MAX_VIN_THRES_H 0x24
37 #define LTC2945_MIN_VIN_THRES_H 0x26
38 #define LTC2945_ADIN_H 0x28
39 #define LTC2945_MAX_ADIN_H 0x2a
40 #define LTC2945_MIN_ADIN_H 0x2c
41 #define LTC2945_MAX_ADIN_THRES_H 0x2e
42 #define LTC2945_MIN_ADIN_THRES_H 0x30
43 #define LTC2945_MIN_ADIN_THRES_L 0x31
44
45 /* Fault register bits */
46
47 #define FAULT_ADIN_UV (1 << 0)
48 #define FAULT_ADIN_OV (1 << 1)
49 #define FAULT_VIN_UV (1 << 2)
50 #define FAULT_VIN_OV (1 << 3)
51 #define FAULT_SENSE_UV (1 << 4)
52 #define FAULT_SENSE_OV (1 << 5)
53 #define FAULT_POWER_UV (1 << 6)
54 #define FAULT_POWER_OV (1 << 7)
55
56 /* Control register bits */
57
58 #define CONTROL_MULT_SELECT (1 << 0)
59 #define CONTROL_TEST_MODE (1 << 4)
60
61 static const struct of_device_id __maybe_unused ltc2945_of_match[] = {
62 { .compatible = "adi,ltc2945" },
63 { }
64 };
65 MODULE_DEVICE_TABLE(of, ltc2945_of_match);
66
67 /**
68 * struct ltc2945_data - LTC2945 device data
69 * @regmap: regmap device
70 * @shunt_resistor: shunt resistor value in micro ohms (1000 by default)
71 */
72 struct ltc2945_data {
73 struct regmap *regmap;
74 u32 shunt_resistor;
75 };
76
is_power_reg(u8 reg)77 static inline bool is_power_reg(u8 reg)
78 {
79 return reg < LTC2945_SENSE_H;
80 }
81
82 /* Return the value from the given register in uW, mV, or mA */
ltc2945_reg_to_val(struct device * dev,u8 reg)83 static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
84 {
85 struct ltc2945_data *data = dev_get_drvdata(dev);
86 struct regmap *regmap = data->regmap;
87 u32 shunt_resistor = data->shunt_resistor;
88 unsigned int control;
89 u8 buf[3];
90 long long val;
91 int ret;
92
93 ret = regmap_bulk_read(regmap, reg, buf,
94 is_power_reg(reg) ? 3 : 2);
95 if (ret < 0)
96 return ret;
97
98 if (is_power_reg(reg)) {
99 /* 24-bit power */
100 val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
101 } else {
102 /* 12-bit current, voltage */
103 val = (buf[0] << 4) + (buf[1] >> 4);
104 }
105
106 switch (reg) {
107 case LTC2945_POWER_H:
108 case LTC2945_MAX_POWER_H:
109 case LTC2945_MIN_POWER_H:
110 case LTC2945_MAX_POWER_THRES_H:
111 case LTC2945_MIN_POWER_THRES_H:
112 /*
113 * Convert to uW
114 * Control register bit 0 selects if voltage at SENSE+/VDD
115 * or voltage at ADIN is used to measure power.
116 */
117 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
118 if (ret < 0)
119 return ret;
120 if (control & CONTROL_MULT_SELECT) {
121 /* 25 mV * 25 uV = 0.625 uV resolution. */
122 val *= 625LL;
123 } else {
124 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
125 val = (val * 25LL) >> 1;
126 }
127 val *= 1000;
128 /* Overflow check: Assuming max 24-bit power, val is at most 53 bits right now. */
129 val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
130 /*
131 * Overflow check: After division, depending on shunt resistor,
132 * val can still be > 32 bits so returning long long makes sense
133 */
134
135 break;
136 case LTC2945_VIN_H:
137 case LTC2945_MAX_VIN_H:
138 case LTC2945_MIN_VIN_H:
139 case LTC2945_MAX_VIN_THRES_H:
140 case LTC2945_MIN_VIN_THRES_H:
141 /* 25 mV resolution. Convert to mV. */
142 val *= 25;
143 break;
144 case LTC2945_ADIN_H:
145 case LTC2945_MAX_ADIN_H:
146 case LTC2945_MIN_ADIN_THRES_H:
147 case LTC2945_MAX_ADIN_THRES_H:
148 case LTC2945_MIN_ADIN_H:
149 /* 0.5mV resolution. Convert to mV. */
150 val = val >> 1;
151 break;
152 case LTC2945_SENSE_H:
153 case LTC2945_MAX_SENSE_H:
154 case LTC2945_MIN_SENSE_H:
155 case LTC2945_MAX_SENSE_THRES_H:
156 case LTC2945_MIN_SENSE_THRES_H:
157 /* 25 uV resolution. Convert to mA. */
158 val *= 25 * 1000;
159 /* Overflow check: Assuming max 12-bit sense, val is at most 27 bits right now */
160 val = DIV_ROUND_CLOSEST_ULL(val, shunt_resistor);
161 /* Overflow check: After division, <= 27 bits */
162 break;
163 default:
164 return -EINVAL;
165 }
166 return val;
167 }
168
ltc2945_val_to_reg(struct device * dev,u8 reg,unsigned long long val)169 static long long ltc2945_val_to_reg(struct device *dev, u8 reg,
170 unsigned long long val)
171 {
172 struct ltc2945_data *data = dev_get_drvdata(dev);
173 struct regmap *regmap = data->regmap;
174 u32 shunt_resistor = data->shunt_resistor;
175 unsigned int control;
176 int ret;
177
178 /* Ensure we don't overflow */
179 val = clamp_val(val, 0, U32_MAX);
180
181 switch (reg) {
182 case LTC2945_POWER_H:
183 case LTC2945_MAX_POWER_H:
184 case LTC2945_MIN_POWER_H:
185 case LTC2945_MAX_POWER_THRES_H:
186 case LTC2945_MIN_POWER_THRES_H:
187 /*
188 * Control register bit 0 selects if voltage at SENSE+/VDD
189 * or voltage at ADIN is used to measure power, which in turn
190 * determines register calculations.
191 */
192 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
193 if (ret < 0)
194 return ret;
195 if (control & CONTROL_MULT_SELECT) {
196 /* 25 mV * 25 uV = 0.625 uV resolution. */
197 val *= shunt_resistor;
198 /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
199 val = DIV_ROUND_CLOSEST_ULL(val, 625 * 1000);
200 /* Overflow check: val is now <= 44 bits */
201 } else {
202 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
203 val *= shunt_resistor;
204 /* Overflow check: Assuming 32-bit val and shunt resistor, val <= 64bits */
205 val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000) * 2;
206 /* Overflow check: val is now <= 51 bits */
207 }
208 break;
209 case LTC2945_VIN_H:
210 case LTC2945_MAX_VIN_H:
211 case LTC2945_MIN_VIN_H:
212 case LTC2945_MAX_VIN_THRES_H:
213 case LTC2945_MIN_VIN_THRES_H:
214 /* 25 mV resolution. */
215 val = DIV_ROUND_CLOSEST_ULL(val, 25);
216 break;
217 case LTC2945_ADIN_H:
218 case LTC2945_MAX_ADIN_H:
219 case LTC2945_MIN_ADIN_THRES_H:
220 case LTC2945_MAX_ADIN_THRES_H:
221 case LTC2945_MIN_ADIN_H:
222 /* 0.5mV resolution. */
223 val *= 2;
224 break;
225 case LTC2945_SENSE_H:
226 case LTC2945_MAX_SENSE_H:
227 case LTC2945_MIN_SENSE_H:
228 case LTC2945_MAX_SENSE_THRES_H:
229 case LTC2945_MIN_SENSE_THRES_H:
230 /* 25 uV resolution. Convert to mA. */
231 val *= shunt_resistor;
232 /* Overflow check: Assuming 32-bit val and 32-bit shunt resistor, val is 64bits */
233 val = DIV_ROUND_CLOSEST_ULL(val, 25 * 1000);
234 /* Overflow check: val is now <= 50 bits */
235 break;
236 default:
237 return -EINVAL;
238 }
239 return val;
240 }
241
ltc2945_value_show(struct device * dev,struct device_attribute * da,char * buf)242 static ssize_t ltc2945_value_show(struct device *dev,
243 struct device_attribute *da, char *buf)
244 {
245 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
246 long long value;
247
248 value = ltc2945_reg_to_val(dev, attr->index);
249 if (value < 0)
250 return value;
251 return sysfs_emit(buf, "%lld\n", value);
252 }
253
ltc2945_value_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)254 static ssize_t ltc2945_value_store(struct device *dev,
255 struct device_attribute *da,
256 const char *buf, size_t count)
257 {
258 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
259 struct ltc2945_data *data = dev_get_drvdata(dev);
260 struct regmap *regmap = data->regmap;
261 u8 reg = attr->index;
262 unsigned int val;
263 u8 regbuf[3];
264 int num_regs;
265 long long regval;
266 int ret;
267
268 ret = kstrtouint(buf, 10, &val);
269 if (ret)
270 return ret;
271
272 /* convert to register value, then clamp and write result */
273 regval = ltc2945_val_to_reg(dev, reg, val);
274 if (regval < 0)
275 return regval;
276 if (is_power_reg(reg)) {
277 regval = clamp_val(regval, 0, 0xffffff);
278 regbuf[0] = regval >> 16;
279 regbuf[1] = (regval >> 8) & 0xff;
280 regbuf[2] = regval;
281 num_regs = 3;
282 } else {
283 regval = clamp_val(regval, 0, 0xfff) << 4;
284 regbuf[0] = regval >> 8;
285 regbuf[1] = regval & 0xff;
286 num_regs = 2;
287 }
288 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
289 return ret < 0 ? ret : count;
290 }
291
ltc2945_history_store(struct device * dev,struct device_attribute * da,const char * buf,size_t count)292 static ssize_t ltc2945_history_store(struct device *dev,
293 struct device_attribute *da,
294 const char *buf, size_t count)
295 {
296 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
297 struct ltc2945_data *data = dev_get_drvdata(dev);
298 struct regmap *regmap = data->regmap;
299 u8 reg = attr->index;
300 int num_regs = is_power_reg(reg) ? 3 : 2;
301 u8 buf_min[3] = { 0xff, 0xff, 0xff };
302 u8 buf_max[3] = { 0, 0, 0 };
303 unsigned long val;
304 int ret;
305
306 ret = kstrtoul(buf, 10, &val);
307 if (ret)
308 return ret;
309 if (val != 1)
310 return -EINVAL;
311
312 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
313 CONTROL_TEST_MODE);
314
315 /* Reset minimum */
316 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
317 if (ret)
318 return ret;
319
320 switch (reg) {
321 case LTC2945_MIN_POWER_H:
322 reg = LTC2945_MAX_POWER_H;
323 break;
324 case LTC2945_MIN_SENSE_H:
325 reg = LTC2945_MAX_SENSE_H;
326 break;
327 case LTC2945_MIN_VIN_H:
328 reg = LTC2945_MAX_VIN_H;
329 break;
330 case LTC2945_MIN_ADIN_H:
331 reg = LTC2945_MAX_ADIN_H;
332 break;
333 default:
334 WARN_ONCE(1, "Bad register: 0x%x\n", reg);
335 return -EINVAL;
336 }
337 /* Reset maximum */
338 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
339
340 /* Try resetting test mode even if there was an error */
341 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
342
343 return ret ? : count;
344 }
345
ltc2945_bool_show(struct device * dev,struct device_attribute * da,char * buf)346 static ssize_t ltc2945_bool_show(struct device *dev,
347 struct device_attribute *da, char *buf)
348 {
349 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
350 struct ltc2945_data *data = dev_get_drvdata(dev);
351 struct regmap *regmap = data->regmap;
352 unsigned int fault;
353 int ret;
354
355 ret = regmap_read(regmap, LTC2945_FAULT, &fault);
356 if (ret < 0)
357 return ret;
358
359 fault &= attr->index;
360 if (fault) /* Clear reported faults in chip register */
361 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
362
363 return sysfs_emit(buf, "%d\n", !!fault);
364 }
365
366 /* Input voltages */
367
368 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
369 static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
370 static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
371 static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
372 static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
373 static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
374 LTC2945_MIN_VIN_H);
375
376 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
377 static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
378 static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
379 static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
380 static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
381 static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
382 LTC2945_MIN_ADIN_H);
383
384 /* Voltage alarms */
385
386 static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
387 static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
388 static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
389 static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);
390
391 /* Currents (via sense resistor) */
392
393 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
394 static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
395 LTC2945_MIN_SENSE_THRES_H);
396 static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
397 LTC2945_MAX_SENSE_THRES_H);
398 static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
399 static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
400 LTC2945_MAX_SENSE_H);
401 static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
402 LTC2945_MIN_SENSE_H);
403
404 /* Current alarms */
405
406 static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
407 static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);
408
409 /* Power */
410
411 static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
412 static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
413 LTC2945_MIN_POWER_THRES_H);
414 static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
415 LTC2945_MAX_POWER_THRES_H);
416 static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
417 LTC2945_MIN_POWER_H);
418 static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
419 LTC2945_MAX_POWER_H);
420 static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
421 LTC2945_MIN_POWER_H);
422
423 /* Power alarms */
424
425 static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
426 static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);
427
428 static struct attribute *ltc2945_attrs[] = {
429 &sensor_dev_attr_in1_input.dev_attr.attr,
430 &sensor_dev_attr_in1_min.dev_attr.attr,
431 &sensor_dev_attr_in1_max.dev_attr.attr,
432 &sensor_dev_attr_in1_lowest.dev_attr.attr,
433 &sensor_dev_attr_in1_highest.dev_attr.attr,
434 &sensor_dev_attr_in1_reset_history.dev_attr.attr,
435 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
436 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
437
438 &sensor_dev_attr_in2_input.dev_attr.attr,
439 &sensor_dev_attr_in2_min.dev_attr.attr,
440 &sensor_dev_attr_in2_max.dev_attr.attr,
441 &sensor_dev_attr_in2_lowest.dev_attr.attr,
442 &sensor_dev_attr_in2_highest.dev_attr.attr,
443 &sensor_dev_attr_in2_reset_history.dev_attr.attr,
444 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
445 &sensor_dev_attr_in2_max_alarm.dev_attr.attr,
446
447 &sensor_dev_attr_curr1_input.dev_attr.attr,
448 &sensor_dev_attr_curr1_min.dev_attr.attr,
449 &sensor_dev_attr_curr1_max.dev_attr.attr,
450 &sensor_dev_attr_curr1_lowest.dev_attr.attr,
451 &sensor_dev_attr_curr1_highest.dev_attr.attr,
452 &sensor_dev_attr_curr1_reset_history.dev_attr.attr,
453 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
454 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
455
456 &sensor_dev_attr_power1_input.dev_attr.attr,
457 &sensor_dev_attr_power1_min.dev_attr.attr,
458 &sensor_dev_attr_power1_max.dev_attr.attr,
459 &sensor_dev_attr_power1_input_lowest.dev_attr.attr,
460 &sensor_dev_attr_power1_input_highest.dev_attr.attr,
461 &sensor_dev_attr_power1_reset_history.dev_attr.attr,
462 &sensor_dev_attr_power1_min_alarm.dev_attr.attr,
463 &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
464
465 NULL,
466 };
467 ATTRIBUTE_GROUPS(ltc2945);
468
469 static const struct regmap_config ltc2945_regmap_config = {
470 .reg_bits = 8,
471 .val_bits = 8,
472 .max_register = LTC2945_MIN_ADIN_THRES_L,
473 };
474
ltc2945_probe(struct i2c_client * client)475 static int ltc2945_probe(struct i2c_client *client)
476 {
477 struct device *dev = &client->dev;
478 struct device *hwmon_dev;
479 struct regmap *regmap;
480 struct ltc2945_data *data;
481
482 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
483 if (!data)
484 return -ENOMEM;
485 dev_set_drvdata(dev, data);
486
487 regmap = devm_regmap_init_i2c(client, <c2945_regmap_config);
488 if (IS_ERR(regmap)) {
489 dev_err(dev, "failed to allocate register map\n");
490 return PTR_ERR(regmap);
491 }
492
493 data->regmap = regmap;
494 if (device_property_read_u32(dev, "shunt-resistor-micro-ohms",
495 &data->shunt_resistor))
496 data->shunt_resistor = 1000;
497
498 if (data->shunt_resistor == 0)
499 return -EINVAL;
500
501 /* Clear faults */
502 regmap_write(regmap, LTC2945_FAULT, 0x00);
503
504 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
505 data,
506 ltc2945_groups);
507 return PTR_ERR_OR_ZERO(hwmon_dev);
508 }
509
510 static const struct i2c_device_id ltc2945_id[] = {
511 {"ltc2945", 0},
512 { }
513 };
514
515 MODULE_DEVICE_TABLE(i2c, ltc2945_id);
516
517 static struct i2c_driver ltc2945_driver = {
518 .driver = {
519 .name = "ltc2945",
520 .of_match_table = of_match_ptr(ltc2945_of_match),
521 },
522 .probe = ltc2945_probe,
523 .id_table = ltc2945_id,
524 };
525
526 module_i2c_driver(ltc2945_driver);
527
528 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
529 MODULE_DESCRIPTION("LTC2945 driver");
530 MODULE_LICENSE("GPL");
531