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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 <[email protected]>
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/math64.h>
13#include <linux/module.h>
14#include <linux/regmap.h>
15
16/* ISL28022 registers */
17#define ISL28022_REG_CONFIG 0x00
18#define ISL28022_REG_SHUNT 0x01
19#define ISL28022_REG_BUS 0x02
20#define ISL28022_REG_POWER 0x03
21#define ISL28022_REG_CURRENT 0x04
22#define ISL28022_REG_CALIB 0x05
23#define ISL28022_REG_SHUNT_THR 0x06
24#define ISL28022_REG_BUS_THR 0x07
25#define ISL28022_REG_INT 0x08
26#define ISL28022_REG_AUX 0x09
27#define ISL28022_REG_MAX ISL28022_REG_AUX
28
29/* ISL28022 config flags */
30/* mode flags */
31#define ISL28022_MODE_SHIFT 0
32#define ISL28022_MODE_MASK 0x0007
33
34#define ISL28022_MODE_PWR_DOWN 0x0
35#define ISL28022_MODE_TRG_S 0x1
36#define ISL28022_MODE_TRG_B 0x2
37#define ISL28022_MODE_TRG_SB 0x3
38#define ISL28022_MODE_ADC_OFF 0x4
39#define ISL28022_MODE_CONT_S 0x5
40#define ISL28022_MODE_CONT_B 0x6
41#define ISL28022_MODE_CONT_SB 0x7
42
43/* shunt ADC settings */
44#define ISL28022_SADC_SHIFT 3
45#define ISL28022_SADC_MASK 0x0078
46
47#define ISL28022_BADC_SHIFT 7
48#define ISL28022_BADC_MASK 0x0780
49
50#define ISL28022_ADC_12 0x0 /* 12 bit ADC */
51#define ISL28022_ADC_13 0x1 /* 13 bit ADC */
52#define ISL28022_ADC_14 0x2 /* 14 bit ADC */
53#define ISL28022_ADC_15 0x3 /* 15 bit ADC */
54#define ISL28022_ADC_15_1 0x8 /* 15 bit ADC, 1 sample */
55#define ISL28022_ADC_15_2 0x9 /* 15 bit ADC, 2 samples */
56#define ISL28022_ADC_15_4 0xA /* 15 bit ADC, 4 samples */
57#define ISL28022_ADC_15_8 0xB /* 15 bit ADC, 8 samples */
58#define ISL28022_ADC_15_16 0xC /* 15 bit ADC, 16 samples */
59#define ISL28022_ADC_15_32 0xD /* 15 bit ADC, 32 samples */
60#define ISL28022_ADC_15_64 0xE /* 15 bit ADC, 64 samples */
61#define ISL28022_ADC_15_128 0xF /* 15 bit ADC, 128 samples */
62
63/* shunt voltage range */
64#define ISL28022_PG_SHIFT 11
65#define ISL28022_PG_MASK 0x1800
66
67#define ISL28022_PG_40 0x0 /* +/-40 mV */
68#define ISL28022_PG_80 0x1 /* +/-80 mV */
69#define ISL28022_PG_160 0x2 /* +/-160 mV */
70#define ISL28022_PG_320 0x3 /* +/-3200 mV */
71
72/* bus voltage range */
73#define ISL28022_BRNG_SHIFT 13
74#define ISL28022_BRNG_MASK 0x6000
75
76#define ISL28022_BRNG_16 0x0 /* 16 V */
77#define ISL28022_BRNG_32 0x1 /* 32 V */
78#define ISL28022_BRNG_60 0x3 /* 60 V */
79
80/* reset */
81#define ISL28022_RESET 0x8000
82
83struct isl28022_data {
84 struct regmap *regmap;
85 u32 shunt;
86 u32 gain;
87 u32 average;
88};
89
90static int isl28022_read_in(struct device *dev, u32 attr, int channel, long *val)
91{
92 struct isl28022_data *data = dev_get_drvdata(dev);
93 unsigned int regval;
94 int err;
95 u16 sign_bit;
96
97 switch (channel) {
98 case 0:
99 switch (attr) {
100 case hwmon_in_input:
101 err = regmap_read(data->regmap,
102 ISL28022_REG_BUS, &regval);
103 if (err < 0)
104 return err;
105 /* driver supports only 60V mode (BRNG 11) */
106 *val = (long)(((u16)regval) & 0xFFFC);
107 break;
108 default:
109 return -EOPNOTSUPP;
110 }
111 break;
112 case 1:
113 switch (attr) {
114 case hwmon_in_input:
115 err = regmap_read(data->regmap,
116 ISL28022_REG_SHUNT, &regval);
117 if (err < 0)
118 return err;
119 switch (data->gain) {
120 case 8:
121 sign_bit = (regval >> 15) & 0x01;
122 *val = (long)((((u16)regval) & 0x7FFF) -
123 (sign_bit * 32768)) / 100;
124 break;
125 case 4:
126 sign_bit = (regval >> 14) & 0x01;
127 *val = (long)((((u16)regval) & 0x3FFF) -
128 (sign_bit * 16384)) / 100;
129 break;
130 case 2:
131 sign_bit = (regval >> 13) & 0x01;
132 *val = (long)((((u16)regval) & 0x1FFF) -
133 (sign_bit * 8192)) / 100;
134 break;
135 case 1:
136 sign_bit = (regval >> 12) & 0x01;
137 *val = (long)((((u16)regval) & 0x0FFF) -
138 (sign_bit * 4096)) / 100;
139 break;
140 }
141 break;
142 default:
143 return -EOPNOTSUPP;
144 }
145 break;
146 default:
147 return -EOPNOTSUPP;
148 }
149
150 return 0;
151}
152
153static int isl28022_read_current(struct device *dev, u32 attr, long *val)
154{
155 struct isl28022_data *data = dev_get_drvdata(dev);
156 unsigned int regval;
157 int err;
158 u16 sign_bit;
159
160 switch (attr) {
161 case hwmon_curr_input:
162 err = regmap_read(data->regmap,
163 ISL28022_REG_CURRENT, &regval);
164 if (err < 0)
165 return err;
166 sign_bit = (regval >> 15) & 0x01;
167 *val = (((long)(((u16)regval) & 0x7FFF) - (sign_bit * 32768)) *
168 1250L * (long)data->gain) / (long)data->shunt;
169 break;
170 default:
171 return -EOPNOTSUPP;
172 }
173
174 return 0;
175}
176
177static int isl28022_read_power(struct device *dev, u32 attr, long *val)
178{
179 struct isl28022_data *data = dev_get_drvdata(dev);
180 unsigned int regval;
181 int err;
182
183 switch (attr) {
184 case hwmon_power_input:
185 err = regmap_read(data->regmap,
186 ISL28022_REG_POWER, &regval);
187 if (err < 0)
188 return err;
189 *val = min(div_u64(51200000ULL * data->gain * regval,
190 data->shunt), LONG_MAX);
191 break;
192 default:
193 return -EOPNOTSUPP;
194 }
195
196 return 0;
197}
198
199static int isl28022_read(struct device *dev, enum hwmon_sensor_types type,
200 u32 attr, int channel, long *val)
201{
202 switch (type) {
203 case hwmon_in:
204 return isl28022_read_in(dev, attr, channel, val);
205 case hwmon_curr:
206 return isl28022_read_current(dev, attr, val);
207 case hwmon_power:
208 return isl28022_read_power(dev, attr, val);
209 default:
210 return -EOPNOTSUPP;
211 }
212 return 0;
213}
214
215static umode_t isl28022_is_visible(const void *data, enum hwmon_sensor_types type,
216 u32 attr, int channel)
217{
218 switch (type) {
219 case hwmon_in:
220 switch (attr) {
221 case hwmon_in_input:
222 return 0444;
223 default:
224 break;
225 }
226 break;
227 case hwmon_curr:
228 switch (attr) {
229 case hwmon_curr_input:
230 return 0444;
231 default:
232 break;
233 }
234 break;
235 case hwmon_power:
236 switch (attr) {
237 case hwmon_power_input:
238 return 0444;
239 default:
240 break;
241 }
242 break;
243 default:
244 break;
245 }
246 return 0;
247}
248
249static const struct hwmon_channel_info *isl28022_info[] = {
250 HWMON_CHANNEL_INFO(in,
251 HWMON_I_INPUT, /* channel 0: bus voltage (mV) */
252 HWMON_I_INPUT), /* channel 1: shunt voltage (mV) */
253 HWMON_CHANNEL_INFO(curr,
254 HWMON_C_INPUT), /* channel 1: current (mA) */
255 HWMON_CHANNEL_INFO(power,
256 HWMON_P_INPUT), /* channel 1: power (µW) */
257 NULL
258};
259
260static const struct hwmon_ops isl28022_hwmon_ops = {
261 .is_visible = isl28022_is_visible,
262 .read = isl28022_read,
263};
264
265static const struct hwmon_chip_info isl28022_chip_info = {
266 .ops = &isl28022_hwmon_ops,
267 .info = isl28022_info,
268};
269
270static bool isl28022_is_writeable_reg(struct device *dev, unsigned int reg)
271{
272 switch (reg) {
273 case ISL28022_REG_CONFIG:
274 case ISL28022_REG_CALIB:
275 case ISL28022_REG_SHUNT_THR:
276 case ISL28022_REG_BUS_THR:
277 case ISL28022_REG_INT:
278 case ISL28022_REG_AUX:
279 return true;
280 }
281
282 return false;
283}
284
285static bool isl28022_is_volatile_reg(struct device *dev, unsigned int reg)
286{
287 switch (reg) {
288 case ISL28022_REG_CONFIG:
289 case ISL28022_REG_SHUNT:
290 case ISL28022_REG_BUS:
291 case ISL28022_REG_POWER:
292 case ISL28022_REG_CURRENT:
293 case ISL28022_REG_INT:
294 case ISL28022_REG_AUX:
295 return true;
296 }
297 return true;
298}
299
300static const struct regmap_config isl28022_regmap_config = {
301 .reg_bits = 8,
302 .val_bits = 16,
303 .max_register = ISL28022_REG_MAX,
304 .writeable_reg = isl28022_is_writeable_reg,
305 .volatile_reg = isl28022_is_volatile_reg,
306 .val_format_endian = REGMAP_ENDIAN_BIG,
307 .cache_type = REGCACHE_MAPLE,
308 .use_single_read = true,
309 .use_single_write = true,
310};
311
312static int shunt_voltage_show(struct seq_file *seqf, void *unused)
313{
314 struct isl28022_data *data = seqf->private;
315 unsigned int regval;
316 int err;
317
318 err = regmap_read(data->regmap,
319 ISL28022_REG_SHUNT, &regval);
320 if (err)
321 return err;
322
323 /* print shunt voltage in micro volt */
324 seq_printf(seqf, "%d\n", regval * 10);
325
326 return 0;
327}
328DEFINE_SHOW_ATTRIBUTE(shunt_voltage);
329
330/*
331 * read property values and make consistency checks.
332 *
333 * following values for shunt range and resistor are allowed:
334 * 40 mV -> gain 1, shunt min. 800 micro ohms
335 * 80 mV -> gain 2, shunt min. 1600 micro ohms
336 * 160 mV -> gain 4, shunt min. 3200 micro ohms
337 * 320 mV -> gain 8, shunt min. 6400 micro ohms
338 */
339static int isl28022_read_properties(struct device *dev, struct isl28022_data *data)
340{
341 const char *propname;
342 u32 val;
343 int err;
344
345 propname = "shunt-resistor-micro-ohms";
346 if (device_property_present(dev, propname)) {
347 err = device_property_read_u32(dev, propname, &val);
348 if (err)
349 return err;
350 } else {
351 val = 10000;
352 }
353 data->shunt = val;
354
355 propname = "renesas,shunt-range-microvolt";
356 if (device_property_present(dev, propname)) {
357 err = device_property_read_u32(dev, propname, &val);
358 if (err)
359 return err;
360 } else {
361 val = 320000;
362 }
363
364 switch (val) {
365 case 40000:
366 data->gain = 1;
367 if (data->shunt < 800)
368 goto shunt_invalid;
369 break;
370 case 80000:
371 data->gain = 2;
372 if (data->shunt < 1600)
373 goto shunt_invalid;
374 break;
375 case 160000:
376 data->gain = 4;
377 if (data->shunt < 3200)
378 goto shunt_invalid;
379 break;
380 case 320000:
381 data->gain = 8;
382 if (data->shunt < 6400)
383 goto shunt_invalid;
384 break;
385 default:
386 return dev_err_probe(dev, -EINVAL, "%s invalid value %u\n", propname, val);
387 }
388
389 propname = "renesas,average-samples";
390 if (device_property_present(dev, propname)) {
391 err = device_property_read_u32(dev, propname, &val);
392 if (err)
393 return err;
394 } else {
395 val = 1;
396 }
397 if (val > 128 || hweight32(val) != 1)
398 return dev_err_probe(dev, -EINVAL, "%s invalid value %u\n", propname, val);
399
400 data->average = val;
401
402 return 0;
403
404shunt_invalid:
405 return dev_err_probe(dev, -EINVAL,
406 "renesas,shunt-resistor-microvolt invalid value %d\n",
407 data->shunt);
408}
409
410/*
411 * write configuration and calibration registers
412 *
413 * The driver supports only shunt and bus continuous ADC mode at 15bit resolution
414 * with averaging from 1 to 128 samples (pow of 2) on both channels.
415 * Shunt voltage gain 1,2,4 or 8 is allowed.
416 * The bus voltage range is 60V fixed.
417 */
418static int isl28022_config(struct isl28022_data *data)
419{
420 int err;
421 u16 config;
422 u16 calib;
423
424 config = (ISL28022_MODE_CONT_SB << ISL28022_MODE_SHIFT) |
425 (ISL28022_BRNG_60 << ISL28022_BRNG_SHIFT) |
426 (__ffs(data->gain) << ISL28022_PG_SHIFT) |
427 ((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_SADC_SHIFT) |
428 ((ISL28022_ADC_15_1 + __ffs(data->average)) << ISL28022_BADC_SHIFT);
429
430 calib = data->shunt ? 0x8000 / data->gain : 0;
431
432 err = regmap_write(data->regmap, ISL28022_REG_CONFIG, config);
433 if (err < 0)
434 return err;
435
436 return regmap_write(data->regmap, ISL28022_REG_CALIB, calib);
437}
438
439static int isl28022_probe(struct i2c_client *client)
440{
441 struct device *dev = &client->dev;
442 struct device *hwmon_dev;
443 struct isl28022_data *data;
444 int err;
445
446 if (!i2c_check_functionality(client->adapter,
447 I2C_FUNC_SMBUS_BYTE_DATA |
448 I2C_FUNC_SMBUS_WORD_DATA))
449 return -ENODEV;
450
451 data = devm_kzalloc(dev, sizeof(struct isl28022_data), GFP_KERNEL);
452 if (!data)
453 return -ENOMEM;
454
455 err = isl28022_read_properties(dev, data);
456 if (err)
457 return err;
458
459 data->regmap = devm_regmap_init_i2c(client, &isl28022_regmap_config);
460 if (IS_ERR(data->regmap))
461 return PTR_ERR(data->regmap);
462
463 err = isl28022_config(data);
464 if (err)
465 return err;
466
467 debugfs_create_file("shunt_voltage", 0444, client->debugfs, data, &shunt_voltage_fops);
468
469 hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
470 data, &isl28022_chip_info, NULL);
471 if (IS_ERR(hwmon_dev))
472 return PTR_ERR(hwmon_dev);
473
474 return 0;
475}
476
477static const struct i2c_device_id isl28022_ids[] = {
478 { .name = "isl28022" },
479 { /* LIST END */ }
480};
481MODULE_DEVICE_TABLE(i2c, isl28022_ids);
482
483static const struct of_device_id __maybe_unused isl28022_of_match[] = {
484 { .compatible = "renesas,isl28022"},
485 { /* LIST END */ }
486};
487MODULE_DEVICE_TABLE(of, isl28022_of_match);
488
489static struct i2c_driver isl28022_driver = {
490 .class = I2C_CLASS_HWMON,
491 .driver = {
492 .name = "isl28022",
493 },
494 .probe = isl28022_probe,
495 .id_table = isl28022_ids,
496};
497module_i2c_driver(isl28022_driver);
498
499MODULE_AUTHOR("Carsten Spieß <[email protected]>");
500MODULE_DESCRIPTION("ISL28022 driver");
501MODULE_LICENSE("GPL");