1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * isl28022.c - driver for Renesas ISL28022 power monitor chip monitoring
4  *
5  * Copyright (c) 2023 Carsten Spieß <mail@carsten-spiess.de>
6  */
7 
8 #include <linux/debugfs.h>
9 #include <linux/err.h>
10 #include <linux/hwmon.h>
11 #include <linux/i2c.h>
12 #include <linux/module.h>
13 #include <linux/regmap.h>
14 
15 /* ISL28022 registers */
16 #define ISL28022_REG_CONFIG	0x00
17 #define ISL28022_REG_SHUNT	0x01
18 #define ISL28022_REG_BUS	0x02
19 #define ISL28022_REG_POWER	0x03
20 #define ISL28022_REG_CURRENT	0x04
21 #define ISL28022_REG_CALIB	0x05
22 #define ISL28022_REG_SHUNT_THR	0x06
23 #define ISL28022_REG_BUS_THR	0x07
24 #define ISL28022_REG_INT	0x08
25 #define ISL28022_REG_AUX	0x09
26 #define ISL28022_REG_MAX	ISL28022_REG_AUX
27 
28 /* ISL28022 config flags */
29 /* mode flags */
30 #define ISL28022_MODE_SHIFT	0
31 #define ISL28022_MODE_MASK	0x0007
32 
33 #define ISL28022_MODE_PWR_DOWN	0x0
34 #define ISL28022_MODE_TRG_S	0x1
35 #define ISL28022_MODE_TRG_B	0x2
36 #define ISL28022_MODE_TRG_SB	0x3
37 #define ISL28022_MODE_ADC_OFF	0x4
38 #define ISL28022_MODE_CONT_S	0x5
39 #define ISL28022_MODE_CONT_B	0x6
40 #define ISL28022_MODE_CONT_SB	0x7
41 
42 /* shunt ADC settings */
43 #define ISL28022_SADC_SHIFT	3
44 #define ISL28022_SADC_MASK	0x0078
45 
46 #define ISL28022_BADC_SHIFT	7
47 #define ISL28022_BADC_MASK	0x0780
48 
49 #define ISL28022_ADC_12		0x0	/* 12 bit ADC */
50 #define ISL28022_ADC_13		0x1	/* 13 bit ADC */
51 #define ISL28022_ADC_14		0x2	/* 14 bit ADC */
52 #define ISL28022_ADC_15		0x3	/* 15 bit ADC */
53 #define ISL28022_ADC_15_1	0x8	/* 15 bit ADC, 1 sample */
54 #define ISL28022_ADC_15_2	0x9	/* 15 bit ADC, 2 samples */
55 #define ISL28022_ADC_15_4	0xA	/* 15 bit ADC, 4 samples */
56 #define ISL28022_ADC_15_8	0xB	/* 15 bit ADC, 8 samples */
57 #define ISL28022_ADC_15_16	0xC	/* 15 bit ADC, 16 samples */
58 #define ISL28022_ADC_15_32	0xD	/* 15 bit ADC, 32 samples */
59 #define ISL28022_ADC_15_64	0xE	/* 15 bit ADC, 64 samples */
60 #define ISL28022_ADC_15_128	0xF	/* 15 bit ADC, 128 samples */
61 
62 /* shunt voltage range */
63 #define ISL28022_PG_SHIFT	11
64 #define ISL28022_PG_MASK	0x1800
65 
66 #define ISL28022_PG_40		0x0	/* +/-40 mV */
67 #define ISL28022_PG_80		0x1	/* +/-80 mV */
68 #define ISL28022_PG_160		0x2	/* +/-160 mV */
69 #define ISL28022_PG_320		0x3	/* +/-3200 mV */
70 
71 /* bus voltage range */
72 #define ISL28022_BRNG_SHIFT	13
73 #define ISL28022_BRNG_MASK	0x6000
74 
75 #define ISL28022_BRNG_16	0x0	/* 16 V */
76 #define ISL28022_BRNG_32	0x1	/* 32 V */
77 #define ISL28022_BRNG_60	0x3	/* 60 V */
78 
79 /* reset */
80 #define ISL28022_RESET		0x8000
81 
82 struct isl28022_data {
83 	struct regmap		*regmap;
84 	u32			shunt;
85 	u32			gain;
86 	u32			average;
87 };
88 
isl28022_read_in(struct device * dev,u32 attr,int channel,long * val)89 static int isl28022_read_in(struct device *dev, u32 attr, int channel, long *val)
90 {
91 	struct isl28022_data *data = dev_get_drvdata(dev);
92 	unsigned int regval;
93 	int err;
94 	u16 sign_bit;
95 
96 	switch (channel) {
97 	case 0:
98 		switch (attr) {
99 		case hwmon_in_input:
100 			err = regmap_read(data->regmap,
101 					  ISL28022_REG_BUS, &regval);
102 			if (err < 0)
103 				return err;
104 			/* driver supports only 60V mode (BRNG 11) */
105 			*val = (long)(((u16)regval) & 0xFFFC);
106 			break;
107 		default:
108 			return -EOPNOTSUPP;
109 		}
110 		break;
111 	case 1:
112 		switch (attr) {
113 		case hwmon_in_input:
114 			err = regmap_read(data->regmap,
115 					  ISL28022_REG_SHUNT, &regval);
116 			if (err < 0)
117 				return err;
118 			switch (data->gain) {
119 			case 8:
120 				sign_bit = (regval >> 15) & 0x01;
121 				*val = (long)((((u16)regval) & 0x7FFF) -
122 					(sign_bit * 32768)) / 100;
123 				break;
124 			case 4:
125 				sign_bit = (regval >> 14) & 0x01;
126 				*val = (long)((((u16)regval) & 0x3FFF) -
127 					(sign_bit * 16384)) / 100;
128 				break;
129 			case 2:
130 				sign_bit = (regval >> 13) & 0x01;
131 				*val = (long)((((u16)regval) & 0x1FFF) -
132 					(sign_bit * 8192)) / 100;
133 				break;
134 			case 1:
135 				sign_bit = (regval >> 12) & 0x01;
136 				*val = (long)((((u16)regval) & 0x0FFF) -
137 					(sign_bit * 4096)) / 100;
138 				break;
139 			}
140 			break;
141 		default:
142 			return -EOPNOTSUPP;
143 		}
144 		break;
145 	default:
146 		return -EOPNOTSUPP;
147 	}
148 
149 	return 0;
150 }
151 
isl28022_read_current(struct device * dev,u32 attr,long * val)152 static int isl28022_read_current(struct device *dev, u32 attr, long *val)
153 {
154 	struct isl28022_data *data = dev_get_drvdata(dev);
155 	unsigned int regval;
156 	int err;
157 
158 	switch (attr) {
159 	case hwmon_curr_input:
160 		err = regmap_read(data->regmap,
161 				  ISL28022_REG_CURRENT, &regval);
162 		if (err < 0)
163 			return err;
164 		*val = ((long)regval * 1250L * (long)data->gain) /
165 			(long)data->shunt;
166 		break;
167 	default:
168 		return -EOPNOTSUPP;
169 	}
170 
171 	return 0;
172 }
173 
isl28022_read_power(struct device * dev,u32 attr,long * val)174 static int isl28022_read_power(struct device *dev, u32 attr, long *val)
175 {
176 	struct isl28022_data *data = dev_get_drvdata(dev);
177 	unsigned int regval;
178 	int err;
179 
180 	switch (attr) {
181 	case hwmon_power_input:
182 		err = regmap_read(data->regmap,
183 				  ISL28022_REG_POWER, &regval);
184 		if (err < 0)
185 			return err;
186 		*val = ((51200000L * ((long)data->gain)) /
187 			(long)data->shunt) * (long)regval;
188 		break;
189 	default:
190 		return -EOPNOTSUPP;
191 	}
192 
193 	return 0;
194 }
195 
isl28022_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)196 static int isl28022_read(struct device *dev, enum hwmon_sensor_types type,
197 			 u32 attr, int channel, long *val)
198 {
199 	switch (type) {
200 	case hwmon_in:
201 		return isl28022_read_in(dev, attr, channel, val);
202 	case hwmon_curr:
203 		return isl28022_read_current(dev, attr, val);
204 	case hwmon_power:
205 		return isl28022_read_power(dev, attr, val);
206 	default:
207 		return -EOPNOTSUPP;
208 	}
209 	return 0;
210 }
211 
isl28022_is_visible(const void * data,enum hwmon_sensor_types type,u32 attr,int channel)212 static umode_t isl28022_is_visible(const void *data, enum hwmon_sensor_types type,
213 				   u32 attr, int channel)
214 {
215 	switch (type) {
216 	case hwmon_in:
217 		switch (attr) {
218 		case hwmon_in_input:
219 			return 0444;
220 		default:
221 			break;
222 		}
223 		break;
224 	case hwmon_curr:
225 		switch (attr) {
226 		case hwmon_curr_input:
227 			return 0444;
228 		default:
229 			break;
230 		}
231 		break;
232 	case hwmon_power:
233 		switch (attr) {
234 		case hwmon_power_input:
235 			return 0444;
236 		default:
237 			break;
238 		}
239 		break;
240 	default:
241 		break;
242 	}
243 	return 0;
244 }
245 
246 static const struct hwmon_channel_info *isl28022_info[] = {
247 	HWMON_CHANNEL_INFO(in,
248 			   HWMON_I_INPUT,	/* channel 0: bus voltage (mV) */
249 			   HWMON_I_INPUT),	/* channel 1: shunt voltage (mV) */
250 	HWMON_CHANNEL_INFO(curr,
251 			   HWMON_C_INPUT),	/* channel 1: current (mA) */
252 	HWMON_CHANNEL_INFO(power,
253 			   HWMON_P_INPUT),	/* channel 1: power (µW) */
254 	NULL
255 };
256 
257 static const struct hwmon_ops isl28022_hwmon_ops = {
258 	.is_visible = isl28022_is_visible,
259 	.read = isl28022_read,
260 };
261 
262 static const struct hwmon_chip_info isl28022_chip_info = {
263 	.ops = &isl28022_hwmon_ops,
264 	.info = isl28022_info,
265 };
266 
isl28022_is_writeable_reg(struct device * dev,unsigned int reg)267 static bool isl28022_is_writeable_reg(struct device *dev, unsigned int reg)
268 {
269 	switch (reg) {
270 	case ISL28022_REG_CONFIG:
271 	case ISL28022_REG_CALIB:
272 	case ISL28022_REG_SHUNT_THR:
273 	case ISL28022_REG_BUS_THR:
274 	case ISL28022_REG_INT:
275 	case ISL28022_REG_AUX:
276 		return true;
277 	}
278 
279 	return false;
280 }
281 
isl28022_is_volatile_reg(struct device * dev,unsigned int reg)282 static bool isl28022_is_volatile_reg(struct device *dev, unsigned int reg)
283 {
284 	switch (reg) {
285 	case ISL28022_REG_CONFIG:
286 	case ISL28022_REG_SHUNT:
287 	case ISL28022_REG_BUS:
288 	case ISL28022_REG_POWER:
289 	case ISL28022_REG_CURRENT:
290 	case ISL28022_REG_INT:
291 	case ISL28022_REG_AUX:
292 		return true;
293 	}
294 	return true;
295 }
296 
297 static const struct regmap_config isl28022_regmap_config = {
298 	.reg_bits = 8,
299 	.val_bits = 16,
300 	.max_register = ISL28022_REG_MAX,
301 	.writeable_reg = isl28022_is_writeable_reg,
302 	.volatile_reg = isl28022_is_volatile_reg,
303 	.val_format_endian = REGMAP_ENDIAN_BIG,
304 	.cache_type = REGCACHE_RBTREE,
305 	.use_single_read = true,
306 	.use_single_write = true,
307 };
308 
shunt_voltage_show(struct seq_file * seqf,void * unused)309 static int shunt_voltage_show(struct seq_file *seqf, void *unused)
310 {
311 	struct isl28022_data *data = seqf->private;
312 	unsigned int regval;
313 	int err;
314 
315 	err = regmap_read(data->regmap,
316 			  ISL28022_REG_SHUNT, &regval);
317 	if (err)
318 		return err;
319 
320 	/* print shunt voltage in micro volt  */
321 	seq_printf(seqf, "%d\n", regval * 10);
322 
323 	return 0;
324 }
325 DEFINE_SHOW_ATTRIBUTE(shunt_voltage);
326 
327 /*
328  * read property values and make consistency checks.
329  *
330  * following values for shunt range and resistor are allowed:
331  *   40 mV -> gain 1, shunt min.  800 micro ohms
332  *   80 mV -> gain 2, shunt min. 1600 micro ohms
333  *  160 mV -> gain 4, shunt min. 3200 micro ohms
334  *  320 mV -> gain 8, shunt min. 6400 micro ohms
335  */
isl28022_read_properties(struct device * dev,struct isl28022_data * data)336 static int isl28022_read_properties(struct device *dev, struct isl28022_data *data)
337 {
338 	u32 val;
339 	int err;
340 
341 	err = device_property_read_u32(dev, "shunt-resistor-micro-ohms", &val);
342 	if (err == -EINVAL)
343 		val = 10000;
344 	else if (err < 0)
345 		return err;
346 	data->shunt = val;
347 
348 	err = device_property_read_u32(dev, "renesas,shunt-range-microvolt", &val);
349 	if (err == -EINVAL)
350 		val = 320000;
351 	else if (err < 0)
352 		return err;
353 
354 	switch (val) {
355 	case 40000:
356 		data->gain = 1;
357 		if (data->shunt < 800)
358 			goto shunt_invalid;
359 		break;
360 	case 80000:
361 		data->gain = 2;
362 		if (data->shunt < 1600)
363 			goto shunt_invalid;
364 		break;
365 	case 160000:
366 		data->gain = 4;
367 		if (data->shunt < 3200)
368 			goto shunt_invalid;
369 		break;
370 	case 320000:
371 		data->gain = 8;
372 		if (data->shunt < 6400)
373 			goto shunt_invalid;
374 		break;
375 	default:
376 		return dev_err_probe(dev, -EINVAL,
377 				     "renesas,shunt-range-microvolt invalid value %d\n",
378 				     val);
379 	}
380 
381 	err = device_property_read_u32(dev, "renesas,average-samples", &val);
382 	if (err == -EINVAL)
383 		val = 1;
384 	else if (err < 0)
385 		return err;
386 	if (val > 128 || hweight32(val) != 1)
387 		return dev_err_probe(dev, -EINVAL,
388 				     "renesas,average-samples invalid value %d\n",
389 				     val);
390 
391 	data->average = val;
392 
393 	return 0;
394 
395 shunt_invalid:
396 	return dev_err_probe(dev, -EINVAL,
397 			     "renesas,shunt-resistor-microvolt invalid value %d\n",
398 			     data->shunt);
399 }
400 
401 /*
402  * write configuration and calibration registers
403  *
404  * The driver supports only shunt and bus continuous ADC mode at 15bit resolution
405  * with averaging from 1 to 128 samples (pow of 2) on both channels.
406  * Shunt voltage gain 1,2,4 or 8 is allowed.
407  * The bus voltage range is 60V fixed.
408  */
isl28022_config(struct isl28022_data * data)409 static int isl28022_config(struct isl28022_data *data)
410 {
411 	int err;
412 	u16 config;
413 	u16 calib;
414 
415 	config = (ISL28022_MODE_CONT_SB << ISL28022_MODE_SHIFT) |
416 			(ISL28022_BRNG_60 << ISL28022_BRNG_SHIFT) |
417 			(__ffs(data->gain) << ISL28022_PG_SHIFT) |
418 			((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_SADC_SHIFT) |
419 			((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_BADC_SHIFT);
420 
421 	calib = data->shunt ? 0x8000 / data->gain : 0;
422 
423 	err = regmap_write(data->regmap, ISL28022_REG_CONFIG, config);
424 	if (err < 0)
425 		return err;
426 
427 	return regmap_write(data->regmap, ISL28022_REG_CALIB, calib);
428 }
429 
isl28022_probe(struct i2c_client * client)430 static int isl28022_probe(struct i2c_client *client)
431 {
432 	struct device *dev = &client->dev;
433 	struct device *hwmon_dev;
434 	struct isl28022_data *data;
435 	int err;
436 
437 	if (!i2c_check_functionality(client->adapter,
438 				     I2C_FUNC_SMBUS_BYTE_DATA |
439 				     I2C_FUNC_SMBUS_WORD_DATA))
440 		return -ENODEV;
441 
442 	data = devm_kzalloc(dev, sizeof(struct isl28022_data), GFP_KERNEL);
443 	if (!data)
444 		return -ENOMEM;
445 
446 	err = isl28022_read_properties(dev, data);
447 	if (err)
448 		return err;
449 
450 	data->regmap = devm_regmap_init_i2c(client, &isl28022_regmap_config);
451 	if (IS_ERR(data->regmap))
452 		return PTR_ERR(data->regmap);
453 
454 	err = isl28022_config(data);
455 	if (err)
456 		return err;
457 
458 	debugfs_create_file("shunt_voltage", 0444, client->debugfs, data, &shunt_voltage_fops);
459 
460 	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
461 							 data, &isl28022_chip_info, NULL);
462 	if (IS_ERR(hwmon_dev))
463 		return PTR_ERR(hwmon_dev);
464 
465 	return 0;
466 }
467 
468 static const struct i2c_device_id isl28022_ids[] = {
469 	{ "isl28022" },
470 	{ /* LIST END */ }
471 };
472 MODULE_DEVICE_TABLE(i2c, isl28022_ids);
473 
474 static const struct of_device_id __maybe_unused isl28022_of_match[] = {
475 	{ .compatible = "renesas,isl28022"},
476 	{ /* LIST END */ }
477 };
478 MODULE_DEVICE_TABLE(of, isl28022_of_match);
479 
480 static struct i2c_driver isl28022_driver = {
481 	.class		= I2C_CLASS_HWMON,
482 	.driver = {
483 		.name	= "isl28022",
484 	},
485 	.probe	= isl28022_probe,
486 	.id_table	= isl28022_ids,
487 };
488 module_i2c_driver(isl28022_driver);
489 
490 MODULE_AUTHOR("Carsten Spieß <mail@carsten-spiess.de>");
491 MODULE_DESCRIPTION("ISL28022 driver");
492 MODULE_LICENSE("GPL");
493