1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AD7266/65 SPI ADC driver
4 *
5 * Copyright 2012 Analog Devices Inc.
6 */
7
8 #include <linux/device.h>
9 #include <linux/kernel.h>
10 #include <linux/slab.h>
11 #include <linux/spi/spi.h>
12 #include <linux/regulator/consumer.h>
13 #include <linux/err.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/module.h>
16
17 #include <linux/interrupt.h>
18
19 #include <linux/iio/iio.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include <linux/iio/triggered_buffer.h>
23
24 #include <linux/platform_data/ad7266.h>
25
26 #define AD7266_INTERNAL_REF_MV 2500
27
28 struct ad7266_state {
29 struct spi_device *spi;
30 unsigned long vref_mv;
31
32 struct spi_transfer single_xfer[3];
33 struct spi_message single_msg;
34
35 enum ad7266_range range;
36 enum ad7266_mode mode;
37 bool fixed_addr;
38 struct gpio_desc *gpios[3];
39
40 /*
41 * DMA (thus cache coherency maintenance) may require the
42 * transfer buffers to live in their own cache lines.
43 * The buffer needs to be large enough to hold two samples (4 bytes) and
44 * the naturally aligned timestamp (8 bytes).
45 */
46 struct {
47 __be16 sample[2];
48 aligned_s64 timestamp;
49 } data __aligned(IIO_DMA_MINALIGN);
50 };
51
ad7266_wakeup(struct ad7266_state * st)52 static int ad7266_wakeup(struct ad7266_state *st)
53 {
54 /* Any read with >= 2 bytes will wake the device */
55 return spi_read(st->spi, &st->data.sample[0], 2);
56 }
57
ad7266_powerdown(struct ad7266_state * st)58 static int ad7266_powerdown(struct ad7266_state *st)
59 {
60 /* Any read with < 2 bytes will powerdown the device */
61 return spi_read(st->spi, &st->data.sample[0], 1);
62 }
63
ad7266_preenable(struct iio_dev * indio_dev)64 static int ad7266_preenable(struct iio_dev *indio_dev)
65 {
66 struct ad7266_state *st = iio_priv(indio_dev);
67 return ad7266_wakeup(st);
68 }
69
ad7266_postdisable(struct iio_dev * indio_dev)70 static int ad7266_postdisable(struct iio_dev *indio_dev)
71 {
72 struct ad7266_state *st = iio_priv(indio_dev);
73 return ad7266_powerdown(st);
74 }
75
76 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
77 .preenable = &ad7266_preenable,
78 .postdisable = &ad7266_postdisable,
79 };
80
ad7266_trigger_handler(int irq,void * p)81 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
82 {
83 struct iio_poll_func *pf = p;
84 struct iio_dev *indio_dev = pf->indio_dev;
85 struct ad7266_state *st = iio_priv(indio_dev);
86 int ret;
87
88 ret = spi_read(st->spi, st->data.sample, 4);
89 if (ret == 0) {
90 iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
91 pf->timestamp);
92 }
93
94 iio_trigger_notify_done(indio_dev->trig);
95
96 return IRQ_HANDLED;
97 }
98
ad7266_select_input(struct ad7266_state * st,unsigned int nr)99 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
100 {
101 unsigned int i;
102
103 if (st->fixed_addr)
104 return;
105
106 switch (st->mode) {
107 case AD7266_MODE_SINGLE_ENDED:
108 nr >>= 1;
109 break;
110 case AD7266_MODE_PSEUDO_DIFF:
111 nr |= 1;
112 break;
113 case AD7266_MODE_DIFF:
114 nr &= ~1;
115 break;
116 }
117
118 for (i = 0; i < 3; ++i)
119 gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i)));
120 }
121
ad7266_update_scan_mode(struct iio_dev * indio_dev,const unsigned long * scan_mask)122 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
123 const unsigned long *scan_mask)
124 {
125 struct ad7266_state *st = iio_priv(indio_dev);
126 unsigned int nr = find_first_bit(scan_mask,
127 iio_get_masklength(indio_dev));
128
129 ad7266_select_input(st, nr);
130
131 return 0;
132 }
133
ad7266_read_single(struct ad7266_state * st,int * val,unsigned int address)134 static int ad7266_read_single(struct ad7266_state *st, int *val,
135 unsigned int address)
136 {
137 int ret;
138
139 ad7266_select_input(st, address);
140
141 ret = spi_sync(st->spi, &st->single_msg);
142 *val = be16_to_cpu(st->data.sample[address % 2]);
143
144 return ret;
145 }
146
ad7266_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)147 static int ad7266_read_raw(struct iio_dev *indio_dev,
148 struct iio_chan_spec const *chan, int *val, int *val2, long m)
149 {
150 struct ad7266_state *st = iio_priv(indio_dev);
151 unsigned long scale_mv;
152 int ret;
153
154 switch (m) {
155 case IIO_CHAN_INFO_RAW:
156 if (!iio_device_claim_direct(indio_dev))
157 return -EBUSY;
158 ret = ad7266_read_single(st, val, chan->address);
159 iio_device_release_direct(indio_dev);
160
161 if (ret < 0)
162 return ret;
163 *val = (*val >> 2) & 0xfff;
164 if (chan->scan_type.sign == 's')
165 *val = sign_extend32(*val,
166 chan->scan_type.realbits - 1);
167
168 return IIO_VAL_INT;
169 case IIO_CHAN_INFO_SCALE:
170 scale_mv = st->vref_mv;
171 if (st->mode == AD7266_MODE_DIFF)
172 scale_mv *= 2;
173 if (st->range == AD7266_RANGE_2VREF)
174 scale_mv *= 2;
175
176 *val = scale_mv;
177 *val2 = chan->scan_type.realbits;
178 return IIO_VAL_FRACTIONAL_LOG2;
179 case IIO_CHAN_INFO_OFFSET:
180 if (st->range == AD7266_RANGE_2VREF &&
181 st->mode != AD7266_MODE_DIFF)
182 *val = 2048;
183 else
184 *val = 0;
185 return IIO_VAL_INT;
186 }
187 return -EINVAL;
188 }
189
190 #define AD7266_CHAN(_chan, _sign) { \
191 .type = IIO_VOLTAGE, \
192 .indexed = 1, \
193 .channel = (_chan), \
194 .address = (_chan), \
195 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
196 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
197 | BIT(IIO_CHAN_INFO_OFFSET), \
198 .scan_index = (_chan), \
199 .scan_type = { \
200 .sign = (_sign), \
201 .realbits = 12, \
202 .storagebits = 16, \
203 .shift = 2, \
204 .endianness = IIO_BE, \
205 }, \
206 }
207
208 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
209 const struct iio_chan_spec ad7266_channels_##_name[] = { \
210 AD7266_CHAN(0, (_sign)), \
211 AD7266_CHAN(1, (_sign)), \
212 AD7266_CHAN(2, (_sign)), \
213 AD7266_CHAN(3, (_sign)), \
214 AD7266_CHAN(4, (_sign)), \
215 AD7266_CHAN(5, (_sign)), \
216 AD7266_CHAN(6, (_sign)), \
217 AD7266_CHAN(7, (_sign)), \
218 AD7266_CHAN(8, (_sign)), \
219 AD7266_CHAN(9, (_sign)), \
220 AD7266_CHAN(10, (_sign)), \
221 AD7266_CHAN(11, (_sign)), \
222 IIO_CHAN_SOFT_TIMESTAMP(13), \
223 }
224
225 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
226 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
227 AD7266_CHAN(0, (_sign)), \
228 AD7266_CHAN(1, (_sign)), \
229 IIO_CHAN_SOFT_TIMESTAMP(2), \
230 }
231
232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
234 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
235 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
236
237 #define AD7266_CHAN_DIFF(_chan, _sign) { \
238 .type = IIO_VOLTAGE, \
239 .indexed = 1, \
240 .channel = (_chan) * 2, \
241 .channel2 = (_chan) * 2 + 1, \
242 .address = (_chan), \
243 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
244 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
245 | BIT(IIO_CHAN_INFO_OFFSET), \
246 .scan_index = (_chan), \
247 .scan_type = { \
248 .sign = _sign, \
249 .realbits = 12, \
250 .storagebits = 16, \
251 .shift = 2, \
252 .endianness = IIO_BE, \
253 }, \
254 .differential = 1, \
255 }
256
257 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
258 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
259 AD7266_CHAN_DIFF(0, (_sign)), \
260 AD7266_CHAN_DIFF(1, (_sign)), \
261 AD7266_CHAN_DIFF(2, (_sign)), \
262 AD7266_CHAN_DIFF(3, (_sign)), \
263 AD7266_CHAN_DIFF(4, (_sign)), \
264 AD7266_CHAN_DIFF(5, (_sign)), \
265 IIO_CHAN_SOFT_TIMESTAMP(6), \
266 }
267
268 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
269 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
270
271 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
272 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
273 AD7266_CHAN_DIFF(0, (_sign)), \
274 AD7266_CHAN_DIFF(1, (_sign)), \
275 IIO_CHAN_SOFT_TIMESTAMP(2), \
276 }
277
278 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
279 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
280
281 static const struct iio_info ad7266_info = {
282 .read_raw = &ad7266_read_raw,
283 .update_scan_mode = &ad7266_update_scan_mode,
284 };
285
286 static const unsigned long ad7266_available_scan_masks[] = {
287 0x003,
288 0x00c,
289 0x030,
290 0x0c0,
291 0x300,
292 0xc00,
293 0x000,
294 };
295
296 static const unsigned long ad7266_available_scan_masks_diff[] = {
297 0x003,
298 0x00c,
299 0x030,
300 0x000,
301 };
302
303 static const unsigned long ad7266_available_scan_masks_fixed[] = {
304 0x003,
305 0x000,
306 };
307
308 struct ad7266_chan_info {
309 const struct iio_chan_spec *channels;
310 unsigned int num_channels;
311 const unsigned long *scan_masks;
312 };
313
314 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
315 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))
316
317 static const struct ad7266_chan_info ad7266_chan_infos[] = {
318 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
319 .channels = ad7266_channels_u,
320 .num_channels = ARRAY_SIZE(ad7266_channels_u),
321 .scan_masks = ad7266_available_scan_masks,
322 },
323 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
324 .channels = ad7266_channels_u_fixed,
325 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
326 .scan_masks = ad7266_available_scan_masks_fixed,
327 },
328 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
329 .channels = ad7266_channels_s,
330 .num_channels = ARRAY_SIZE(ad7266_channels_s),
331 .scan_masks = ad7266_available_scan_masks,
332 },
333 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
334 .channels = ad7266_channels_s_fixed,
335 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
336 .scan_masks = ad7266_available_scan_masks_fixed,
337 },
338 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
339 .channels = ad7266_channels_diff_u,
340 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
341 .scan_masks = ad7266_available_scan_masks_diff,
342 },
343 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
344 .channels = ad7266_channels_diff_fixed_u,
345 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
346 .scan_masks = ad7266_available_scan_masks_fixed,
347 },
348 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
349 .channels = ad7266_channels_diff_s,
350 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
351 .scan_masks = ad7266_available_scan_masks_diff,
352 },
353 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
354 .channels = ad7266_channels_diff_fixed_s,
355 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
356 .scan_masks = ad7266_available_scan_masks_fixed,
357 },
358 };
359
ad7266_init_channels(struct iio_dev * indio_dev)360 static void ad7266_init_channels(struct iio_dev *indio_dev)
361 {
362 struct ad7266_state *st = iio_priv(indio_dev);
363 bool is_differential, is_signed;
364 const struct ad7266_chan_info *chan_info;
365 int i;
366
367 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
368 is_signed = (st->range == AD7266_RANGE_2VREF) |
369 (st->mode == AD7266_MODE_DIFF);
370
371 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
372 chan_info = &ad7266_chan_infos[i];
373
374 indio_dev->channels = chan_info->channels;
375 indio_dev->num_channels = chan_info->num_channels;
376 indio_dev->available_scan_masks = chan_info->scan_masks;
377 }
378
379 static const char * const ad7266_gpio_labels[] = {
380 "ad0", "ad1", "ad2",
381 };
382
ad7266_probe(struct spi_device * spi)383 static int ad7266_probe(struct spi_device *spi)
384 {
385 const struct ad7266_platform_data *pdata = dev_get_platdata(&spi->dev);
386 struct iio_dev *indio_dev;
387 struct ad7266_state *st;
388 unsigned int i;
389 int ret;
390
391 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
392 if (indio_dev == NULL)
393 return -ENOMEM;
394
395 st = iio_priv(indio_dev);
396
397 ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
398 if (ret < 0 && ret != -ENODEV)
399 return ret;
400
401 st->vref_mv = ret == -ENODEV ? AD7266_INTERNAL_REF_MV : ret / 1000;
402
403 if (pdata) {
404 st->fixed_addr = pdata->fixed_addr;
405 st->mode = pdata->mode;
406 st->range = pdata->range;
407
408 if (!st->fixed_addr) {
409 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
410 st->gpios[i] = devm_gpiod_get(&spi->dev,
411 ad7266_gpio_labels[i],
412 GPIOD_OUT_LOW);
413 if (IS_ERR(st->gpios[i])) {
414 ret = PTR_ERR(st->gpios[i]);
415 return ret;
416 }
417 }
418 }
419 } else {
420 st->fixed_addr = true;
421 st->range = AD7266_RANGE_VREF;
422 st->mode = AD7266_MODE_DIFF;
423 }
424
425 st->spi = spi;
426
427 indio_dev->name = spi_get_device_id(spi)->name;
428 indio_dev->modes = INDIO_DIRECT_MODE;
429 indio_dev->info = &ad7266_info;
430
431 ad7266_init_channels(indio_dev);
432
433 /* wakeup */
434 st->single_xfer[0].rx_buf = &st->data.sample[0];
435 st->single_xfer[0].len = 2;
436 st->single_xfer[0].cs_change = 1;
437 /* conversion */
438 st->single_xfer[1].rx_buf = st->data.sample;
439 st->single_xfer[1].len = 4;
440 st->single_xfer[1].cs_change = 1;
441 /* powerdown */
442 st->single_xfer[2].tx_buf = &st->data.sample[0];
443 st->single_xfer[2].len = 1;
444
445 spi_message_init(&st->single_msg);
446 spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
447 spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
448 spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
449
450 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, &iio_pollfunc_store_time,
451 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
452 if (ret)
453 return ret;
454
455 return devm_iio_device_register(&spi->dev, indio_dev);
456 }
457
458 static const struct spi_device_id ad7266_id[] = {
459 { "ad7265", 0 },
460 { "ad7266", 0 },
461 { }
462 };
463 MODULE_DEVICE_TABLE(spi, ad7266_id);
464
465 static struct spi_driver ad7266_driver = {
466 .driver = {
467 .name = "ad7266",
468 },
469 .probe = ad7266_probe,
470 .id_table = ad7266_id,
471 };
472 module_spi_driver(ad7266_driver);
473
474 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
475 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
476 MODULE_LICENSE("GPL v2");
477