xref: /linux/drivers/power/supply/max1720x_battery.c (revision f28f4890454cc97c18d31ab4686957857cc862b5)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Fuel gauge driver for Maxim 17201/17205
4  *
5  * based on max1721x_battery.c
6  *
7  * Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
8  */
9 
10 #include <linux/bitfield.h>
11 #include <linux/i2c.h>
12 #include <linux/module.h>
13 #include <linux/nvmem-provider.h>
14 #include <linux/power_supply.h>
15 #include <linux/regmap.h>
16 
17 #include <linux/unaligned.h>
18 
19 /* SBS compliant registers */
20 #define MAX172XX_TEMP1			0x34
21 #define MAX172XX_INT_TEMP		0x35
22 #define MAX172XX_TEMP2			0x3B
23 
24 /* Nonvolatile registers */
25 #define MAX1720X_NXTABLE0		0x80
26 #define MAX1720X_NRSENSE		0xCF	/* RSense in 10^-5 Ohm */
27 #define MAX1720X_NDEVICE_NAME4		0xDF
28 
29 /* ModelGauge m5 */
30 #define MAX172XX_STATUS			0x00	/* Status */
31 #define MAX172XX_STATUS_BAT_ABSENT	BIT(3)	/* Battery absent */
32 #define MAX172XX_REPCAP			0x05	/* Average capacity */
33 #define MAX172XX_REPSOC			0x06	/* Percentage of charge */
34 #define MAX172XX_TEMP			0x08	/* Temperature */
35 #define MAX172XX_CURRENT		0x0A	/* Actual current */
36 #define MAX172XX_AVG_CURRENT		0x0B	/* Average current */
37 #define MAX172XX_FULL_CAP		0x10	/* Calculated full capacity */
38 #define MAX172XX_TTE			0x11	/* Time to empty */
39 #define MAX172XX_AVG_TA			0x16	/* Average temperature */
40 #define MAX172XX_CYCLES			0x17
41 #define MAX172XX_DESIGN_CAP		0x18	/* Design capacity */
42 #define MAX172XX_AVG_VCELL		0x19
43 #define MAX172XX_TTF			0x20	/* Time to full */
44 #define MAX172XX_DEV_NAME		0x21	/* Device name */
45 #define MAX172XX_DEV_NAME_TYPE_MASK	GENMASK(3, 0)
46 #define MAX172XX_DEV_NAME_TYPE_MAX17201	BIT(0)
47 #define MAX172XX_DEV_NAME_TYPE_MAX17205	(BIT(0) | BIT(2))
48 #define MAX172XX_QR_TABLE10		0x22
49 #define MAX172XX_BATT			0xDA	/* Battery voltage */
50 #define MAX172XX_ATAVCAP		0xDF
51 
52 static const char *const max1720x_manufacturer = "Maxim Integrated";
53 static const char *const max17201_model = "MAX17201";
54 static const char *const max17205_model = "MAX17205";
55 
56 struct max1720x_device_info {
57 	struct regmap *regmap;
58 	struct regmap *regmap_nv;
59 	struct i2c_client *ancillary;
60 	int rsense;
61 };
62 
63 /*
64  * Model Gauge M5 Algorithm output register
65  * Volatile data (must not be cached)
66  */
67 static const struct regmap_range max1720x_volatile_allow[] = {
68 	regmap_reg_range(MAX172XX_STATUS, MAX172XX_CYCLES),
69 	regmap_reg_range(MAX172XX_AVG_VCELL, MAX172XX_TTF),
70 	regmap_reg_range(MAX172XX_QR_TABLE10, MAX172XX_ATAVCAP),
71 };
72 
73 static const struct regmap_range max1720x_readable_allow[] = {
74 	regmap_reg_range(MAX172XX_STATUS, MAX172XX_ATAVCAP),
75 };
76 
77 static const struct regmap_range max1720x_readable_deny[] = {
78 	/* unused registers */
79 	regmap_reg_range(0x24, 0x26),
80 	regmap_reg_range(0x30, 0x31),
81 	regmap_reg_range(0x33, 0x34),
82 	regmap_reg_range(0x37, 0x37),
83 	regmap_reg_range(0x3B, 0x3C),
84 	regmap_reg_range(0x40, 0x41),
85 	regmap_reg_range(0x43, 0x44),
86 	regmap_reg_range(0x47, 0x49),
87 	regmap_reg_range(0x4B, 0x4C),
88 	regmap_reg_range(0x4E, 0xAF),
89 	regmap_reg_range(0xB1, 0xB3),
90 	regmap_reg_range(0xB5, 0xB7),
91 	regmap_reg_range(0xBF, 0xD0),
92 	regmap_reg_range(0xDB, 0xDB),
93 	regmap_reg_range(0xE0, 0xFF),
94 };
95 
96 static const struct regmap_access_table max1720x_readable_regs = {
97 	.yes_ranges	= max1720x_readable_allow,
98 	.n_yes_ranges	= ARRAY_SIZE(max1720x_readable_allow),
99 	.no_ranges	= max1720x_readable_deny,
100 	.n_no_ranges	= ARRAY_SIZE(max1720x_readable_deny),
101 };
102 
103 static const struct regmap_access_table max1720x_volatile_regs = {
104 	.yes_ranges	= max1720x_volatile_allow,
105 	.n_yes_ranges	= ARRAY_SIZE(max1720x_volatile_allow),
106 	.no_ranges	= max1720x_readable_deny,
107 	.n_no_ranges	= ARRAY_SIZE(max1720x_readable_deny),
108 };
109 
110 static const struct regmap_config max1720x_regmap_cfg = {
111 	.reg_bits = 8,
112 	.val_bits = 16,
113 	.max_register = MAX172XX_ATAVCAP,
114 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
115 	.rd_table = &max1720x_readable_regs,
116 	.volatile_table = &max1720x_volatile_regs,
117 	.cache_type = REGCACHE_RBTREE,
118 };
119 
120 static const struct regmap_range max1720x_nvmem_allow[] = {
121 	regmap_reg_range(MAX172XX_TEMP1, MAX172XX_INT_TEMP),
122 	regmap_reg_range(MAX172XX_TEMP2, MAX172XX_TEMP2),
123 	regmap_reg_range(MAX1720X_NXTABLE0, MAX1720X_NDEVICE_NAME4),
124 };
125 
126 static const struct regmap_range max1720x_nvmem_deny[] = {
127 	regmap_reg_range(0x00, 0x33),
128 	regmap_reg_range(0x36, 0x3A),
129 	regmap_reg_range(0x3C, 0x7F),
130 	regmap_reg_range(0xE0, 0xFF),
131 };
132 
133 static const struct regmap_access_table max1720x_nvmem_regs = {
134 	.yes_ranges	= max1720x_nvmem_allow,
135 	.n_yes_ranges	= ARRAY_SIZE(max1720x_nvmem_allow),
136 	.no_ranges	= max1720x_nvmem_deny,
137 	.n_no_ranges	= ARRAY_SIZE(max1720x_nvmem_deny),
138 };
139 
140 static const struct regmap_config max1720x_nvmem_regmap_cfg = {
141 	.reg_bits = 8,
142 	.val_bits = 16,
143 	.max_register = MAX1720X_NDEVICE_NAME4,
144 	.val_format_endian = REGMAP_ENDIAN_LITTLE,
145 	.rd_table = &max1720x_nvmem_regs,
146 };
147 
148 static const struct nvmem_cell_info max1720x_nvmem_cells[] = {
149 	{ .name = "nXTable0",  .offset = 0,  .bytes = 2, },
150 	{ .name = "nXTable1",  .offset = 2,  .bytes = 2, },
151 	{ .name = "nXTable2",  .offset = 4,  .bytes = 2, },
152 	{ .name = "nXTable3",  .offset = 6,  .bytes = 2, },
153 	{ .name = "nXTable4",  .offset = 8,  .bytes = 2, },
154 	{ .name = "nXTable5",  .offset = 10, .bytes = 2, },
155 	{ .name = "nXTable6",  .offset = 12, .bytes = 2, },
156 	{ .name = "nXTable7",  .offset = 14, .bytes = 2, },
157 	{ .name = "nXTable8",  .offset = 16, .bytes = 2, },
158 	{ .name = "nXTable9",  .offset = 18, .bytes = 2, },
159 	{ .name = "nXTable10", .offset = 20, .bytes = 2, },
160 	{ .name = "nXTable11", .offset = 22, .bytes = 2, },
161 	{ .name = "nUser18C",  .offset = 24, .bytes = 2, },
162 	{ .name = "nUser18D",  .offset = 26, .bytes = 2, },
163 	{ .name = "nODSCTh",   .offset = 28, .bytes = 2, },
164 	{ .name = "nODSCCfg",  .offset = 30, .bytes = 2, },
165 
166 	{ .name = "nOCVTable0",  .offset = 32, .bytes = 2, },
167 	{ .name = "nOCVTable1",  .offset = 34, .bytes = 2, },
168 	{ .name = "nOCVTable2",  .offset = 36, .bytes = 2, },
169 	{ .name = "nOCVTable3",  .offset = 38, .bytes = 2, },
170 	{ .name = "nOCVTable4",  .offset = 40, .bytes = 2, },
171 	{ .name = "nOCVTable5",  .offset = 42, .bytes = 2, },
172 	{ .name = "nOCVTable6",  .offset = 44, .bytes = 2, },
173 	{ .name = "nOCVTable7",  .offset = 46, .bytes = 2, },
174 	{ .name = "nOCVTable8",  .offset = 48, .bytes = 2, },
175 	{ .name = "nOCVTable9",  .offset = 50, .bytes = 2, },
176 	{ .name = "nOCVTable10", .offset = 52, .bytes = 2, },
177 	{ .name = "nOCVTable11", .offset = 54, .bytes = 2, },
178 	{ .name = "nIChgTerm",   .offset = 56, .bytes = 2, },
179 	{ .name = "nFilterCfg",  .offset = 58, .bytes = 2, },
180 	{ .name = "nVEmpty",     .offset = 60, .bytes = 2, },
181 	{ .name = "nLearnCfg",   .offset = 62, .bytes = 2, },
182 
183 	{ .name = "nQRTable00",  .offset = 64, .bytes = 2, },
184 	{ .name = "nQRTable10",  .offset = 66, .bytes = 2, },
185 	{ .name = "nQRTable20",  .offset = 68, .bytes = 2, },
186 	{ .name = "nQRTable30",  .offset = 70, .bytes = 2, },
187 	{ .name = "nCycles",     .offset = 72, .bytes = 2, },
188 	{ .name = "nFullCapNom", .offset = 74, .bytes = 2, },
189 	{ .name = "nRComp0",     .offset = 76, .bytes = 2, },
190 	{ .name = "nTempCo",     .offset = 78, .bytes = 2, },
191 	{ .name = "nIAvgEmpty",  .offset = 80, .bytes = 2, },
192 	{ .name = "nFullCapRep", .offset = 82, .bytes = 2, },
193 	{ .name = "nVoltTemp",   .offset = 84, .bytes = 2, },
194 	{ .name = "nMaxMinCurr", .offset = 86, .bytes = 2, },
195 	{ .name = "nMaxMinVolt", .offset = 88, .bytes = 2, },
196 	{ .name = "nMaxMinTemp", .offset = 90, .bytes = 2, },
197 	{ .name = "nSOC",        .offset = 92, .bytes = 2, },
198 	{ .name = "nTimerH",     .offset = 94, .bytes = 2, },
199 
200 	{ .name = "nConfig",    .offset = 96,  .bytes = 2, },
201 	{ .name = "nRippleCfg", .offset = 98,  .bytes = 2, },
202 	{ .name = "nMiscCfg",   .offset = 100, .bytes = 2, },
203 	{ .name = "nDesignCap", .offset = 102, .bytes = 2, },
204 	{ .name = "nHibCfg",    .offset = 104, .bytes = 2, },
205 	{ .name = "nPackCfg",   .offset = 106, .bytes = 2, },
206 	{ .name = "nRelaxCfg",  .offset = 108, .bytes = 2, },
207 	{ .name = "nConvgCfg",  .offset = 110, .bytes = 2, },
208 	{ .name = "nNVCfg0",    .offset = 112, .bytes = 2, },
209 	{ .name = "nNVCfg1",    .offset = 114, .bytes = 2, },
210 	{ .name = "nNVCfg2",    .offset = 116, .bytes = 2, },
211 	{ .name = "nSBSCfg",    .offset = 118, .bytes = 2, },
212 	{ .name = "nROMID0",    .offset = 120, .bytes = 2, },
213 	{ .name = "nROMID1",    .offset = 122, .bytes = 2, },
214 	{ .name = "nROMID2",    .offset = 124, .bytes = 2, },
215 	{ .name = "nROMID3",    .offset = 126, .bytes = 2, },
216 
217 	{ .name = "nVAlrtTh",      .offset = 128, .bytes = 2, },
218 	{ .name = "nTAlrtTh",      .offset = 130, .bytes = 2, },
219 	{ .name = "nSAlrtTh",      .offset = 132, .bytes = 2, },
220 	{ .name = "nIAlrtTh",      .offset = 134, .bytes = 2, },
221 	{ .name = "nUser1C4",      .offset = 136, .bytes = 2, },
222 	{ .name = "nUser1C5",      .offset = 138, .bytes = 2, },
223 	{ .name = "nFullSOCThr",   .offset = 140, .bytes = 2, },
224 	{ .name = "nTTFCfg",       .offset = 142, .bytes = 2, },
225 	{ .name = "nCGain",        .offset = 144, .bytes = 2, },
226 	{ .name = "nTCurve",       .offset = 146, .bytes = 2, },
227 	{ .name = "nTGain",        .offset = 148, .bytes = 2, },
228 	{ .name = "nTOff",         .offset = 150, .bytes = 2, },
229 	{ .name = "nManfctrName0", .offset = 152, .bytes = 2, },
230 	{ .name = "nManfctrName1", .offset = 154, .bytes = 2, },
231 	{ .name = "nManfctrName2", .offset = 156, .bytes = 2, },
232 	{ .name = "nRSense",       .offset = 158, .bytes = 2, },
233 
234 	{ .name = "nUser1D0",       .offset = 160, .bytes = 2, },
235 	{ .name = "nUser1D1",       .offset = 162, .bytes = 2, },
236 	{ .name = "nAgeFcCfg",      .offset = 164, .bytes = 2, },
237 	{ .name = "nDesignVoltage", .offset = 166, .bytes = 2, },
238 	{ .name = "nUser1D4",       .offset = 168, .bytes = 2, },
239 	{ .name = "nRFastVShdn",    .offset = 170, .bytes = 2, },
240 	{ .name = "nManfctrDate",   .offset = 172, .bytes = 2, },
241 	{ .name = "nFirstUsed",     .offset = 174, .bytes = 2, },
242 	{ .name = "nSerialNumber0", .offset = 176, .bytes = 2, },
243 	{ .name = "nSerialNumber1", .offset = 178, .bytes = 2, },
244 	{ .name = "nSerialNumber2", .offset = 180, .bytes = 2, },
245 	{ .name = "nDeviceName0",   .offset = 182, .bytes = 2, },
246 	{ .name = "nDeviceName1",   .offset = 184, .bytes = 2, },
247 	{ .name = "nDeviceName2",   .offset = 186, .bytes = 2, },
248 	{ .name = "nDeviceName3",   .offset = 188, .bytes = 2, },
249 	{ .name = "nDeviceName4",   .offset = 190, .bytes = 2, },
250 };
251 
252 static const enum power_supply_property max1720x_battery_props[] = {
253 	POWER_SUPPLY_PROP_PRESENT,
254 	POWER_SUPPLY_PROP_CAPACITY,
255 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
256 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
257 	POWER_SUPPLY_PROP_CHARGE_AVG,
258 	POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
259 	POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
260 	POWER_SUPPLY_PROP_TEMP,
261 	POWER_SUPPLY_PROP_CURRENT_NOW,
262 	POWER_SUPPLY_PROP_CURRENT_AVG,
263 	POWER_SUPPLY_PROP_CHARGE_FULL,
264 	POWER_SUPPLY_PROP_MODEL_NAME,
265 	POWER_SUPPLY_PROP_MANUFACTURER,
266 };
267 
268 /* Convert regs value to power_supply units */
269 
270 static int max172xx_time_to_ps(unsigned int reg)
271 {
272 	return reg * 5625 / 1000;	/* in sec. */
273 }
274 
275 static int max172xx_percent_to_ps(unsigned int reg)
276 {
277 	return reg / 256;	/* in percent from 0 to 100 */
278 }
279 
280 static int max172xx_voltage_to_ps(unsigned int reg)
281 {
282 	return reg * 1250;	/* in uV */
283 }
284 
285 static int max172xx_capacity_to_ps(unsigned int reg)
286 {
287 	return reg * 500;	/* in uAh */
288 }
289 
290 /*
291  * Current and temperature is signed values, so unsigned regs
292  * value must be converted to signed type
293  */
294 
295 static int max172xx_temperature_to_ps(unsigned int reg)
296 {
297 	int val = (int16_t)reg;
298 
299 	return val * 10 / 256; /* in tenths of deg. C */
300 }
301 
302 /*
303  * Calculating current registers resolution:
304  *
305  * RSense stored in 10^-5 Ohm, so mesaurment voltage must be
306  * in 10^-11 Volts for get current in uA.
307  * 16 bit current reg fullscale +/-51.2mV is 102400 uV.
308  * So: 102400 / 65535 * 10^5 = 156252
309  */
310 static int max172xx_current_to_voltage(unsigned int reg)
311 {
312 	int val = (int16_t)reg;
313 
314 	return val * 156252;
315 }
316 
317 static int max1720x_battery_get_property(struct power_supply *psy,
318 					 enum power_supply_property psp,
319 					 union power_supply_propval *val)
320 {
321 	struct max1720x_device_info *info = power_supply_get_drvdata(psy);
322 	unsigned int reg_val;
323 	int ret = 0;
324 
325 	switch (psp) {
326 	case POWER_SUPPLY_PROP_PRESENT:
327 		/*
328 		 * POWER_SUPPLY_PROP_PRESENT will always readable via
329 		 * sysfs interface. Value return 0 if battery not
330 		 * present or unaccesable via I2c.
331 		 */
332 		ret = regmap_read(info->regmap, MAX172XX_STATUS, &reg_val);
333 		if (ret < 0) {
334 			val->intval = 0;
335 			return 0;
336 		}
337 
338 		val->intval = !FIELD_GET(MAX172XX_STATUS_BAT_ABSENT, reg_val);
339 		break;
340 	case POWER_SUPPLY_PROP_CAPACITY:
341 		ret = regmap_read(info->regmap, MAX172XX_REPSOC, &reg_val);
342 		val->intval = max172xx_percent_to_ps(reg_val);
343 		break;
344 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
345 		ret = regmap_read(info->regmap, MAX172XX_BATT, &reg_val);
346 		val->intval = max172xx_voltage_to_ps(reg_val);
347 		break;
348 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
349 		ret = regmap_read(info->regmap, MAX172XX_DESIGN_CAP, &reg_val);
350 		val->intval = max172xx_capacity_to_ps(reg_val);
351 		break;
352 	case POWER_SUPPLY_PROP_CHARGE_AVG:
353 		ret = regmap_read(info->regmap, MAX172XX_REPCAP, &reg_val);
354 		val->intval = max172xx_capacity_to_ps(reg_val);
355 		break;
356 	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
357 		ret = regmap_read(info->regmap, MAX172XX_TTE, &reg_val);
358 		val->intval = max172xx_time_to_ps(reg_val);
359 		break;
360 	case POWER_SUPPLY_PROP_TIME_TO_FULL_AVG:
361 		ret = regmap_read(info->regmap, MAX172XX_TTF, &reg_val);
362 		val->intval = max172xx_time_to_ps(reg_val);
363 		break;
364 	case POWER_SUPPLY_PROP_TEMP:
365 		ret = regmap_read(info->regmap, MAX172XX_TEMP, &reg_val);
366 		val->intval = max172xx_temperature_to_ps(reg_val);
367 		break;
368 	case POWER_SUPPLY_PROP_CURRENT_NOW:
369 		ret = regmap_read(info->regmap, MAX172XX_CURRENT, &reg_val);
370 		val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
371 		break;
372 	case POWER_SUPPLY_PROP_CURRENT_AVG:
373 		ret = regmap_read(info->regmap, MAX172XX_AVG_CURRENT, &reg_val);
374 		val->intval = max172xx_current_to_voltage(reg_val) / info->rsense;
375 		break;
376 	case POWER_SUPPLY_PROP_CHARGE_FULL:
377 		ret = regmap_read(info->regmap, MAX172XX_FULL_CAP, &reg_val);
378 		val->intval = max172xx_capacity_to_ps(reg_val);
379 		break;
380 	case POWER_SUPPLY_PROP_MODEL_NAME:
381 		ret = regmap_read(info->regmap, MAX172XX_DEV_NAME, &reg_val);
382 		reg_val = FIELD_GET(MAX172XX_DEV_NAME_TYPE_MASK, reg_val);
383 		if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17201)
384 			val->strval = max17201_model;
385 		else if (reg_val == MAX172XX_DEV_NAME_TYPE_MAX17205)
386 			val->strval = max17205_model;
387 		else
388 			return -ENODEV;
389 		break;
390 	case POWER_SUPPLY_PROP_MANUFACTURER:
391 		val->strval = max1720x_manufacturer;
392 		break;
393 	default:
394 		return -EINVAL;
395 	}
396 
397 	return ret;
398 }
399 
400 static int max1720x_read_temp(struct device *dev, u8 reg, char *buf)
401 {
402 	struct power_supply *psy = dev_get_drvdata(dev);
403 	struct max1720x_device_info *info = power_supply_get_drvdata(psy);
404 	unsigned int val;
405 	int ret;
406 
407 	ret = regmap_read(info->regmap_nv, reg, &val);
408 	if (ret < 0)
409 		return ret;
410 
411 	/*
412 	 * Temperature in degrees Celsius starting at absolute zero, -273C or
413 	 * 0K with an LSb of 0.1C
414 	 */
415 	return sysfs_emit(buf, "%d\n", val - 2730);
416 }
417 
418 static ssize_t temp_ain1_show(struct device *dev, struct device_attribute *attr,
419 			      char *buf)
420 {
421 	return max1720x_read_temp(dev, MAX172XX_TEMP1, buf);
422 }
423 
424 static ssize_t temp_ain2_show(struct device *dev, struct device_attribute *attr,
425 			      char *buf)
426 {
427 	return max1720x_read_temp(dev, MAX172XX_TEMP2, buf);
428 }
429 
430 static ssize_t temp_int_show(struct device *dev, struct device_attribute *attr,
431 			     char *buf)
432 {
433 	return max1720x_read_temp(dev, MAX172XX_INT_TEMP, buf);
434 }
435 
436 static DEVICE_ATTR_RO(temp_ain1);
437 static DEVICE_ATTR_RO(temp_ain2);
438 static DEVICE_ATTR_RO(temp_int);
439 
440 static struct attribute *max1720x_attrs[] = {
441 	&dev_attr_temp_ain1.attr,
442 	&dev_attr_temp_ain2.attr,
443 	&dev_attr_temp_int.attr,
444 	NULL
445 };
446 ATTRIBUTE_GROUPS(max1720x);
447 
448 static
449 int max1720x_nvmem_reg_read(void *priv, unsigned int off, void *val, size_t len)
450 {
451 	struct max1720x_device_info *info = priv;
452 	unsigned int reg = MAX1720X_NXTABLE0 + (off / 2);
453 
454 	return regmap_bulk_read(info->regmap_nv, reg, val, len / 2);
455 }
456 
457 static void max1720x_unregister_ancillary(void *data)
458 {
459 	struct max1720x_device_info *info = data;
460 
461 	i2c_unregister_device(info->ancillary);
462 }
463 
464 static int max1720x_probe_nvmem(struct i2c_client *client,
465 				struct max1720x_device_info *info)
466 {
467 	struct device *dev = &client->dev;
468 	struct nvmem_config nvmem_config = {
469 		.dev = dev,
470 		.name = "max1720x_nvmem",
471 		.cells = max1720x_nvmem_cells,
472 		.ncells = ARRAY_SIZE(max1720x_nvmem_cells),
473 		.read_only = true,
474 		.root_only = true,
475 		.reg_read = max1720x_nvmem_reg_read,
476 		.size = ARRAY_SIZE(max1720x_nvmem_cells) * 2,
477 		.word_size = 2,
478 		.stride = 2,
479 		.priv = info,
480 	};
481 	struct nvmem_device *nvmem;
482 	unsigned int val;
483 	int ret;
484 
485 	info->ancillary = i2c_new_ancillary_device(client, "nvmem", 0xb);
486 	if (IS_ERR(info->ancillary)) {
487 		dev_err(dev, "Failed to initialize ancillary i2c device\n");
488 		return PTR_ERR(info->ancillary);
489 	}
490 
491 	ret = devm_add_action_or_reset(dev, max1720x_unregister_ancillary, info);
492 	if (ret) {
493 		dev_err(dev, "Failed to add unregister callback\n");
494 		return ret;
495 	}
496 
497 	info->regmap_nv = devm_regmap_init_i2c(info->ancillary,
498 					       &max1720x_nvmem_regmap_cfg);
499 	if (IS_ERR(info->regmap_nv)) {
500 		dev_err(dev, "regmap initialization of nvmem failed\n");
501 		return PTR_ERR(info->regmap_nv);
502 	}
503 
504 	ret = regmap_read(info->regmap_nv, MAX1720X_NRSENSE, &val);
505 	if (ret < 0) {
506 		dev_err(dev, "Failed to read sense resistor value\n");
507 		return ret;
508 	}
509 
510 	info->rsense = val;
511 	if (!info->rsense) {
512 		dev_warn(dev, "RSense not calibrated, set 10 mOhms!\n");
513 		info->rsense = 1000; /* in regs in 10^-5 */
514 	}
515 
516 	nvmem = devm_nvmem_register(dev, &nvmem_config);
517 	if (IS_ERR(nvmem)) {
518 		dev_err(dev, "Could not register nvmem!");
519 		return PTR_ERR(nvmem);
520 	}
521 
522 	return 0;
523 }
524 
525 static const struct power_supply_desc max1720x_bat_desc = {
526 	.name = "max1720x",
527 	.no_thermal = true,
528 	.type = POWER_SUPPLY_TYPE_BATTERY,
529 	.properties = max1720x_battery_props,
530 	.num_properties = ARRAY_SIZE(max1720x_battery_props),
531 	.get_property = max1720x_battery_get_property,
532 };
533 
534 static int max1720x_probe(struct i2c_client *client)
535 {
536 	struct power_supply_config psy_cfg = {};
537 	struct device *dev = &client->dev;
538 	struct max1720x_device_info *info;
539 	struct power_supply *bat;
540 	int ret;
541 
542 	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
543 	if (!info)
544 		return -ENOMEM;
545 
546 	psy_cfg.drv_data = info;
547 	psy_cfg.fwnode = dev_fwnode(dev);
548 	psy_cfg.attr_grp = max1720x_groups;
549 	i2c_set_clientdata(client, info);
550 	info->regmap = devm_regmap_init_i2c(client, &max1720x_regmap_cfg);
551 	if (IS_ERR(info->regmap))
552 		return dev_err_probe(dev, PTR_ERR(info->regmap),
553 				     "regmap initialization failed\n");
554 
555 	ret = max1720x_probe_nvmem(client, info);
556 	if (ret)
557 		return dev_err_probe(dev, ret, "Failed to probe nvmem\n");
558 
559 	bat = devm_power_supply_register(dev, &max1720x_bat_desc, &psy_cfg);
560 	if (IS_ERR(bat))
561 		return dev_err_probe(dev, PTR_ERR(bat),
562 				     "Failed to register power supply\n");
563 
564 	return 0;
565 }
566 
567 static const struct of_device_id max1720x_of_match[] = {
568 	{ .compatible = "maxim,max17201" },
569 	{}
570 };
571 MODULE_DEVICE_TABLE(of, max1720x_of_match);
572 
573 static struct i2c_driver max1720x_i2c_driver = {
574 	.driver = {
575 		.name = "max1720x",
576 		.of_match_table = max1720x_of_match,
577 	},
578 	.probe = max1720x_probe,
579 };
580 module_i2c_driver(max1720x_i2c_driver);
581 
582 MODULE_LICENSE("GPL");
583 MODULE_AUTHOR("Dimitri Fedrau <dima.fedrau@gmail.com>");
584 MODULE_DESCRIPTION("Maxim MAX17201/MAX17205 Fuel Gauge IC driver");
585