1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * AD4000 SPI ADC driver
4  *
5  * Copyright 2024 Analog Devices Inc.
6  */
7 #include <linux/bits.h>
8 #include <linux/bitfield.h>
9 #include <linux/byteorder/generic.h>
10 #include <linux/cleanup.h>
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/math.h>
14 #include <linux/module.h>
15 #include <linux/mod_devicetable.h>
16 #include <linux/gpio/consumer.h>
17 #include <linux/regulator/consumer.h>
18 #include <linux/spi/offload/consumer.h>
19 #include <linux/spi/spi.h>
20 #include <linux/units.h>
21 #include <linux/util_macros.h>
22 
23 #include <linux/iio/iio.h>
24 #include <linux/iio/buffer.h>
25 #include <linux/iio/buffer-dmaengine.h>
26 #include <linux/iio/triggered_buffer.h>
27 #include <linux/iio/trigger_consumer.h>
28 
29 #define AD4000_READ_COMMAND	0x54
30 #define AD4000_WRITE_COMMAND	0x14
31 
32 #define AD4000_CONFIG_REG_DEFAULT	0xE1
33 
34 /* AD4000 Configuration Register programmable bits */
35 #define AD4000_CFG_SPAN_COMP		BIT(3) /* Input span compression  */
36 #define AD4000_CFG_HIGHZ		BIT(2) /* High impedance mode  */
37 #define AD4000_CFG_TURBO		BIT(1) /* Turbo mode */
38 
39 #define AD4000_SCALE_OPTIONS		2
40 
41 #define __AD4000_DIFF_CHANNEL(_sign, _real_bits, _storage_bits, _reg_access, _offl)\
42 {										\
43 	.type = IIO_VOLTAGE,							\
44 	.indexed = 1,								\
45 	.differential = 1,							\
46 	.channel = 0,								\
47 	.channel2 = 1,								\
48 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |				\
49 			      BIT(IIO_CHAN_INFO_SCALE) |			\
50 			      (_offl ? BIT(IIO_CHAN_INFO_SAMP_FREQ) : 0),	\
51 	.info_mask_separate_available = _reg_access ? BIT(IIO_CHAN_INFO_SCALE) : 0,\
52 	.scan_index = 0,							\
53 	.scan_type = {								\
54 		.sign = _sign,							\
55 		.realbits = _real_bits,						\
56 		.storagebits = _storage_bits,					\
57 		.shift = (_offl ? 0 : _storage_bits - _real_bits),		\
58 		.endianness = _offl ? IIO_CPU : IIO_BE				\
59 	},									\
60 }
61 
62 #define AD4000_DIFF_CHANNEL(_sign, _real_bits, _reg_access, _offl)		\
63 	__AD4000_DIFF_CHANNEL((_sign), (_real_bits),				\
64 			      (((_offl) || ((_real_bits) > 16)) ? 32 : 16),	\
65 			      (_reg_access), (_offl))
66 
67 /*
68  * When SPI offload is configured, transfers are executed without CPU
69  * intervention so no soft timestamp can be recorded when transfers run.
70  * Because of that, the macros that set timestamp channel are only used when
71  * transfers are not offloaded.
72  */
73 #define AD4000_DIFF_CHANNELS(_sign, _real_bits, _reg_access)			\
74 {										\
75 	AD4000_DIFF_CHANNEL(_sign, _real_bits, _reg_access, 0),			\
76 	IIO_CHAN_SOFT_TIMESTAMP(1),						\
77 }
78 
79 #define __AD4000_PSEUDO_DIFF_CHANNEL(_sign, _real_bits, _storage_bits,		\
80 				     _reg_access, _offl)			\
81 {										\
82 	.type = IIO_VOLTAGE,							\
83 	.indexed = 1,								\
84 	.channel = 0,								\
85 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |				\
86 			      BIT(IIO_CHAN_INFO_SCALE) |			\
87 			      BIT(IIO_CHAN_INFO_OFFSET) |			\
88 			      (_offl ? BIT(IIO_CHAN_INFO_SAMP_FREQ) : 0),	\
89 	.info_mask_separate_available = _reg_access ? BIT(IIO_CHAN_INFO_SCALE) : 0,\
90 	.scan_index = 0,							\
91 	.scan_type = {								\
92 		.sign = _sign,							\
93 		.realbits = _real_bits,						\
94 		.storagebits = _storage_bits,					\
95 		.shift = (_offl ? 0 : _storage_bits - _real_bits),		\
96 		.endianness = _offl ? IIO_CPU : IIO_BE				\
97 	},									\
98 }
99 
100 #define AD4000_PSEUDO_DIFF_CHANNEL(_sign, _real_bits, _reg_access, _offl)	\
101 	__AD4000_PSEUDO_DIFF_CHANNEL((_sign), (_real_bits),			\
102 				     (((_offl) || ((_real_bits) > 16)) ? 32 : 16),\
103 				     (_reg_access), (_offl))
104 
105 #define AD4000_PSEUDO_DIFF_CHANNELS(_sign, _real_bits, _reg_access)		\
106 {										\
107 	AD4000_PSEUDO_DIFF_CHANNEL(_sign, _real_bits, _reg_access, 0),		\
108 	IIO_CHAN_SOFT_TIMESTAMP(1),						\
109 }
110 
111 static const char * const ad4000_power_supplies[] = {
112 	"vdd", "vio"
113 };
114 
115 enum ad4000_sdi {
116 	AD4000_SDI_MOSI,
117 	AD4000_SDI_VIO,
118 	AD4000_SDI_CS,
119 	AD4000_SDI_GND,
120 };
121 
122 /* maps adi,sdi-pin property value to enum */
123 static const char * const ad4000_sdi_pin[] = {
124 	[AD4000_SDI_MOSI] = "sdi",
125 	[AD4000_SDI_VIO] = "high",
126 	[AD4000_SDI_CS] = "cs",
127 	[AD4000_SDI_GND] = "low",
128 };
129 
130 /* Gains stored as fractions of 1000 so they can be expressed by integers. */
131 static const int ad4000_gains[] = {
132 	454, 909, 1000, 1900,
133 };
134 
135 struct ad4000_time_spec {
136 	int t_conv_ns;
137 	int t_quiet2_ns;
138 };
139 
140 /*
141  * Same timing specifications for all of AD4000, AD4001, ..., AD4008, AD4010,
142  * ADAQ4001, and ADAQ4003.
143  */
144 static const struct ad4000_time_spec ad4000_t_spec = {
145 	.t_conv_ns = 320,
146 	.t_quiet2_ns = 60,
147 };
148 
149 /* AD4020, AD4021, AD4022 */
150 static const struct ad4000_time_spec ad4020_t_spec = {
151 	.t_conv_ns = 350,
152 	.t_quiet2_ns = 60,
153 };
154 
155 /* AD7983, AD7984 */
156 static const struct ad4000_time_spec ad7983_t_spec = {
157 	.t_conv_ns = 500,
158 	.t_quiet2_ns = 0,
159 };
160 
161 /* AD7980, AD7982 */
162 static const struct ad4000_time_spec ad7980_t_spec = {
163 	.t_conv_ns = 800,
164 	.t_quiet2_ns = 0,
165 };
166 
167 /* AD7946, AD7686, AD7688, AD7988-5, AD7693 */
168 static const struct ad4000_time_spec ad7686_t_spec = {
169 	.t_conv_ns = 1600,
170 	.t_quiet2_ns = 0,
171 };
172 
173 /* AD7690 */
174 static const struct ad4000_time_spec ad7690_t_spec = {
175 	.t_conv_ns = 2100,
176 	.t_quiet2_ns = 0,
177 };
178 
179 /* AD7942, AD7685, AD7687 */
180 static const struct ad4000_time_spec ad7687_t_spec = {
181 	.t_conv_ns = 3200,
182 	.t_quiet2_ns = 0,
183 };
184 
185 /* AD7691 */
186 static const struct ad4000_time_spec ad7691_t_spec = {
187 	.t_conv_ns = 3700,
188 	.t_quiet2_ns = 0,
189 };
190 
191 /* AD7988-1 */
192 static const struct ad4000_time_spec ad7988_1_t_spec = {
193 	.t_conv_ns = 9500,
194 	.t_quiet2_ns = 0,
195 };
196 
197 struct ad4000_chip_info {
198 	const char *dev_name;
199 	struct iio_chan_spec chan_spec[2];
200 	struct iio_chan_spec reg_access_chan_spec[2];
201 	struct iio_chan_spec offload_chan_spec;
202 	struct iio_chan_spec reg_access_offload_chan_spec;
203 	const struct ad4000_time_spec *time_spec;
204 	bool has_hardware_gain;
205 	int max_rate_hz;
206 };
207 
208 static const struct ad4000_chip_info ad4000_chip_info = {
209 	.dev_name = "ad4000",
210 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
211 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 1),
212 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
213 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 1, 1),
214 	.time_spec = &ad4000_t_spec,
215 	.max_rate_hz = 2 * MEGA,
216 };
217 
218 static const struct ad4000_chip_info ad4001_chip_info = {
219 	.dev_name = "ad4001",
220 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
221 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 16, 1),
222 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
223 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 1, 1),
224 	.time_spec = &ad4000_t_spec,
225 	.max_rate_hz = 2 * MEGA,
226 };
227 
228 static const struct ad4000_chip_info ad4002_chip_info = {
229 	.dev_name = "ad4002",
230 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 0),
231 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 1),
232 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 0, 1),
233 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 1, 1),
234 	.time_spec = &ad4000_t_spec,
235 	.max_rate_hz = 2 * MEGA,
236 };
237 
238 static const struct ad4000_chip_info ad4003_chip_info = {
239 	.dev_name = "ad4003",
240 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
241 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 18, 1),
242 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
243 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 1, 1),
244 	.time_spec = &ad4000_t_spec,
245 	.max_rate_hz = 2 * MEGA,
246 };
247 
248 static const struct ad4000_chip_info ad4004_chip_info = {
249 	.dev_name = "ad4004",
250 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
251 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 1),
252 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
253 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 1, 1),
254 	.time_spec = &ad4000_t_spec,
255 	.max_rate_hz = 1 * MEGA,
256 };
257 
258 static const struct ad4000_chip_info ad4005_chip_info = {
259 	.dev_name = "ad4005",
260 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
261 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 16, 1),
262 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
263 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 1, 1),
264 	.time_spec = &ad4000_t_spec,
265 	.max_rate_hz = 1 * MEGA,
266 };
267 
268 static const struct ad4000_chip_info ad4006_chip_info = {
269 	.dev_name = "ad4006",
270 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 0),
271 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 1),
272 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 0, 1),
273 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 1, 1),
274 	.time_spec = &ad4000_t_spec,
275 	.max_rate_hz = 1 * MEGA,
276 };
277 
278 static const struct ad4000_chip_info ad4007_chip_info = {
279 	.dev_name = "ad4007",
280 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
281 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 18, 1),
282 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
283 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 1, 1),
284 	.time_spec = &ad4000_t_spec,
285 	.max_rate_hz = 1 * MEGA,
286 };
287 
288 static const struct ad4000_chip_info ad4008_chip_info = {
289 	.dev_name = "ad4008",
290 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
291 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 1),
292 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
293 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 1, 1),
294 	.time_spec = &ad4000_t_spec,
295 	.max_rate_hz = 500 * KILO,
296 };
297 
298 static const struct ad4000_chip_info ad4010_chip_info = {
299 	.dev_name = "ad4010",
300 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 0),
301 	.reg_access_chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 18, 1),
302 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 0, 1),
303 	.reg_access_offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 18, 1, 1),
304 	.time_spec = &ad4000_t_spec,
305 	.max_rate_hz = 500 * KILO,
306 };
307 
308 static const struct ad4000_chip_info ad4011_chip_info = {
309 	.dev_name = "ad4011",
310 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
311 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 18, 1),
312 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
313 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 1, 1),
314 	.time_spec = &ad4000_t_spec,
315 	.max_rate_hz = 500 * KILO,
316 };
317 
318 static const struct ad4000_chip_info ad4020_chip_info = {
319 	.dev_name = "ad4020",
320 	.chan_spec = AD4000_DIFF_CHANNELS('s', 20, 0),
321 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 20, 1),
322 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 0, 1),
323 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 1, 1),
324 	.time_spec = &ad4020_t_spec,
325 	.max_rate_hz = 1800 * KILO,
326 };
327 
328 static const struct ad4000_chip_info ad4021_chip_info = {
329 	.dev_name = "ad4021",
330 	.chan_spec = AD4000_DIFF_CHANNELS('s', 20, 0),
331 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 20, 1),
332 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 0, 1),
333 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 1, 1),
334 	.time_spec = &ad4020_t_spec,
335 	.max_rate_hz = 1 * MEGA,
336 };
337 
338 static const struct ad4000_chip_info ad4022_chip_info = {
339 	.dev_name = "ad4022",
340 	.chan_spec = AD4000_DIFF_CHANNELS('s', 20, 0),
341 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 20, 1),
342 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 0, 1),
343 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 20, 1, 1),
344 	.time_spec = &ad4020_t_spec,
345 	.max_rate_hz = 500 * KILO,
346 };
347 
348 static const struct ad4000_chip_info adaq4001_chip_info = {
349 	.dev_name = "adaq4001",
350 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
351 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 16, 1),
352 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
353 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 1, 1),
354 	.time_spec = &ad4000_t_spec,
355 	.has_hardware_gain = true,
356 	.max_rate_hz = 2 * MEGA,
357 };
358 
359 static const struct ad4000_chip_info adaq4003_chip_info = {
360 	.dev_name = "adaq4003",
361 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
362 	.reg_access_chan_spec = AD4000_DIFF_CHANNELS('s', 18, 1),
363 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
364 	.reg_access_offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 1, 1),
365 	.time_spec = &ad4000_t_spec,
366 	.has_hardware_gain = true,
367 	.max_rate_hz = 2 * MEGA,
368 };
369 
370 static const struct ad4000_chip_info ad7685_chip_info = {
371 	.dev_name = "ad7685",
372 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
373 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
374 	.time_spec = &ad7687_t_spec,
375 	.max_rate_hz = 250 * KILO,
376 };
377 
378 static const struct ad4000_chip_info ad7686_chip_info = {
379 	.dev_name = "ad7686",
380 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
381 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
382 	.time_spec = &ad7686_t_spec,
383 	.max_rate_hz = 500 * KILO,
384 };
385 
386 static const struct ad4000_chip_info ad7687_chip_info = {
387 	.dev_name = "ad7687",
388 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
389 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
390 	.time_spec = &ad7687_t_spec,
391 	.max_rate_hz = 250 * KILO,
392 };
393 
394 static const struct ad4000_chip_info ad7688_chip_info = {
395 	.dev_name = "ad7688",
396 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
397 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
398 	.time_spec = &ad7686_t_spec,
399 	.max_rate_hz = 500 * KILO,
400 };
401 
402 static const struct ad4000_chip_info ad7690_chip_info = {
403 	.dev_name = "ad7690",
404 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
405 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
406 	.time_spec = &ad7690_t_spec,
407 	.max_rate_hz = 400 * KILO,
408 };
409 
410 static const struct ad4000_chip_info ad7691_chip_info = {
411 	.dev_name = "ad7691",
412 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
413 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
414 	.time_spec = &ad7691_t_spec,
415 	.max_rate_hz = 250 * KILO,
416 };
417 
418 static const struct ad4000_chip_info ad7693_chip_info = {
419 	.dev_name = "ad7693",
420 	.chan_spec = AD4000_DIFF_CHANNELS('s', 16, 0),
421 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 16, 0, 1),
422 	.time_spec = &ad7686_t_spec,
423 	.max_rate_hz = 500 * KILO,
424 };
425 
426 static const struct ad4000_chip_info ad7942_chip_info = {
427 	.dev_name = "ad7942",
428 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 14, 0),
429 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 14, 0, 1),
430 	.time_spec = &ad7687_t_spec,
431 	.max_rate_hz = 250 * KILO,
432 };
433 
434 static const struct ad4000_chip_info ad7946_chip_info = {
435 	.dev_name = "ad7946",
436 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 14, 0),
437 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 14, 0, 1),
438 	.time_spec = &ad7686_t_spec,
439 	.max_rate_hz = 500 * KILO,
440 };
441 
442 static const struct ad4000_chip_info ad7980_chip_info = {
443 	.dev_name = "ad7980",
444 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
445 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
446 	.time_spec = &ad7980_t_spec,
447 	.max_rate_hz = 1 * MEGA,
448 };
449 
450 static const struct ad4000_chip_info ad7982_chip_info = {
451 	.dev_name = "ad7982",
452 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
453 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
454 	.time_spec = &ad7980_t_spec,
455 	.max_rate_hz = 1 * MEGA,
456 };
457 
458 static const struct ad4000_chip_info ad7983_chip_info = {
459 	.dev_name = "ad7983",
460 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
461 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
462 	.time_spec = &ad7983_t_spec,
463 	.max_rate_hz = 1 * MEGA + 333 * KILO + 333,
464 };
465 
466 static const struct ad4000_chip_info ad7984_chip_info = {
467 	.dev_name = "ad7984",
468 	.chan_spec = AD4000_DIFF_CHANNELS('s', 18, 0),
469 	.offload_chan_spec = AD4000_DIFF_CHANNEL('s', 18, 0, 1),
470 	.time_spec = &ad7983_t_spec,
471 	.max_rate_hz = 1 * MEGA + 333 * KILO + 333,
472 };
473 
474 static const struct ad4000_chip_info ad7988_1_chip_info = {
475 	.dev_name = "ad7988-1",
476 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
477 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
478 	.time_spec = &ad7988_1_t_spec,
479 	.max_rate_hz = 100 * KILO,
480 };
481 
482 static const struct ad4000_chip_info ad7988_5_chip_info = {
483 	.dev_name = "ad7988-5",
484 	.chan_spec = AD4000_PSEUDO_DIFF_CHANNELS('u', 16, 0),
485 	.offload_chan_spec = AD4000_PSEUDO_DIFF_CHANNEL('u', 16, 0, 1),
486 	.time_spec = &ad7686_t_spec,
487 	.max_rate_hz = 500 * KILO,
488 };
489 
490 static const struct spi_offload_config ad4000_offload_config = {
491 	.capability_flags = SPI_OFFLOAD_CAP_TRIGGER |
492 			    SPI_OFFLOAD_CAP_RX_STREAM_DMA,
493 };
494 
495 struct ad4000_state {
496 	struct spi_device *spi;
497 	struct gpio_desc *cnv_gpio;
498 	struct spi_transfer xfers[2];
499 	struct spi_message msg;
500 	struct spi_transfer offload_xfer;
501 	struct spi_message offload_msg;
502 	struct spi_offload *offload;
503 	struct spi_offload_trigger *offload_trigger;
504 	bool using_offload;
505 	unsigned long offload_trigger_hz;
506 	int max_rate_hz;
507 	struct mutex lock; /* Protect read modify write cycle */
508 	int vref_mv;
509 	enum ad4000_sdi sdi_pin;
510 	bool span_comp;
511 	u16 gain_milli;
512 	int scale_tbl[AD4000_SCALE_OPTIONS][2];
513 	const struct ad4000_time_spec *time_spec;
514 
515 	/*
516 	 * DMA (thus cache coherency maintenance) requires the transfer buffers
517 	 * to live in their own cache lines.
518 	 */
519 	struct {
520 		union {
521 			__be16 sample_buf16_be;
522 			__be32 sample_buf32_be;
523 			u16 sample_buf16;
524 			u32 sample_buf32;
525 		} data;
526 		aligned_s64 timestamp;
527 	} scan __aligned(IIO_DMA_MINALIGN);
528 	u8 tx_buf[2];
529 	u8 rx_buf[2];
530 };
531 
532 static void ad4000_fill_scale_tbl(struct ad4000_state *st,
533 				  struct iio_chan_spec const *chan)
534 {
535 	int val, tmp0, tmp1;
536 	int scale_bits;
537 	u64 tmp2;
538 
539 	/*
540 	 * ADCs that output two's complement code have one less bit to express
541 	 * voltage magnitude.
542 	 */
543 	if (chan->scan_type.sign == 's')
544 		scale_bits = chan->scan_type.realbits - 1;
545 	else
546 		scale_bits = chan->scan_type.realbits;
547 
548 	/*
549 	 * The gain is stored as a fraction of 1000 and, as we need to
550 	 * divide vref_mv by the gain, we invert the gain/1000 fraction.
551 	 * Also multiply by an extra MILLI to preserve precision.
552 	 * Thus, we have MILLI * MILLI equals MICRO as fraction numerator.
553 	 */
554 	val = mult_frac(st->vref_mv, MICRO, st->gain_milli);
555 
556 	/* Would multiply by NANO here but we multiplied by extra MILLI */
557 	tmp2 = shift_right((u64)val * MICRO, scale_bits);
558 	tmp0 = div_s64_rem(tmp2, NANO, &tmp1);
559 
560 	/* Store scale for when span compression is disabled */
561 	st->scale_tbl[0][0] = tmp0; /* Integer part */
562 	st->scale_tbl[0][1] = abs(tmp1); /* Fractional part */
563 
564 	/* Store scale for when span compression is enabled */
565 	st->scale_tbl[1][0] = tmp0;
566 
567 	/* The integer part is always zero so don't bother to divide it. */
568 	if (chan->differential)
569 		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 4, 5);
570 	else
571 		st->scale_tbl[1][1] = DIV_ROUND_CLOSEST(abs(tmp1) * 9, 10);
572 }
573 
574 static int ad4000_write_reg(struct ad4000_state *st, uint8_t val)
575 {
576 	st->tx_buf[0] = AD4000_WRITE_COMMAND;
577 	st->tx_buf[1] = val;
578 	return spi_write(st->spi, st->tx_buf, ARRAY_SIZE(st->tx_buf));
579 }
580 
581 static int ad4000_read_reg(struct ad4000_state *st, unsigned int *val)
582 {
583 	struct spi_transfer t = {
584 		.tx_buf = st->tx_buf,
585 		.rx_buf = st->rx_buf,
586 		.len = 2,
587 	};
588 	int ret;
589 
590 	st->tx_buf[0] = AD4000_READ_COMMAND;
591 	ret = spi_sync_transfer(st->spi, &t, 1);
592 	if (ret < 0)
593 		return ret;
594 
595 	*val = st->rx_buf[1];
596 	return ret;
597 }
598 
599 static int ad4000_set_sampling_freq(struct ad4000_state *st, int freq)
600 {
601 	struct spi_offload_trigger_config config = {
602 		.type = SPI_OFFLOAD_TRIGGER_PERIODIC,
603 		.periodic = {
604 			.frequency_hz = freq,
605 		},
606 	};
607 	int ret;
608 
609 	ret = spi_offload_trigger_validate(st->offload_trigger, &config);
610 	if (ret)
611 		return ret;
612 
613 	st->offload_trigger_hz = config.periodic.frequency_hz;
614 
615 	return 0;
616 }
617 
618 static int ad4000_convert_and_acquire(struct ad4000_state *st)
619 {
620 	int ret;
621 
622 	/*
623 	 * In 4-wire mode, the CNV line is held high for the entire conversion
624 	 * and acquisition process. In other modes, the CNV GPIO is optional
625 	 * and, if provided, replaces controller CS. If CNV GPIO is not defined
626 	 * gpiod_set_value_cansleep() has no effect.
627 	 */
628 	gpiod_set_value_cansleep(st->cnv_gpio, 1);
629 	ret = spi_sync(st->spi, &st->msg);
630 	gpiod_set_value_cansleep(st->cnv_gpio, 0);
631 
632 	return ret;
633 }
634 
635 static int ad4000_single_conversion(struct iio_dev *indio_dev,
636 				    const struct iio_chan_spec *chan, int *val)
637 {
638 	struct ad4000_state *st = iio_priv(indio_dev);
639 	u32 sample;
640 	int ret;
641 
642 	ret = ad4000_convert_and_acquire(st);
643 	if (ret < 0)
644 		return ret;
645 
646 	if (chan->scan_type.endianness == IIO_BE) {
647 		if (chan->scan_type.realbits > 16)
648 			sample = be32_to_cpu(st->scan.data.sample_buf32_be);
649 		else
650 			sample = be16_to_cpu(st->scan.data.sample_buf16_be);
651 	} else {
652 		if (chan->scan_type.realbits > 16)
653 			sample = st->scan.data.sample_buf32;
654 		else
655 			sample = st->scan.data.sample_buf16;
656 	}
657 
658 	sample >>= chan->scan_type.shift;
659 
660 	if (chan->scan_type.sign == 's')
661 		*val = sign_extend32(sample, chan->scan_type.realbits - 1);
662 	else
663 		*val = sample;
664 
665 	return IIO_VAL_INT;
666 }
667 
668 static int ad4000_read_raw(struct iio_dev *indio_dev,
669 			   struct iio_chan_spec const *chan, int *val,
670 			   int *val2, long info)
671 {
672 	struct ad4000_state *st = iio_priv(indio_dev);
673 	int ret;
674 
675 	switch (info) {
676 	case IIO_CHAN_INFO_RAW:
677 		if (!iio_device_claim_direct(indio_dev))
678 			return -EBUSY;
679 
680 		ret = ad4000_single_conversion(indio_dev, chan, val);
681 		iio_device_release_direct(indio_dev);
682 		return ret;
683 	case IIO_CHAN_INFO_SCALE:
684 		*val = st->scale_tbl[st->span_comp][0];
685 		*val2 = st->scale_tbl[st->span_comp][1];
686 		return IIO_VAL_INT_PLUS_NANO;
687 	case IIO_CHAN_INFO_OFFSET:
688 		*val = 0;
689 		if (st->span_comp)
690 			*val = mult_frac(st->vref_mv, 1, 10);
691 
692 		return IIO_VAL_INT;
693 	case IIO_CHAN_INFO_SAMP_FREQ:
694 		*val = st->offload_trigger_hz;
695 		return IIO_VAL_INT;
696 	default:
697 		return -EINVAL;
698 	}
699 }
700 
701 static int ad4000_read_avail(struct iio_dev *indio_dev,
702 			     struct iio_chan_spec const *chan,
703 			     const int **vals, int *type, int *length,
704 			     long info)
705 {
706 	struct ad4000_state *st = iio_priv(indio_dev);
707 
708 	switch (info) {
709 	case IIO_CHAN_INFO_SCALE:
710 		*vals = (int *)st->scale_tbl;
711 		*length = AD4000_SCALE_OPTIONS * 2;
712 		*type = IIO_VAL_INT_PLUS_NANO;
713 		return IIO_AVAIL_LIST;
714 	default:
715 		return -EINVAL;
716 	}
717 }
718 
719 static int ad4000_write_raw_get_fmt(struct iio_dev *indio_dev,
720 				    struct iio_chan_spec const *chan, long mask)
721 {
722 	switch (mask) {
723 	case IIO_CHAN_INFO_SCALE:
724 		return IIO_VAL_INT_PLUS_NANO;
725 	default:
726 		return IIO_VAL_INT_PLUS_MICRO;
727 	}
728 }
729 
730 static int __ad4000_write_raw(struct iio_dev *indio_dev,
731 			      struct iio_chan_spec const *chan,
732 			      int val2)
733 {
734 	struct ad4000_state *st = iio_priv(indio_dev);
735 	unsigned int reg_val;
736 	bool span_comp_en;
737 	int ret;
738 
739 	guard(mutex)(&st->lock);
740 
741 	ret = ad4000_read_reg(st, &reg_val);
742 	if (ret < 0)
743 		return ret;
744 
745 	span_comp_en = val2 == st->scale_tbl[1][1];
746 	reg_val &= ~AD4000_CFG_SPAN_COMP;
747 	reg_val |= FIELD_PREP(AD4000_CFG_SPAN_COMP, span_comp_en);
748 
749 	ret = ad4000_write_reg(st, reg_val);
750 	if (ret < 0)
751 		return ret;
752 
753 	st->span_comp = span_comp_en;
754 	return 0;
755 }
756 
757 static int ad4000_write_raw(struct iio_dev *indio_dev,
758 			    struct iio_chan_spec const *chan,
759 			    int val, int val2, long mask)
760 {
761 	struct ad4000_state *st = iio_priv(indio_dev);
762 	int ret;
763 
764 	switch (mask) {
765 	case IIO_CHAN_INFO_SCALE:
766 		if (!iio_device_claim_direct(indio_dev))
767 			return -EBUSY;
768 		ret = __ad4000_write_raw(indio_dev, chan, val2);
769 		iio_device_release_direct(indio_dev);
770 		return ret;
771 	case IIO_CHAN_INFO_SAMP_FREQ:
772 		if (val < 1 || val > st->max_rate_hz)
773 			return -EINVAL;
774 
775 		if (!iio_device_claim_direct(indio_dev))
776 			return -EBUSY;
777 		ret = ad4000_set_sampling_freq(st, val);
778 		iio_device_release_direct(indio_dev);
779 		return ret;
780 	default:
781 		return -EINVAL;
782 	}
783 }
784 
785 static irqreturn_t ad4000_trigger_handler(int irq, void *p)
786 {
787 	struct iio_poll_func *pf = p;
788 	struct iio_dev *indio_dev = pf->indio_dev;
789 	struct ad4000_state *st = iio_priv(indio_dev);
790 	int ret;
791 
792 	ret = ad4000_convert_and_acquire(st);
793 	if (ret < 0)
794 		goto err_out;
795 
796 	iio_push_to_buffers_with_ts(indio_dev, &st->scan, sizeof(st->scan),
797 				    pf->timestamp);
798 
799 err_out:
800 	iio_trigger_notify_done(indio_dev->trig);
801 	return IRQ_HANDLED;
802 }
803 
804 static const struct iio_info ad4000_reg_access_info = {
805 	.read_raw = &ad4000_read_raw,
806 	.read_avail = &ad4000_read_avail,
807 	.write_raw = &ad4000_write_raw,
808 	.write_raw_get_fmt = &ad4000_write_raw_get_fmt,
809 };
810 
811 static const struct iio_info ad4000_offload_info = {
812 	.read_raw = &ad4000_read_raw,
813 	.write_raw = &ad4000_write_raw,
814 	.write_raw_get_fmt = &ad4000_write_raw_get_fmt,
815 };
816 
817 static const struct iio_info ad4000_info = {
818 	.read_raw = &ad4000_read_raw,
819 };
820 
821 static int ad4000_offload_buffer_postenable(struct iio_dev *indio_dev)
822 {
823 	struct ad4000_state *st = iio_priv(indio_dev);
824 	struct spi_offload_trigger_config config = {
825 		.type = SPI_OFFLOAD_TRIGGER_PERIODIC,
826 		.periodic = {
827 			.frequency_hz = st->offload_trigger_hz,
828 		},
829 	};
830 
831 	return spi_offload_trigger_enable(st->offload, st->offload_trigger,
832 					  &config);
833 }
834 
835 static int ad4000_offload_buffer_predisable(struct iio_dev *indio_dev)
836 {
837 	struct ad4000_state *st = iio_priv(indio_dev);
838 
839 	spi_offload_trigger_disable(st->offload, st->offload_trigger);
840 
841 	return 0;
842 }
843 
844 static const struct iio_buffer_setup_ops ad4000_offload_buffer_setup_ops = {
845 	.postenable = &ad4000_offload_buffer_postenable,
846 	.predisable = &ad4000_offload_buffer_predisable,
847 };
848 
849 static int ad4000_spi_offload_setup(struct iio_dev *indio_dev,
850 				    struct ad4000_state *st)
851 {
852 	struct spi_device *spi = st->spi;
853 	struct device *dev = &spi->dev;
854 	struct dma_chan *rx_dma;
855 	int ret;
856 
857 	st->offload_trigger = devm_spi_offload_trigger_get(dev, st->offload,
858 							   SPI_OFFLOAD_TRIGGER_PERIODIC);
859 	if (IS_ERR(st->offload_trigger))
860 		return dev_err_probe(dev, PTR_ERR(st->offload_trigger),
861 				     "Failed to get offload trigger\n");
862 
863 	ret = ad4000_set_sampling_freq(st, st->max_rate_hz);
864 	if (ret)
865 		return dev_err_probe(dev, ret,
866 				     "Failed to set sampling frequency\n");
867 
868 	rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev, st->offload);
869 	if (IS_ERR(rx_dma))
870 		return dev_err_probe(dev, PTR_ERR(rx_dma),
871 				     "Failed to get offload RX DMA\n");
872 
873 	ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev, rx_dma,
874 							  IIO_BUFFER_DIRECTION_IN);
875 	if (ret)
876 		return dev_err_probe(dev, ret, "Failed to setup DMA buffer\n");
877 
878 	return 0;
879 }
880 
881 /*
882  * This executes a data sample transfer when using SPI offloading. The device
883  * connections should be in "3-wire" mode, selected either when the adi,sdi-pin
884  * device tree property is absent or set to "high". Also, the ADC CNV pin must
885  * be connected to a SPI controller CS (it can't be connected to a GPIO).
886  *
887  * In order to achieve the maximum sample rate, we only do one transfer per
888  * SPI offload trigger. Because the ADC output has a one sample latency (delay)
889  * when the device is wired in "3-wire" mode and only one transfer per sample is
890  * being made in turbo mode, the first data sample is not valid because it
891  * contains the output of an earlier conversion result. We also set transfer
892  * `bits_per_word` to achieve higher throughput by using the minimum number of
893  * SCLK cycles. Also, a delay is added to make sure we meet the minimum quiet
894  * time before releasing the CS line.
895  *
896  * Note that, with `bits_per_word` set to the number of ADC precision bits,
897  * transfers use larger word sizes that get stored in 'in-memory wordsizes' that
898  * are always in native CPU byte order. Because of that, IIO buffer elements
899  * ought to be read in CPU endianness which requires setting IIO scan_type
900  * endianness accordingly (i.e. IIO_CPU).
901  */
902 static int ad4000_prepare_offload_message(struct ad4000_state *st,
903 					  const struct iio_chan_spec *chan)
904 {
905 	struct spi_transfer *xfer = &st->offload_xfer;
906 
907 	xfer->bits_per_word = chan->scan_type.realbits;
908 	xfer->len = chan->scan_type.realbits > 16 ? 4 : 2;
909 	xfer->delay.value = st->time_spec->t_quiet2_ns;
910 	xfer->delay.unit = SPI_DELAY_UNIT_NSECS;
911 	xfer->offload_flags = SPI_OFFLOAD_XFER_RX_STREAM;
912 
913 	spi_message_init_with_transfers(&st->offload_msg, xfer, 1);
914 	st->offload_msg.offload = st->offload;
915 
916 	return devm_spi_optimize_message(&st->spi->dev, st->spi, &st->offload_msg);
917 }
918 
919 /*
920  * This executes a data sample transfer for when the device connections are
921  * in "3-wire" mode, selected when the adi,sdi-pin device tree property is
922  * absent or set to "high". In this connection mode, the ADC SDI pin is
923  * connected to MOSI or to VIO and ADC CNV pin is connected either to a SPI
924  * controller CS or to a GPIO.
925  * AD4000 series of devices initiate conversions on the rising edge of CNV pin.
926  *
927  * If the CNV pin is connected to an SPI controller CS line (which is by default
928  * active low), the ADC readings would have a latency (delay) of one read.
929  * Moreover, since we also do ADC sampling for filling the buffer on triggered
930  * buffer mode, the timestamps of buffer readings would be disarranged.
931  * To prevent the read latency and reduce the time discrepancy between the
932  * sample read request and the time of actual sampling by the ADC, do a
933  * preparatory transfer to pulse the CS/CNV line.
934  */
935 static int ad4000_prepare_3wire_mode_message(struct ad4000_state *st,
936 					     const struct iio_chan_spec *chan)
937 {
938 	struct spi_transfer *xfers = st->xfers;
939 
940 	xfers[0].cs_change = 1;
941 	xfers[0].cs_change_delay.value = st->time_spec->t_conv_ns;
942 	xfers[0].cs_change_delay.unit = SPI_DELAY_UNIT_NSECS;
943 
944 	xfers[1].rx_buf = &st->scan.data;
945 	xfers[1].len = chan->scan_type.realbits > 16 ? 4 : 2;
946 
947 	/*
948 	 * If the device is set up for SPI offloading, IIO channel scan_type is
949 	 * set to IIO_CPU. When that is the case, use larger SPI word sizes for
950 	 * single-shot reads too. Thus, sample data can be correctly handled in
951 	 * ad4000_single_conversion() according to scan_type endianness.
952 	 */
953 	if (chan->scan_type.endianness != IIO_BE)
954 		xfers[1].bits_per_word = chan->scan_type.realbits;
955 	xfers[1].delay.value = st->time_spec->t_quiet2_ns;
956 	xfers[1].delay.unit = SPI_DELAY_UNIT_NSECS;
957 
958 	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
959 
960 	return devm_spi_optimize_message(&st->spi->dev, st->spi, &st->msg);
961 }
962 
963 /*
964  * This executes a data sample transfer for when the device connections are
965  * in "4-wire" mode, selected when the adi,sdi-pin device tree property is
966  * set to "cs". In this connection mode, the controller CS pin is connected to
967  * ADC SDI pin and a GPIO is connected to ADC CNV pin.
968  * The GPIO connected to ADC CNV pin is set outside of the SPI transfer.
969  */
970 static int ad4000_prepare_4wire_mode_message(struct ad4000_state *st,
971 					     const struct iio_chan_spec *chan)
972 {
973 	struct spi_transfer *xfers = st->xfers;
974 
975 	/*
976 	 * Dummy transfer to cause enough delay between CNV going high and SDI
977 	 * going low.
978 	 */
979 	xfers[0].cs_off = 1;
980 	xfers[0].delay.value = st->time_spec->t_conv_ns;
981 	xfers[0].delay.unit = SPI_DELAY_UNIT_NSECS;
982 
983 	xfers[1].rx_buf = &st->scan.data;
984 	xfers[1].len = BITS_TO_BYTES(chan->scan_type.storagebits);
985 
986 	spi_message_init_with_transfers(&st->msg, st->xfers, 2);
987 
988 	return devm_spi_optimize_message(&st->spi->dev, st->spi, &st->msg);
989 }
990 
991 static int ad4000_config(struct ad4000_state *st)
992 {
993 	unsigned int reg_val = AD4000_CONFIG_REG_DEFAULT;
994 
995 	if (device_property_present(&st->spi->dev, "adi,high-z-input"))
996 		reg_val |= FIELD_PREP(AD4000_CFG_HIGHZ, 1);
997 
998 	if (st->using_offload)
999 		reg_val |= FIELD_PREP(AD4000_CFG_TURBO, 1);
1000 
1001 	return ad4000_write_reg(st, reg_val);
1002 }
1003 
1004 static int ad4000_probe(struct spi_device *spi)
1005 {
1006 	const struct ad4000_chip_info *chip;
1007 	struct device *dev = &spi->dev;
1008 	struct iio_dev *indio_dev;
1009 	struct ad4000_state *st;
1010 	int gain_idx, ret;
1011 
1012 	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
1013 	if (!indio_dev)
1014 		return -ENOMEM;
1015 
1016 	chip = spi_get_device_match_data(spi);
1017 	if (!chip)
1018 		return -EINVAL;
1019 
1020 	st = iio_priv(indio_dev);
1021 	st->spi = spi;
1022 	st->time_spec = chip->time_spec;
1023 	st->max_rate_hz = chip->max_rate_hz;
1024 
1025 	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(ad4000_power_supplies),
1026 					     ad4000_power_supplies);
1027 	if (ret)
1028 		return dev_err_probe(dev, ret, "Failed to enable power supplies\n");
1029 
1030 	ret = devm_regulator_get_enable_read_voltage(dev, "ref");
1031 	if (ret < 0)
1032 		return dev_err_probe(dev, ret,
1033 				     "Failed to get ref regulator reference\n");
1034 	st->vref_mv = ret / 1000;
1035 
1036 	st->cnv_gpio = devm_gpiod_get_optional(dev, "cnv", GPIOD_OUT_HIGH);
1037 	if (IS_ERR(st->cnv_gpio))
1038 		return dev_err_probe(dev, PTR_ERR(st->cnv_gpio),
1039 				     "Failed to get CNV GPIO");
1040 
1041 	st->offload = devm_spi_offload_get(dev, spi, &ad4000_offload_config);
1042 	ret = PTR_ERR_OR_ZERO(st->offload);
1043 	if (ret && ret != -ENODEV)
1044 		return dev_err_probe(dev, ret, "Failed to get offload\n");
1045 
1046 	st->using_offload = !IS_ERR(st->offload);
1047 	if (st->using_offload) {
1048 		indio_dev->setup_ops = &ad4000_offload_buffer_setup_ops;
1049 		ret = ad4000_spi_offload_setup(indio_dev, st);
1050 		if (ret)
1051 			return ret;
1052 	} else {
1053 		ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
1054 						      &iio_pollfunc_store_time,
1055 						      &ad4000_trigger_handler,
1056 						      NULL);
1057 		if (ret)
1058 			return ret;
1059 	}
1060 
1061 	ret = device_property_match_property_string(dev, "adi,sdi-pin",
1062 						    ad4000_sdi_pin,
1063 						    ARRAY_SIZE(ad4000_sdi_pin));
1064 	if (ret < 0 && ret != -EINVAL)
1065 		return dev_err_probe(dev, ret,
1066 				     "getting adi,sdi-pin property failed\n");
1067 
1068 	/* Default to usual SPI connections if pin properties are not present */
1069 	st->sdi_pin = ret == -EINVAL ? AD4000_SDI_MOSI : ret;
1070 	switch (st->sdi_pin) {
1071 	case AD4000_SDI_MOSI:
1072 		indio_dev->info = &ad4000_reg_access_info;
1073 
1074 		/*
1075 		 * In "3-wire mode", the ADC SDI line must be kept high when
1076 		 * data is not being clocked out of the controller.
1077 		 * Request the SPI controller to make MOSI idle high.
1078 		 */
1079 		spi->mode |= SPI_MOSI_IDLE_HIGH;
1080 		ret = spi_setup(spi);
1081 		if (ret < 0)
1082 			return ret;
1083 
1084 		if (st->using_offload) {
1085 			indio_dev->channels = &chip->reg_access_offload_chan_spec;
1086 			indio_dev->num_channels = 1;
1087 			ret = ad4000_prepare_offload_message(st, indio_dev->channels);
1088 			if (ret)
1089 				return dev_err_probe(dev, ret,
1090 						     "Failed to optimize SPI msg\n");
1091 		} else {
1092 			indio_dev->channels = chip->reg_access_chan_spec;
1093 			indio_dev->num_channels = ARRAY_SIZE(chip->reg_access_chan_spec);
1094 		}
1095 
1096 		/*
1097 		 * Call ad4000_prepare_3wire_mode_message() so single-shot read
1098 		 * SPI messages are always initialized.
1099 		 */
1100 		ret = ad4000_prepare_3wire_mode_message(st, &indio_dev->channels[0]);
1101 		if (ret)
1102 			return dev_err_probe(dev, ret,
1103 					     "Failed to optimize SPI msg\n");
1104 
1105 		ret = ad4000_config(st);
1106 		if (ret < 0)
1107 			return dev_err_probe(dev, ret, "Failed to config device\n");
1108 
1109 		break;
1110 	case AD4000_SDI_VIO:
1111 		if (st->using_offload) {
1112 			indio_dev->info = &ad4000_offload_info;
1113 			indio_dev->channels = &chip->offload_chan_spec;
1114 			indio_dev->num_channels = 1;
1115 
1116 			ret = ad4000_prepare_offload_message(st, indio_dev->channels);
1117 			if (ret)
1118 				return dev_err_probe(dev, ret,
1119 						     "Failed to optimize SPI msg\n");
1120 		} else {
1121 			indio_dev->info = &ad4000_info;
1122 			indio_dev->channels = chip->chan_spec;
1123 			indio_dev->num_channels = ARRAY_SIZE(chip->chan_spec);
1124 		}
1125 
1126 		ret = ad4000_prepare_3wire_mode_message(st, &indio_dev->channels[0]);
1127 		if (ret)
1128 			return dev_err_probe(dev, ret,
1129 					     "Failed to optimize SPI msg\n");
1130 
1131 		break;
1132 	case AD4000_SDI_CS:
1133 		if (st->using_offload)
1134 			return dev_err_probe(dev, -EPROTONOSUPPORT,
1135 					     "Unsupported sdi-pin + offload config\n");
1136 		indio_dev->info = &ad4000_info;
1137 		indio_dev->channels = chip->chan_spec;
1138 		indio_dev->num_channels = ARRAY_SIZE(chip->chan_spec);
1139 		ret = ad4000_prepare_4wire_mode_message(st, &indio_dev->channels[0]);
1140 		if (ret)
1141 			return dev_err_probe(dev, ret,
1142 					     "Failed to optimize SPI msg\n");
1143 
1144 		break;
1145 	case AD4000_SDI_GND:
1146 		return dev_err_probe(dev, -EPROTONOSUPPORT,
1147 				     "Unsupported connection mode\n");
1148 
1149 	default:
1150 		return dev_err_probe(dev, -EINVAL, "Unrecognized connection mode\n");
1151 	}
1152 
1153 	indio_dev->name = chip->dev_name;
1154 
1155 	ret = devm_mutex_init(dev, &st->lock);
1156 	if (ret)
1157 		return ret;
1158 
1159 	st->gain_milli = 1000;
1160 	if (chip->has_hardware_gain) {
1161 		ret = device_property_read_u16(dev, "adi,gain-milli",
1162 					       &st->gain_milli);
1163 		if (!ret) {
1164 			/* Match gain value from dt to one of supported gains */
1165 			gain_idx = find_closest(st->gain_milli, ad4000_gains,
1166 						ARRAY_SIZE(ad4000_gains));
1167 			st->gain_milli = ad4000_gains[gain_idx];
1168 		} else {
1169 			return dev_err_probe(dev, ret,
1170 					     "Failed to read gain property\n");
1171 		}
1172 	}
1173 
1174 	ad4000_fill_scale_tbl(st, &indio_dev->channels[0]);
1175 
1176 	return devm_iio_device_register(dev, indio_dev);
1177 }
1178 
1179 static const struct spi_device_id ad4000_id[] = {
1180 	{ "ad4000", (kernel_ulong_t)&ad4000_chip_info },
1181 	{ "ad4001", (kernel_ulong_t)&ad4001_chip_info },
1182 	{ "ad4002", (kernel_ulong_t)&ad4002_chip_info },
1183 	{ "ad4003", (kernel_ulong_t)&ad4003_chip_info },
1184 	{ "ad4004", (kernel_ulong_t)&ad4004_chip_info },
1185 	{ "ad4005", (kernel_ulong_t)&ad4005_chip_info },
1186 	{ "ad4006", (kernel_ulong_t)&ad4006_chip_info },
1187 	{ "ad4007", (kernel_ulong_t)&ad4007_chip_info },
1188 	{ "ad4008", (kernel_ulong_t)&ad4008_chip_info },
1189 	{ "ad4010", (kernel_ulong_t)&ad4010_chip_info },
1190 	{ "ad4011", (kernel_ulong_t)&ad4011_chip_info },
1191 	{ "ad4020", (kernel_ulong_t)&ad4020_chip_info },
1192 	{ "ad4021", (kernel_ulong_t)&ad4021_chip_info },
1193 	{ "ad4022", (kernel_ulong_t)&ad4022_chip_info },
1194 	{ "adaq4001", (kernel_ulong_t)&adaq4001_chip_info },
1195 	{ "adaq4003", (kernel_ulong_t)&adaq4003_chip_info },
1196 	{ "ad7685", (kernel_ulong_t)&ad7685_chip_info },
1197 	{ "ad7686", (kernel_ulong_t)&ad7686_chip_info },
1198 	{ "ad7687", (kernel_ulong_t)&ad7687_chip_info },
1199 	{ "ad7688", (kernel_ulong_t)&ad7688_chip_info },
1200 	{ "ad7690", (kernel_ulong_t)&ad7690_chip_info },
1201 	{ "ad7691", (kernel_ulong_t)&ad7691_chip_info },
1202 	{ "ad7693", (kernel_ulong_t)&ad7693_chip_info },
1203 	{ "ad7942", (kernel_ulong_t)&ad7942_chip_info },
1204 	{ "ad7946", (kernel_ulong_t)&ad7946_chip_info },
1205 	{ "ad7980", (kernel_ulong_t)&ad7980_chip_info },
1206 	{ "ad7982", (kernel_ulong_t)&ad7982_chip_info },
1207 	{ "ad7983", (kernel_ulong_t)&ad7983_chip_info },
1208 	{ "ad7984", (kernel_ulong_t)&ad7984_chip_info },
1209 	{ "ad7988-1", (kernel_ulong_t)&ad7988_1_chip_info },
1210 	{ "ad7988-5", (kernel_ulong_t)&ad7988_5_chip_info },
1211 	{ }
1212 };
1213 MODULE_DEVICE_TABLE(spi, ad4000_id);
1214 
1215 static const struct of_device_id ad4000_of_match[] = {
1216 	{ .compatible = "adi,ad4000", .data = &ad4000_chip_info },
1217 	{ .compatible = "adi,ad4001", .data = &ad4001_chip_info },
1218 	{ .compatible = "adi,ad4002", .data = &ad4002_chip_info },
1219 	{ .compatible = "adi,ad4003", .data = &ad4003_chip_info },
1220 	{ .compatible = "adi,ad4004", .data = &ad4004_chip_info },
1221 	{ .compatible = "adi,ad4005", .data = &ad4005_chip_info },
1222 	{ .compatible = "adi,ad4006", .data = &ad4006_chip_info },
1223 	{ .compatible = "adi,ad4007", .data = &ad4007_chip_info },
1224 	{ .compatible = "adi,ad4008", .data = &ad4008_chip_info },
1225 	{ .compatible = "adi,ad4010", .data = &ad4010_chip_info },
1226 	{ .compatible = "adi,ad4011", .data = &ad4011_chip_info },
1227 	{ .compatible = "adi,ad4020", .data = &ad4020_chip_info },
1228 	{ .compatible = "adi,ad4021", .data = &ad4021_chip_info },
1229 	{ .compatible = "adi,ad4022", .data = &ad4022_chip_info },
1230 	{ .compatible = "adi,adaq4001", .data = &adaq4001_chip_info },
1231 	{ .compatible = "adi,adaq4003", .data = &adaq4003_chip_info },
1232 	{ .compatible = "adi,ad7685", .data = &ad7685_chip_info },
1233 	{ .compatible = "adi,ad7686", .data = &ad7686_chip_info },
1234 	{ .compatible = "adi,ad7687", .data = &ad7687_chip_info },
1235 	{ .compatible = "adi,ad7688", .data = &ad7688_chip_info },
1236 	{ .compatible = "adi,ad7690", .data = &ad7690_chip_info },
1237 	{ .compatible = "adi,ad7691", .data = &ad7691_chip_info },
1238 	{ .compatible = "adi,ad7693", .data = &ad7693_chip_info },
1239 	{ .compatible = "adi,ad7942", .data = &ad7942_chip_info },
1240 	{ .compatible = "adi,ad7946", .data = &ad7946_chip_info },
1241 	{ .compatible = "adi,ad7980", .data = &ad7980_chip_info },
1242 	{ .compatible = "adi,ad7982", .data = &ad7982_chip_info },
1243 	{ .compatible = "adi,ad7983", .data = &ad7983_chip_info },
1244 	{ .compatible = "adi,ad7984", .data = &ad7984_chip_info },
1245 	{ .compatible = "adi,ad7988-1", .data = &ad7988_1_chip_info },
1246 	{ .compatible = "adi,ad7988-5", .data = &ad7988_5_chip_info },
1247 	{ }
1248 };
1249 MODULE_DEVICE_TABLE(of, ad4000_of_match);
1250 
1251 static struct spi_driver ad4000_driver = {
1252 	.driver = {
1253 		.name   = "ad4000",
1254 		.of_match_table = ad4000_of_match,
1255 	},
1256 	.probe          = ad4000_probe,
1257 	.id_table       = ad4000_id,
1258 };
1259 module_spi_driver(ad4000_driver);
1260 
1261 MODULE_AUTHOR("Marcelo Schmitt <marcelo.schmitt@analog.com>");
1262 MODULE_DESCRIPTION("Analog Devices AD4000 ADC driver");
1263 MODULE_LICENSE("GPL");
1264 MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER");
1265