1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Analog Devices AD7466/7/8 AD7476/5/7/8 (A) SPI ADC driver
4 * TI ADC081S/ADC101S/ADC121S 8/10/12-bit SPI ADC driver
5 *
6 * Copyright 2010 Analog Devices Inc.
7 */
8
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/sysfs.h>
13 #include <linux/spi/spi.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/err.h>
17 #include <linux/module.h>
18 #include <linux/bitops.h>
19 #include <linux/delay.h>
20
21 #include <linux/iio/iio.h>
22 #include <linux/iio/sysfs.h>
23 #include <linux/iio/buffer.h>
24 #include <linux/iio/trigger_consumer.h>
25 #include <linux/iio/triggered_buffer.h>
26
27 struct ad7476_state;
28
29 struct ad7476_chip_info {
30 unsigned int int_vref_uv;
31 struct iio_chan_spec channel[2];
32 /* channels used when convst gpio is defined */
33 struct iio_chan_spec convst_channel[2];
34 void (*reset)(struct ad7476_state *);
35 bool has_vref;
36 bool has_vdrive;
37 };
38
39 struct ad7476_state {
40 struct spi_device *spi;
41 const struct ad7476_chip_info *chip_info;
42 struct regulator *ref_reg;
43 struct gpio_desc *convst_gpio;
44 struct spi_transfer xfer;
45 struct spi_message msg;
46 /*
47 * DMA (thus cache coherency maintenance) may require the
48 * transfer buffers to live in their own cache lines.
49 * Make the buffer large enough for one 16 bit sample and one 64 bit
50 * aligned 64 bit timestamp.
51 */
52 unsigned char data[ALIGN(2, sizeof(s64)) + sizeof(s64)] __aligned(IIO_DMA_MINALIGN);
53 };
54
55 enum ad7476_supported_device_ids {
56 ID_AD7091,
57 ID_AD7091R,
58 ID_AD7273,
59 ID_AD7274,
60 ID_AD7276,
61 ID_AD7277,
62 ID_AD7278,
63 ID_AD7466,
64 ID_AD7467,
65 ID_AD7468,
66 ID_AD7475,
67 ID_AD7495,
68 ID_AD7940,
69 ID_ADC081S,
70 ID_ADC101S,
71 ID_ADC121S,
72 ID_ADS7866,
73 ID_ADS7867,
74 ID_ADS7868,
75 ID_LTC2314_14,
76 };
77
ad7091_convst(struct ad7476_state * st)78 static void ad7091_convst(struct ad7476_state *st)
79 {
80 if (!st->convst_gpio)
81 return;
82
83 gpiod_set_value(st->convst_gpio, 0);
84 udelay(1); /* CONVST pulse width: 10 ns min */
85 gpiod_set_value(st->convst_gpio, 1);
86 udelay(1); /* Conversion time: 650 ns max */
87 }
88
ad7476_trigger_handler(int irq,void * p)89 static irqreturn_t ad7476_trigger_handler(int irq, void *p)
90 {
91 struct iio_poll_func *pf = p;
92 struct iio_dev *indio_dev = pf->indio_dev;
93 struct ad7476_state *st = iio_priv(indio_dev);
94 int b_sent;
95
96 ad7091_convst(st);
97
98 b_sent = spi_sync(st->spi, &st->msg);
99 if (b_sent < 0)
100 goto done;
101
102 iio_push_to_buffers_with_timestamp(indio_dev, st->data,
103 iio_get_time_ns(indio_dev));
104 done:
105 iio_trigger_notify_done(indio_dev->trig);
106
107 return IRQ_HANDLED;
108 }
109
ad7091_reset(struct ad7476_state * st)110 static void ad7091_reset(struct ad7476_state *st)
111 {
112 /* Any transfers with 8 scl cycles will reset the device */
113 spi_read(st->spi, st->data, 1);
114 }
115
ad7476_scan_direct(struct ad7476_state * st)116 static int ad7476_scan_direct(struct ad7476_state *st)
117 {
118 int ret;
119
120 ad7091_convst(st);
121
122 ret = spi_sync(st->spi, &st->msg);
123 if (ret)
124 return ret;
125
126 return be16_to_cpup((__be16 *)st->data);
127 }
128
ad7476_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)129 static int ad7476_read_raw(struct iio_dev *indio_dev,
130 struct iio_chan_spec const *chan,
131 int *val,
132 int *val2,
133 long m)
134 {
135 int ret;
136 struct ad7476_state *st = iio_priv(indio_dev);
137 int scale_uv;
138
139 switch (m) {
140 case IIO_CHAN_INFO_RAW:
141 ret = iio_device_claim_direct_mode(indio_dev);
142 if (ret)
143 return ret;
144 ret = ad7476_scan_direct(st);
145 iio_device_release_direct_mode(indio_dev);
146
147 if (ret < 0)
148 return ret;
149 *val = (ret >> st->chip_info->channel[0].scan_type.shift) &
150 GENMASK(st->chip_info->channel[0].scan_type.realbits - 1, 0);
151 return IIO_VAL_INT;
152 case IIO_CHAN_INFO_SCALE:
153 if (st->ref_reg) {
154 scale_uv = regulator_get_voltage(st->ref_reg);
155 if (scale_uv < 0)
156 return scale_uv;
157 } else {
158 scale_uv = st->chip_info->int_vref_uv;
159 }
160 *val = scale_uv / 1000;
161 *val2 = chan->scan_type.realbits;
162 return IIO_VAL_FRACTIONAL_LOG2;
163 }
164 return -EINVAL;
165 }
166
167 #define _AD7476_CHAN(bits, _shift, _info_mask_sep) \
168 { \
169 .type = IIO_VOLTAGE, \
170 .indexed = 1, \
171 .info_mask_separate = _info_mask_sep, \
172 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
173 .scan_type = { \
174 .sign = 'u', \
175 .realbits = (bits), \
176 .storagebits = 16, \
177 .shift = (_shift), \
178 .endianness = IIO_BE, \
179 }, \
180 }
181
182 #define ADC081S_CHAN(bits) _AD7476_CHAN((bits), 12 - (bits), \
183 BIT(IIO_CHAN_INFO_RAW))
184 #define AD7476_CHAN(bits) _AD7476_CHAN((bits), 13 - (bits), \
185 BIT(IIO_CHAN_INFO_RAW))
186 #define AD7940_CHAN(bits) _AD7476_CHAN((bits), 15 - (bits), \
187 BIT(IIO_CHAN_INFO_RAW))
188 #define AD7091R_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), 0)
189 #define AD7091R_CONVST_CHAN(bits) _AD7476_CHAN((bits), 16 - (bits), \
190 BIT(IIO_CHAN_INFO_RAW))
191 #define ADS786X_CHAN(bits) _AD7476_CHAN((bits), 12 - (bits), \
192 BIT(IIO_CHAN_INFO_RAW))
193
194 static const struct ad7476_chip_info ad7476_chip_info_tbl[] = {
195 [ID_AD7091] = {
196 .channel[0] = AD7091R_CHAN(12),
197 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
198 .convst_channel[0] = AD7091R_CONVST_CHAN(12),
199 .convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
200 .reset = ad7091_reset,
201 },
202 [ID_AD7091R] = {
203 .channel[0] = AD7091R_CHAN(12),
204 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
205 .convst_channel[0] = AD7091R_CONVST_CHAN(12),
206 .convst_channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
207 .int_vref_uv = 2500000,
208 .has_vref = true,
209 .reset = ad7091_reset,
210 },
211 [ID_AD7273] = {
212 .channel[0] = AD7940_CHAN(10),
213 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
214 .has_vref = true,
215 },
216 [ID_AD7274] = {
217 .channel[0] = AD7940_CHAN(12),
218 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
219 .has_vref = true,
220 },
221 [ID_AD7276] = {
222 .channel[0] = AD7940_CHAN(12),
223 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
224 },
225 [ID_AD7277] = {
226 .channel[0] = AD7940_CHAN(10),
227 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
228 },
229 [ID_AD7278] = {
230 .channel[0] = AD7940_CHAN(8),
231 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
232 },
233 [ID_AD7466] = {
234 .channel[0] = AD7476_CHAN(12),
235 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
236 },
237 [ID_AD7467] = {
238 .channel[0] = AD7476_CHAN(10),
239 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
240 },
241 [ID_AD7468] = {
242 .channel[0] = AD7476_CHAN(8),
243 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
244 },
245 [ID_AD7475] = {
246 .channel[0] = AD7476_CHAN(12),
247 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
248 .has_vref = true,
249 .has_vdrive = true,
250 },
251 [ID_AD7495] = {
252 .channel[0] = AD7476_CHAN(12),
253 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
254 .int_vref_uv = 2500000,
255 .has_vdrive = true,
256 },
257 [ID_AD7940] = {
258 .channel[0] = AD7940_CHAN(14),
259 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
260 },
261 [ID_ADC081S] = {
262 .channel[0] = ADC081S_CHAN(8),
263 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
264 },
265 [ID_ADC101S] = {
266 .channel[0] = ADC081S_CHAN(10),
267 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
268 },
269 [ID_ADC121S] = {
270 .channel[0] = ADC081S_CHAN(12),
271 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
272 },
273 [ID_ADS7866] = {
274 .channel[0] = ADS786X_CHAN(12),
275 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
276 },
277 [ID_ADS7867] = {
278 .channel[0] = ADS786X_CHAN(10),
279 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
280 },
281 [ID_ADS7868] = {
282 .channel[0] = ADS786X_CHAN(8),
283 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
284 },
285 [ID_LTC2314_14] = {
286 .channel[0] = AD7940_CHAN(14),
287 .channel[1] = IIO_CHAN_SOFT_TIMESTAMP(1),
288 .has_vref = true,
289 },
290 };
291
292 static const struct iio_info ad7476_info = {
293 .read_raw = &ad7476_read_raw,
294 };
295
ad7476_reg_disable(void * data)296 static void ad7476_reg_disable(void *data)
297 {
298 struct regulator *reg = data;
299
300 regulator_disable(reg);
301 }
302
ad7476_probe(struct spi_device * spi)303 static int ad7476_probe(struct spi_device *spi)
304 {
305 struct ad7476_state *st;
306 struct iio_dev *indio_dev;
307 struct regulator *reg;
308 int ret;
309
310 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
311 if (!indio_dev)
312 return -ENOMEM;
313
314 st = iio_priv(indio_dev);
315 st->chip_info =
316 &ad7476_chip_info_tbl[spi_get_device_id(spi)->driver_data];
317
318 reg = devm_regulator_get(&spi->dev, "vcc");
319 if (IS_ERR(reg))
320 return PTR_ERR(reg);
321
322 ret = regulator_enable(reg);
323 if (ret)
324 return ret;
325
326 ret = devm_add_action_or_reset(&spi->dev, ad7476_reg_disable, reg);
327 if (ret)
328 return ret;
329
330 /* Either vcc or vref (below) as appropriate */
331 if (!st->chip_info->int_vref_uv)
332 st->ref_reg = reg;
333
334 if (st->chip_info->has_vref) {
335
336 /* If a device has an internal reference vref is optional */
337 if (st->chip_info->int_vref_uv) {
338 reg = devm_regulator_get_optional(&spi->dev, "vref");
339 if (IS_ERR(reg) && (PTR_ERR(reg) != -ENODEV))
340 return PTR_ERR(reg);
341 } else {
342 reg = devm_regulator_get(&spi->dev, "vref");
343 if (IS_ERR(reg))
344 return PTR_ERR(reg);
345 }
346
347 if (!IS_ERR(reg)) {
348 ret = regulator_enable(reg);
349 if (ret)
350 return ret;
351
352 ret = devm_add_action_or_reset(&spi->dev,
353 ad7476_reg_disable,
354 reg);
355 if (ret)
356 return ret;
357 st->ref_reg = reg;
358 } else {
359 /*
360 * Can only get here if device supports both internal
361 * and external reference, but the regulator connected
362 * to the external reference is not connected.
363 * Set the reference regulator pointer to NULL to
364 * indicate this.
365 */
366 st->ref_reg = NULL;
367 }
368 }
369
370 if (st->chip_info->has_vdrive) {
371 ret = devm_regulator_get_enable(&spi->dev, "vdrive");
372 if (ret)
373 return ret;
374 }
375
376 st->convst_gpio = devm_gpiod_get_optional(&spi->dev,
377 "adi,conversion-start",
378 GPIOD_OUT_LOW);
379 if (IS_ERR(st->convst_gpio))
380 return PTR_ERR(st->convst_gpio);
381
382 st->spi = spi;
383
384 indio_dev->name = spi_get_device_id(spi)->name;
385 indio_dev->modes = INDIO_DIRECT_MODE;
386 indio_dev->channels = st->chip_info->channel;
387 indio_dev->num_channels = 2;
388 indio_dev->info = &ad7476_info;
389
390 if (st->convst_gpio)
391 indio_dev->channels = st->chip_info->convst_channel;
392 /* Setup default message */
393
394 st->xfer.rx_buf = &st->data;
395 st->xfer.len = st->chip_info->channel[0].scan_type.storagebits / 8;
396
397 spi_message_init(&st->msg);
398 spi_message_add_tail(&st->xfer, &st->msg);
399
400 ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
401 &ad7476_trigger_handler, NULL);
402 if (ret)
403 return ret;
404
405 if (st->chip_info->reset)
406 st->chip_info->reset(st);
407
408 return devm_iio_device_register(&spi->dev, indio_dev);
409 }
410
411 static const struct spi_device_id ad7476_id[] = {
412 {"ad7091", ID_AD7091},
413 {"ad7091r", ID_AD7091R},
414 {"ad7273", ID_AD7273},
415 {"ad7274", ID_AD7274},
416 {"ad7276", ID_AD7276},
417 {"ad7277", ID_AD7277},
418 {"ad7278", ID_AD7278},
419 {"ad7466", ID_AD7466},
420 {"ad7467", ID_AD7467},
421 {"ad7468", ID_AD7468},
422 {"ad7475", ID_AD7475},
423 {"ad7476", ID_AD7466},
424 {"ad7476a", ID_AD7466},
425 {"ad7477", ID_AD7467},
426 {"ad7477a", ID_AD7467},
427 {"ad7478", ID_AD7468},
428 {"ad7478a", ID_AD7468},
429 {"ad7495", ID_AD7495},
430 {"ad7910", ID_AD7467},
431 {"ad7920", ID_AD7466},
432 {"ad7940", ID_AD7940},
433 {"adc081s", ID_ADC081S},
434 {"adc101s", ID_ADC101S},
435 {"adc121s", ID_ADC121S},
436 {"ads7866", ID_ADS7866},
437 {"ads7867", ID_ADS7867},
438 {"ads7868", ID_ADS7868},
439 {"ltc2314-14", ID_LTC2314_14},
440 {}
441 };
442 MODULE_DEVICE_TABLE(spi, ad7476_id);
443
444 static struct spi_driver ad7476_driver = {
445 .driver = {
446 .name = "ad7476",
447 },
448 .probe = ad7476_probe,
449 .id_table = ad7476_id,
450 };
451 module_spi_driver(ad7476_driver);
452
453 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
454 MODULE_DESCRIPTION("Analog Devices AD7476 and similar 1-channel ADCs");
455 MODULE_LICENSE("GPL v2");
456