isl28022.c

  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
 82struct isl28022_data {
 83	struct regmap		*regmap;
 84	u32			shunt;
 85	u32			gain;
 86	u32			average;
 87};
 88
 89static 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
152static 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	u16 sign_bit;
158
159	switch (attr) {
160	case hwmon_curr_input:
161		err = regmap_read(data->regmap,
162				  ISL28022_REG_CURRENT, &regval);
163		if (err < 0)
164			return err;
165		sign_bit = (regval >> 15) & 0x01;
166		*val = (((long)(((u16)regval) & 0x7FFF) - (sign_bit * 32768)) *
167			1250L * (long)data->gain) / (long)data->shunt;
168		break;
169	default:
170		return -EOPNOTSUPP;
171	}
172
173	return 0;
174}
175
176static int isl28022_read_power(struct device *dev, u32 attr, long *val)
177{
178	struct isl28022_data *data = dev_get_drvdata(dev);
179	unsigned int regval;
180	int err;
181
182	switch (attr) {
183	case hwmon_power_input:
184		err = regmap_read(data->regmap,
185				  ISL28022_REG_POWER, &regval);
186		if (err < 0)
187			return err;
188		*val = ((51200000L * ((long)data->gain)) /
189			(long)data->shunt) * (long)regval;
190		break;
191	default:
192		return -EOPNOTSUPP;
193	}
194
195	return 0;
196}
197
198static int isl28022_read(struct device *dev, enum hwmon_sensor_types type,
199			 u32 attr, int channel, long *val)
200{
201	switch (type) {
202	case hwmon_in:
203		return isl28022_read_in(dev, attr, channel, val);
204	case hwmon_curr:
205		return isl28022_read_current(dev, attr, val);
206	case hwmon_power:
207		return isl28022_read_power(dev, attr, val);
208	default:
209		return -EOPNOTSUPP;
210	}
211	return 0;
212}
213
214static umode_t isl28022_is_visible(const void *data, enum hwmon_sensor_types type,
215				   u32 attr, int channel)
216{
217	switch (type) {
218	case hwmon_in:
219		switch (attr) {
220		case hwmon_in_input:
221			return 0444;
222		default:
223			break;
224		}
225		break;
226	case hwmon_curr:
227		switch (attr) {
228		case hwmon_curr_input:
229			return 0444;
230		default:
231			break;
232		}
233		break;
234	case hwmon_power:
235		switch (attr) {
236		case hwmon_power_input:
237			return 0444;
238		default:
239			break;
240		}
241		break;
242	default:
243		break;
244	}
245	return 0;
246}
247
248static const struct hwmon_channel_info *isl28022_info[] = {
249	HWMON_CHANNEL_INFO(in,
250			   HWMON_I_INPUT,	/* channel 0: bus voltage (mV) */
251			   HWMON_I_INPUT),	/* channel 1: shunt voltage (mV) */
252	HWMON_CHANNEL_INFO(curr,
253			   HWMON_C_INPUT),	/* channel 1: current (mA) */
254	HWMON_CHANNEL_INFO(power,
255			   HWMON_P_INPUT),	/* channel 1: power (µW) */
256	NULL
257};
258
259static const struct hwmon_ops isl28022_hwmon_ops = {
260	.is_visible = isl28022_is_visible,
261	.read = isl28022_read,
262};
263
264static const struct hwmon_chip_info isl28022_chip_info = {
265	.ops = &isl28022_hwmon_ops,
266	.info = isl28022_info,
267};
268
269static bool isl28022_is_writeable_reg(struct device *dev, unsigned int reg)
270{
271	switch (reg) {
272	case ISL28022_REG_CONFIG:
273	case ISL28022_REG_CALIB:
274	case ISL28022_REG_SHUNT_THR:
275	case ISL28022_REG_BUS_THR:
276	case ISL28022_REG_INT:
277	case ISL28022_REG_AUX:
278		return true;
279	}
280
281	return false;
282}
283
284static bool isl28022_is_volatile_reg(struct device *dev, unsigned int reg)
285{
286	switch (reg) {
287	case ISL28022_REG_CONFIG:
288	case ISL28022_REG_SHUNT:
289	case ISL28022_REG_BUS:
290	case ISL28022_REG_POWER:
291	case ISL28022_REG_CURRENT:
292	case ISL28022_REG_INT:
293	case ISL28022_REG_AUX:
294		return true;
295	}
296	return true;
297}
298
299static const struct regmap_config isl28022_regmap_config = {
300	.reg_bits = 8,
301	.val_bits = 16,
302	.max_register = ISL28022_REG_MAX,
303	.writeable_reg = isl28022_is_writeable_reg,
304	.volatile_reg = isl28022_is_volatile_reg,
305	.val_format_endian = REGMAP_ENDIAN_BIG,
306	.cache_type = REGCACHE_MAPLE,
307	.use_single_read = true,
308	.use_single_write = true,
309};
310
311static int shunt_voltage_show(struct seq_file *seqf, void *unused)
312{
313	struct isl28022_data *data = seqf->private;
314	unsigned int regval;
315	int err;
316
317	err = regmap_read(data->regmap,
318			  ISL28022_REG_SHUNT, &regval);
319	if (err)
320		return err;
321
322	/* print shunt voltage in micro volt  */
323	seq_printf(seqf, "%d\n", regval * 10);
324
325	return 0;
326}
327DEFINE_SHOW_ATTRIBUTE(shunt_voltage);
328
329/*
330 * read property values and make consistency checks.
331 *
332 * following values for shunt range and resistor are allowed:
333 *   40 mV -> gain 1, shunt min.  800 micro ohms
334 *   80 mV -> gain 2, shunt min. 1600 micro ohms
335 *  160 mV -> gain 4, shunt min. 3200 micro ohms
336 *  320 mV -> gain 8, shunt min. 6400 micro ohms
337 */
338static int isl28022_read_properties(struct device *dev, struct isl28022_data *data)
339{
340	u32 val;
341	int err;
342
343	err = device_property_read_u32(dev, "shunt-resistor-micro-ohms", &val);
344	if (err == -EINVAL)
345		val = 10000;
346	else if (err < 0)
347		return err;
348	data->shunt = val;
349
350	err = device_property_read_u32(dev, "renesas,shunt-range-microvolt", &val);
351	if (err == -EINVAL)
352		val = 320000;
353	else if (err < 0)
354		return err;
355
356	switch (val) {
357	case 40000:
358		data->gain = 1;
359		if (data->shunt < 800)
360			goto shunt_invalid;
361		break;
362	case 80000:
363		data->gain = 2;
364		if (data->shunt < 1600)
365			goto shunt_invalid;
366		break;
367	case 160000:
368		data->gain = 4;
369		if (data->shunt < 3200)
370			goto shunt_invalid;
371		break;
372	case 320000:
373		data->gain = 8;
374		if (data->shunt < 6400)
375			goto shunt_invalid;
376		break;
377	default:
378		return dev_err_probe(dev, -EINVAL,
379				     "renesas,shunt-range-microvolt invalid value %d\n",
380				     val);
381	}
382
383	err = device_property_read_u32(dev, "renesas,average-samples", &val);
384	if (err == -EINVAL)
385		val = 1;
386	else if (err < 0)
387		return err;
388	if (val > 128 || hweight32(val) != 1)
389		return dev_err_probe(dev, -EINVAL,
390				     "renesas,average-samples invalid value %d\n",
391				     val);
392
393	data->average = val;
394
395	return 0;
396
397shunt_invalid:
398	return dev_err_probe(dev, -EINVAL,
399			     "renesas,shunt-resistor-microvolt invalid value %d\n",
400			     data->shunt);
401}
402
403/*
404 * write configuration and calibration registers
405 *
406 * The driver supports only shunt and bus continuous ADC mode at 15bit resolution
407 * with averaging from 1 to 128 samples (pow of 2) on both channels.
408 * Shunt voltage gain 1,2,4 or 8 is allowed.
409 * The bus voltage range is 60V fixed.
410 */
411static int isl28022_config(struct isl28022_data *data)
412{
413	int err;
414	u16 config;
415	u16 calib;
416
417	config = (ISL28022_MODE_CONT_SB << ISL28022_MODE_SHIFT) |
418			(ISL28022_BRNG_60 << ISL28022_BRNG_SHIFT) |
419			(__ffs(data->gain) << ISL28022_PG_SHIFT) |
420			((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_SADC_SHIFT) |
421			((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_BADC_SHIFT);
422
423	calib = data->shunt ? 0x8000 / data->gain : 0;
424
425	err = regmap_write(data->regmap, ISL28022_REG_CONFIG, config);
426	if (err < 0)
427		return err;
428
429	return regmap_write(data->regmap, ISL28022_REG_CALIB, calib);
430}
431
432static int isl28022_probe(struct i2c_client *client)
433{
434	struct device *dev = &client->dev;
435	struct device *hwmon_dev;
436	struct isl28022_data *data;
437	int err;
438
439	if (!i2c_check_functionality(client->adapter,
440				     I2C_FUNC_SMBUS_BYTE_DATA |
441				     I2C_FUNC_SMBUS_WORD_DATA))
442		return -ENODEV;
443
444	data = devm_kzalloc(dev, sizeof(struct isl28022_data), GFP_KERNEL);
445	if (!data)
446		return -ENOMEM;
447
448	err = isl28022_read_properties(dev, data);
449	if (err)
450		return err;
451
452	data->regmap = devm_regmap_init_i2c(client, &isl28022_regmap_config);
453	if (IS_ERR(data->regmap))
454		return PTR_ERR(data->regmap);
455
456	err = isl28022_config(data);
457	if (err)
458		return err;
459
460	debugfs_create_file("shunt_voltage", 0444, client->debugfs, data, &shunt_voltage_fops);
461
462	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
463							 data, &isl28022_chip_info, NULL);
464	if (IS_ERR(hwmon_dev))
465		return PTR_ERR(hwmon_dev);
466
467	return 0;
468}
469
470static const struct i2c_device_id isl28022_ids[] = {
471	{ "isl28022" },
472	{ /* LIST END */ }
473};
474MODULE_DEVICE_TABLE(i2c, isl28022_ids);
475
476static const struct of_device_id __maybe_unused isl28022_of_match[] = {
477	{ .compatible = "renesas,isl28022"},
478	{ /* LIST END */ }
479};
480MODULE_DEVICE_TABLE(of, isl28022_of_match);
481
482static struct i2c_driver isl28022_driver = {
483	.class		= I2C_CLASS_HWMON,
484	.driver = {
485		.name	= "isl28022",
486	},
487	.probe	= isl28022_probe,
488	.id_table	= isl28022_ids,
489};
490module_i2c_driver(isl28022_driver);
491
492MODULE_AUTHOR("Carsten Spieß <mail@carsten-spiess.de>");
493MODULE_DESCRIPTION("ISL28022 driver");
494MODULE_LICENSE("GPL");