1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
4 * driver
5 *
6 * Copyright 2019 Analog Devices Inc.
7 */
8#include <linux/bitfield.h>
9#include <linux/completion.h>
10#include <linux/device.h>
11#include <linux/kernel.h>
12#include <linux/iio/iio.h>
13#include <linux/interrupt.h>
14#include <linux/list.h>
15#include <linux/mod_devicetable.h>
16#include <linux/module.h>
17#include <linux/property.h>
18#include <linux/regmap.h>
19#include <linux/spi/spi.h>
20
21#include <asm/byteorder.h>
22#include <asm/unaligned.h>
23
24/* register map */
25#define LTC2983_STATUS_REG 0x0000
26#define LTC2983_TEMP_RES_START_REG 0x0010
27#define LTC2983_TEMP_RES_END_REG 0x005F
28#define LTC2983_EEPROM_KEY_REG 0x00B0
29#define LTC2983_EEPROM_READ_STATUS_REG 0x00D0
30#define LTC2983_GLOBAL_CONFIG_REG 0x00F0
31#define LTC2983_MULT_CHANNEL_START_REG 0x00F4
32#define LTC2983_MULT_CHANNEL_END_REG 0x00F7
33#define LTC2986_EEPROM_STATUS_REG 0x00F9
34#define LTC2983_MUX_CONFIG_REG 0x00FF
35#define LTC2983_CHAN_ASSIGN_START_REG 0x0200
36#define LTC2983_CHAN_ASSIGN_END_REG 0x024F
37#define LTC2983_CUST_SENS_TBL_START_REG 0x0250
38#define LTC2983_CUST_SENS_TBL_END_REG 0x03CF
39
40#define LTC2983_DIFFERENTIAL_CHAN_MIN 2
41#define LTC2983_MIN_CHANNELS_NR 1
42#define LTC2983_SLEEP 0x97
43#define LTC2983_CUSTOM_STEINHART_SIZE 24
44#define LTC2983_CUSTOM_SENSOR_ENTRY_SZ 6
45#define LTC2983_CUSTOM_STEINHART_ENTRY_SZ 4
46
47#define LTC2983_EEPROM_KEY 0xA53C0F5A
48#define LTC2983_EEPROM_WRITE_CMD 0x15
49#define LTC2983_EEPROM_READ_CMD 0x16
50#define LTC2983_EEPROM_STATUS_FAILURE_MASK GENMASK(3, 1)
51#define LTC2983_EEPROM_READ_FAILURE_MASK GENMASK(7, 0)
52
53#define LTC2983_EEPROM_WRITE_TIME_MS 2600
54#define LTC2983_EEPROM_READ_TIME_MS 20
55
56#define LTC2983_CHAN_START_ADDR(chan) \
57 (((chan - 1) * 4) + LTC2983_CHAN_ASSIGN_START_REG)
58#define LTC2983_CHAN_RES_ADDR(chan) \
59 (((chan - 1) * 4) + LTC2983_TEMP_RES_START_REG)
60#define LTC2983_THERMOCOUPLE_DIFF_MASK BIT(3)
61#define LTC2983_THERMOCOUPLE_SGL(x) \
62 FIELD_PREP(LTC2983_THERMOCOUPLE_DIFF_MASK, x)
63#define LTC2983_THERMOCOUPLE_OC_CURR_MASK GENMASK(1, 0)
64#define LTC2983_THERMOCOUPLE_OC_CURR(x) \
65 FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CURR_MASK, x)
66#define LTC2983_THERMOCOUPLE_OC_CHECK_MASK BIT(2)
67#define LTC2983_THERMOCOUPLE_OC_CHECK(x) \
68 FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CHECK_MASK, x)
69
70#define LTC2983_THERMISTOR_DIFF_MASK BIT(2)
71#define LTC2983_THERMISTOR_SGL(x) \
72 FIELD_PREP(LTC2983_THERMISTOR_DIFF_MASK, x)
73#define LTC2983_THERMISTOR_R_SHARE_MASK BIT(1)
74#define LTC2983_THERMISTOR_R_SHARE(x) \
75 FIELD_PREP(LTC2983_THERMISTOR_R_SHARE_MASK, x)
76#define LTC2983_THERMISTOR_C_ROTATE_MASK BIT(0)
77#define LTC2983_THERMISTOR_C_ROTATE(x) \
78 FIELD_PREP(LTC2983_THERMISTOR_C_ROTATE_MASK, x)
79
80#define LTC2983_DIODE_DIFF_MASK BIT(2)
81#define LTC2983_DIODE_SGL(x) \
82 FIELD_PREP(LTC2983_DIODE_DIFF_MASK, x)
83#define LTC2983_DIODE_3_CONV_CYCLE_MASK BIT(1)
84#define LTC2983_DIODE_3_CONV_CYCLE(x) \
85 FIELD_PREP(LTC2983_DIODE_3_CONV_CYCLE_MASK, x)
86#define LTC2983_DIODE_AVERAGE_ON_MASK BIT(0)
87#define LTC2983_DIODE_AVERAGE_ON(x) \
88 FIELD_PREP(LTC2983_DIODE_AVERAGE_ON_MASK, x)
89
90#define LTC2983_RTD_4_WIRE_MASK BIT(3)
91#define LTC2983_RTD_ROTATION_MASK BIT(1)
92#define LTC2983_RTD_C_ROTATE(x) \
93 FIELD_PREP(LTC2983_RTD_ROTATION_MASK, x)
94#define LTC2983_RTD_KELVIN_R_SENSE_MASK GENMASK(3, 2)
95#define LTC2983_RTD_N_WIRES_MASK GENMASK(3, 2)
96#define LTC2983_RTD_N_WIRES(x) \
97 FIELD_PREP(LTC2983_RTD_N_WIRES_MASK, x)
98#define LTC2983_RTD_R_SHARE_MASK BIT(0)
99#define LTC2983_RTD_R_SHARE(x) \
100 FIELD_PREP(LTC2983_RTD_R_SHARE_MASK, 1)
101
102#define LTC2983_COMMON_HARD_FAULT_MASK GENMASK(31, 30)
103#define LTC2983_COMMON_SOFT_FAULT_MASK GENMASK(27, 25)
104
105#define LTC2983_STATUS_START_MASK BIT(7)
106#define LTC2983_STATUS_START(x) FIELD_PREP(LTC2983_STATUS_START_MASK, x)
107#define LTC2983_STATUS_UP_MASK GENMASK(7, 6)
108#define LTC2983_STATUS_UP(reg) FIELD_GET(LTC2983_STATUS_UP_MASK, reg)
109
110#define LTC2983_STATUS_CHAN_SEL_MASK GENMASK(4, 0)
111#define LTC2983_STATUS_CHAN_SEL(x) \
112 FIELD_PREP(LTC2983_STATUS_CHAN_SEL_MASK, x)
113
114#define LTC2983_TEMP_UNITS_MASK BIT(2)
115#define LTC2983_TEMP_UNITS(x) FIELD_PREP(LTC2983_TEMP_UNITS_MASK, x)
116
117#define LTC2983_NOTCH_FREQ_MASK GENMASK(1, 0)
118#define LTC2983_NOTCH_FREQ(x) FIELD_PREP(LTC2983_NOTCH_FREQ_MASK, x)
119
120#define LTC2983_RES_VALID_MASK BIT(24)
121#define LTC2983_DATA_MASK GENMASK(23, 0)
122#define LTC2983_DATA_SIGN_BIT 23
123
124#define LTC2983_CHAN_TYPE_MASK GENMASK(31, 27)
125#define LTC2983_CHAN_TYPE(x) FIELD_PREP(LTC2983_CHAN_TYPE_MASK, x)
126
127/* cold junction for thermocouples and rsense for rtd's and thermistor's */
128#define LTC2983_CHAN_ASSIGN_MASK GENMASK(26, 22)
129#define LTC2983_CHAN_ASSIGN(x) FIELD_PREP(LTC2983_CHAN_ASSIGN_MASK, x)
130
131#define LTC2983_CUSTOM_LEN_MASK GENMASK(5, 0)
132#define LTC2983_CUSTOM_LEN(x) FIELD_PREP(LTC2983_CUSTOM_LEN_MASK, x)
133
134#define LTC2983_CUSTOM_ADDR_MASK GENMASK(11, 6)
135#define LTC2983_CUSTOM_ADDR(x) FIELD_PREP(LTC2983_CUSTOM_ADDR_MASK, x)
136
137#define LTC2983_THERMOCOUPLE_CFG_MASK GENMASK(21, 18)
138#define LTC2983_THERMOCOUPLE_CFG(x) \
139 FIELD_PREP(LTC2983_THERMOCOUPLE_CFG_MASK, x)
140#define LTC2983_THERMOCOUPLE_HARD_FAULT_MASK GENMASK(31, 29)
141#define LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK GENMASK(28, 25)
142
143#define LTC2983_RTD_CFG_MASK GENMASK(21, 18)
144#define LTC2983_RTD_CFG(x) FIELD_PREP(LTC2983_RTD_CFG_MASK, x)
145#define LTC2983_RTD_EXC_CURRENT_MASK GENMASK(17, 14)
146#define LTC2983_RTD_EXC_CURRENT(x) \
147 FIELD_PREP(LTC2983_RTD_EXC_CURRENT_MASK, x)
148#define LTC2983_RTD_CURVE_MASK GENMASK(13, 12)
149#define LTC2983_RTD_CURVE(x) FIELD_PREP(LTC2983_RTD_CURVE_MASK, x)
150
151#define LTC2983_THERMISTOR_CFG_MASK GENMASK(21, 19)
152#define LTC2983_THERMISTOR_CFG(x) \
153 FIELD_PREP(LTC2983_THERMISTOR_CFG_MASK, x)
154#define LTC2983_THERMISTOR_EXC_CURRENT_MASK GENMASK(18, 15)
155#define LTC2983_THERMISTOR_EXC_CURRENT(x) \
156 FIELD_PREP(LTC2983_THERMISTOR_EXC_CURRENT_MASK, x)
157
158#define LTC2983_DIODE_CFG_MASK GENMASK(26, 24)
159#define LTC2983_DIODE_CFG(x) FIELD_PREP(LTC2983_DIODE_CFG_MASK, x)
160#define LTC2983_DIODE_EXC_CURRENT_MASK GENMASK(23, 22)
161#define LTC2983_DIODE_EXC_CURRENT(x) \
162 FIELD_PREP(LTC2983_DIODE_EXC_CURRENT_MASK, x)
163#define LTC2983_DIODE_IDEAL_FACTOR_MASK GENMASK(21, 0)
164#define LTC2983_DIODE_IDEAL_FACTOR(x) \
165 FIELD_PREP(LTC2983_DIODE_IDEAL_FACTOR_MASK, x)
166
167#define LTC2983_R_SENSE_VAL_MASK GENMASK(26, 0)
168#define LTC2983_R_SENSE_VAL(x) FIELD_PREP(LTC2983_R_SENSE_VAL_MASK, x)
169
170#define LTC2983_ADC_SINGLE_ENDED_MASK BIT(26)
171#define LTC2983_ADC_SINGLE_ENDED(x) \
172 FIELD_PREP(LTC2983_ADC_SINGLE_ENDED_MASK, x)
173
174enum {
175 LTC2983_SENSOR_THERMOCOUPLE = 1,
176 LTC2983_SENSOR_THERMOCOUPLE_CUSTOM = 9,
177 LTC2983_SENSOR_RTD = 10,
178 LTC2983_SENSOR_RTD_CUSTOM = 18,
179 LTC2983_SENSOR_THERMISTOR = 19,
180 LTC2983_SENSOR_THERMISTOR_STEINHART = 26,
181 LTC2983_SENSOR_THERMISTOR_CUSTOM = 27,
182 LTC2983_SENSOR_DIODE = 28,
183 LTC2983_SENSOR_SENSE_RESISTOR = 29,
184 LTC2983_SENSOR_DIRECT_ADC = 30,
185 LTC2983_SENSOR_ACTIVE_TEMP = 31,
186};
187
188#define to_thermocouple(_sensor) \
189 container_of(_sensor, struct ltc2983_thermocouple, sensor)
190
191#define to_rtd(_sensor) \
192 container_of(_sensor, struct ltc2983_rtd, sensor)
193
194#define to_thermistor(_sensor) \
195 container_of(_sensor, struct ltc2983_thermistor, sensor)
196
197#define to_diode(_sensor) \
198 container_of(_sensor, struct ltc2983_diode, sensor)
199
200#define to_rsense(_sensor) \
201 container_of(_sensor, struct ltc2983_rsense, sensor)
202
203#define to_adc(_sensor) \
204 container_of(_sensor, struct ltc2983_adc, sensor)
205
206#define to_temp(_sensor) \
207 container_of(_sensor, struct ltc2983_temp, sensor)
208
209struct ltc2983_chip_info {
210 const char *name;
211 unsigned int max_channels_nr;
212 bool has_temp;
213 bool has_eeprom;
214};
215
216struct ltc2983_data {
217 const struct ltc2983_chip_info *info;
218 struct regmap *regmap;
219 struct spi_device *spi;
220 struct mutex lock;
221 struct completion completion;
222 struct iio_chan_spec *iio_chan;
223 struct ltc2983_sensor **sensors;
224 u32 mux_delay_config;
225 u32 filter_notch_freq;
226 u16 custom_table_size;
227 u8 num_channels;
228 u8 iio_channels;
229 /*
230 * DMA (thus cache coherency maintenance) may require the
231 * transfer buffers to live in their own cache lines.
232 * Holds the converted temperature
233 */
234 __be32 temp __aligned(IIO_DMA_MINALIGN);
235 __be32 chan_val;
236 __be32 eeprom_key;
237};
238
239struct ltc2983_sensor {
240 int (*fault_handler)(const struct ltc2983_data *st, const u32 result);
241 int (*assign_chan)(struct ltc2983_data *st,
242 const struct ltc2983_sensor *sensor);
243 /* specifies the sensor channel */
244 u32 chan;
245 /* sensor type */
246 u32 type;
247};
248
249struct ltc2983_custom_sensor {
250 /* raw table sensor data */
251 void *table;
252 size_t size;
253 /* address offset */
254 s8 offset;
255 bool is_steinhart;
256};
257
258struct ltc2983_thermocouple {
259 struct ltc2983_sensor sensor;
260 struct ltc2983_custom_sensor *custom;
261 u32 sensor_config;
262 u32 cold_junction_chan;
263};
264
265struct ltc2983_rtd {
266 struct ltc2983_sensor sensor;
267 struct ltc2983_custom_sensor *custom;
268 u32 sensor_config;
269 u32 r_sense_chan;
270 u32 excitation_current;
271 u32 rtd_curve;
272};
273
274struct ltc2983_thermistor {
275 struct ltc2983_sensor sensor;
276 struct ltc2983_custom_sensor *custom;
277 u32 sensor_config;
278 u32 r_sense_chan;
279 u32 excitation_current;
280};
281
282struct ltc2983_diode {
283 struct ltc2983_sensor sensor;
284 u32 sensor_config;
285 u32 excitation_current;
286 u32 ideal_factor_value;
287};
288
289struct ltc2983_rsense {
290 struct ltc2983_sensor sensor;
291 u32 r_sense_val;
292};
293
294struct ltc2983_adc {
295 struct ltc2983_sensor sensor;
296 bool single_ended;
297};
298
299struct ltc2983_temp {
300 struct ltc2983_sensor sensor;
301 struct ltc2983_custom_sensor *custom;
302 bool single_ended;
303};
304
305/*
306 * Convert to Q format numbers. These number's are integers where
307 * the number of integer and fractional bits are specified. The resolution
308 * is given by 1/@resolution and tell us the number of fractional bits. For
309 * instance a resolution of 2^-10 means we have 10 fractional bits.
310 */
311static u32 __convert_to_raw(const u64 val, const u32 resolution)
312{
313 u64 __res = val * resolution;
314
315 /* all values are multiplied by 1000000 to remove the fraction */
316 do_div(__res, 1000000);
317
318 return __res;
319}
320
321static u32 __convert_to_raw_sign(const u64 val, const u32 resolution)
322{
323 s64 __res = -(s32)val;
324
325 __res = __convert_to_raw(val: __res, resolution);
326
327 return (u32)-__res;
328}
329
330static int __ltc2983_fault_handler(const struct ltc2983_data *st,
331 const u32 result, const u32 hard_mask,
332 const u32 soft_mask)
333{
334 const struct device *dev = &st->spi->dev;
335
336 if (result & hard_mask) {
337 dev_err(dev, "Invalid conversion: Sensor HARD fault\n");
338 return -EIO;
339 } else if (result & soft_mask) {
340 /* just print a warning */
341 dev_warn(dev, "Suspicious conversion: Sensor SOFT fault\n");
342 }
343
344 return 0;
345}
346
347static int __ltc2983_chan_assign_common(struct ltc2983_data *st,
348 const struct ltc2983_sensor *sensor,
349 u32 chan_val)
350{
351 u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
352
353 chan_val |= LTC2983_CHAN_TYPE(sensor->type);
354 dev_dbg(&st->spi->dev, "Assign reg:0x%04X, val:0x%08X\n", reg,
355 chan_val);
356 st->chan_val = cpu_to_be32(chan_val);
357 return regmap_bulk_write(map: st->regmap, reg, val: &st->chan_val,
358 val_count: sizeof(st->chan_val));
359}
360
361static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
362 struct ltc2983_custom_sensor *custom,
363 u32 *chan_val)
364{
365 u32 reg;
366 u8 mult = custom->is_steinhart ? LTC2983_CUSTOM_STEINHART_ENTRY_SZ :
367 LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
368 const struct device *dev = &st->spi->dev;
369 /*
370 * custom->size holds the raw size of the table. However, when
371 * configuring the sensor channel, we must write the number of
372 * entries of the table minus 1. For steinhart sensors 0 is written
373 * since the size is constant!
374 */
375 const u8 len = custom->is_steinhart ? 0 :
376 (custom->size / LTC2983_CUSTOM_SENSOR_ENTRY_SZ) - 1;
377 /*
378 * Check if the offset was assigned already. It should be for steinhart
379 * sensors. When coming from sleep, it should be assigned for all.
380 */
381 if (custom->offset < 0) {
382 /*
383 * This needs to be done again here because, from the moment
384 * when this test was done (successfully) for this custom
385 * sensor, a steinhart sensor might have been added changing
386 * custom_table_size...
387 */
388 if (st->custom_table_size + custom->size >
389 (LTC2983_CUST_SENS_TBL_END_REG -
390 LTC2983_CUST_SENS_TBL_START_REG) + 1) {
391 dev_err(dev,
392 "Not space left(%d) for new custom sensor(%zu)",
393 st->custom_table_size,
394 custom->size);
395 return -EINVAL;
396 }
397
398 custom->offset = st->custom_table_size /
399 LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
400 st->custom_table_size += custom->size;
401 }
402
403 reg = (custom->offset * mult) + LTC2983_CUST_SENS_TBL_START_REG;
404
405 *chan_val |= LTC2983_CUSTOM_LEN(len);
406 *chan_val |= LTC2983_CUSTOM_ADDR(custom->offset);
407 dev_dbg(dev, "Assign custom sensor, reg:0x%04X, off:%d, sz:%zu",
408 reg, custom->offset,
409 custom->size);
410 /* write custom sensor table */
411 return regmap_bulk_write(map: st->regmap, reg, val: custom->table, val_count: custom->size);
412}
413
414static struct ltc2983_custom_sensor *
415__ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle *fn,
416 const char *propname, const bool is_steinhart,
417 const u32 resolution, const bool has_signed)
418{
419 struct ltc2983_custom_sensor *new_custom;
420 struct device *dev = &st->spi->dev;
421 /*
422 * For custom steinhart, the full u32 is taken. For all the others
423 * the MSB is discarded.
424 */
425 const u8 n_size = is_steinhart ? 4 : 3;
426 u8 index, n_entries;
427 int ret;
428
429 if (is_steinhart)
430 n_entries = fwnode_property_count_u32(fwnode: fn, propname);
431 else
432 n_entries = fwnode_property_count_u64(fwnode: fn, propname);
433 /* n_entries must be an even number */
434 if (!n_entries || (n_entries % 2) != 0) {
435 dev_err(dev, "Number of entries either 0 or not even\n");
436 return ERR_PTR(error: -EINVAL);
437 }
438
439 new_custom = devm_kzalloc(dev, size: sizeof(*new_custom), GFP_KERNEL);
440 if (!new_custom)
441 return ERR_PTR(error: -ENOMEM);
442
443 new_custom->size = n_entries * n_size;
444 /* check Steinhart size */
445 if (is_steinhart && new_custom->size != LTC2983_CUSTOM_STEINHART_SIZE) {
446 dev_err(dev, "Steinhart sensors size(%zu) must be %u\n", new_custom->size,
447 LTC2983_CUSTOM_STEINHART_SIZE);
448 return ERR_PTR(error: -EINVAL);
449 }
450 /* Check space on the table. */
451 if (st->custom_table_size + new_custom->size >
452 (LTC2983_CUST_SENS_TBL_END_REG -
453 LTC2983_CUST_SENS_TBL_START_REG) + 1) {
454 dev_err(dev, "No space left(%d) for new custom sensor(%zu)",
455 st->custom_table_size, new_custom->size);
456 return ERR_PTR(error: -EINVAL);
457 }
458
459 /* allocate the table */
460 if (is_steinhart)
461 new_custom->table = devm_kcalloc(dev, n: n_entries, size: sizeof(u32), GFP_KERNEL);
462 else
463 new_custom->table = devm_kcalloc(dev, n: n_entries, size: sizeof(u64), GFP_KERNEL);
464 if (!new_custom->table)
465 return ERR_PTR(error: -ENOMEM);
466
467 /*
468 * Steinhart sensors are configured with raw values in the firmware
469 * node. For the other sensors we must convert the value to raw.
470 * The odd index's correspond to temperatures and always have 1/1024
471 * of resolution. Temperatures also come in Kelvin, so signed values
472 * are not possible.
473 */
474 if (is_steinhart) {
475 ret = fwnode_property_read_u32_array(fwnode: fn, propname, val: new_custom->table, nval: n_entries);
476 if (ret < 0)
477 return ERR_PTR(error: ret);
478
479 cpu_to_be32_array(dst: new_custom->table, src: new_custom->table, len: n_entries);
480 } else {
481 ret = fwnode_property_read_u64_array(fwnode: fn, propname, val: new_custom->table, nval: n_entries);
482 if (ret < 0)
483 return ERR_PTR(error: ret);
484
485 for (index = 0; index < n_entries; index++) {
486 u64 temp = ((u64 *)new_custom->table)[index];
487
488 if ((index % 2) != 0)
489 temp = __convert_to_raw(val: temp, resolution: 1024);
490 else if (has_signed && (s64)temp < 0)
491 temp = __convert_to_raw_sign(val: temp, resolution);
492 else
493 temp = __convert_to_raw(val: temp, resolution);
494
495 put_unaligned_be24(val: temp, p: new_custom->table + index * 3);
496 }
497 }
498
499 new_custom->is_steinhart = is_steinhart;
500 /*
501 * This is done to first add all the steinhart sensors to the table,
502 * in order to maximize the table usage. If we mix adding steinhart
503 * with the other sensors, we might have to do some roundup to make
504 * sure that sensor_addr - 0x250(start address) is a multiple of 4
505 * (for steinhart), and a multiple of 6 for all the other sensors.
506 * Since we have const 24 bytes for steinhart sensors and 24 is
507 * also a multiple of 6, we guarantee that the first non-steinhart
508 * sensor will sit in a correct address without the need of filling
509 * addresses.
510 */
511 if (is_steinhart) {
512 new_custom->offset = st->custom_table_size /
513 LTC2983_CUSTOM_STEINHART_ENTRY_SZ;
514 st->custom_table_size += new_custom->size;
515 } else {
516 /* mark as unset. This is checked later on the assign phase */
517 new_custom->offset = -1;
518 }
519
520 return new_custom;
521}
522
523static int ltc2983_thermocouple_fault_handler(const struct ltc2983_data *st,
524 const u32 result)
525{
526 return __ltc2983_fault_handler(st, result,
527 LTC2983_THERMOCOUPLE_HARD_FAULT_MASK,
528 LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK);
529}
530
531static int ltc2983_common_fault_handler(const struct ltc2983_data *st,
532 const u32 result)
533{
534 return __ltc2983_fault_handler(st, result,
535 LTC2983_COMMON_HARD_FAULT_MASK,
536 LTC2983_COMMON_SOFT_FAULT_MASK);
537}
538
539static int ltc2983_thermocouple_assign_chan(struct ltc2983_data *st,
540 const struct ltc2983_sensor *sensor)
541{
542 struct ltc2983_thermocouple *thermo = to_thermocouple(sensor);
543 u32 chan_val;
544
545 chan_val = LTC2983_CHAN_ASSIGN(thermo->cold_junction_chan);
546 chan_val |= LTC2983_THERMOCOUPLE_CFG(thermo->sensor_config);
547
548 if (thermo->custom) {
549 int ret;
550
551 ret = __ltc2983_chan_custom_sensor_assign(st, custom: thermo->custom,
552 chan_val: &chan_val);
553 if (ret)
554 return ret;
555 }
556 return __ltc2983_chan_assign_common(st, sensor, chan_val);
557}
558
559static int ltc2983_rtd_assign_chan(struct ltc2983_data *st,
560 const struct ltc2983_sensor *sensor)
561{
562 struct ltc2983_rtd *rtd = to_rtd(sensor);
563 u32 chan_val;
564
565 chan_val = LTC2983_CHAN_ASSIGN(rtd->r_sense_chan);
566 chan_val |= LTC2983_RTD_CFG(rtd->sensor_config);
567 chan_val |= LTC2983_RTD_EXC_CURRENT(rtd->excitation_current);
568 chan_val |= LTC2983_RTD_CURVE(rtd->rtd_curve);
569
570 if (rtd->custom) {
571 int ret;
572
573 ret = __ltc2983_chan_custom_sensor_assign(st, custom: rtd->custom,
574 chan_val: &chan_val);
575 if (ret)
576 return ret;
577 }
578 return __ltc2983_chan_assign_common(st, sensor, chan_val);
579}
580
581static int ltc2983_thermistor_assign_chan(struct ltc2983_data *st,
582 const struct ltc2983_sensor *sensor)
583{
584 struct ltc2983_thermistor *thermistor = to_thermistor(sensor);
585 u32 chan_val;
586
587 chan_val = LTC2983_CHAN_ASSIGN(thermistor->r_sense_chan);
588 chan_val |= LTC2983_THERMISTOR_CFG(thermistor->sensor_config);
589 chan_val |=
590 LTC2983_THERMISTOR_EXC_CURRENT(thermistor->excitation_current);
591
592 if (thermistor->custom) {
593 int ret;
594
595 ret = __ltc2983_chan_custom_sensor_assign(st,
596 custom: thermistor->custom,
597 chan_val: &chan_val);
598 if (ret)
599 return ret;
600 }
601 return __ltc2983_chan_assign_common(st, sensor, chan_val);
602}
603
604static int ltc2983_diode_assign_chan(struct ltc2983_data *st,
605 const struct ltc2983_sensor *sensor)
606{
607 struct ltc2983_diode *diode = to_diode(sensor);
608 u32 chan_val;
609
610 chan_val = LTC2983_DIODE_CFG(diode->sensor_config);
611 chan_val |= LTC2983_DIODE_EXC_CURRENT(diode->excitation_current);
612 chan_val |= LTC2983_DIODE_IDEAL_FACTOR(diode->ideal_factor_value);
613
614 return __ltc2983_chan_assign_common(st, sensor, chan_val);
615}
616
617static int ltc2983_r_sense_assign_chan(struct ltc2983_data *st,
618 const struct ltc2983_sensor *sensor)
619{
620 struct ltc2983_rsense *rsense = to_rsense(sensor);
621 u32 chan_val;
622
623 chan_val = LTC2983_R_SENSE_VAL(rsense->r_sense_val);
624
625 return __ltc2983_chan_assign_common(st, sensor, chan_val);
626}
627
628static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
629 const struct ltc2983_sensor *sensor)
630{
631 struct ltc2983_adc *adc = to_adc(sensor);
632 u32 chan_val;
633
634 chan_val = LTC2983_ADC_SINGLE_ENDED(adc->single_ended);
635
636 return __ltc2983_chan_assign_common(st, sensor, chan_val);
637}
638
639static int ltc2983_temp_assign_chan(struct ltc2983_data *st,
640 const struct ltc2983_sensor *sensor)
641{
642 struct ltc2983_temp *temp = to_temp(sensor);
643 u32 chan_val;
644 int ret;
645
646 chan_val = LTC2983_ADC_SINGLE_ENDED(temp->single_ended);
647
648 ret = __ltc2983_chan_custom_sensor_assign(st, custom: temp->custom, chan_val: &chan_val);
649 if (ret)
650 return ret;
651
652 return __ltc2983_chan_assign_common(st, sensor, chan_val);
653}
654
655static struct ltc2983_sensor *
656ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data *st,
657 const struct ltc2983_sensor *sensor)
658{
659 struct ltc2983_thermocouple *thermo;
660 struct fwnode_handle *ref;
661 u32 oc_current;
662 int ret;
663
664 thermo = devm_kzalloc(dev: &st->spi->dev, size: sizeof(*thermo), GFP_KERNEL);
665 if (!thermo)
666 return ERR_PTR(error: -ENOMEM);
667
668 if (fwnode_property_read_bool(fwnode: child, propname: "adi,single-ended"))
669 thermo->sensor_config = LTC2983_THERMOCOUPLE_SGL(1);
670
671 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,sensor-oc-current-microamp", val: &oc_current);
672 if (!ret) {
673 switch (oc_current) {
674 case 10:
675 thermo->sensor_config |=
676 LTC2983_THERMOCOUPLE_OC_CURR(0);
677 break;
678 case 100:
679 thermo->sensor_config |=
680 LTC2983_THERMOCOUPLE_OC_CURR(1);
681 break;
682 case 500:
683 thermo->sensor_config |=
684 LTC2983_THERMOCOUPLE_OC_CURR(2);
685 break;
686 case 1000:
687 thermo->sensor_config |=
688 LTC2983_THERMOCOUPLE_OC_CURR(3);
689 break;
690 default:
691 dev_err(&st->spi->dev,
692 "Invalid open circuit current:%u", oc_current);
693 return ERR_PTR(error: -EINVAL);
694 }
695
696 thermo->sensor_config |= LTC2983_THERMOCOUPLE_OC_CHECK(1);
697 }
698 /* validate channel index */
699 if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK) &&
700 sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
701 dev_err(&st->spi->dev,
702 "Invalid chann:%d for differential thermocouple",
703 sensor->chan);
704 return ERR_PTR(error: -EINVAL);
705 }
706
707 ref = fwnode_find_reference(fwnode: child, name: "adi,cold-junction-handle", index: 0);
708 if (IS_ERR(ptr: ref)) {
709 ref = NULL;
710 } else {
711 ret = fwnode_property_read_u32(fwnode: ref, propname: "reg", val: &thermo->cold_junction_chan);
712 if (ret) {
713 /*
714 * This would be catched later but we can just return
715 * the error right away.
716 */
717 dev_err(&st->spi->dev, "Property reg must be given\n");
718 goto fail;
719 }
720 }
721
722 /* check custom sensor */
723 if (sensor->type == LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
724 const char *propname = "adi,custom-thermocouple";
725
726 thermo->custom = __ltc2983_custom_sensor_new(st, fn: child,
727 propname, is_steinhart: false,
728 resolution: 16384, has_signed: true);
729 if (IS_ERR(ptr: thermo->custom)) {
730 ret = PTR_ERR(ptr: thermo->custom);
731 goto fail;
732 }
733 }
734
735 /* set common parameters */
736 thermo->sensor.fault_handler = ltc2983_thermocouple_fault_handler;
737 thermo->sensor.assign_chan = ltc2983_thermocouple_assign_chan;
738
739 fwnode_handle_put(fwnode: ref);
740 return &thermo->sensor;
741
742fail:
743 fwnode_handle_put(fwnode: ref);
744 return ERR_PTR(error: ret);
745}
746
747static struct ltc2983_sensor *
748ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
749 const struct ltc2983_sensor *sensor)
750{
751 struct ltc2983_rtd *rtd;
752 int ret = 0;
753 struct device *dev = &st->spi->dev;
754 struct fwnode_handle *ref;
755 u32 excitation_current = 0, n_wires = 0;
756
757 rtd = devm_kzalloc(dev, size: sizeof(*rtd), GFP_KERNEL);
758 if (!rtd)
759 return ERR_PTR(error: -ENOMEM);
760
761 ref = fwnode_find_reference(fwnode: child, name: "adi,rsense-handle", index: 0);
762 if (IS_ERR(ptr: ref)) {
763 dev_err(dev, "Property adi,rsense-handle missing or invalid");
764 return ERR_CAST(ptr: ref);
765 }
766
767 ret = fwnode_property_read_u32(fwnode: ref, propname: "reg", val: &rtd->r_sense_chan);
768 if (ret) {
769 dev_err(dev, "Property reg must be given\n");
770 goto fail;
771 }
772
773 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,number-of-wires", val: &n_wires);
774 if (!ret) {
775 switch (n_wires) {
776 case 2:
777 rtd->sensor_config = LTC2983_RTD_N_WIRES(0);
778 break;
779 case 3:
780 rtd->sensor_config = LTC2983_RTD_N_WIRES(1);
781 break;
782 case 4:
783 rtd->sensor_config = LTC2983_RTD_N_WIRES(2);
784 break;
785 case 5:
786 /* 4 wires, Kelvin Rsense */
787 rtd->sensor_config = LTC2983_RTD_N_WIRES(3);
788 break;
789 default:
790 dev_err(dev, "Invalid number of wires:%u\n", n_wires);
791 ret = -EINVAL;
792 goto fail;
793 }
794 }
795
796 if (fwnode_property_read_bool(fwnode: child, propname: "adi,rsense-share")) {
797 /* Current rotation is only available with rsense sharing */
798 if (fwnode_property_read_bool(fwnode: child, propname: "adi,current-rotate")) {
799 if (n_wires == 2 || n_wires == 3) {
800 dev_err(dev,
801 "Rotation not allowed for 2/3 Wire RTDs");
802 ret = -EINVAL;
803 goto fail;
804 }
805 rtd->sensor_config |= LTC2983_RTD_C_ROTATE(1);
806 } else {
807 rtd->sensor_config |= LTC2983_RTD_R_SHARE(1);
808 }
809 }
810 /*
811 * rtd channel indexes are a bit more complicated to validate.
812 * For 4wire RTD with rotation, the channel selection cannot be
813 * >=19 since the chann + 1 is used in this configuration.
814 * For 4wire RTDs with kelvin rsense, the rsense channel cannot be
815 * <=1 since chanel - 1 and channel - 2 are used.
816 */
817 if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
818 /* 4-wire */
819 u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
820 max = st->info->max_channels_nr;
821
822 if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
823 max = st->info->max_channels_nr - 1;
824
825 if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
826 == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
827 (rtd->r_sense_chan <= min)) {
828 /* kelvin rsense*/
829 dev_err(dev,
830 "Invalid rsense chann:%d to use in kelvin rsense",
831 rtd->r_sense_chan);
832
833 ret = -EINVAL;
834 goto fail;
835 }
836
837 if (sensor->chan < min || sensor->chan > max) {
838 dev_err(dev, "Invalid chann:%d for the rtd config",
839 sensor->chan);
840
841 ret = -EINVAL;
842 goto fail;
843 }
844 } else {
845 /* same as differential case */
846 if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
847 dev_err(&st->spi->dev,
848 "Invalid chann:%d for RTD", sensor->chan);
849
850 ret = -EINVAL;
851 goto fail;
852 }
853 }
854
855 /* check custom sensor */
856 if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
857 rtd->custom = __ltc2983_custom_sensor_new(st, fn: child,
858 propname: "adi,custom-rtd",
859 is_steinhart: false, resolution: 2048, has_signed: false);
860 if (IS_ERR(ptr: rtd->custom)) {
861 ret = PTR_ERR(ptr: rtd->custom);
862 goto fail;
863 }
864 }
865
866 /* set common parameters */
867 rtd->sensor.fault_handler = ltc2983_common_fault_handler;
868 rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
869
870 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,excitation-current-microamp",
871 val: &excitation_current);
872 if (ret) {
873 /* default to 5uA */
874 rtd->excitation_current = 1;
875 } else {
876 switch (excitation_current) {
877 case 5:
878 rtd->excitation_current = 0x01;
879 break;
880 case 10:
881 rtd->excitation_current = 0x02;
882 break;
883 case 25:
884 rtd->excitation_current = 0x03;
885 break;
886 case 50:
887 rtd->excitation_current = 0x04;
888 break;
889 case 100:
890 rtd->excitation_current = 0x05;
891 break;
892 case 250:
893 rtd->excitation_current = 0x06;
894 break;
895 case 500:
896 rtd->excitation_current = 0x07;
897 break;
898 case 1000:
899 rtd->excitation_current = 0x08;
900 break;
901 default:
902 dev_err(&st->spi->dev,
903 "Invalid value for excitation current(%u)",
904 excitation_current);
905 ret = -EINVAL;
906 goto fail;
907 }
908 }
909
910 fwnode_property_read_u32(fwnode: child, propname: "adi,rtd-curve", val: &rtd->rtd_curve);
911
912 fwnode_handle_put(fwnode: ref);
913 return &rtd->sensor;
914fail:
915 fwnode_handle_put(fwnode: ref);
916 return ERR_PTR(error: ret);
917}
918
919static struct ltc2983_sensor *
920ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *st,
921 const struct ltc2983_sensor *sensor)
922{
923 struct ltc2983_thermistor *thermistor;
924 struct device *dev = &st->spi->dev;
925 struct fwnode_handle *ref;
926 u32 excitation_current = 0;
927 int ret = 0;
928
929 thermistor = devm_kzalloc(dev, size: sizeof(*thermistor), GFP_KERNEL);
930 if (!thermistor)
931 return ERR_PTR(error: -ENOMEM);
932
933 ref = fwnode_find_reference(fwnode: child, name: "adi,rsense-handle", index: 0);
934 if (IS_ERR(ptr: ref)) {
935 dev_err(dev, "Property adi,rsense-handle missing or invalid");
936 return ERR_CAST(ptr: ref);
937 }
938
939 ret = fwnode_property_read_u32(fwnode: ref, propname: "reg", val: &thermistor->r_sense_chan);
940 if (ret) {
941 dev_err(dev, "rsense channel must be configured...\n");
942 goto fail;
943 }
944
945 if (fwnode_property_read_bool(fwnode: child, propname: "adi,single-ended")) {
946 thermistor->sensor_config = LTC2983_THERMISTOR_SGL(1);
947 } else if (fwnode_property_read_bool(fwnode: child, propname: "adi,rsense-share")) {
948 /* rotation is only possible if sharing rsense */
949 if (fwnode_property_read_bool(fwnode: child, propname: "adi,current-rotate"))
950 thermistor->sensor_config =
951 LTC2983_THERMISTOR_C_ROTATE(1);
952 else
953 thermistor->sensor_config =
954 LTC2983_THERMISTOR_R_SHARE(1);
955 }
956 /* validate channel index */
957 if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK) &&
958 sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
959 dev_err(&st->spi->dev,
960 "Invalid chann:%d for differential thermistor",
961 sensor->chan);
962 ret = -EINVAL;
963 goto fail;
964 }
965
966 /* check custom sensor */
967 if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
968 bool steinhart = false;
969 const char *propname;
970
971 if (sensor->type == LTC2983_SENSOR_THERMISTOR_STEINHART) {
972 steinhart = true;
973 propname = "adi,custom-steinhart";
974 } else {
975 propname = "adi,custom-thermistor";
976 }
977
978 thermistor->custom = __ltc2983_custom_sensor_new(st, fn: child,
979 propname,
980 is_steinhart: steinhart,
981 resolution: 64, has_signed: false);
982 if (IS_ERR(ptr: thermistor->custom)) {
983 ret = PTR_ERR(ptr: thermistor->custom);
984 goto fail;
985 }
986 }
987 /* set common parameters */
988 thermistor->sensor.fault_handler = ltc2983_common_fault_handler;
989 thermistor->sensor.assign_chan = ltc2983_thermistor_assign_chan;
990
991 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,excitation-current-nanoamp",
992 val: &excitation_current);
993 if (ret) {
994 /* Auto range is not allowed for custom sensors */
995 if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
996 /* default to 1uA */
997 thermistor->excitation_current = 0x03;
998 else
999 /* default to auto-range */
1000 thermistor->excitation_current = 0x0c;
1001 } else {
1002 switch (excitation_current) {
1003 case 0:
1004 /* auto range */
1005 if (sensor->type >=
1006 LTC2983_SENSOR_THERMISTOR_STEINHART) {
1007 dev_err(&st->spi->dev,
1008 "Auto Range not allowed for custom sensors\n");
1009 ret = -EINVAL;
1010 goto fail;
1011 }
1012 thermistor->excitation_current = 0x0c;
1013 break;
1014 case 250:
1015 thermistor->excitation_current = 0x01;
1016 break;
1017 case 500:
1018 thermistor->excitation_current = 0x02;
1019 break;
1020 case 1000:
1021 thermistor->excitation_current = 0x03;
1022 break;
1023 case 5000:
1024 thermistor->excitation_current = 0x04;
1025 break;
1026 case 10000:
1027 thermistor->excitation_current = 0x05;
1028 break;
1029 case 25000:
1030 thermistor->excitation_current = 0x06;
1031 break;
1032 case 50000:
1033 thermistor->excitation_current = 0x07;
1034 break;
1035 case 100000:
1036 thermistor->excitation_current = 0x08;
1037 break;
1038 case 250000:
1039 thermistor->excitation_current = 0x09;
1040 break;
1041 case 500000:
1042 thermistor->excitation_current = 0x0a;
1043 break;
1044 case 1000000:
1045 thermistor->excitation_current = 0x0b;
1046 break;
1047 default:
1048 dev_err(&st->spi->dev,
1049 "Invalid value for excitation current(%u)",
1050 excitation_current);
1051 ret = -EINVAL;
1052 goto fail;
1053 }
1054 }
1055
1056 fwnode_handle_put(fwnode: ref);
1057 return &thermistor->sensor;
1058fail:
1059 fwnode_handle_put(fwnode: ref);
1060 return ERR_PTR(error: ret);
1061}
1062
1063static struct ltc2983_sensor *
1064ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *st,
1065 const struct ltc2983_sensor *sensor)
1066{
1067 struct ltc2983_diode *diode;
1068 u32 temp = 0, excitation_current = 0;
1069 int ret;
1070
1071 diode = devm_kzalloc(dev: &st->spi->dev, size: sizeof(*diode), GFP_KERNEL);
1072 if (!diode)
1073 return ERR_PTR(error: -ENOMEM);
1074
1075 if (fwnode_property_read_bool(fwnode: child, propname: "adi,single-ended"))
1076 diode->sensor_config = LTC2983_DIODE_SGL(1);
1077
1078 if (fwnode_property_read_bool(fwnode: child, propname: "adi,three-conversion-cycles"))
1079 diode->sensor_config |= LTC2983_DIODE_3_CONV_CYCLE(1);
1080
1081 if (fwnode_property_read_bool(fwnode: child, propname: "adi,average-on"))
1082 diode->sensor_config |= LTC2983_DIODE_AVERAGE_ON(1);
1083
1084 /* validate channel index */
1085 if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
1086 sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1087 dev_err(&st->spi->dev,
1088 "Invalid chann:%d for differential thermistor",
1089 sensor->chan);
1090 return ERR_PTR(error: -EINVAL);
1091 }
1092 /* set common parameters */
1093 diode->sensor.fault_handler = ltc2983_common_fault_handler;
1094 diode->sensor.assign_chan = ltc2983_diode_assign_chan;
1095
1096 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,excitation-current-microamp",
1097 val: &excitation_current);
1098 if (!ret) {
1099 switch (excitation_current) {
1100 case 10:
1101 diode->excitation_current = 0x00;
1102 break;
1103 case 20:
1104 diode->excitation_current = 0x01;
1105 break;
1106 case 40:
1107 diode->excitation_current = 0x02;
1108 break;
1109 case 80:
1110 diode->excitation_current = 0x03;
1111 break;
1112 default:
1113 dev_err(&st->spi->dev,
1114 "Invalid value for excitation current(%u)",
1115 excitation_current);
1116 return ERR_PTR(error: -EINVAL);
1117 }
1118 }
1119
1120 fwnode_property_read_u32(fwnode: child, propname: "adi,ideal-factor-value", val: &temp);
1121
1122 /* 2^20 resolution */
1123 diode->ideal_factor_value = __convert_to_raw(val: temp, resolution: 1048576);
1124
1125 return &diode->sensor;
1126}
1127
1128static struct ltc2983_sensor *ltc2983_r_sense_new(struct fwnode_handle *child,
1129 struct ltc2983_data *st,
1130 const struct ltc2983_sensor *sensor)
1131{
1132 struct ltc2983_rsense *rsense;
1133 int ret;
1134 u32 temp;
1135
1136 rsense = devm_kzalloc(dev: &st->spi->dev, size: sizeof(*rsense), GFP_KERNEL);
1137 if (!rsense)
1138 return ERR_PTR(error: -ENOMEM);
1139
1140 /* validate channel index */
1141 if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1142 dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
1143 sensor->chan);
1144 return ERR_PTR(error: -EINVAL);
1145 }
1146
1147 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,rsense-val-milli-ohms", val: &temp);
1148 if (ret) {
1149 dev_err(&st->spi->dev, "Property adi,rsense-val-milli-ohms missing\n");
1150 return ERR_PTR(error: -EINVAL);
1151 }
1152 /*
1153 * Times 1000 because we have milli-ohms and __convert_to_raw
1154 * expects scales of 1000000 which are used for all other
1155 * properties.
1156 * 2^10 resolution
1157 */
1158 rsense->r_sense_val = __convert_to_raw(val: (u64)temp * 1000, resolution: 1024);
1159
1160 /* set common parameters */
1161 rsense->sensor.assign_chan = ltc2983_r_sense_assign_chan;
1162
1163 return &rsense->sensor;
1164}
1165
1166static struct ltc2983_sensor *ltc2983_adc_new(struct fwnode_handle *child,
1167 struct ltc2983_data *st,
1168 const struct ltc2983_sensor *sensor)
1169{
1170 struct ltc2983_adc *adc;
1171
1172 adc = devm_kzalloc(dev: &st->spi->dev, size: sizeof(*adc), GFP_KERNEL);
1173 if (!adc)
1174 return ERR_PTR(error: -ENOMEM);
1175
1176 if (fwnode_property_read_bool(fwnode: child, propname: "adi,single-ended"))
1177 adc->single_ended = true;
1178
1179 if (!adc->single_ended &&
1180 sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1181 dev_err(&st->spi->dev, "Invalid chan:%d for differential adc\n",
1182 sensor->chan);
1183 return ERR_PTR(error: -EINVAL);
1184 }
1185 /* set common parameters */
1186 adc->sensor.assign_chan = ltc2983_adc_assign_chan;
1187 adc->sensor.fault_handler = ltc2983_common_fault_handler;
1188
1189 return &adc->sensor;
1190}
1191
1192static struct ltc2983_sensor *ltc2983_temp_new(struct fwnode_handle *child,
1193 struct ltc2983_data *st,
1194 const struct ltc2983_sensor *sensor)
1195{
1196 struct ltc2983_temp *temp;
1197
1198 temp = devm_kzalloc(dev: &st->spi->dev, size: sizeof(*temp), GFP_KERNEL);
1199 if (!temp)
1200 return ERR_PTR(error: -ENOMEM);
1201
1202 if (fwnode_property_read_bool(fwnode: child, propname: "adi,single-ended"))
1203 temp->single_ended = true;
1204
1205 if (!temp->single_ended &&
1206 sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1207 dev_err(&st->spi->dev, "Invalid chan:%d for differential temp\n",
1208 sensor->chan);
1209 return ERR_PTR(error: -EINVAL);
1210 }
1211
1212 temp->custom = __ltc2983_custom_sensor_new(st, fn: child, propname: "adi,custom-temp",
1213 is_steinhart: false, resolution: 4096, has_signed: true);
1214 if (IS_ERR(ptr: temp->custom))
1215 return ERR_CAST(ptr: temp->custom);
1216
1217 /* set common parameters */
1218 temp->sensor.assign_chan = ltc2983_temp_assign_chan;
1219 temp->sensor.fault_handler = ltc2983_common_fault_handler;
1220
1221 return &temp->sensor;
1222}
1223
1224static int ltc2983_chan_read(struct ltc2983_data *st,
1225 const struct ltc2983_sensor *sensor, int *val)
1226{
1227 u32 start_conversion = 0;
1228 int ret;
1229 unsigned long time;
1230
1231 start_conversion = LTC2983_STATUS_START(true);
1232 start_conversion |= LTC2983_STATUS_CHAN_SEL(sensor->chan);
1233 dev_dbg(&st->spi->dev, "Start conversion on chan:%d, status:%02X\n",
1234 sensor->chan, start_conversion);
1235 /* start conversion */
1236 ret = regmap_write(map: st->regmap, LTC2983_STATUS_REG, val: start_conversion);
1237 if (ret)
1238 return ret;
1239
1240 reinit_completion(x: &st->completion);
1241 /*
1242 * wait for conversion to complete.
1243 * 300 ms should be more than enough to complete the conversion.
1244 * Depending on the sensor configuration, there are 2/3 conversions
1245 * cycles of 82ms.
1246 */
1247 time = wait_for_completion_timeout(x: &st->completion,
1248 timeout: msecs_to_jiffies(m: 300));
1249 if (!time) {
1250 dev_warn(&st->spi->dev, "Conversion timed out\n");
1251 return -ETIMEDOUT;
1252 }
1253
1254 /* read the converted data */
1255 ret = regmap_bulk_read(map: st->regmap, LTC2983_CHAN_RES_ADDR(sensor->chan),
1256 val: &st->temp, val_count: sizeof(st->temp));
1257 if (ret)
1258 return ret;
1259
1260 *val = __be32_to_cpu(st->temp);
1261
1262 if (!(LTC2983_RES_VALID_MASK & *val)) {
1263 dev_err(&st->spi->dev, "Invalid conversion detected\n");
1264 return -EIO;
1265 }
1266
1267 ret = sensor->fault_handler(st, *val);
1268 if (ret)
1269 return ret;
1270
1271 *val = sign_extend32(value: (*val) & LTC2983_DATA_MASK, LTC2983_DATA_SIGN_BIT);
1272 return 0;
1273}
1274
1275static int ltc2983_read_raw(struct iio_dev *indio_dev,
1276 struct iio_chan_spec const *chan,
1277 int *val, int *val2, long mask)
1278{
1279 struct ltc2983_data *st = iio_priv(indio_dev);
1280 int ret;
1281
1282 /* sanity check */
1283 if (chan->address >= st->num_channels) {
1284 dev_err(&st->spi->dev, "Invalid chan address:%ld",
1285 chan->address);
1286 return -EINVAL;
1287 }
1288
1289 switch (mask) {
1290 case IIO_CHAN_INFO_RAW:
1291 mutex_lock(&st->lock);
1292 ret = ltc2983_chan_read(st, sensor: st->sensors[chan->address], val);
1293 mutex_unlock(lock: &st->lock);
1294 return ret ?: IIO_VAL_INT;
1295 case IIO_CHAN_INFO_SCALE:
1296 switch (chan->type) {
1297 case IIO_TEMP:
1298 /* value in milli degrees */
1299 *val = 1000;
1300 /* 2^10 */
1301 *val2 = 1024;
1302 return IIO_VAL_FRACTIONAL;
1303 case IIO_VOLTAGE:
1304 /* value in millivolt */
1305 *val = 1000;
1306 /* 2^21 */
1307 *val2 = 2097152;
1308 return IIO_VAL_FRACTIONAL;
1309 default:
1310 return -EINVAL;
1311 }
1312 }
1313
1314 return -EINVAL;
1315}
1316
1317static int ltc2983_reg_access(struct iio_dev *indio_dev,
1318 unsigned int reg,
1319 unsigned int writeval,
1320 unsigned int *readval)
1321{
1322 struct ltc2983_data *st = iio_priv(indio_dev);
1323
1324 if (readval)
1325 return regmap_read(map: st->regmap, reg, val: readval);
1326 else
1327 return regmap_write(map: st->regmap, reg, val: writeval);
1328}
1329
1330static irqreturn_t ltc2983_irq_handler(int irq, void *data)
1331{
1332 struct ltc2983_data *st = data;
1333
1334 complete(&st->completion);
1335 return IRQ_HANDLED;
1336}
1337
1338#define LTC2983_CHAN(__type, index, __address) ({ \
1339 struct iio_chan_spec __chan = { \
1340 .type = __type, \
1341 .indexed = 1, \
1342 .channel = index, \
1343 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
1344 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
1345 .address = __address, \
1346 }; \
1347 __chan; \
1348})
1349
1350static int ltc2983_parse_fw(struct ltc2983_data *st)
1351{
1352 struct device *dev = &st->spi->dev;
1353 struct fwnode_handle *child;
1354 int ret = 0, chan = 0, channel_avail_mask = 0;
1355
1356 device_property_read_u32(dev, propname: "adi,mux-delay-config-us", val: &st->mux_delay_config);
1357
1358 device_property_read_u32(dev, propname: "adi,filter-notch-freq", val: &st->filter_notch_freq);
1359
1360 st->num_channels = device_get_child_node_count(dev);
1361 if (!st->num_channels) {
1362 dev_err(&st->spi->dev, "At least one channel must be given!");
1363 return -EINVAL;
1364 }
1365
1366 st->sensors = devm_kcalloc(dev, n: st->num_channels, size: sizeof(*st->sensors),
1367 GFP_KERNEL);
1368 if (!st->sensors)
1369 return -ENOMEM;
1370
1371 st->iio_channels = st->num_channels;
1372 device_for_each_child_node(dev, child) {
1373 struct ltc2983_sensor sensor;
1374
1375 ret = fwnode_property_read_u32(fwnode: child, propname: "reg", val: &sensor.chan);
1376 if (ret) {
1377 dev_err(dev, "reg property must given for child nodes\n");
1378 goto put_child;
1379 }
1380
1381 /* check if we have a valid channel */
1382 if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
1383 sensor.chan > st->info->max_channels_nr) {
1384 ret = -EINVAL;
1385 dev_err(dev, "chan:%d must be from %u to %u\n", sensor.chan,
1386 LTC2983_MIN_CHANNELS_NR, st->info->max_channels_nr);
1387 goto put_child;
1388 } else if (channel_avail_mask & BIT(sensor.chan)) {
1389 ret = -EINVAL;
1390 dev_err(dev, "chan:%d already in use\n", sensor.chan);
1391 goto put_child;
1392 }
1393
1394 ret = fwnode_property_read_u32(fwnode: child, propname: "adi,sensor-type", val: &sensor.type);
1395 if (ret) {
1396 dev_err(dev,
1397 "adi,sensor-type property must given for child nodes\n");
1398 goto put_child;
1399 }
1400
1401 dev_dbg(dev, "Create new sensor, type %u, chann %u",
1402 sensor.type,
1403 sensor.chan);
1404
1405 if (sensor.type >= LTC2983_SENSOR_THERMOCOUPLE &&
1406 sensor.type <= LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
1407 st->sensors[chan] = ltc2983_thermocouple_new(child, st,
1408 sensor: &sensor);
1409 } else if (sensor.type >= LTC2983_SENSOR_RTD &&
1410 sensor.type <= LTC2983_SENSOR_RTD_CUSTOM) {
1411 st->sensors[chan] = ltc2983_rtd_new(child, st, sensor: &sensor);
1412 } else if (sensor.type >= LTC2983_SENSOR_THERMISTOR &&
1413 sensor.type <= LTC2983_SENSOR_THERMISTOR_CUSTOM) {
1414 st->sensors[chan] = ltc2983_thermistor_new(child, st,
1415 sensor: &sensor);
1416 } else if (sensor.type == LTC2983_SENSOR_DIODE) {
1417 st->sensors[chan] = ltc2983_diode_new(child, st,
1418 sensor: &sensor);
1419 } else if (sensor.type == LTC2983_SENSOR_SENSE_RESISTOR) {
1420 st->sensors[chan] = ltc2983_r_sense_new(child, st,
1421 sensor: &sensor);
1422 /* don't add rsense to iio */
1423 st->iio_channels--;
1424 } else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
1425 st->sensors[chan] = ltc2983_adc_new(child, st, sensor: &sensor);
1426 } else if (st->info->has_temp &&
1427 sensor.type == LTC2983_SENSOR_ACTIVE_TEMP) {
1428 st->sensors[chan] = ltc2983_temp_new(child, st, sensor: &sensor);
1429 } else {
1430 dev_err(dev, "Unknown sensor type %d\n", sensor.type);
1431 ret = -EINVAL;
1432 goto put_child;
1433 }
1434
1435 if (IS_ERR(ptr: st->sensors[chan])) {
1436 dev_err(dev, "Failed to create sensor %ld",
1437 PTR_ERR(st->sensors[chan]));
1438 ret = PTR_ERR(ptr: st->sensors[chan]);
1439 goto put_child;
1440 }
1441 /* set generic sensor parameters */
1442 st->sensors[chan]->chan = sensor.chan;
1443 st->sensors[chan]->type = sensor.type;
1444
1445 channel_avail_mask |= BIT(sensor.chan);
1446 chan++;
1447 }
1448
1449 return 0;
1450put_child:
1451 fwnode_handle_put(fwnode: child);
1452 return ret;
1453}
1454
1455static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
1456 unsigned int wait_time, unsigned int status_reg,
1457 unsigned long status_fail_mask)
1458{
1459 unsigned long time;
1460 unsigned int val;
1461 int ret;
1462
1463 ret = regmap_bulk_write(map: st->regmap, LTC2983_EEPROM_KEY_REG,
1464 val: &st->eeprom_key, val_count: sizeof(st->eeprom_key));
1465 if (ret)
1466 return ret;
1467
1468 reinit_completion(x: &st->completion);
1469
1470 ret = regmap_write(map: st->regmap, LTC2983_STATUS_REG,
1471 LTC2983_STATUS_START(true) | cmd);
1472 if (ret)
1473 return ret;
1474
1475 time = wait_for_completion_timeout(x: &st->completion,
1476 timeout: msecs_to_jiffies(m: wait_time));
1477 if (!time) {
1478 dev_err(&st->spi->dev, "EEPROM command timed out\n");
1479 return -ETIMEDOUT;
1480 }
1481
1482 ret = regmap_read(map: st->regmap, reg: status_reg, val: &val);
1483 if (ret)
1484 return ret;
1485
1486 if (val & status_fail_mask) {
1487 dev_err(&st->spi->dev, "EEPROM command failed: 0x%02X\n", val);
1488 return -EINVAL;
1489 }
1490
1491 return 0;
1492}
1493
1494static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
1495{
1496 u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0, status;
1497 int ret;
1498
1499 /* make sure the device is up: start bit (7) is 0 and done bit (6) is 1 */
1500 ret = regmap_read_poll_timeout(st->regmap, LTC2983_STATUS_REG, status,
1501 LTC2983_STATUS_UP(status) == 1, 25000,
1502 25000 * 10);
1503 if (ret) {
1504 dev_err(&st->spi->dev, "Device startup timed out\n");
1505 return ret;
1506 }
1507
1508 ret = regmap_update_bits(map: st->regmap, LTC2983_GLOBAL_CONFIG_REG,
1509 LTC2983_NOTCH_FREQ_MASK,
1510 LTC2983_NOTCH_FREQ(st->filter_notch_freq));
1511 if (ret)
1512 return ret;
1513
1514 ret = regmap_write(map: st->regmap, LTC2983_MUX_CONFIG_REG,
1515 val: st->mux_delay_config);
1516 if (ret)
1517 return ret;
1518
1519 if (st->info->has_eeprom && !assign_iio) {
1520 ret = ltc2983_eeprom_cmd(st, LTC2983_EEPROM_READ_CMD,
1521 LTC2983_EEPROM_READ_TIME_MS,
1522 LTC2983_EEPROM_READ_STATUS_REG,
1523 LTC2983_EEPROM_READ_FAILURE_MASK);
1524 if (!ret)
1525 return 0;
1526 }
1527
1528 for (chan = 0; chan < st->num_channels; chan++) {
1529 u32 chan_type = 0, *iio_chan;
1530
1531 ret = st->sensors[chan]->assign_chan(st, st->sensors[chan]);
1532 if (ret)
1533 return ret;
1534 /*
1535 * The assign_iio flag is necessary for when the device is
1536 * coming out of sleep. In that case, we just need to
1537 * re-configure the device channels.
1538 * We also don't assign iio channels for rsense.
1539 */
1540 if (st->sensors[chan]->type == LTC2983_SENSOR_SENSE_RESISTOR ||
1541 !assign_iio)
1542 continue;
1543
1544 /* assign iio channel */
1545 if (st->sensors[chan]->type != LTC2983_SENSOR_DIRECT_ADC) {
1546 chan_type = IIO_TEMP;
1547 iio_chan = &iio_chan_t;
1548 } else {
1549 chan_type = IIO_VOLTAGE;
1550 iio_chan = &iio_chan_v;
1551 }
1552
1553 /*
1554 * add chan as the iio .address so that, we can directly
1555 * reference the sensor given the iio_chan_spec
1556 */
1557 st->iio_chan[iio_idx++] = LTC2983_CHAN(chan_type, (*iio_chan)++,
1558 chan);
1559 }
1560
1561 return 0;
1562}
1563
1564static const struct regmap_range ltc2983_reg_ranges[] = {
1565 regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
1566 regmap_reg_range(LTC2983_TEMP_RES_START_REG, LTC2983_TEMP_RES_END_REG),
1567 regmap_reg_range(LTC2983_EEPROM_KEY_REG, LTC2983_EEPROM_KEY_REG),
1568 regmap_reg_range(LTC2983_EEPROM_READ_STATUS_REG,
1569 LTC2983_EEPROM_READ_STATUS_REG),
1570 regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG, LTC2983_GLOBAL_CONFIG_REG),
1571 regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
1572 LTC2983_MULT_CHANNEL_END_REG),
1573 regmap_reg_range(LTC2986_EEPROM_STATUS_REG, LTC2986_EEPROM_STATUS_REG),
1574 regmap_reg_range(LTC2983_MUX_CONFIG_REG, LTC2983_MUX_CONFIG_REG),
1575 regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
1576 LTC2983_CHAN_ASSIGN_END_REG),
1577 regmap_reg_range(LTC2983_CUST_SENS_TBL_START_REG,
1578 LTC2983_CUST_SENS_TBL_END_REG),
1579};
1580
1581static const struct regmap_access_table ltc2983_reg_table = {
1582 .yes_ranges = ltc2983_reg_ranges,
1583 .n_yes_ranges = ARRAY_SIZE(ltc2983_reg_ranges),
1584};
1585
1586/*
1587 * The reg_bits are actually 12 but the device needs the first *complete*
1588 * byte for the command (R/W).
1589 */
1590static const struct regmap_config ltc2983_regmap_config = {
1591 .reg_bits = 24,
1592 .val_bits = 8,
1593 .wr_table = &ltc2983_reg_table,
1594 .rd_table = &ltc2983_reg_table,
1595 .read_flag_mask = GENMASK(1, 0),
1596 .write_flag_mask = BIT(1),
1597};
1598
1599static const struct iio_info ltc2983_iio_info = {
1600 .read_raw = ltc2983_read_raw,
1601 .debugfs_reg_access = ltc2983_reg_access,
1602};
1603
1604static int ltc2983_probe(struct spi_device *spi)
1605{
1606 struct ltc2983_data *st;
1607 struct iio_dev *indio_dev;
1608 struct gpio_desc *gpio;
1609 int ret;
1610
1611 indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*st));
1612 if (!indio_dev)
1613 return -ENOMEM;
1614
1615 st = iio_priv(indio_dev);
1616
1617 st->info = spi_get_device_match_data(sdev: spi);
1618 if (!st->info)
1619 return -ENODEV;
1620
1621 st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
1622 if (IS_ERR(ptr: st->regmap)) {
1623 dev_err(&spi->dev, "Failed to initialize regmap\n");
1624 return PTR_ERR(ptr: st->regmap);
1625 }
1626
1627 mutex_init(&st->lock);
1628 init_completion(x: &st->completion);
1629 st->spi = spi;
1630 st->eeprom_key = cpu_to_be32(LTC2983_EEPROM_KEY);
1631 spi_set_drvdata(spi, data: st);
1632
1633 ret = ltc2983_parse_fw(st);
1634 if (ret)
1635 return ret;
1636
1637 gpio = devm_gpiod_get_optional(dev: &st->spi->dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
1638 if (IS_ERR(ptr: gpio))
1639 return PTR_ERR(ptr: gpio);
1640
1641 if (gpio) {
1642 /* bring the device out of reset */
1643 usleep_range(min: 1000, max: 1200);
1644 gpiod_set_value_cansleep(desc: gpio, value: 0);
1645 }
1646
1647 st->iio_chan = devm_kzalloc(dev: &spi->dev,
1648 size: st->iio_channels * sizeof(*st->iio_chan),
1649 GFP_KERNEL);
1650 if (!st->iio_chan)
1651 return -ENOMEM;
1652
1653 ret = ltc2983_setup(st, assign_iio: true);
1654 if (ret)
1655 return ret;
1656
1657 ret = devm_request_irq(dev: &spi->dev, irq: spi->irq, handler: ltc2983_irq_handler,
1658 IRQF_TRIGGER_RISING, devname: st->info->name, dev_id: st);
1659 if (ret) {
1660 dev_err(&spi->dev, "failed to request an irq, %d", ret);
1661 return ret;
1662 }
1663
1664 if (st->info->has_eeprom) {
1665 ret = ltc2983_eeprom_cmd(st, LTC2983_EEPROM_WRITE_CMD,
1666 LTC2983_EEPROM_WRITE_TIME_MS,
1667 LTC2986_EEPROM_STATUS_REG,
1668 LTC2983_EEPROM_STATUS_FAILURE_MASK);
1669 if (ret)
1670 return ret;
1671 }
1672
1673 indio_dev->name = st->info->name;
1674 indio_dev->num_channels = st->iio_channels;
1675 indio_dev->channels = st->iio_chan;
1676 indio_dev->modes = INDIO_DIRECT_MODE;
1677 indio_dev->info = &ltc2983_iio_info;
1678
1679 return devm_iio_device_register(&spi->dev, indio_dev);
1680}
1681
1682static int ltc2983_resume(struct device *dev)
1683{
1684 struct ltc2983_data *st = spi_get_drvdata(spi: to_spi_device(dev));
1685 int dummy;
1686
1687 /* dummy read to bring the device out of sleep */
1688 regmap_read(map: st->regmap, LTC2983_STATUS_REG, val: &dummy);
1689 /* we need to re-assign the channels */
1690 return ltc2983_setup(st, assign_iio: false);
1691}
1692
1693static int ltc2983_suspend(struct device *dev)
1694{
1695 struct ltc2983_data *st = spi_get_drvdata(spi: to_spi_device(dev));
1696
1697 return regmap_write(map: st->regmap, LTC2983_STATUS_REG, LTC2983_SLEEP);
1698}
1699
1700static DEFINE_SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
1701 ltc2983_resume);
1702
1703static const struct ltc2983_chip_info ltc2983_chip_info_data = {
1704 .name = "ltc2983",
1705 .max_channels_nr = 20,
1706};
1707
1708static const struct ltc2983_chip_info ltc2984_chip_info_data = {
1709 .name = "ltc2984",
1710 .max_channels_nr = 20,
1711 .has_eeprom = true,
1712};
1713
1714static const struct ltc2983_chip_info ltc2986_chip_info_data = {
1715 .name = "ltc2986",
1716 .max_channels_nr = 10,
1717 .has_temp = true,
1718 .has_eeprom = true,
1719};
1720
1721static const struct ltc2983_chip_info ltm2985_chip_info_data = {
1722 .name = "ltm2985",
1723 .max_channels_nr = 10,
1724 .has_temp = true,
1725 .has_eeprom = true,
1726};
1727
1728static const struct spi_device_id ltc2983_id_table[] = {
1729 { "ltc2983", (kernel_ulong_t)&ltc2983_chip_info_data },
1730 { "ltc2984", (kernel_ulong_t)&ltc2984_chip_info_data },
1731 { "ltc2986", (kernel_ulong_t)&ltc2986_chip_info_data },
1732 { "ltm2985", (kernel_ulong_t)&ltm2985_chip_info_data },
1733 {},
1734};
1735MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
1736
1737static const struct of_device_id ltc2983_of_match[] = {
1738 { .compatible = "adi,ltc2983", .data = &ltc2983_chip_info_data },
1739 { .compatible = "adi,ltc2984", .data = &ltc2984_chip_info_data },
1740 { .compatible = "adi,ltc2986", .data = &ltc2986_chip_info_data },
1741 { .compatible = "adi,ltm2985", .data = &ltm2985_chip_info_data },
1742 {},
1743};
1744MODULE_DEVICE_TABLE(of, ltc2983_of_match);
1745
1746static struct spi_driver ltc2983_driver = {
1747 .driver = {
1748 .name = "ltc2983",
1749 .of_match_table = ltc2983_of_match,
1750 .pm = pm_sleep_ptr(&ltc2983_pm_ops),
1751 },
1752 .probe = ltc2983_probe,
1753 .id_table = ltc2983_id_table,
1754};
1755
1756module_spi_driver(ltc2983_driver);
1757
1758MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
1759MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature sensors");
1760MODULE_LICENSE("GPL");
1761

source code of linux/drivers/iio/temperature/ltc2983.c