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_GLOBAL_CONFIG_REG		0x00F0
29 #define LTC2983_MULT_CHANNEL_START_REG		0x00F4
30 #define LTC2983_MULT_CHANNEL_END_REG		0x00F7
31 #define LTC2983_MUX_CONFIG_REG			0x00FF
32 #define LTC2983_CHAN_ASSIGN_START_REG		0x0200
33 #define LTC2983_CHAN_ASSIGN_END_REG		0x024F
34 #define LTC2983_CUST_SENS_TBL_START_REG		0x0250
35 #define LTC2983_CUST_SENS_TBL_END_REG		0x03CF
36 
37 #define LTC2983_DIFFERENTIAL_CHAN_MIN		2
38 #define LTC2983_MAX_CHANNELS_NR			20
39 #define LTC2983_MIN_CHANNELS_NR			1
40 #define LTC2983_SLEEP				0x97
41 #define LTC2983_CUSTOM_STEINHART_SIZE		24
42 #define LTC2983_CUSTOM_SENSOR_ENTRY_SZ		6
43 #define LTC2983_CUSTOM_STEINHART_ENTRY_SZ	4
44 
45 #define LTC2983_CHAN_START_ADDR(chan) \
46 			(((chan - 1) * 4) + LTC2983_CHAN_ASSIGN_START_REG)
47 #define LTC2983_CHAN_RES_ADDR(chan) \
48 			(((chan - 1) * 4) + LTC2983_TEMP_RES_START_REG)
49 #define LTC2983_THERMOCOUPLE_DIFF_MASK		BIT(3)
50 #define LTC2983_THERMOCOUPLE_SGL(x) \
51 				FIELD_PREP(LTC2983_THERMOCOUPLE_DIFF_MASK, x)
52 #define LTC2983_THERMOCOUPLE_OC_CURR_MASK	GENMASK(1, 0)
53 #define LTC2983_THERMOCOUPLE_OC_CURR(x) \
54 				FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CURR_MASK, x)
55 #define LTC2983_THERMOCOUPLE_OC_CHECK_MASK	BIT(2)
56 #define LTC2983_THERMOCOUPLE_OC_CHECK(x) \
57 			FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CHECK_MASK, x)
58 
59 #define LTC2983_THERMISTOR_DIFF_MASK		BIT(2)
60 #define LTC2983_THERMISTOR_SGL(x) \
61 				FIELD_PREP(LTC2983_THERMISTOR_DIFF_MASK, x)
62 #define LTC2983_THERMISTOR_R_SHARE_MASK		BIT(1)
63 #define LTC2983_THERMISTOR_R_SHARE(x) \
64 				FIELD_PREP(LTC2983_THERMISTOR_R_SHARE_MASK, x)
65 #define LTC2983_THERMISTOR_C_ROTATE_MASK	BIT(0)
66 #define LTC2983_THERMISTOR_C_ROTATE(x) \
67 				FIELD_PREP(LTC2983_THERMISTOR_C_ROTATE_MASK, x)
68 
69 #define LTC2983_DIODE_DIFF_MASK			BIT(2)
70 #define LTC2983_DIODE_SGL(x) \
71 			FIELD_PREP(LTC2983_DIODE_DIFF_MASK, x)
72 #define LTC2983_DIODE_3_CONV_CYCLE_MASK		BIT(1)
73 #define LTC2983_DIODE_3_CONV_CYCLE(x) \
74 				FIELD_PREP(LTC2983_DIODE_3_CONV_CYCLE_MASK, x)
75 #define LTC2983_DIODE_AVERAGE_ON_MASK		BIT(0)
76 #define LTC2983_DIODE_AVERAGE_ON(x) \
77 				FIELD_PREP(LTC2983_DIODE_AVERAGE_ON_MASK, x)
78 
79 #define LTC2983_RTD_4_WIRE_MASK			BIT(3)
80 #define LTC2983_RTD_ROTATION_MASK		BIT(1)
81 #define LTC2983_RTD_C_ROTATE(x) \
82 			FIELD_PREP(LTC2983_RTD_ROTATION_MASK, x)
83 #define LTC2983_RTD_KELVIN_R_SENSE_MASK		GENMASK(3, 2)
84 #define LTC2983_RTD_N_WIRES_MASK		GENMASK(3, 2)
85 #define LTC2983_RTD_N_WIRES(x) \
86 			FIELD_PREP(LTC2983_RTD_N_WIRES_MASK, x)
87 #define LTC2983_RTD_R_SHARE_MASK		BIT(0)
88 #define LTC2983_RTD_R_SHARE(x) \
89 			FIELD_PREP(LTC2983_RTD_R_SHARE_MASK, 1)
90 
91 #define LTC2983_COMMON_HARD_FAULT_MASK	GENMASK(31, 30)
92 #define LTC2983_COMMON_SOFT_FAULT_MASK	GENMASK(27, 25)
93 
94 #define	LTC2983_STATUS_START_MASK	BIT(7)
95 #define	LTC2983_STATUS_START(x)		FIELD_PREP(LTC2983_STATUS_START_MASK, x)
96 #define	LTC2983_STATUS_UP_MASK		GENMASK(7, 6)
97 #define	LTC2983_STATUS_UP(reg)		FIELD_GET(LTC2983_STATUS_UP_MASK, reg)
98 
99 #define	LTC2983_STATUS_CHAN_SEL_MASK	GENMASK(4, 0)
100 #define	LTC2983_STATUS_CHAN_SEL(x) \
101 				FIELD_PREP(LTC2983_STATUS_CHAN_SEL_MASK, x)
102 
103 #define LTC2983_TEMP_UNITS_MASK		BIT(2)
104 #define LTC2983_TEMP_UNITS(x)		FIELD_PREP(LTC2983_TEMP_UNITS_MASK, x)
105 
106 #define LTC2983_NOTCH_FREQ_MASK		GENMASK(1, 0)
107 #define LTC2983_NOTCH_FREQ(x)		FIELD_PREP(LTC2983_NOTCH_FREQ_MASK, x)
108 
109 #define LTC2983_RES_VALID_MASK		BIT(24)
110 #define LTC2983_DATA_MASK		GENMASK(23, 0)
111 #define LTC2983_DATA_SIGN_BIT		23
112 
113 #define LTC2983_CHAN_TYPE_MASK		GENMASK(31, 27)
114 #define LTC2983_CHAN_TYPE(x)		FIELD_PREP(LTC2983_CHAN_TYPE_MASK, x)
115 
116 /* cold junction for thermocouples and rsense for rtd's and thermistor's */
117 #define LTC2983_CHAN_ASSIGN_MASK	GENMASK(26, 22)
118 #define LTC2983_CHAN_ASSIGN(x)		FIELD_PREP(LTC2983_CHAN_ASSIGN_MASK, x)
119 
120 #define LTC2983_CUSTOM_LEN_MASK		GENMASK(5, 0)
121 #define LTC2983_CUSTOM_LEN(x)		FIELD_PREP(LTC2983_CUSTOM_LEN_MASK, x)
122 
123 #define LTC2983_CUSTOM_ADDR_MASK	GENMASK(11, 6)
124 #define LTC2983_CUSTOM_ADDR(x)		FIELD_PREP(LTC2983_CUSTOM_ADDR_MASK, x)
125 
126 #define LTC2983_THERMOCOUPLE_CFG_MASK	GENMASK(21, 18)
127 #define LTC2983_THERMOCOUPLE_CFG(x) \
128 				FIELD_PREP(LTC2983_THERMOCOUPLE_CFG_MASK, x)
129 #define LTC2983_THERMOCOUPLE_HARD_FAULT_MASK	GENMASK(31, 29)
130 #define LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK	GENMASK(28, 25)
131 
132 #define LTC2983_RTD_CFG_MASK		GENMASK(21, 18)
133 #define LTC2983_RTD_CFG(x)		FIELD_PREP(LTC2983_RTD_CFG_MASK, x)
134 #define LTC2983_RTD_EXC_CURRENT_MASK	GENMASK(17, 14)
135 #define LTC2983_RTD_EXC_CURRENT(x) \
136 				FIELD_PREP(LTC2983_RTD_EXC_CURRENT_MASK, x)
137 #define LTC2983_RTD_CURVE_MASK		GENMASK(13, 12)
138 #define LTC2983_RTD_CURVE(x)		FIELD_PREP(LTC2983_RTD_CURVE_MASK, x)
139 
140 #define LTC2983_THERMISTOR_CFG_MASK	GENMASK(21, 19)
141 #define LTC2983_THERMISTOR_CFG(x) \
142 				FIELD_PREP(LTC2983_THERMISTOR_CFG_MASK, x)
143 #define LTC2983_THERMISTOR_EXC_CURRENT_MASK	GENMASK(18, 15)
144 #define LTC2983_THERMISTOR_EXC_CURRENT(x) \
145 			FIELD_PREP(LTC2983_THERMISTOR_EXC_CURRENT_MASK, x)
146 
147 #define LTC2983_DIODE_CFG_MASK		GENMASK(26, 24)
148 #define LTC2983_DIODE_CFG(x)		FIELD_PREP(LTC2983_DIODE_CFG_MASK, x)
149 #define LTC2983_DIODE_EXC_CURRENT_MASK	GENMASK(23, 22)
150 #define LTC2983_DIODE_EXC_CURRENT(x) \
151 				FIELD_PREP(LTC2983_DIODE_EXC_CURRENT_MASK, x)
152 #define LTC2983_DIODE_IDEAL_FACTOR_MASK	GENMASK(21, 0)
153 #define LTC2983_DIODE_IDEAL_FACTOR(x) \
154 				FIELD_PREP(LTC2983_DIODE_IDEAL_FACTOR_MASK, x)
155 
156 #define LTC2983_R_SENSE_VAL_MASK	GENMASK(26, 0)
157 #define LTC2983_R_SENSE_VAL(x)		FIELD_PREP(LTC2983_R_SENSE_VAL_MASK, x)
158 
159 #define LTC2983_ADC_SINGLE_ENDED_MASK	BIT(26)
160 #define LTC2983_ADC_SINGLE_ENDED(x) \
161 				FIELD_PREP(LTC2983_ADC_SINGLE_ENDED_MASK, x)
162 
163 enum {
164 	LTC2983_SENSOR_THERMOCOUPLE = 1,
165 	LTC2983_SENSOR_THERMOCOUPLE_CUSTOM = 9,
166 	LTC2983_SENSOR_RTD = 10,
167 	LTC2983_SENSOR_RTD_CUSTOM = 18,
168 	LTC2983_SENSOR_THERMISTOR = 19,
169 	LTC2983_SENSOR_THERMISTOR_STEINHART = 26,
170 	LTC2983_SENSOR_THERMISTOR_CUSTOM = 27,
171 	LTC2983_SENSOR_DIODE = 28,
172 	LTC2983_SENSOR_SENSE_RESISTOR = 29,
173 	LTC2983_SENSOR_DIRECT_ADC = 30,
174 };
175 
176 #define to_thermocouple(_sensor) \
177 		container_of(_sensor, struct ltc2983_thermocouple, sensor)
178 
179 #define to_rtd(_sensor) \
180 		container_of(_sensor, struct ltc2983_rtd, sensor)
181 
182 #define to_thermistor(_sensor) \
183 		container_of(_sensor, struct ltc2983_thermistor, sensor)
184 
185 #define to_diode(_sensor) \
186 		container_of(_sensor, struct ltc2983_diode, sensor)
187 
188 #define to_rsense(_sensor) \
189 		container_of(_sensor, struct ltc2983_rsense, sensor)
190 
191 #define to_adc(_sensor) \
192 		container_of(_sensor, struct ltc2983_adc, sensor)
193 
194 struct ltc2983_data {
195 	struct regmap *regmap;
196 	struct spi_device *spi;
197 	struct mutex lock;
198 	struct completion completion;
199 	struct iio_chan_spec *iio_chan;
200 	struct ltc2983_sensor **sensors;
201 	u32 mux_delay_config;
202 	u32 filter_notch_freq;
203 	u16 custom_table_size;
204 	u8 num_channels;
205 	u8 iio_channels;
206 	/*
207 	 * DMA (thus cache coherency maintenance) may require the
208 	 * transfer buffers to live in their own cache lines.
209 	 * Holds the converted temperature
210 	 */
211 	__be32 temp __aligned(IIO_DMA_MINALIGN);
212 };
213 
214 struct ltc2983_sensor {
215 	int (*fault_handler)(const struct ltc2983_data *st, const u32 result);
216 	int (*assign_chan)(struct ltc2983_data *st,
217 			   const struct ltc2983_sensor *sensor);
218 	/* specifies the sensor channel */
219 	u32 chan;
220 	/* sensor type */
221 	u32 type;
222 };
223 
224 struct ltc2983_custom_sensor {
225 	/* raw table sensor data */
226 	void *table;
227 	size_t size;
228 	/* address offset */
229 	s8 offset;
230 	bool is_steinhart;
231 };
232 
233 struct ltc2983_thermocouple {
234 	struct ltc2983_sensor sensor;
235 	struct ltc2983_custom_sensor *custom;
236 	u32 sensor_config;
237 	u32 cold_junction_chan;
238 };
239 
240 struct ltc2983_rtd {
241 	struct ltc2983_sensor sensor;
242 	struct ltc2983_custom_sensor *custom;
243 	u32 sensor_config;
244 	u32 r_sense_chan;
245 	u32 excitation_current;
246 	u32 rtd_curve;
247 };
248 
249 struct ltc2983_thermistor {
250 	struct ltc2983_sensor sensor;
251 	struct ltc2983_custom_sensor *custom;
252 	u32 sensor_config;
253 	u32 r_sense_chan;
254 	u32 excitation_current;
255 };
256 
257 struct ltc2983_diode {
258 	struct ltc2983_sensor sensor;
259 	u32 sensor_config;
260 	u32 excitation_current;
261 	u32 ideal_factor_value;
262 };
263 
264 struct ltc2983_rsense {
265 	struct ltc2983_sensor sensor;
266 	u32 r_sense_val;
267 };
268 
269 struct ltc2983_adc {
270 	struct ltc2983_sensor sensor;
271 	bool single_ended;
272 };
273 
274 /*
275  * Convert to Q format numbers. These number's are integers where
276  * the number of integer and fractional bits are specified. The resolution
277  * is given by 1/@resolution and tell us the number of fractional bits. For
278  * instance a resolution of 2^-10 means we have 10 fractional bits.
279  */
280 static u32 __convert_to_raw(const u64 val, const u32 resolution)
281 {
282 	u64 __res = val * resolution;
283 
284 	/* all values are multiplied by 1000000 to remove the fraction */
285 	do_div(__res, 1000000);
286 
287 	return __res;
288 }
289 
290 static u32 __convert_to_raw_sign(const u64 val, const u32 resolution)
291 {
292 	s64 __res = -(s32)val;
293 
294 	__res = __convert_to_raw(__res, resolution);
295 
296 	return (u32)-__res;
297 }
298 
299 static int __ltc2983_fault_handler(const struct ltc2983_data *st,
300 				   const u32 result, const u32 hard_mask,
301 				   const u32 soft_mask)
302 {
303 	const struct device *dev = &st->spi->dev;
304 
305 	if (result & hard_mask) {
306 		dev_err(dev, "Invalid conversion: Sensor HARD fault\n");
307 		return -EIO;
308 	} else if (result & soft_mask) {
309 		/* just print a warning */
310 		dev_warn(dev, "Suspicious conversion: Sensor SOFT fault\n");
311 	}
312 
313 	return 0;
314 }
315 
316 static int __ltc2983_chan_assign_common(const struct ltc2983_data *st,
317 					const struct ltc2983_sensor *sensor,
318 					u32 chan_val)
319 {
320 	u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
321 	__be32 __chan_val;
322 
323 	chan_val |= LTC2983_CHAN_TYPE(sensor->type);
324 	dev_dbg(&st->spi->dev, "Assign reg:0x%04X, val:0x%08X\n", reg,
325 		chan_val);
326 	__chan_val = cpu_to_be32(chan_val);
327 	return regmap_bulk_write(st->regmap, reg, &__chan_val,
328 				 sizeof(__chan_val));
329 }
330 
331 static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
332 					  struct ltc2983_custom_sensor *custom,
333 					  u32 *chan_val)
334 {
335 	u32 reg;
336 	u8 mult = custom->is_steinhart ? LTC2983_CUSTOM_STEINHART_ENTRY_SZ :
337 		LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
338 	const struct device *dev = &st->spi->dev;
339 	/*
340 	 * custom->size holds the raw size of the table. However, when
341 	 * configuring the sensor channel, we must write the number of
342 	 * entries of the table minus 1. For steinhart sensors 0 is written
343 	 * since the size is constant!
344 	 */
345 	const u8 len = custom->is_steinhart ? 0 :
346 		(custom->size / LTC2983_CUSTOM_SENSOR_ENTRY_SZ) - 1;
347 	/*
348 	 * Check if the offset was assigned already. It should be for steinhart
349 	 * sensors. When coming from sleep, it should be assigned for all.
350 	 */
351 	if (custom->offset < 0) {
352 		/*
353 		 * This needs to be done again here because, from the moment
354 		 * when this test was done (successfully) for this custom
355 		 * sensor, a steinhart sensor might have been added changing
356 		 * custom_table_size...
357 		 */
358 		if (st->custom_table_size + custom->size >
359 		    (LTC2983_CUST_SENS_TBL_END_REG -
360 		     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
361 			dev_err(dev,
362 				"Not space left(%d) for new custom sensor(%zu)",
363 				st->custom_table_size,
364 				custom->size);
365 			return -EINVAL;
366 		}
367 
368 		custom->offset = st->custom_table_size /
369 					LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
370 		st->custom_table_size += custom->size;
371 	}
372 
373 	reg = (custom->offset * mult) + LTC2983_CUST_SENS_TBL_START_REG;
374 
375 	*chan_val |= LTC2983_CUSTOM_LEN(len);
376 	*chan_val |= LTC2983_CUSTOM_ADDR(custom->offset);
377 	dev_dbg(dev, "Assign custom sensor, reg:0x%04X, off:%d, sz:%zu",
378 		reg, custom->offset,
379 		custom->size);
380 	/* write custom sensor table */
381 	return regmap_bulk_write(st->regmap, reg, custom->table, custom->size);
382 }
383 
384 static struct ltc2983_custom_sensor *
385 __ltc2983_custom_sensor_new(struct ltc2983_data *st, const struct fwnode_handle *fn,
386 			    const char *propname, const bool is_steinhart,
387 			    const u32 resolution, const bool has_signed)
388 {
389 	struct ltc2983_custom_sensor *new_custom;
390 	struct device *dev = &st->spi->dev;
391 	/*
392 	 * For custom steinhart, the full u32 is taken. For all the others
393 	 * the MSB is discarded.
394 	 */
395 	const u8 n_size = is_steinhart ? 4 : 3;
396 	u8 index, n_entries;
397 	int ret;
398 
399 	if (is_steinhart)
400 		n_entries = fwnode_property_count_u32(fn, propname);
401 	else
402 		n_entries = fwnode_property_count_u64(fn, propname);
403 	/* n_entries must be an even number */
404 	if (!n_entries || (n_entries % 2) != 0) {
405 		dev_err(dev, "Number of entries either 0 or not even\n");
406 		return ERR_PTR(-EINVAL);
407 	}
408 
409 	new_custom = devm_kzalloc(dev, sizeof(*new_custom), GFP_KERNEL);
410 	if (!new_custom)
411 		return ERR_PTR(-ENOMEM);
412 
413 	new_custom->size = n_entries * n_size;
414 	/* check Steinhart size */
415 	if (is_steinhart && new_custom->size != LTC2983_CUSTOM_STEINHART_SIZE) {
416 		dev_err(dev, "Steinhart sensors size(%zu) must be %u\n", new_custom->size,
417 			LTC2983_CUSTOM_STEINHART_SIZE);
418 		return ERR_PTR(-EINVAL);
419 	}
420 	/* Check space on the table. */
421 	if (st->custom_table_size + new_custom->size >
422 	    (LTC2983_CUST_SENS_TBL_END_REG -
423 	     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
424 		dev_err(dev, "No space left(%d) for new custom sensor(%zu)",
425 				st->custom_table_size, new_custom->size);
426 		return ERR_PTR(-EINVAL);
427 	}
428 
429 	/* allocate the table */
430 	if (is_steinhart)
431 		new_custom->table = devm_kcalloc(dev, n_entries, sizeof(u32), GFP_KERNEL);
432 	else
433 		new_custom->table = devm_kcalloc(dev, n_entries, sizeof(u64), GFP_KERNEL);
434 	if (!new_custom->table)
435 		return ERR_PTR(-ENOMEM);
436 
437 	/*
438 	 * Steinhart sensors are configured with raw values in the firmware
439 	 * node. For the other sensors we must convert the value to raw.
440 	 * The odd index's correspond to temperatures and always have 1/1024
441 	 * of resolution. Temperatures also come in Kelvin, so signed values
442 	 * are not possible.
443 	 */
444 	if (is_steinhart) {
445 		ret = fwnode_property_read_u32_array(fn, propname, new_custom->table, n_entries);
446 		if (ret < 0)
447 			return ERR_PTR(ret);
448 
449 		cpu_to_be32_array(new_custom->table, new_custom->table, n_entries);
450 	} else {
451 		ret = fwnode_property_read_u64_array(fn, propname, new_custom->table, n_entries);
452 		if (ret < 0)
453 			return ERR_PTR(ret);
454 
455 		for (index = 0; index < n_entries; index++) {
456 			u64 temp = ((u64 *)new_custom->table)[index];
457 
458 			if ((index % 2) != 0)
459 				temp = __convert_to_raw(temp, 1024);
460 			else if (has_signed && (s64)temp < 0)
461 				temp = __convert_to_raw_sign(temp, resolution);
462 			else
463 				temp = __convert_to_raw(temp, resolution);
464 
465 			put_unaligned_be24(temp, new_custom->table + index * 3);
466 		}
467 	}
468 
469 	new_custom->is_steinhart = is_steinhart;
470 	/*
471 	 * This is done to first add all the steinhart sensors to the table,
472 	 * in order to maximize the table usage. If we mix adding steinhart
473 	 * with the other sensors, we might have to do some roundup to make
474 	 * sure that sensor_addr - 0x250(start address) is a multiple of 4
475 	 * (for steinhart), and a multiple of 6 for all the other sensors.
476 	 * Since we have const 24 bytes for steinhart sensors and 24 is
477 	 * also a multiple of 6, we guarantee that the first non-steinhart
478 	 * sensor will sit in a correct address without the need of filling
479 	 * addresses.
480 	 */
481 	if (is_steinhart) {
482 		new_custom->offset = st->custom_table_size /
483 					LTC2983_CUSTOM_STEINHART_ENTRY_SZ;
484 		st->custom_table_size += new_custom->size;
485 	} else {
486 		/* mark as unset. This is checked later on the assign phase */
487 		new_custom->offset = -1;
488 	}
489 
490 	return new_custom;
491 }
492 
493 static int ltc2983_thermocouple_fault_handler(const struct ltc2983_data *st,
494 					      const u32 result)
495 {
496 	return __ltc2983_fault_handler(st, result,
497 				       LTC2983_THERMOCOUPLE_HARD_FAULT_MASK,
498 				       LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK);
499 }
500 
501 static int ltc2983_common_fault_handler(const struct ltc2983_data *st,
502 					const u32 result)
503 {
504 	return __ltc2983_fault_handler(st, result,
505 				       LTC2983_COMMON_HARD_FAULT_MASK,
506 				       LTC2983_COMMON_SOFT_FAULT_MASK);
507 }
508 
509 static int ltc2983_thermocouple_assign_chan(struct ltc2983_data *st,
510 				const struct ltc2983_sensor *sensor)
511 {
512 	struct ltc2983_thermocouple *thermo = to_thermocouple(sensor);
513 	u32 chan_val;
514 
515 	chan_val = LTC2983_CHAN_ASSIGN(thermo->cold_junction_chan);
516 	chan_val |= LTC2983_THERMOCOUPLE_CFG(thermo->sensor_config);
517 
518 	if (thermo->custom) {
519 		int ret;
520 
521 		ret = __ltc2983_chan_custom_sensor_assign(st, thermo->custom,
522 							  &chan_val);
523 		if (ret)
524 			return ret;
525 	}
526 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
527 }
528 
529 static int ltc2983_rtd_assign_chan(struct ltc2983_data *st,
530 				   const struct ltc2983_sensor *sensor)
531 {
532 	struct ltc2983_rtd *rtd = to_rtd(sensor);
533 	u32 chan_val;
534 
535 	chan_val = LTC2983_CHAN_ASSIGN(rtd->r_sense_chan);
536 	chan_val |= LTC2983_RTD_CFG(rtd->sensor_config);
537 	chan_val |= LTC2983_RTD_EXC_CURRENT(rtd->excitation_current);
538 	chan_val |= LTC2983_RTD_CURVE(rtd->rtd_curve);
539 
540 	if (rtd->custom) {
541 		int ret;
542 
543 		ret = __ltc2983_chan_custom_sensor_assign(st, rtd->custom,
544 							  &chan_val);
545 		if (ret)
546 			return ret;
547 	}
548 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
549 }
550 
551 static int ltc2983_thermistor_assign_chan(struct ltc2983_data *st,
552 					  const struct ltc2983_sensor *sensor)
553 {
554 	struct ltc2983_thermistor *thermistor = to_thermistor(sensor);
555 	u32 chan_val;
556 
557 	chan_val = LTC2983_CHAN_ASSIGN(thermistor->r_sense_chan);
558 	chan_val |= LTC2983_THERMISTOR_CFG(thermistor->sensor_config);
559 	chan_val |=
560 		LTC2983_THERMISTOR_EXC_CURRENT(thermistor->excitation_current);
561 
562 	if (thermistor->custom) {
563 		int ret;
564 
565 		ret = __ltc2983_chan_custom_sensor_assign(st,
566 							  thermistor->custom,
567 							  &chan_val);
568 		if (ret)
569 			return ret;
570 	}
571 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
572 }
573 
574 static int ltc2983_diode_assign_chan(struct ltc2983_data *st,
575 				     const struct ltc2983_sensor *sensor)
576 {
577 	struct ltc2983_diode *diode = to_diode(sensor);
578 	u32 chan_val;
579 
580 	chan_val = LTC2983_DIODE_CFG(diode->sensor_config);
581 	chan_val |= LTC2983_DIODE_EXC_CURRENT(diode->excitation_current);
582 	chan_val |= LTC2983_DIODE_IDEAL_FACTOR(diode->ideal_factor_value);
583 
584 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
585 }
586 
587 static int ltc2983_r_sense_assign_chan(struct ltc2983_data *st,
588 				       const struct ltc2983_sensor *sensor)
589 {
590 	struct ltc2983_rsense *rsense = to_rsense(sensor);
591 	u32 chan_val;
592 
593 	chan_val = LTC2983_R_SENSE_VAL(rsense->r_sense_val);
594 
595 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
596 }
597 
598 static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
599 				   const struct ltc2983_sensor *sensor)
600 {
601 	struct ltc2983_adc *adc = to_adc(sensor);
602 	u32 chan_val;
603 
604 	chan_val = LTC2983_ADC_SINGLE_ENDED(adc->single_ended);
605 
606 	return __ltc2983_chan_assign_common(st, sensor, chan_val);
607 }
608 
609 static struct ltc2983_sensor *
610 ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data *st,
611 			 const struct ltc2983_sensor *sensor)
612 {
613 	struct ltc2983_thermocouple *thermo;
614 	struct fwnode_handle *ref;
615 	u32 oc_current;
616 	int ret;
617 
618 	thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo), GFP_KERNEL);
619 	if (!thermo)
620 		return ERR_PTR(-ENOMEM);
621 
622 	if (fwnode_property_read_bool(child, "adi,single-ended"))
623 		thermo->sensor_config = LTC2983_THERMOCOUPLE_SGL(1);
624 
625 	ret = fwnode_property_read_u32(child, "adi,sensor-oc-current-microamp", &oc_current);
626 	if (!ret) {
627 		switch (oc_current) {
628 		case 10:
629 			thermo->sensor_config |=
630 					LTC2983_THERMOCOUPLE_OC_CURR(0);
631 			break;
632 		case 100:
633 			thermo->sensor_config |=
634 					LTC2983_THERMOCOUPLE_OC_CURR(1);
635 			break;
636 		case 500:
637 			thermo->sensor_config |=
638 					LTC2983_THERMOCOUPLE_OC_CURR(2);
639 			break;
640 		case 1000:
641 			thermo->sensor_config |=
642 					LTC2983_THERMOCOUPLE_OC_CURR(3);
643 			break;
644 		default:
645 			dev_err(&st->spi->dev,
646 				"Invalid open circuit current:%u", oc_current);
647 			return ERR_PTR(-EINVAL);
648 		}
649 
650 		thermo->sensor_config |= LTC2983_THERMOCOUPLE_OC_CHECK(1);
651 	}
652 	/* validate channel index */
653 	if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK) &&
654 	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
655 		dev_err(&st->spi->dev,
656 			"Invalid chann:%d for differential thermocouple",
657 			sensor->chan);
658 		return ERR_PTR(-EINVAL);
659 	}
660 
661 	ref = fwnode_find_reference(child, "adi,cold-junction-handle", 0);
662 	if (IS_ERR(ref)) {
663 		ref = NULL;
664 	} else {
665 		ret = fwnode_property_read_u32(ref, "reg", &thermo->cold_junction_chan);
666 		if (ret) {
667 			/*
668 			 * This would be catched later but we can just return
669 			 * the error right away.
670 			 */
671 			dev_err(&st->spi->dev, "Property reg must be given\n");
672 			goto fail;
673 		}
674 	}
675 
676 	/* check custom sensor */
677 	if (sensor->type == LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
678 		const char *propname = "adi,custom-thermocouple";
679 
680 		thermo->custom = __ltc2983_custom_sensor_new(st, child,
681 							     propname, false,
682 							     16384, true);
683 		if (IS_ERR(thermo->custom)) {
684 			ret = PTR_ERR(thermo->custom);
685 			goto fail;
686 		}
687 	}
688 
689 	/* set common parameters */
690 	thermo->sensor.fault_handler = ltc2983_thermocouple_fault_handler;
691 	thermo->sensor.assign_chan = ltc2983_thermocouple_assign_chan;
692 
693 	fwnode_handle_put(ref);
694 	return &thermo->sensor;
695 
696 fail:
697 	fwnode_handle_put(ref);
698 	return ERR_PTR(ret);
699 }
700 
701 static struct ltc2983_sensor *
702 ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
703 		const struct ltc2983_sensor *sensor)
704 {
705 	struct ltc2983_rtd *rtd;
706 	int ret = 0;
707 	struct device *dev = &st->spi->dev;
708 	struct fwnode_handle *ref;
709 	u32 excitation_current = 0, n_wires = 0;
710 
711 	rtd = devm_kzalloc(dev, sizeof(*rtd), GFP_KERNEL);
712 	if (!rtd)
713 		return ERR_PTR(-ENOMEM);
714 
715 	ref = fwnode_find_reference(child, "adi,rsense-handle", 0);
716 	if (IS_ERR(ref)) {
717 		dev_err(dev, "Property adi,rsense-handle missing or invalid");
718 		return ERR_CAST(ref);
719 	}
720 
721 	ret = fwnode_property_read_u32(ref, "reg", &rtd->r_sense_chan);
722 	if (ret) {
723 		dev_err(dev, "Property reg must be given\n");
724 		goto fail;
725 	}
726 
727 	ret = fwnode_property_read_u32(child, "adi,number-of-wires", &n_wires);
728 	if (!ret) {
729 		switch (n_wires) {
730 		case 2:
731 			rtd->sensor_config = LTC2983_RTD_N_WIRES(0);
732 			break;
733 		case 3:
734 			rtd->sensor_config = LTC2983_RTD_N_WIRES(1);
735 			break;
736 		case 4:
737 			rtd->sensor_config = LTC2983_RTD_N_WIRES(2);
738 			break;
739 		case 5:
740 			/* 4 wires, Kelvin Rsense */
741 			rtd->sensor_config = LTC2983_RTD_N_WIRES(3);
742 			break;
743 		default:
744 			dev_err(dev, "Invalid number of wires:%u\n", n_wires);
745 			ret = -EINVAL;
746 			goto fail;
747 		}
748 	}
749 
750 	if (fwnode_property_read_bool(child, "adi,rsense-share")) {
751 		/* Current rotation is only available with rsense sharing */
752 		if (fwnode_property_read_bool(child, "adi,current-rotate")) {
753 			if (n_wires == 2 || n_wires == 3) {
754 				dev_err(dev,
755 					"Rotation not allowed for 2/3 Wire RTDs");
756 				ret = -EINVAL;
757 				goto fail;
758 			}
759 			rtd->sensor_config |= LTC2983_RTD_C_ROTATE(1);
760 		} else {
761 			rtd->sensor_config |= LTC2983_RTD_R_SHARE(1);
762 		}
763 	}
764 	/*
765 	 * rtd channel indexes are a bit more complicated to validate.
766 	 * For 4wire RTD with rotation, the channel selection cannot be
767 	 * >=19 since the chann + 1 is used in this configuration.
768 	 * For 4wire RTDs with kelvin rsense, the rsense channel cannot be
769 	 * <=1 since chanel - 1 and channel - 2 are used.
770 	 */
771 	if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
772 		/* 4-wire */
773 		u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
774 			max = LTC2983_MAX_CHANNELS_NR;
775 
776 		if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
777 			max = LTC2983_MAX_CHANNELS_NR - 1;
778 
779 		if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
780 		     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
781 		    (rtd->r_sense_chan <=  min)) {
782 			/* kelvin rsense*/
783 			dev_err(dev,
784 				"Invalid rsense chann:%d to use in kelvin rsense",
785 				rtd->r_sense_chan);
786 
787 			ret = -EINVAL;
788 			goto fail;
789 		}
790 
791 		if (sensor->chan < min || sensor->chan > max) {
792 			dev_err(dev, "Invalid chann:%d for the rtd config",
793 				sensor->chan);
794 
795 			ret = -EINVAL;
796 			goto fail;
797 		}
798 	} else {
799 		/* same as differential case */
800 		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
801 			dev_err(&st->spi->dev,
802 				"Invalid chann:%d for RTD", sensor->chan);
803 
804 			ret = -EINVAL;
805 			goto fail;
806 		}
807 	}
808 
809 	/* check custom sensor */
810 	if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
811 		rtd->custom = __ltc2983_custom_sensor_new(st, child,
812 							  "adi,custom-rtd",
813 							  false, 2048, false);
814 		if (IS_ERR(rtd->custom)) {
815 			ret = PTR_ERR(rtd->custom);
816 			goto fail;
817 		}
818 	}
819 
820 	/* set common parameters */
821 	rtd->sensor.fault_handler = ltc2983_common_fault_handler;
822 	rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
823 
824 	ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
825 				       &excitation_current);
826 	if (ret) {
827 		/* default to 5uA */
828 		rtd->excitation_current = 1;
829 	} else {
830 		switch (excitation_current) {
831 		case 5:
832 			rtd->excitation_current = 0x01;
833 			break;
834 		case 10:
835 			rtd->excitation_current = 0x02;
836 			break;
837 		case 25:
838 			rtd->excitation_current = 0x03;
839 			break;
840 		case 50:
841 			rtd->excitation_current = 0x04;
842 			break;
843 		case 100:
844 			rtd->excitation_current = 0x05;
845 			break;
846 		case 250:
847 			rtd->excitation_current = 0x06;
848 			break;
849 		case 500:
850 			rtd->excitation_current = 0x07;
851 			break;
852 		case 1000:
853 			rtd->excitation_current = 0x08;
854 			break;
855 		default:
856 			dev_err(&st->spi->dev,
857 				"Invalid value for excitation current(%u)",
858 				excitation_current);
859 			ret = -EINVAL;
860 			goto fail;
861 		}
862 	}
863 
864 	fwnode_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
865 
866 	fwnode_handle_put(ref);
867 	return &rtd->sensor;
868 fail:
869 	fwnode_handle_put(ref);
870 	return ERR_PTR(ret);
871 }
872 
873 static struct ltc2983_sensor *
874 ltc2983_thermistor_new(const struct fwnode_handle *child, struct ltc2983_data *st,
875 		       const struct ltc2983_sensor *sensor)
876 {
877 	struct ltc2983_thermistor *thermistor;
878 	struct device *dev = &st->spi->dev;
879 	struct fwnode_handle *ref;
880 	u32 excitation_current = 0;
881 	int ret = 0;
882 
883 	thermistor = devm_kzalloc(dev, sizeof(*thermistor), GFP_KERNEL);
884 	if (!thermistor)
885 		return ERR_PTR(-ENOMEM);
886 
887 	ref = fwnode_find_reference(child, "adi,rsense-handle", 0);
888 	if (IS_ERR(ref)) {
889 		dev_err(dev, "Property adi,rsense-handle missing or invalid");
890 		return ERR_CAST(ref);
891 	}
892 
893 	ret = fwnode_property_read_u32(ref, "reg", &thermistor->r_sense_chan);
894 	if (ret) {
895 		dev_err(dev, "rsense channel must be configured...\n");
896 		goto fail;
897 	}
898 
899 	if (fwnode_property_read_bool(child, "adi,single-ended")) {
900 		thermistor->sensor_config = LTC2983_THERMISTOR_SGL(1);
901 	} else if (fwnode_property_read_bool(child, "adi,rsense-share")) {
902 		/* rotation is only possible if sharing rsense */
903 		if (fwnode_property_read_bool(child, "adi,current-rotate"))
904 			thermistor->sensor_config =
905 						LTC2983_THERMISTOR_C_ROTATE(1);
906 		else
907 			thermistor->sensor_config =
908 						LTC2983_THERMISTOR_R_SHARE(1);
909 	}
910 	/* validate channel index */
911 	if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK) &&
912 	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
913 		dev_err(&st->spi->dev,
914 			"Invalid chann:%d for differential thermistor",
915 			sensor->chan);
916 		ret = -EINVAL;
917 		goto fail;
918 	}
919 
920 	/* check custom sensor */
921 	if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
922 		bool steinhart = false;
923 		const char *propname;
924 
925 		if (sensor->type == LTC2983_SENSOR_THERMISTOR_STEINHART) {
926 			steinhart = true;
927 			propname = "adi,custom-steinhart";
928 		} else {
929 			propname = "adi,custom-thermistor";
930 		}
931 
932 		thermistor->custom = __ltc2983_custom_sensor_new(st, child,
933 								 propname,
934 								 steinhart,
935 								 64, false);
936 		if (IS_ERR(thermistor->custom)) {
937 			ret = PTR_ERR(thermistor->custom);
938 			goto fail;
939 		}
940 	}
941 	/* set common parameters */
942 	thermistor->sensor.fault_handler = ltc2983_common_fault_handler;
943 	thermistor->sensor.assign_chan = ltc2983_thermistor_assign_chan;
944 
945 	ret = fwnode_property_read_u32(child, "adi,excitation-current-nanoamp",
946 				       &excitation_current);
947 	if (ret) {
948 		/* Auto range is not allowed for custom sensors */
949 		if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
950 			/* default to 1uA */
951 			thermistor->excitation_current = 0x03;
952 		else
953 			/* default to auto-range */
954 			thermistor->excitation_current = 0x0c;
955 	} else {
956 		switch (excitation_current) {
957 		case 0:
958 			/* auto range */
959 			if (sensor->type >=
960 			    LTC2983_SENSOR_THERMISTOR_STEINHART) {
961 				dev_err(&st->spi->dev,
962 					"Auto Range not allowed for custom sensors\n");
963 				ret = -EINVAL;
964 				goto fail;
965 			}
966 			thermistor->excitation_current = 0x0c;
967 			break;
968 		case 250:
969 			thermistor->excitation_current = 0x01;
970 			break;
971 		case 500:
972 			thermistor->excitation_current = 0x02;
973 			break;
974 		case 1000:
975 			thermistor->excitation_current = 0x03;
976 			break;
977 		case 5000:
978 			thermistor->excitation_current = 0x04;
979 			break;
980 		case 10000:
981 			thermistor->excitation_current = 0x05;
982 			break;
983 		case 25000:
984 			thermistor->excitation_current = 0x06;
985 			break;
986 		case 50000:
987 			thermistor->excitation_current = 0x07;
988 			break;
989 		case 100000:
990 			thermistor->excitation_current = 0x08;
991 			break;
992 		case 250000:
993 			thermistor->excitation_current = 0x09;
994 			break;
995 		case 500000:
996 			thermistor->excitation_current = 0x0a;
997 			break;
998 		case 1000000:
999 			thermistor->excitation_current = 0x0b;
1000 			break;
1001 		default:
1002 			dev_err(&st->spi->dev,
1003 				"Invalid value for excitation current(%u)",
1004 				excitation_current);
1005 			ret = -EINVAL;
1006 			goto fail;
1007 		}
1008 	}
1009 
1010 	fwnode_handle_put(ref);
1011 	return &thermistor->sensor;
1012 fail:
1013 	fwnode_handle_put(ref);
1014 	return ERR_PTR(ret);
1015 }
1016 
1017 static struct ltc2983_sensor *
1018 ltc2983_diode_new(const struct fwnode_handle *child, const struct ltc2983_data *st,
1019 		  const struct ltc2983_sensor *sensor)
1020 {
1021 	struct ltc2983_diode *diode;
1022 	u32 temp = 0, excitation_current = 0;
1023 	int ret;
1024 
1025 	diode = devm_kzalloc(&st->spi->dev, sizeof(*diode), GFP_KERNEL);
1026 	if (!diode)
1027 		return ERR_PTR(-ENOMEM);
1028 
1029 	if (fwnode_property_read_bool(child, "adi,single-ended"))
1030 		diode->sensor_config = LTC2983_DIODE_SGL(1);
1031 
1032 	if (fwnode_property_read_bool(child, "adi,three-conversion-cycles"))
1033 		diode->sensor_config |= LTC2983_DIODE_3_CONV_CYCLE(1);
1034 
1035 	if (fwnode_property_read_bool(child, "adi,average-on"))
1036 		diode->sensor_config |= LTC2983_DIODE_AVERAGE_ON(1);
1037 
1038 	/* validate channel index */
1039 	if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
1040 	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1041 		dev_err(&st->spi->dev,
1042 			"Invalid chann:%d for differential thermistor",
1043 			sensor->chan);
1044 		return ERR_PTR(-EINVAL);
1045 	}
1046 	/* set common parameters */
1047 	diode->sensor.fault_handler = ltc2983_common_fault_handler;
1048 	diode->sensor.assign_chan = ltc2983_diode_assign_chan;
1049 
1050 	ret = fwnode_property_read_u32(child, "adi,excitation-current-microamp",
1051 				       &excitation_current);
1052 	if (!ret) {
1053 		switch (excitation_current) {
1054 		case 10:
1055 			diode->excitation_current = 0x00;
1056 			break;
1057 		case 20:
1058 			diode->excitation_current = 0x01;
1059 			break;
1060 		case 40:
1061 			diode->excitation_current = 0x02;
1062 			break;
1063 		case 80:
1064 			diode->excitation_current = 0x03;
1065 			break;
1066 		default:
1067 			dev_err(&st->spi->dev,
1068 				"Invalid value for excitation current(%u)",
1069 				excitation_current);
1070 			return ERR_PTR(-EINVAL);
1071 		}
1072 	}
1073 
1074 	fwnode_property_read_u32(child, "adi,ideal-factor-value", &temp);
1075 
1076 	/* 2^20 resolution */
1077 	diode->ideal_factor_value = __convert_to_raw(temp, 1048576);
1078 
1079 	return &diode->sensor;
1080 }
1081 
1082 static struct ltc2983_sensor *ltc2983_r_sense_new(struct fwnode_handle *child,
1083 					struct ltc2983_data *st,
1084 					const struct ltc2983_sensor *sensor)
1085 {
1086 	struct ltc2983_rsense *rsense;
1087 	int ret;
1088 	u32 temp;
1089 
1090 	rsense = devm_kzalloc(&st->spi->dev, sizeof(*rsense), GFP_KERNEL);
1091 	if (!rsense)
1092 		return ERR_PTR(-ENOMEM);
1093 
1094 	/* validate channel index */
1095 	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1096 		dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
1097 			sensor->chan);
1098 		return ERR_PTR(-EINVAL);
1099 	}
1100 
1101 	ret = fwnode_property_read_u32(child, "adi,rsense-val-milli-ohms", &temp);
1102 	if (ret) {
1103 		dev_err(&st->spi->dev, "Property adi,rsense-val-milli-ohms missing\n");
1104 		return ERR_PTR(-EINVAL);
1105 	}
1106 	/*
1107 	 * Times 1000 because we have milli-ohms and __convert_to_raw
1108 	 * expects scales of 1000000 which are used for all other
1109 	 * properties.
1110 	 * 2^10 resolution
1111 	 */
1112 	rsense->r_sense_val = __convert_to_raw((u64)temp * 1000, 1024);
1113 
1114 	/* set common parameters */
1115 	rsense->sensor.assign_chan = ltc2983_r_sense_assign_chan;
1116 
1117 	return &rsense->sensor;
1118 }
1119 
1120 static struct ltc2983_sensor *ltc2983_adc_new(struct fwnode_handle *child,
1121 					 struct ltc2983_data *st,
1122 					 const struct ltc2983_sensor *sensor)
1123 {
1124 	struct ltc2983_adc *adc;
1125 
1126 	adc = devm_kzalloc(&st->spi->dev, sizeof(*adc), GFP_KERNEL);
1127 	if (!adc)
1128 		return ERR_PTR(-ENOMEM);
1129 
1130 	if (fwnode_property_read_bool(child, "adi,single-ended"))
1131 		adc->single_ended = true;
1132 
1133 	if (!adc->single_ended &&
1134 	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
1135 		dev_err(&st->spi->dev, "Invalid chan:%d for differential adc\n",
1136 			sensor->chan);
1137 		return ERR_PTR(-EINVAL);
1138 	}
1139 	/* set common parameters */
1140 	adc->sensor.assign_chan = ltc2983_adc_assign_chan;
1141 	adc->sensor.fault_handler = ltc2983_common_fault_handler;
1142 
1143 	return &adc->sensor;
1144 }
1145 
1146 static int ltc2983_chan_read(struct ltc2983_data *st,
1147 			const struct ltc2983_sensor *sensor, int *val)
1148 {
1149 	u32 start_conversion = 0;
1150 	int ret;
1151 	unsigned long time;
1152 
1153 	start_conversion = LTC2983_STATUS_START(true);
1154 	start_conversion |= LTC2983_STATUS_CHAN_SEL(sensor->chan);
1155 	dev_dbg(&st->spi->dev, "Start conversion on chan:%d, status:%02X\n",
1156 		sensor->chan, start_conversion);
1157 	/* start conversion */
1158 	ret = regmap_write(st->regmap, LTC2983_STATUS_REG, start_conversion);
1159 	if (ret)
1160 		return ret;
1161 
1162 	reinit_completion(&st->completion);
1163 	/*
1164 	 * wait for conversion to complete.
1165 	 * 300 ms should be more than enough to complete the conversion.
1166 	 * Depending on the sensor configuration, there are 2/3 conversions
1167 	 * cycles of 82ms.
1168 	 */
1169 	time = wait_for_completion_timeout(&st->completion,
1170 					   msecs_to_jiffies(300));
1171 	if (!time) {
1172 		dev_warn(&st->spi->dev, "Conversion timed out\n");
1173 		return -ETIMEDOUT;
1174 	}
1175 
1176 	/* read the converted data */
1177 	ret = regmap_bulk_read(st->regmap, LTC2983_CHAN_RES_ADDR(sensor->chan),
1178 			       &st->temp, sizeof(st->temp));
1179 	if (ret)
1180 		return ret;
1181 
1182 	*val = __be32_to_cpu(st->temp);
1183 
1184 	if (!(LTC2983_RES_VALID_MASK & *val)) {
1185 		dev_err(&st->spi->dev, "Invalid conversion detected\n");
1186 		return -EIO;
1187 	}
1188 
1189 	ret = sensor->fault_handler(st, *val);
1190 	if (ret)
1191 		return ret;
1192 
1193 	*val = sign_extend32((*val) & LTC2983_DATA_MASK, LTC2983_DATA_SIGN_BIT);
1194 	return 0;
1195 }
1196 
1197 static int ltc2983_read_raw(struct iio_dev *indio_dev,
1198 			    struct iio_chan_spec const *chan,
1199 			    int *val, int *val2, long mask)
1200 {
1201 	struct ltc2983_data *st = iio_priv(indio_dev);
1202 	int ret;
1203 
1204 	/* sanity check */
1205 	if (chan->address >= st->num_channels) {
1206 		dev_err(&st->spi->dev, "Invalid chan address:%ld",
1207 			chan->address);
1208 		return -EINVAL;
1209 	}
1210 
1211 	switch (mask) {
1212 	case IIO_CHAN_INFO_RAW:
1213 		mutex_lock(&st->lock);
1214 		ret = ltc2983_chan_read(st, st->sensors[chan->address], val);
1215 		mutex_unlock(&st->lock);
1216 		return ret ?: IIO_VAL_INT;
1217 	case IIO_CHAN_INFO_SCALE:
1218 		switch (chan->type) {
1219 		case IIO_TEMP:
1220 			/* value in milli degrees */
1221 			*val = 1000;
1222 			/* 2^10 */
1223 			*val2 = 1024;
1224 			return IIO_VAL_FRACTIONAL;
1225 		case IIO_VOLTAGE:
1226 			/* value in millivolt */
1227 			*val = 1000;
1228 			/* 2^21 */
1229 			*val2 = 2097152;
1230 			return IIO_VAL_FRACTIONAL;
1231 		default:
1232 			return -EINVAL;
1233 		}
1234 	}
1235 
1236 	return -EINVAL;
1237 }
1238 
1239 static int ltc2983_reg_access(struct iio_dev *indio_dev,
1240 			      unsigned int reg,
1241 			      unsigned int writeval,
1242 			      unsigned int *readval)
1243 {
1244 	struct ltc2983_data *st = iio_priv(indio_dev);
1245 
1246 	if (readval)
1247 		return regmap_read(st->regmap, reg, readval);
1248 	else
1249 		return regmap_write(st->regmap, reg, writeval);
1250 }
1251 
1252 static irqreturn_t ltc2983_irq_handler(int irq, void *data)
1253 {
1254 	struct ltc2983_data *st = data;
1255 
1256 	complete(&st->completion);
1257 	return IRQ_HANDLED;
1258 }
1259 
1260 #define LTC2983_CHAN(__type, index, __address) ({ \
1261 	struct iio_chan_spec __chan = { \
1262 		.type = __type, \
1263 		.indexed = 1, \
1264 		.channel = index, \
1265 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
1266 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
1267 		.address = __address, \
1268 	}; \
1269 	__chan; \
1270 })
1271 
1272 static int ltc2983_parse_dt(struct ltc2983_data *st)
1273 {
1274 	struct device *dev = &st->spi->dev;
1275 	struct fwnode_handle *child;
1276 	int ret = 0, chan = 0, channel_avail_mask = 0;
1277 
1278 	device_property_read_u32(dev, "adi,mux-delay-config-us", &st->mux_delay_config);
1279 
1280 	device_property_read_u32(dev, "adi,filter-notch-freq", &st->filter_notch_freq);
1281 
1282 	st->num_channels = device_get_child_node_count(dev);
1283 	if (!st->num_channels) {
1284 		dev_err(&st->spi->dev, "At least one channel must be given!");
1285 		return -EINVAL;
1286 	}
1287 
1288 	st->sensors = devm_kcalloc(dev, st->num_channels, sizeof(*st->sensors),
1289 				   GFP_KERNEL);
1290 	if (!st->sensors)
1291 		return -ENOMEM;
1292 
1293 	st->iio_channels = st->num_channels;
1294 	device_for_each_child_node(dev, child) {
1295 		struct ltc2983_sensor sensor;
1296 
1297 		ret = fwnode_property_read_u32(child, "reg", &sensor.chan);
1298 		if (ret) {
1299 			dev_err(dev, "reg property must given for child nodes\n");
1300 			goto put_child;
1301 		}
1302 
1303 		/* check if we have a valid channel */
1304 		if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
1305 		    sensor.chan > LTC2983_MAX_CHANNELS_NR) {
1306 			ret = -EINVAL;
1307 			dev_err(dev, "chan:%d must be from %u to %u\n", sensor.chan,
1308 				LTC2983_MIN_CHANNELS_NR, LTC2983_MAX_CHANNELS_NR);
1309 			goto put_child;
1310 		} else if (channel_avail_mask & BIT(sensor.chan)) {
1311 			ret = -EINVAL;
1312 			dev_err(dev, "chan:%d already in use\n", sensor.chan);
1313 			goto put_child;
1314 		}
1315 
1316 		ret = fwnode_property_read_u32(child, "adi,sensor-type", &sensor.type);
1317 		if (ret) {
1318 			dev_err(dev,
1319 				"adi,sensor-type property must given for child nodes\n");
1320 			goto put_child;
1321 		}
1322 
1323 		dev_dbg(dev, "Create new sensor, type %u, chann %u",
1324 								sensor.type,
1325 								sensor.chan);
1326 
1327 		if (sensor.type >= LTC2983_SENSOR_THERMOCOUPLE &&
1328 		    sensor.type <= LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
1329 			st->sensors[chan] = ltc2983_thermocouple_new(child, st,
1330 								     &sensor);
1331 		} else if (sensor.type >= LTC2983_SENSOR_RTD &&
1332 			   sensor.type <= LTC2983_SENSOR_RTD_CUSTOM) {
1333 			st->sensors[chan] = ltc2983_rtd_new(child, st, &sensor);
1334 		} else if (sensor.type >= LTC2983_SENSOR_THERMISTOR &&
1335 			   sensor.type <= LTC2983_SENSOR_THERMISTOR_CUSTOM) {
1336 			st->sensors[chan] = ltc2983_thermistor_new(child, st,
1337 								   &sensor);
1338 		} else if (sensor.type == LTC2983_SENSOR_DIODE) {
1339 			st->sensors[chan] = ltc2983_diode_new(child, st,
1340 							      &sensor);
1341 		} else if (sensor.type == LTC2983_SENSOR_SENSE_RESISTOR) {
1342 			st->sensors[chan] = ltc2983_r_sense_new(child, st,
1343 								&sensor);
1344 			/* don't add rsense to iio */
1345 			st->iio_channels--;
1346 		} else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
1347 			st->sensors[chan] = ltc2983_adc_new(child, st, &sensor);
1348 		} else {
1349 			dev_err(dev, "Unknown sensor type %d\n", sensor.type);
1350 			ret = -EINVAL;
1351 			goto put_child;
1352 		}
1353 
1354 		if (IS_ERR(st->sensors[chan])) {
1355 			dev_err(dev, "Failed to create sensor %ld",
1356 				PTR_ERR(st->sensors[chan]));
1357 			ret = PTR_ERR(st->sensors[chan]);
1358 			goto put_child;
1359 		}
1360 		/* set generic sensor parameters */
1361 		st->sensors[chan]->chan = sensor.chan;
1362 		st->sensors[chan]->type = sensor.type;
1363 
1364 		channel_avail_mask |= BIT(sensor.chan);
1365 		chan++;
1366 	}
1367 
1368 	return 0;
1369 put_child:
1370 	fwnode_handle_put(child);
1371 	return ret;
1372 }
1373 
1374 static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
1375 {
1376 	u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0, status;
1377 	int ret;
1378 
1379 	/* make sure the device is up: start bit (7) is 0 and done bit (6) is 1 */
1380 	ret = regmap_read_poll_timeout(st->regmap, LTC2983_STATUS_REG, status,
1381 				       LTC2983_STATUS_UP(status) == 1, 25000,
1382 				       25000 * 10);
1383 	if (ret) {
1384 		dev_err(&st->spi->dev, "Device startup timed out\n");
1385 		return ret;
1386 	}
1387 
1388 	ret = regmap_update_bits(st->regmap, LTC2983_GLOBAL_CONFIG_REG,
1389 				 LTC2983_NOTCH_FREQ_MASK,
1390 				 LTC2983_NOTCH_FREQ(st->filter_notch_freq));
1391 	if (ret)
1392 		return ret;
1393 
1394 	ret = regmap_write(st->regmap, LTC2983_MUX_CONFIG_REG,
1395 			   st->mux_delay_config);
1396 	if (ret)
1397 		return ret;
1398 
1399 	for (chan = 0; chan < st->num_channels; chan++) {
1400 		u32 chan_type = 0, *iio_chan;
1401 
1402 		ret = st->sensors[chan]->assign_chan(st, st->sensors[chan]);
1403 		if (ret)
1404 			return ret;
1405 		/*
1406 		 * The assign_iio flag is necessary for when the device is
1407 		 * coming out of sleep. In that case, we just need to
1408 		 * re-configure the device channels.
1409 		 * We also don't assign iio channels for rsense.
1410 		 */
1411 		if (st->sensors[chan]->type == LTC2983_SENSOR_SENSE_RESISTOR ||
1412 		    !assign_iio)
1413 			continue;
1414 
1415 		/* assign iio channel */
1416 		if (st->sensors[chan]->type != LTC2983_SENSOR_DIRECT_ADC) {
1417 			chan_type = IIO_TEMP;
1418 			iio_chan = &iio_chan_t;
1419 		} else {
1420 			chan_type = IIO_VOLTAGE;
1421 			iio_chan = &iio_chan_v;
1422 		}
1423 
1424 		/*
1425 		 * add chan as the iio .address so that, we can directly
1426 		 * reference the sensor given the iio_chan_spec
1427 		 */
1428 		st->iio_chan[iio_idx++] = LTC2983_CHAN(chan_type, (*iio_chan)++,
1429 						       chan);
1430 	}
1431 
1432 	return 0;
1433 }
1434 
1435 static const struct regmap_range ltc2983_reg_ranges[] = {
1436 	regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
1437 	regmap_reg_range(LTC2983_TEMP_RES_START_REG, LTC2983_TEMP_RES_END_REG),
1438 	regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG, LTC2983_GLOBAL_CONFIG_REG),
1439 	regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
1440 			 LTC2983_MULT_CHANNEL_END_REG),
1441 	regmap_reg_range(LTC2983_MUX_CONFIG_REG, LTC2983_MUX_CONFIG_REG),
1442 	regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
1443 			 LTC2983_CHAN_ASSIGN_END_REG),
1444 	regmap_reg_range(LTC2983_CUST_SENS_TBL_START_REG,
1445 			 LTC2983_CUST_SENS_TBL_END_REG),
1446 };
1447 
1448 static const struct regmap_access_table ltc2983_reg_table = {
1449 	.yes_ranges = ltc2983_reg_ranges,
1450 	.n_yes_ranges = ARRAY_SIZE(ltc2983_reg_ranges),
1451 };
1452 
1453 /*
1454  *  The reg_bits are actually 12 but the device needs the first *complete*
1455  *  byte for the command (R/W).
1456  */
1457 static const struct regmap_config ltc2983_regmap_config = {
1458 	.reg_bits = 24,
1459 	.val_bits = 8,
1460 	.wr_table = &ltc2983_reg_table,
1461 	.rd_table = &ltc2983_reg_table,
1462 	.read_flag_mask = GENMASK(1, 0),
1463 	.write_flag_mask = BIT(1),
1464 };
1465 
1466 static const struct  iio_info ltc2983_iio_info = {
1467 	.read_raw = ltc2983_read_raw,
1468 	.debugfs_reg_access = ltc2983_reg_access,
1469 };
1470 
1471 static int ltc2983_probe(struct spi_device *spi)
1472 {
1473 	struct ltc2983_data *st;
1474 	struct iio_dev *indio_dev;
1475 	struct gpio_desc *gpio;
1476 	const char *name = spi_get_device_id(spi)->name;
1477 	int ret;
1478 
1479 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
1480 	if (!indio_dev)
1481 		return -ENOMEM;
1482 
1483 	st = iio_priv(indio_dev);
1484 
1485 	st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
1486 	if (IS_ERR(st->regmap)) {
1487 		dev_err(&spi->dev, "Failed to initialize regmap\n");
1488 		return PTR_ERR(st->regmap);
1489 	}
1490 
1491 	mutex_init(&st->lock);
1492 	init_completion(&st->completion);
1493 	st->spi = spi;
1494 	spi_set_drvdata(spi, st);
1495 
1496 	ret = ltc2983_parse_dt(st);
1497 	if (ret)
1498 		return ret;
1499 
1500 	gpio = devm_gpiod_get_optional(&st->spi->dev, "reset", GPIOD_OUT_HIGH);
1501 	if (IS_ERR(gpio))
1502 		return PTR_ERR(gpio);
1503 
1504 	if (gpio) {
1505 		/* bring the device out of reset */
1506 		usleep_range(1000, 1200);
1507 		gpiod_set_value_cansleep(gpio, 0);
1508 	}
1509 
1510 	st->iio_chan = devm_kzalloc(&spi->dev,
1511 				    st->iio_channels * sizeof(*st->iio_chan),
1512 				    GFP_KERNEL);
1513 	if (!st->iio_chan)
1514 		return -ENOMEM;
1515 
1516 	ret = ltc2983_setup(st, true);
1517 	if (ret)
1518 		return ret;
1519 
1520 	ret = devm_request_irq(&spi->dev, spi->irq, ltc2983_irq_handler,
1521 			       IRQF_TRIGGER_RISING, name, st);
1522 	if (ret) {
1523 		dev_err(&spi->dev, "failed to request an irq, %d", ret);
1524 		return ret;
1525 	}
1526 
1527 	indio_dev->name = name;
1528 	indio_dev->num_channels = st->iio_channels;
1529 	indio_dev->channels = st->iio_chan;
1530 	indio_dev->modes = INDIO_DIRECT_MODE;
1531 	indio_dev->info = &ltc2983_iio_info;
1532 
1533 	return devm_iio_device_register(&spi->dev, indio_dev);
1534 }
1535 
1536 static int ltc2983_resume(struct device *dev)
1537 {
1538 	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
1539 	int dummy;
1540 
1541 	/* dummy read to bring the device out of sleep */
1542 	regmap_read(st->regmap, LTC2983_STATUS_REG, &dummy);
1543 	/* we need to re-assign the channels */
1544 	return ltc2983_setup(st, false);
1545 }
1546 
1547 static int ltc2983_suspend(struct device *dev)
1548 {
1549 	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
1550 
1551 	return regmap_write(st->regmap, LTC2983_STATUS_REG, LTC2983_SLEEP);
1552 }
1553 
1554 static DEFINE_SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
1555 				ltc2983_resume);
1556 
1557 static const struct spi_device_id ltc2983_id_table[] = {
1558 	{ "ltc2983" },
1559 	{},
1560 };
1561 MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
1562 
1563 static const struct of_device_id ltc2983_of_match[] = {
1564 	{ .compatible = "adi,ltc2983" },
1565 	{},
1566 };
1567 MODULE_DEVICE_TABLE(of, ltc2983_of_match);
1568 
1569 static struct spi_driver ltc2983_driver = {
1570 	.driver = {
1571 		.name = "ltc2983",
1572 		.of_match_table = ltc2983_of_match,
1573 		.pm = pm_sleep_ptr(&ltc2983_pm_ops),
1574 	},
1575 	.probe = ltc2983_probe,
1576 	.id_table = ltc2983_id_table,
1577 };
1578 
1579 module_spi_driver(ltc2983_driver);
1580 
1581 MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
1582 MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature sensors");
1583 MODULE_LICENSE("GPL");
1584