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1 | /* |
2 | * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver | |
3 | * | |
4 | * Copyright (c) 2016 Akinobu Mita <akinobu.mita@gmail.com> | |
5 | * | |
6 | * This file is subject to the terms and conditions of version 2 of | |
7 | * the GNU General Public License. See the file COPYING in the main | |
8 | * directory of this archive for more details. | |
9 | * | |
10 | * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/interrupt.h> | |
15 | #include <linux/completion.h> | |
16 | #include <linux/clk.h> | |
17 | #include <linux/spi/spi.h> | |
18 | #include <linux/iio/iio.h> | |
19 | #include <linux/iio/buffer.h> | |
20 | #include <linux/iio/trigger.h> | |
21 | #include <linux/iio/triggered_buffer.h> | |
22 | #include <linux/iio/trigger_consumer.h> | |
23 | #include <linux/regulator/consumer.h> | |
24 | ||
25 | #define ADC12138_MODE_AUTO_CAL 0x08 | |
26 | #define ADC12138_MODE_READ_STATUS 0x0c | |
27 | #define ADC12138_MODE_ACQUISITION_TIME_6 0x0e | |
28 | #define ADC12138_MODE_ACQUISITION_TIME_10 0x4e | |
29 | #define ADC12138_MODE_ACQUISITION_TIME_18 0x8e | |
30 | #define ADC12138_MODE_ACQUISITION_TIME_34 0xce | |
31 | ||
32 | #define ADC12138_STATUS_CAL BIT(6) | |
33 | ||
34 | enum { | |
35 | adc12130, | |
36 | adc12132, | |
37 | adc12138, | |
38 | }; | |
39 | ||
40 | struct adc12138 { | |
41 | struct spi_device *spi; | |
42 | unsigned int id; | |
43 | /* conversion clock */ | |
44 | struct clk *cclk; | |
45 | /* positive analog voltage reference */ | |
46 | struct regulator *vref_p; | |
47 | /* negative analog voltage reference */ | |
48 | struct regulator *vref_n; | |
49 | struct mutex lock; | |
50 | struct completion complete; | |
51 | /* The number of cclk periods for the S/H's acquisition time */ | |
52 | unsigned int acquisition_time; | |
53 | ||
54 | u8 tx_buf[2] ____cacheline_aligned; | |
55 | u8 rx_buf[2]; | |
56 | }; | |
57 | ||
58 | #define ADC12138_VOLTAGE_CHANNEL(chan) \ | |
59 | { \ | |
60 | .type = IIO_VOLTAGE, \ | |
61 | .indexed = 1, \ | |
62 | .channel = chan, \ | |
63 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
64 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ | |
65 | | BIT(IIO_CHAN_INFO_OFFSET), \ | |
66 | .scan_index = chan, \ | |
67 | .scan_type = { \ | |
68 | .sign = 's', \ | |
69 | .realbits = 13, \ | |
70 | .storagebits = 16, \ | |
71 | .shift = 3, \ | |
72 | .endianness = IIO_BE, \ | |
73 | }, \ | |
74 | } | |
75 | ||
76 | #define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \ | |
77 | { \ | |
78 | .type = IIO_VOLTAGE, \ | |
79 | .indexed = 1, \ | |
80 | .channel = (chan1), \ | |
81 | .channel2 = (chan2), \ | |
82 | .differential = 1, \ | |
83 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ | |
84 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ | |
85 | | BIT(IIO_CHAN_INFO_OFFSET), \ | |
86 | .scan_index = si, \ | |
87 | .scan_type = { \ | |
88 | .sign = 's', \ | |
89 | .realbits = 13, \ | |
90 | .storagebits = 16, \ | |
91 | .shift = 3, \ | |
92 | .endianness = IIO_BE, \ | |
93 | }, \ | |
94 | } | |
95 | ||
96 | static const struct iio_chan_spec adc12132_channels[] = { | |
97 | ADC12138_VOLTAGE_CHANNEL(0), | |
98 | ADC12138_VOLTAGE_CHANNEL(1), | |
99 | ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2), | |
100 | ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3), | |
101 | IIO_CHAN_SOFT_TIMESTAMP(4), | |
102 | }; | |
103 | ||
104 | static const struct iio_chan_spec adc12138_channels[] = { | |
105 | ADC12138_VOLTAGE_CHANNEL(0), | |
106 | ADC12138_VOLTAGE_CHANNEL(1), | |
107 | ADC12138_VOLTAGE_CHANNEL(2), | |
108 | ADC12138_VOLTAGE_CHANNEL(3), | |
109 | ADC12138_VOLTAGE_CHANNEL(4), | |
110 | ADC12138_VOLTAGE_CHANNEL(5), | |
111 | ADC12138_VOLTAGE_CHANNEL(6), | |
112 | ADC12138_VOLTAGE_CHANNEL(7), | |
113 | ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8), | |
114 | ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9), | |
115 | ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10), | |
116 | ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11), | |
117 | ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12), | |
118 | ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13), | |
119 | ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14), | |
120 | ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15), | |
121 | IIO_CHAN_SOFT_TIMESTAMP(16), | |
122 | }; | |
123 | ||
124 | static int adc12138_mode_programming(struct adc12138 *adc, u8 mode, | |
125 | void *rx_buf, int len) | |
126 | { | |
127 | struct spi_transfer xfer = { | |
128 | .tx_buf = adc->tx_buf, | |
129 | .rx_buf = adc->rx_buf, | |
130 | .len = len, | |
131 | }; | |
132 | int ret; | |
133 | ||
134 | /* Skip unused bits for ADC12130 and ADC12132 */ | |
135 | if (adc->id != adc12138) | |
136 | mode = (mode & 0xc0) | ((mode & 0x0f) << 2); | |
137 | ||
138 | adc->tx_buf[0] = mode; | |
139 | ||
140 | ret = spi_sync_transfer(adc->spi, &xfer, 1); | |
141 | if (ret) | |
142 | return ret; | |
143 | ||
144 | memcpy(rx_buf, adc->rx_buf, len); | |
145 | ||
146 | return 0; | |
147 | } | |
148 | ||
149 | static int adc12138_read_status(struct adc12138 *adc) | |
150 | { | |
151 | u8 rx_buf[2]; | |
152 | int ret; | |
153 | ||
154 | ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS, | |
155 | rx_buf, 2); | |
156 | if (ret) | |
157 | return ret; | |
158 | ||
159 | return (rx_buf[0] << 1) | (rx_buf[1] >> 7); | |
160 | } | |
161 | ||
162 | static int __adc12138_start_conv(struct adc12138 *adc, | |
163 | struct iio_chan_spec const *channel, | |
164 | void *data, int len) | |
165 | ||
166 | { | |
167 | const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 }; | |
168 | u8 mode = (ch_to_mux[channel->channel] << 4) | | |
169 | (channel->differential ? 0 : 0x80); | |
170 | ||
171 | return adc12138_mode_programming(adc, mode, data, len); | |
172 | } | |
173 | ||
174 | static int adc12138_start_conv(struct adc12138 *adc, | |
175 | struct iio_chan_spec const *channel) | |
176 | { | |
177 | u8 trash; | |
178 | ||
179 | return __adc12138_start_conv(adc, channel, &trash, 1); | |
180 | } | |
181 | ||
182 | static int adc12138_start_and_read_conv(struct adc12138 *adc, | |
183 | struct iio_chan_spec const *channel, | |
184 | __be16 *data) | |
185 | { | |
186 | return __adc12138_start_conv(adc, channel, data, 2); | |
187 | } | |
188 | ||
189 | static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value) | |
190 | { | |
191 | /* Issue a read status instruction and read previous conversion data */ | |
192 | return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS, | |
193 | value, sizeof(*value)); | |
194 | } | |
195 | ||
196 | static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout) | |
197 | { | |
198 | if (!wait_for_completion_timeout(&adc->complete, timeout)) | |
199 | return -ETIMEDOUT; | |
200 | ||
201 | return 0; | |
202 | } | |
203 | ||
204 | static int adc12138_adc_conversion(struct adc12138 *adc, | |
205 | struct iio_chan_spec const *channel, | |
206 | __be16 *value) | |
207 | { | |
208 | int ret; | |
209 | ||
210 | reinit_completion(&adc->complete); | |
211 | ||
212 | ret = adc12138_start_conv(adc, channel); | |
213 | if (ret) | |
214 | return ret; | |
215 | ||
216 | ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100)); | |
217 | if (ret) | |
218 | return ret; | |
219 | ||
220 | return adc12138_read_conv_data(adc, value); | |
221 | } | |
222 | ||
223 | static int adc12138_read_raw(struct iio_dev *iio, | |
224 | struct iio_chan_spec const *channel, int *value, | |
225 | int *shift, long mask) | |
226 | { | |
227 | struct adc12138 *adc = iio_priv(iio); | |
228 | int ret; | |
229 | __be16 data; | |
230 | ||
231 | switch (mask) { | |
232 | case IIO_CHAN_INFO_RAW: | |
233 | mutex_lock(&adc->lock); | |
234 | ret = adc12138_adc_conversion(adc, channel, &data); | |
235 | mutex_unlock(&adc->lock); | |
236 | if (ret) | |
237 | return ret; | |
238 | ||
239 | *value = sign_extend32(be16_to_cpu(data) >> 3, 12); | |
240 | ||
241 | return IIO_VAL_INT; | |
242 | case IIO_CHAN_INFO_SCALE: | |
243 | ret = regulator_get_voltage(adc->vref_p); | |
244 | if (ret < 0) | |
245 | return ret; | |
246 | *value = ret; | |
247 | ||
248 | if (!IS_ERR(adc->vref_n)) { | |
249 | ret = regulator_get_voltage(adc->vref_n); | |
250 | if (ret < 0) | |
251 | return ret; | |
252 | *value -= ret; | |
253 | } | |
254 | ||
255 | /* convert regulator output voltage to mV */ | |
256 | *value /= 1000; | |
257 | *shift = channel->scan_type.realbits - 1; | |
258 | ||
259 | return IIO_VAL_FRACTIONAL_LOG2; | |
260 | case IIO_CHAN_INFO_OFFSET: | |
261 | if (!IS_ERR(adc->vref_n)) { | |
262 | *value = regulator_get_voltage(adc->vref_n); | |
263 | if (*value < 0) | |
264 | return *value; | |
265 | } else { | |
266 | *value = 0; | |
267 | } | |
268 | ||
269 | /* convert regulator output voltage to mV */ | |
270 | *value /= 1000; | |
271 | ||
272 | return IIO_VAL_INT; | |
273 | } | |
274 | ||
275 | return -EINVAL; | |
276 | } | |
277 | ||
278 | static const struct iio_info adc12138_info = { | |
279 | .read_raw = adc12138_read_raw, | |
280 | .driver_module = THIS_MODULE, | |
281 | }; | |
282 | ||
283 | static int adc12138_init(struct adc12138 *adc) | |
284 | { | |
285 | int ret; | |
286 | int status; | |
287 | u8 mode; | |
288 | u8 trash; | |
289 | ||
290 | reinit_completion(&adc->complete); | |
291 | ||
292 | ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1); | |
293 | if (ret) | |
294 | return ret; | |
295 | ||
296 | /* data output at this time has no significance */ | |
297 | status = adc12138_read_status(adc); | |
298 | if (status < 0) | |
299 | return status; | |
300 | ||
301 | adc12138_wait_eoc(adc, msecs_to_jiffies(100)); | |
302 | ||
303 | status = adc12138_read_status(adc); | |
304 | if (status & ADC12138_STATUS_CAL) { | |
305 | dev_warn(&adc->spi->dev, | |
306 | "Auto Cal sequence is still in progress: %#x\n", | |
307 | status); | |
308 | return -EIO; | |
309 | } | |
310 | ||
311 | switch (adc->acquisition_time) { | |
312 | case 6: | |
313 | mode = ADC12138_MODE_ACQUISITION_TIME_6; | |
314 | break; | |
315 | case 10: | |
316 | mode = ADC12138_MODE_ACQUISITION_TIME_10; | |
317 | break; | |
318 | case 18: | |
319 | mode = ADC12138_MODE_ACQUISITION_TIME_18; | |
320 | break; | |
321 | case 34: | |
322 | mode = ADC12138_MODE_ACQUISITION_TIME_34; | |
323 | break; | |
324 | default: | |
325 | return -EINVAL; | |
326 | } | |
327 | ||
328 | return adc12138_mode_programming(adc, mode, &trash, 1); | |
329 | } | |
330 | ||
331 | static irqreturn_t adc12138_trigger_handler(int irq, void *p) | |
332 | { | |
333 | struct iio_poll_func *pf = p; | |
334 | struct iio_dev *indio_dev = pf->indio_dev; | |
335 | struct adc12138 *adc = iio_priv(indio_dev); | |
336 | __be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */ | |
337 | __be16 trash; | |
338 | int ret; | |
339 | int scan_index; | |
340 | int i = 0; | |
341 | ||
342 | mutex_lock(&adc->lock); | |
343 | ||
344 | for_each_set_bit(scan_index, indio_dev->active_scan_mask, | |
345 | indio_dev->masklength) { | |
346 | const struct iio_chan_spec *scan_chan = | |
347 | &indio_dev->channels[scan_index]; | |
348 | ||
349 | reinit_completion(&adc->complete); | |
350 | ||
351 | ret = adc12138_start_and_read_conv(adc, scan_chan, | |
352 | i ? &data[i - 1] : &trash); | |
353 | if (ret) { | |
354 | dev_warn(&adc->spi->dev, | |
355 | "failed to start conversion\n"); | |
356 | goto out; | |
357 | } | |
358 | ||
359 | ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100)); | |
360 | if (ret) { | |
361 | dev_warn(&adc->spi->dev, "wait eoc timeout\n"); | |
362 | goto out; | |
363 | } | |
364 | ||
365 | i++; | |
366 | } | |
367 | ||
368 | if (i) { | |
369 | ret = adc12138_read_conv_data(adc, &data[i - 1]); | |
370 | if (ret) { | |
371 | dev_warn(&adc->spi->dev, | |
372 | "failed to get conversion data\n"); | |
373 | goto out; | |
374 | } | |
375 | } | |
376 | ||
377 | iio_push_to_buffers_with_timestamp(indio_dev, data, | |
378 | iio_get_time_ns(indio_dev)); | |
379 | out: | |
380 | mutex_unlock(&adc->lock); | |
381 | ||
382 | iio_trigger_notify_done(indio_dev->trig); | |
383 | ||
384 | return IRQ_HANDLED; | |
385 | } | |
386 | ||
387 | static irqreturn_t adc12138_eoc_handler(int irq, void *p) | |
388 | { | |
389 | struct iio_dev *indio_dev = p; | |
390 | struct adc12138 *adc = iio_priv(indio_dev); | |
391 | ||
392 | complete(&adc->complete); | |
393 | ||
394 | return IRQ_HANDLED; | |
395 | } | |
396 | ||
397 | static int adc12138_probe(struct spi_device *spi) | |
398 | { | |
399 | struct iio_dev *indio_dev; | |
400 | struct adc12138 *adc; | |
401 | int ret; | |
402 | ||
403 | indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc)); | |
404 | if (!indio_dev) | |
405 | return -ENOMEM; | |
406 | ||
407 | adc = iio_priv(indio_dev); | |
408 | adc->spi = spi; | |
409 | adc->id = spi_get_device_id(spi)->driver_data; | |
410 | mutex_init(&adc->lock); | |
411 | init_completion(&adc->complete); | |
412 | ||
413 | indio_dev->name = spi_get_device_id(spi)->name; | |
414 | indio_dev->dev.parent = &spi->dev; | |
415 | indio_dev->info = &adc12138_info; | |
416 | indio_dev->modes = INDIO_DIRECT_MODE; | |
417 | ||
418 | switch (adc->id) { | |
419 | case adc12130: | |
420 | case adc12132: | |
421 | indio_dev->channels = adc12132_channels; | |
422 | indio_dev->num_channels = ARRAY_SIZE(adc12132_channels); | |
423 | break; | |
424 | case adc12138: | |
425 | indio_dev->channels = adc12138_channels; | |
426 | indio_dev->num_channels = ARRAY_SIZE(adc12138_channels); | |
427 | break; | |
428 | default: | |
429 | return -EINVAL; | |
430 | } | |
431 | ||
432 | ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time", | |
433 | &adc->acquisition_time); | |
434 | if (ret) | |
435 | adc->acquisition_time = 10; | |
436 | ||
437 | adc->cclk = devm_clk_get(&spi->dev, NULL); | |
438 | if (IS_ERR(adc->cclk)) | |
439 | return PTR_ERR(adc->cclk); | |
440 | ||
441 | adc->vref_p = devm_regulator_get(&spi->dev, "vref-p"); | |
442 | if (IS_ERR(adc->vref_p)) | |
443 | return PTR_ERR(adc->vref_p); | |
444 | ||
445 | adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n"); | |
446 | if (IS_ERR(adc->vref_n)) { | |
447 | /* | |
448 | * Assume vref_n is 0V if an optional regulator is not | |
449 | * specified, otherwise return the error code. | |
450 | */ | |
451 | ret = PTR_ERR(adc->vref_n); | |
452 | if (ret != -ENODEV) | |
453 | return ret; | |
454 | } | |
455 | ||
456 | ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler, | |
457 | IRQF_TRIGGER_RISING, indio_dev->name, indio_dev); | |
458 | if (ret) | |
459 | return ret; | |
460 | ||
461 | ret = clk_prepare_enable(adc->cclk); | |
462 | if (ret) | |
463 | return ret; | |
464 | ||
465 | ret = regulator_enable(adc->vref_p); | |
466 | if (ret) | |
467 | goto err_clk_disable; | |
468 | ||
469 | if (!IS_ERR(adc->vref_n)) { | |
470 | ret = regulator_enable(adc->vref_n); | |
471 | if (ret) | |
472 | goto err_vref_p_disable; | |
473 | } | |
474 | ||
475 | ret = adc12138_init(adc); | |
476 | if (ret) | |
477 | goto err_vref_n_disable; | |
478 | ||
479 | spi_set_drvdata(spi, indio_dev); | |
480 | ||
481 | ret = iio_triggered_buffer_setup(indio_dev, NULL, | |
482 | adc12138_trigger_handler, NULL); | |
483 | if (ret) | |
484 | goto err_vref_n_disable; | |
485 | ||
486 | ret = iio_device_register(indio_dev); | |
487 | if (ret) | |
488 | goto err_buffer_cleanup; | |
489 | ||
490 | return 0; | |
491 | err_buffer_cleanup: | |
492 | iio_triggered_buffer_cleanup(indio_dev); | |
493 | err_vref_n_disable: | |
494 | if (!IS_ERR(adc->vref_n)) | |
495 | regulator_disable(adc->vref_n); | |
496 | err_vref_p_disable: | |
497 | regulator_disable(adc->vref_p); | |
498 | err_clk_disable: | |
499 | clk_disable_unprepare(adc->cclk); | |
500 | ||
501 | return ret; | |
502 | } | |
503 | ||
504 | static int adc12138_remove(struct spi_device *spi) | |
505 | { | |
506 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
507 | struct adc12138 *adc = iio_priv(indio_dev); | |
508 | ||
509 | iio_device_unregister(indio_dev); | |
510 | iio_triggered_buffer_cleanup(indio_dev); | |
511 | if (!IS_ERR(adc->vref_n)) | |
512 | regulator_disable(adc->vref_n); | |
513 | regulator_disable(adc->vref_p); | |
514 | clk_disable_unprepare(adc->cclk); | |
515 | ||
516 | return 0; | |
517 | } | |
518 | ||
519 | #ifdef CONFIG_OF | |
520 | ||
521 | static const struct of_device_id adc12138_dt_ids[] = { | |
522 | { .compatible = "ti,adc12130", }, | |
523 | { .compatible = "ti,adc12132", }, | |
524 | { .compatible = "ti,adc12138", }, | |
525 | {} | |
526 | }; | |
527 | MODULE_DEVICE_TABLE(of, adc12138_dt_ids); | |
528 | ||
529 | #endif | |
530 | ||
531 | static const struct spi_device_id adc12138_id[] = { | |
532 | { "adc12130", adc12130 }, | |
533 | { "adc12132", adc12132 }, | |
534 | { "adc12138", adc12138 }, | |
535 | {} | |
536 | }; | |
537 | MODULE_DEVICE_TABLE(spi, adc12138_id); | |
538 | ||
539 | static struct spi_driver adc12138_driver = { | |
540 | .driver = { | |
541 | .name = "adc12138", | |
542 | .of_match_table = of_match_ptr(adc12138_dt_ids), | |
543 | }, | |
544 | .probe = adc12138_probe, | |
545 | .remove = adc12138_remove, | |
546 | .id_table = adc12138_id, | |
547 | }; | |
548 | module_spi_driver(adc12138_driver); | |
549 | ||
550 | MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>"); | |
551 | MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver"); | |
552 | MODULE_LICENSE("GPL v2"); |