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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
61static 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 */
67static 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
148static 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
220static 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
232static 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 (is_power_reg(reg)) {
252 regval = clamp_val(regval, 0, 0xffffff);
253 regbuf[0] = regval >> 16;
254 regbuf[1] = (regval >> 8) & 0xff;
255 regbuf[2] = regval;
256 num_regs = 3;
257 } else {
258 regval = clamp_val(regval, 0, 0xfff) << 4;
259 regbuf[0] = regval >> 8;
260 regbuf[1] = regval & 0xff;
261 num_regs = 2;
262 }
263 ret = regmap_bulk_write(regmap, reg, regbuf, num_regs);
264 return ret < 0 ? ret : count;
265}
266
267static ssize_t ltc2945_history_store(struct device *dev,
268 struct device_attribute *da,
269 const char *buf, size_t count)
270{
271 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
272 struct regmap *regmap = dev_get_drvdata(dev);
273 u8 reg = attr->index;
274 int num_regs = is_power_reg(reg) ? 3 : 2;
275 u8 buf_min[3] = { 0xff, 0xff, 0xff };
276 u8 buf_max[3] = { 0, 0, 0 };
277 unsigned long val;
278 int ret;
279
280 ret = kstrtoul(buf, 10, &val);
281 if (ret)
282 return ret;
283 if (val != 1)
284 return -EINVAL;
285
286 ret = regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE,
287 CONTROL_TEST_MODE);
288
289 /* Reset minimum */
290 ret = regmap_bulk_write(regmap, reg, buf_min, num_regs);
291 if (ret)
292 return ret;
293
294 switch (reg) {
295 case LTC2945_MIN_POWER_H:
296 reg = LTC2945_MAX_POWER_H;
297 break;
298 case LTC2945_MIN_SENSE_H:
299 reg = LTC2945_MAX_SENSE_H;
300 break;
301 case LTC2945_MIN_VIN_H:
302 reg = LTC2945_MAX_VIN_H;
303 break;
304 case LTC2945_MIN_ADIN_H:
305 reg = LTC2945_MAX_ADIN_H;
306 break;
307 default:
308 WARN_ONCE(1, "Bad register: 0x%x\n", reg);
309 return -EINVAL;
310 }
311 /* Reset maximum */
312 ret = regmap_bulk_write(regmap, reg, buf_max, num_regs);
313
314 /* Try resetting test mode even if there was an error */
315 regmap_update_bits(regmap, LTC2945_CONTROL, CONTROL_TEST_MODE, 0);
316
317 return ret ? : count;
318}
319
320static ssize_t ltc2945_bool_show(struct device *dev,
321 struct device_attribute *da, char *buf)
322{
323 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
324 struct regmap *regmap = dev_get_drvdata(dev);
325 unsigned int fault;
326 int ret;
327
328 ret = regmap_read(regmap, LTC2945_FAULT, &fault);
329 if (ret < 0)
330 return ret;
331
332 fault &= attr->index;
333 if (fault) /* Clear reported faults in chip register */
334 regmap_update_bits(regmap, LTC2945_FAULT, attr->index, 0);
335
336 return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
337}
338
339/* Input voltages */
340
341static SENSOR_DEVICE_ATTR_RO(in1_input, ltc2945_value, LTC2945_VIN_H);
342static SENSOR_DEVICE_ATTR_RW(in1_min, ltc2945_value, LTC2945_MIN_VIN_THRES_H);
343static SENSOR_DEVICE_ATTR_RW(in1_max, ltc2945_value, LTC2945_MAX_VIN_THRES_H);
344static SENSOR_DEVICE_ATTR_RO(in1_lowest, ltc2945_value, LTC2945_MIN_VIN_H);
345static SENSOR_DEVICE_ATTR_RO(in1_highest, ltc2945_value, LTC2945_MAX_VIN_H);
346static SENSOR_DEVICE_ATTR_WO(in1_reset_history, ltc2945_history,
347 LTC2945_MIN_VIN_H);
348
349static SENSOR_DEVICE_ATTR_RO(in2_input, ltc2945_value, LTC2945_ADIN_H);
350static SENSOR_DEVICE_ATTR_RW(in2_min, ltc2945_value, LTC2945_MIN_ADIN_THRES_H);
351static SENSOR_DEVICE_ATTR_RW(in2_max, ltc2945_value, LTC2945_MAX_ADIN_THRES_H);
352static SENSOR_DEVICE_ATTR_RO(in2_lowest, ltc2945_value, LTC2945_MIN_ADIN_H);
353static SENSOR_DEVICE_ATTR_RO(in2_highest, ltc2945_value, LTC2945_MAX_ADIN_H);
354static SENSOR_DEVICE_ATTR_WO(in2_reset_history, ltc2945_history,
355 LTC2945_MIN_ADIN_H);
356
357/* Voltage alarms */
358
359static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc2945_bool, FAULT_VIN_UV);
360static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc2945_bool, FAULT_VIN_OV);
361static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc2945_bool, FAULT_ADIN_UV);
362static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc2945_bool, FAULT_ADIN_OV);
363
364/* Currents (via sense resistor) */
365
366static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc2945_value, LTC2945_SENSE_H);
367static SENSOR_DEVICE_ATTR_RW(curr1_min, ltc2945_value,
368 LTC2945_MIN_SENSE_THRES_H);
369static SENSOR_DEVICE_ATTR_RW(curr1_max, ltc2945_value,
370 LTC2945_MAX_SENSE_THRES_H);
371static SENSOR_DEVICE_ATTR_RO(curr1_lowest, ltc2945_value, LTC2945_MIN_SENSE_H);
372static SENSOR_DEVICE_ATTR_RO(curr1_highest, ltc2945_value,
373 LTC2945_MAX_SENSE_H);
374static SENSOR_DEVICE_ATTR_WO(curr1_reset_history, ltc2945_history,
375 LTC2945_MIN_SENSE_H);
376
377/* Current alarms */
378
379static SENSOR_DEVICE_ATTR_RO(curr1_min_alarm, ltc2945_bool, FAULT_SENSE_UV);
380static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc2945_bool, FAULT_SENSE_OV);
381
382/* Power */
383
384static SENSOR_DEVICE_ATTR_RO(power1_input, ltc2945_value, LTC2945_POWER_H);
385static SENSOR_DEVICE_ATTR_RW(power1_min, ltc2945_value,
386 LTC2945_MIN_POWER_THRES_H);
387static SENSOR_DEVICE_ATTR_RW(power1_max, ltc2945_value,
388 LTC2945_MAX_POWER_THRES_H);
389static SENSOR_DEVICE_ATTR_RO(power1_input_lowest, ltc2945_value,
390 LTC2945_MIN_POWER_H);
391static SENSOR_DEVICE_ATTR_RO(power1_input_highest, ltc2945_value,
392 LTC2945_MAX_POWER_H);
393static SENSOR_DEVICE_ATTR_WO(power1_reset_history, ltc2945_history,
394 LTC2945_MIN_POWER_H);
395
396/* Power alarms */
397
398static SENSOR_DEVICE_ATTR_RO(power1_min_alarm, ltc2945_bool, FAULT_POWER_UV);
399static SENSOR_DEVICE_ATTR_RO(power1_max_alarm, ltc2945_bool, FAULT_POWER_OV);
400
401static struct attribute *ltc2945_attrs[] = {
402 &sensor_dev_attr_in1_input.dev_attr.attr,
403 &sensor_dev_attr_in1_min.dev_attr.attr,
404 &sensor_dev_attr_in1_max.dev_attr.attr,
405 &sensor_dev_attr_in1_lowest.dev_attr.attr,
406 &sensor_dev_attr_in1_highest.dev_attr.attr,
407 &sensor_dev_attr_in1_reset_history.dev_attr.attr,
408 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
409 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
410
411 &sensor_dev_attr_in2_input.dev_attr.attr,
412 &sensor_dev_attr_in2_min.dev_attr.attr,
413 &sensor_dev_attr_in2_max.dev_attr.attr,
414 &sensor_dev_attr_in2_lowest.dev_attr.attr,
415 &sensor_dev_attr_in2_highest.dev_attr.attr,
416 &sensor_dev_attr_in2_reset_history.dev_attr.attr,
417 &sensor_dev_attr_in2_min_alarm.dev_attr.attr,
418 &sensor_dev_attr_in2_max_alarm.dev_attr.attr,
419
420 &sensor_dev_attr_curr1_input.dev_attr.attr,
421 &sensor_dev_attr_curr1_min.dev_attr.attr,
422 &sensor_dev_attr_curr1_max.dev_attr.attr,
423 &sensor_dev_attr_curr1_lowest.dev_attr.attr,
424 &sensor_dev_attr_curr1_highest.dev_attr.attr,
425 &sensor_dev_attr_curr1_reset_history.dev_attr.attr,
426 &sensor_dev_attr_curr1_min_alarm.dev_attr.attr,
427 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
428
429 &sensor_dev_attr_power1_input.dev_attr.attr,
430 &sensor_dev_attr_power1_min.dev_attr.attr,
431 &sensor_dev_attr_power1_max.dev_attr.attr,
432 &sensor_dev_attr_power1_input_lowest.dev_attr.attr,
433 &sensor_dev_attr_power1_input_highest.dev_attr.attr,
434 &sensor_dev_attr_power1_reset_history.dev_attr.attr,
435 &sensor_dev_attr_power1_min_alarm.dev_attr.attr,
436 &sensor_dev_attr_power1_max_alarm.dev_attr.attr,
437
438 NULL,
439};
440ATTRIBUTE_GROUPS(ltc2945);
441
442static const struct regmap_config ltc2945_regmap_config = {
443 .reg_bits = 8,
444 .val_bits = 8,
445 .max_register = LTC2945_MIN_ADIN_THRES_L,
446};
447
448static int ltc2945_probe(struct i2c_client *client,
449 const struct i2c_device_id *id)
450{
451 struct device *dev = &client->dev;
452 struct device *hwmon_dev;
453 struct regmap *regmap;
454
455 regmap = devm_regmap_init_i2c(client, <c2945_regmap_config);
456 if (IS_ERR(regmap)) {
457 dev_err(dev, "failed to allocate register map\n");
458 return PTR_ERR(regmap);
459 }
460
461 /* Clear faults */
462 regmap_write(regmap, LTC2945_FAULT, 0x00);
463
464 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
465 regmap,
466 ltc2945_groups);
467 return PTR_ERR_OR_ZERO(hwmon_dev);
468}
469
470static const struct i2c_device_id ltc2945_id[] = {
471 {"ltc2945", 0},
472 { }
473};
474
475MODULE_DEVICE_TABLE(i2c, ltc2945_id);
476
477static struct i2c_driver ltc2945_driver = {
478 .driver = {
479 .name = "ltc2945",
480 },
481 .probe = ltc2945_probe,
482 .id_table = ltc2945_id,
483};
484
485module_i2c_driver(ltc2945_driver);
486
487MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
488MODULE_DESCRIPTION("LTC2945 driver");
489MODULE_LICENSE("GPL");