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
is_power_reg(u8 reg)61 static inline bool is_power_reg(u8 reg)
62 {
63 return reg < LTC2945_SENSE_H;
64 }
65
66 /* Return the value from the given register in uW, mV, or mA */
ltc2945_reg_to_val(struct device *dev, u8 reg)67 static long long ltc2945_reg_to_val(struct device *dev, u8 reg)
68 {
69 struct regmap *regmap = dev_get_drvdata(dev);
70 unsigned int control;
71 u8 buf[3];
72 long long val;
73 int ret;
74
75 ret = regmap_bulk_read(regmap, reg, buf,
76 is_power_reg(reg) ? 3 : 2);
77 if (ret < 0)
78 return ret;
79
80 if (is_power_reg(reg)) {
81 /* power */
82 val = (buf[0] << 16) + (buf[1] << 8) + buf[2];
83 } else {
84 /* current, voltage */
85 val = (buf[0] << 4) + (buf[1] >> 4);
86 }
87
88 switch (reg) {
89 case LTC2945_POWER_H:
90 case LTC2945_MAX_POWER_H:
91 case LTC2945_MIN_POWER_H:
92 case LTC2945_MAX_POWER_THRES_H:
93 case LTC2945_MIN_POWER_THRES_H:
94 /*
95 * Convert to uW by assuming current is measured with
96 * an 1mOhm sense resistor, similar to current
97 * measurements.
98 * Control register bit 0 selects if voltage at SENSE+/VDD
99 * or voltage at ADIN is used to measure power.
100 */
101 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
102 if (ret < 0)
103 return ret;
104 if (control & CONTROL_MULT_SELECT) {
105 /* 25 mV * 25 uV = 0.625 uV resolution. */
106 val *= 625LL;
107 } else {
108 /* 0.5 mV * 25 uV = 0.0125 uV resolution. */
109 val = (val * 25LL) >> 1;
110 }
111 break;
112 case LTC2945_VIN_H:
113 case LTC2945_MAX_VIN_H:
114 case LTC2945_MIN_VIN_H:
115 case LTC2945_MAX_VIN_THRES_H:
116 case LTC2945_MIN_VIN_THRES_H:
117 /* 25 mV resolution. Convert to mV. */
118 val *= 25;
119 break;
120 case LTC2945_ADIN_H:
121 case LTC2945_MAX_ADIN_H:
122 case LTC2945_MIN_ADIN_THRES_H:
123 case LTC2945_MAX_ADIN_THRES_H:
124 case LTC2945_MIN_ADIN_H:
125 /* 0.5mV resolution. Convert to mV. */
126 val = val >> 1;
127 break;
128 case LTC2945_SENSE_H:
129 case LTC2945_MAX_SENSE_H:
130 case LTC2945_MIN_SENSE_H:
131 case LTC2945_MAX_SENSE_THRES_H:
132 case LTC2945_MIN_SENSE_THRES_H:
133 /*
134 * 25 uV resolution. Convert to current as measured with
135 * an 1 mOhm sense resistor, in mA. If a different sense
136 * resistor is installed, calculate the actual current by
137 * dividing the reported current by the sense resistor value
138 * in mOhm.
139 */
140 val *= 25;
141 break;
142 default:
143 return -EINVAL;
144 }
145 return val;
146 }
147
ltc2945_val_to_reg(struct device *dev, u8 reg, unsigned long val)148 static int ltc2945_val_to_reg(struct device *dev, u8 reg,
149 unsigned long val)
150 {
151 struct regmap *regmap = dev_get_drvdata(dev);
152 unsigned int control;
153 int ret;
154
155 switch (reg) {
156 case LTC2945_POWER_H:
157 case LTC2945_MAX_POWER_H:
158 case LTC2945_MIN_POWER_H:
159 case LTC2945_MAX_POWER_THRES_H:
160 case LTC2945_MIN_POWER_THRES_H:
161 /*
162 * Convert to register value by assuming current is measured
163 * with an 1mOhm sense resistor, similar to current
164 * measurements.
165 * Control register bit 0 selects if voltage at SENSE+/VDD
166 * or voltage at ADIN is used to measure power, which in turn
167 * determines register calculations.
168 */
169 ret = regmap_read(regmap, LTC2945_CONTROL, &control);
170 if (ret < 0)
171 return ret;
172 if (control & CONTROL_MULT_SELECT) {
173 /* 25 mV * 25 uV = 0.625 uV resolution. */
174 val = DIV_ROUND_CLOSEST(val, 625);
175 } else {
176 /*
177 * 0.5 mV * 25 uV = 0.0125 uV resolution.
178 * Divide first to avoid overflow;
179 * accept loss of accuracy.
180 */
181 val = DIV_ROUND_CLOSEST(val, 25) * 2;
182 }
183 break;
184 case LTC2945_VIN_H:
185 case LTC2945_MAX_VIN_H:
186 case LTC2945_MIN_VIN_H:
187 case LTC2945_MAX_VIN_THRES_H:
188 case LTC2945_MIN_VIN_THRES_H:
189 /* 25 mV resolution. */
190 val /= 25;
191 break;
192 case LTC2945_ADIN_H:
193 case LTC2945_MAX_ADIN_H:
194 case LTC2945_MIN_ADIN_THRES_H:
195 case LTC2945_MAX_ADIN_THRES_H:
196 case LTC2945_MIN_ADIN_H:
197 /* 0.5mV resolution. */
198 val *= 2;
199 break;
200 case LTC2945_SENSE_H:
201 case LTC2945_MAX_SENSE_H:
202 case LTC2945_MIN_SENSE_H:
203 case LTC2945_MAX_SENSE_THRES_H:
204 case LTC2945_MIN_SENSE_THRES_H:
205 /*
206 * 25 uV resolution. Convert to current as measured with
207 * an 1 mOhm sense resistor, in mA. If a different sense
208 * resistor is installed, calculate the actual current by
209 * dividing the reported current by the sense resistor value
210 * in mOhm.
211 */
212 val = DIV_ROUND_CLOSEST(val, 25);
213 break;
214 default:
215 return -EINVAL;
216 }
217 return val;
218 }
219
ltc2945_value_show(struct device *dev, struct device_attribute *da, char *buf)220 static ssize_t ltc2945_value_show(struct device *dev,
221 struct device_attribute *da, char *buf)
222 {
223 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
224 long long value;
225
226 value = ltc2945_reg_to_val(dev, attr->index);
227 if (value < 0)
228 return value;
229 return snprintf(buf, PAGE_SIZE, "%lld\n", value);
230 }
231
ltc2945_value_store(struct device *dev, struct device_attribute *da, const char *buf, size_t count)232 static ssize_t ltc2945_value_store(struct device *dev,
233 struct device_attribute *da,
234 const char *buf, size_t count)
235 {
236 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
237 struct regmap *regmap = dev_get_drvdata(dev);
238 u8 reg = attr->index;
239 unsigned long val;
240 u8 regbuf[3];
241 int num_regs;
242 int regval;
243 int ret;
244
245 ret = kstrtoul(buf, 10, &val);
246 if (ret)
247 return ret;
248
249 /* convert to register value, then clamp and write result */
250 regval = ltc2945_val_to_reg(dev, reg, val);
251 if (regval < 0)
252 return regval;
253 if (is_power_reg(reg)) {
254 regval = clamp_val(regval, 0, 0xffffff);
255 regbuf[0] = regval >> 16;
256 regbuf[1] = (regval >> 8) & 0xff;
257 regbuf[2] = regval;
258 num_regs = 3;
259 } else {
260 regval = clamp_val(regval, 0, 0xfff) << 4;
261 regbuf[0] = regval >> 8;
262 regbuf[1] = regval & 0xff;
263 num_regs = 2;
264 }
265 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
266 return ret < 0 ? ret : count;
267 }
268
ltc2945_history_store(struct device *dev, struct device_attribute *da, const char *buf, size_t count)269 static ssize_t ltc2945_history_store(struct device *dev,
270 struct device_attribute *da,
271 const char *buf, size_t count)
272 {
273 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
274 struct regmap *regmap = dev_get_drvdata(dev);
275 u8 reg = attr->index;
276 int num_regs = is_power_reg(reg) ? 3 : 2;
277 u8 buf_min[3] = { 0xff, 0xff, 0xff };
278 u8 buf_max[3] = { 0, 0, 0 };
279 unsigned long val;
280 int ret;
281
282 ret = kstrtoul(buf, 10, &val);
283 if (ret)
284 return ret;
285 if (val != 1)
286 return -EINVAL;
287
288 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
289 CONTROL_TEST_MODE);
290
291 /* Reset minimum */
292 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
293 if (ret)
294 return ret;
295
296 switch (reg) {
297 case LTC2945_MIN_POWER_H:
298 reg = LTC2945_MAX_POWER_H;
299 break;
300 case LTC2945_MIN_SENSE_H:
301 reg = LTC2945_MAX_SENSE_H;
302 break;
303 case LTC2945_MIN_VIN_H:
304 reg = LTC2945_MAX_VIN_H;
305 break;
306 case LTC2945_MIN_ADIN_H:
307 reg = LTC2945_MAX_ADIN_H;
308 break;
309 default:
310 WARN_ONCE(1, "Bad register: 0x%x\n", reg);
311 return -EINVAL;
312 }
313 /* Reset maximum */
314 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
315
316 /* Try resetting test mode even if there was an error */
317 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
318
319 return ret ? : count;
320 }
321
ltc2945_bool_show(struct device *dev, struct device_attribute *da, char *buf)322 static ssize_t ltc2945_bool_show(struct device *dev,
323 struct device_attribute *da, char *buf)
324 {
325 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
326 struct regmap *regmap = dev_get_drvdata(dev);
327 unsigned int fault;
328 int ret;
329
330 ret = regmap_read(regmap, LTC2945_FAULT, &fault);
331 if (ret < 0)
332 return ret;
333
334 fault &= attr->index;
335 if (fault) /* Clear reported faults in chip register */
336 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
337
338 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
339 }
340
341 /* Input voltages */
342
343 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
344 static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
345 static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
346 static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
347 static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
348 static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
349 LTC2945_MIN_VIN_H);
350
351 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
352 static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
353 static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
354 static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
355 static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
356 static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
357 LTC2945_MIN_ADIN_H);
358
359 /* Voltage alarms */
360
361 static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
362 static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
363 static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
364 static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);
365
366 /* Currents (via sense resistor) */
367
368 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
369 static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
370 LTC2945_MIN_SENSE_THRES_H);
371 static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
372 LTC2945_MAX_SENSE_THRES_H);
373 static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
374 static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
375 LTC2945_MAX_SENSE_H);
376 static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
377 LTC2945_MIN_SENSE_H);
378
379 /* Current alarms */
380
381 static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
382 static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);
383
384 /* Power */
385
386 static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
387 static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
388 LTC2945_MIN_POWER_THRES_H);
389 static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
390 LTC2945_MAX_POWER_THRES_H);
391 static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
392 LTC2945_MIN_POWER_H);
393 static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
394 LTC2945_MAX_POWER_H);
395 static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
396 LTC2945_MIN_POWER_H);
397
398 /* Power alarms */
399
400 static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
401 static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);
402
403 static struct attribute *ltc2945_attrs[] = {
404 &sensor_dev_attr_in1_input.dev_attr.attr,
405 &sensor_dev_attr_in1_min.dev_attr.attr,
406 &sensor_dev_attr_in1_max.dev_attr.attr,
407 &sensor_dev_attr_in1_lowest.dev_attr.attr,
408 &sensor_dev_attr_in1_highest.dev_attr.attr,
409 &sensor_dev_attr_in1_reset_history.dev_attr.attr,
410 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
411 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
412
413 &sensor_dev_attr_in2_input.dev_attr.attr,
414 &sensor_dev_attr_in2_min.dev_attr.attr,
415 &sensor_dev_attr_in2_max.dev_attr.attr,
416 &sensor_dev_attr_in2_lowest.dev_attr.attr,
417 &sensor_dev_attr_in2_highest.dev_attr.attr,
418 &sensor_dev_attr_in2_reset_history.dev_attr.attr,
419 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
420 &sensor_dev_attr_in2_max_alarm.dev_attr.attr,
421
422 &sensor_dev_attr_curr1_input.dev_attr.attr,
423 &sensor_dev_attr_curr1_min.dev_attr.attr,
424 &sensor_dev_attr_curr1_max.dev_attr.attr,
425 &sensor_dev_attr_curr1_lowest.dev_attr.attr,
426 &sensor_dev_attr_curr1_highest.dev_attr.attr,
427 &sensor_dev_attr_curr1_reset_history.dev_attr.attr,
428 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
429 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
430
431 &sensor_dev_attr_power1_input.dev_attr.attr,
432 &sensor_dev_attr_power1_min.dev_attr.attr,
433 &sensor_dev_attr_power1_max.dev_attr.attr,
434 &sensor_dev_attr_power1_input_lowest.dev_attr.attr,
435 &sensor_dev_attr_power1_input_highest.dev_attr.attr,
436 &sensor_dev_attr_power1_reset_history.dev_attr.attr,
437 &sensor_dev_attr_power1_min_alarm.dev_attr.attr,
438 &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
439
440 NULL,
441 };
442 ATTRIBUTE_GROUPS(ltc2945);
443
444 static const struct regmap_config ltc2945_regmap_config = {
445 .reg_bits = 8,
446 .val_bits = 8,
447 .max_register = LTC2945_MIN_ADIN_THRES_L,
448 };
449
ltc2945_probe(struct i2c_client *client)450 static int ltc2945_probe(struct i2c_client *client)
451 {
452 struct device *dev = &client->dev;
453 struct device *hwmon_dev;
454 struct regmap *regmap;
455
456 regmap = devm_regmap_init_i2c(client, <c2945_regmap_config);
457 if (IS_ERR(regmap)) {
458 dev_err(dev, "failed to allocate register map\n");
459 return PTR_ERR(regmap);
460 }
461
462 /* Clear faults */
463 regmap_write(regmap, LTC2945_FAULT, 0x00);
464
465 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
466 regmap,
467 ltc2945_groups);
468 return PTR_ERR_OR_ZERO(hwmon_dev);
469 }
470
471 static const struct i2c_device_id ltc2945_id[] = {
472 {"ltc2945", 0},
473 { }
474 };
475
476 MODULE_DEVICE_TABLE(i2c, ltc2945_id);
477
478 static struct i2c_driver ltc2945_driver = {
479 .driver = {
480 .name = "ltc2945",
481 },
482 .probe_new = ltc2945_probe,
483 .id_table = ltc2945_id,
484 };
485
486 module_i2c_driver(ltc2945_driver);
487
488 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
489 MODULE_DESCRIPTION("LTC2945 driver");
490 MODULE_LICENSE("GPL");
491