drivers/hwmon/ltc2945.c at v5.0

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