1 /*
2 * AD7606 SPI ADC driver
3 *
4 * Copyright 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2.
7 */
8
9 #include <linux/interrupt.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/sysfs.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/err.h>
16 #include <linux/gpio/consumer.h>
17 #include <linux/delay.h>
18 #include <linux/sched.h>
19 #include <linux/module.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 #include "ad7606.h"
28
29 /* Scales are computed as 2.5/2**16 and 5/2**16 respectively */
30 static const unsigned int scale_avail[2][2] = {
31 {0, 38147}, {0, 76294}
32 };
33
ad7606_reset(struct ad7606_state * st)34 static int ad7606_reset(struct ad7606_state *st)
35 {
36 if (st->gpio_reset) {
37 gpiod_set_value(st->gpio_reset, 1);
38 ndelay(100); /* t_reset >= 100ns */
39 gpiod_set_value(st->gpio_reset, 0);
40 return 0;
41 }
42
43 return -ENODEV;
44 }
45
ad7606_read_samples(struct ad7606_state * st)46 static int ad7606_read_samples(struct ad7606_state *st)
47 {
48 unsigned int num = st->chip_info->num_channels;
49 u16 *data = st->data;
50 int ret;
51
52 /*
53 * The frstdata signal is set to high while and after reading the sample
54 * of the first channel and low for all other channels. This can be used
55 * to check that the incoming data is correctly aligned. During normal
56 * operation the data should never become unaligned, but some glitch or
57 * electrostatic discharge might cause an extra read or clock cycle.
58 * Monitoring the frstdata signal allows to recover from such failure
59 * situations.
60 */
61
62 if (st->gpio_frstdata) {
63 ret = st->bops->read_block(st->dev, 1, data);
64 if (ret)
65 return ret;
66
67 if (!gpiod_get_value(st->gpio_frstdata)) {
68 ad7606_reset(st);
69 return -EIO;
70 }
71
72 data++;
73 num--;
74 }
75
76 return st->bops->read_block(st->dev, num, data);
77 }
78
ad7606_trigger_handler(int irq,void * p)79 static irqreturn_t ad7606_trigger_handler(int irq, void *p)
80 {
81 struct iio_poll_func *pf = p;
82 struct ad7606_state *st = iio_priv(pf->indio_dev);
83
84 gpiod_set_value(st->gpio_convst, 1);
85
86 return IRQ_HANDLED;
87 }
88
89 /**
90 * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
91 * @work_s: the work struct through which this was scheduled
92 *
93 * Currently there is no option in this driver to disable the saving of
94 * timestamps within the ring.
95 * I think the one copy of this at a time was to avoid problems if the
96 * trigger was set far too high and the reads then locked up the computer.
97 **/
ad7606_poll_bh_to_ring(struct work_struct * work_s)98 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
99 {
100 struct ad7606_state *st = container_of(work_s, struct ad7606_state,
101 poll_work);
102 struct iio_dev *indio_dev = iio_priv_to_dev(st);
103 int ret;
104
105 ret = ad7606_read_samples(st);
106 if (ret == 0)
107 iio_push_to_buffers_with_timestamp(indio_dev, st->data,
108 iio_get_time_ns(indio_dev));
109
110 gpiod_set_value(st->gpio_convst, 0);
111 iio_trigger_notify_done(indio_dev->trig);
112 }
113
ad7606_scan_direct(struct iio_dev * indio_dev,unsigned int ch)114 static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
115 {
116 struct ad7606_state *st = iio_priv(indio_dev);
117 int ret;
118
119 st->done = false;
120 gpiod_set_value(st->gpio_convst, 1);
121
122 ret = wait_event_interruptible(st->wq_data_avail, st->done);
123 if (ret)
124 goto error_ret;
125
126 ret = ad7606_read_samples(st);
127 if (ret == 0)
128 ret = st->data[ch];
129
130 error_ret:
131 gpiod_set_value(st->gpio_convst, 0);
132
133 return ret;
134 }
135
ad7606_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)136 static int ad7606_read_raw(struct iio_dev *indio_dev,
137 struct iio_chan_spec const *chan,
138 int *val,
139 int *val2,
140 long m)
141 {
142 int ret;
143 struct ad7606_state *st = iio_priv(indio_dev);
144
145 switch (m) {
146 case IIO_CHAN_INFO_RAW:
147 ret = iio_device_claim_direct_mode(indio_dev);
148 if (ret)
149 return ret;
150
151 ret = ad7606_scan_direct(indio_dev, chan->address);
152 iio_device_release_direct_mode(indio_dev);
153
154 if (ret < 0)
155 return ret;
156 *val = (short)ret;
157 return IIO_VAL_INT;
158 case IIO_CHAN_INFO_SCALE:
159 *val = scale_avail[st->range][0];
160 *val2 = scale_avail[st->range][1];
161 return IIO_VAL_INT_PLUS_MICRO;
162 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
163 *val = st->oversampling;
164 return IIO_VAL_INT;
165 }
166 return -EINVAL;
167 }
168
in_voltage_scale_available_show(struct device * dev,struct device_attribute * attr,char * buf)169 static ssize_t in_voltage_scale_available_show(struct device *dev,
170 struct device_attribute *attr,
171 char *buf)
172 {
173 int i, len = 0;
174
175 for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
176 len += scnprintf(buf + len, PAGE_SIZE - len, "%d.%06u ",
177 scale_avail[i][0], scale_avail[i][1]);
178
179 buf[len - 1] = '\n';
180
181 return len;
182 }
183
184 static IIO_DEVICE_ATTR_RO(in_voltage_scale_available, 0);
185
ad7606_oversampling_get_index(unsigned int val)186 static int ad7606_oversampling_get_index(unsigned int val)
187 {
188 unsigned char supported[] = {1, 2, 4, 8, 16, 32, 64};
189 int i;
190
191 for (i = 0; i < ARRAY_SIZE(supported); i++)
192 if (val == supported[i])
193 return i;
194
195 return -EINVAL;
196 }
197
ad7606_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)198 static int ad7606_write_raw(struct iio_dev *indio_dev,
199 struct iio_chan_spec const *chan,
200 int val,
201 int val2,
202 long mask)
203 {
204 struct ad7606_state *st = iio_priv(indio_dev);
205 int values[3];
206 int ret, i;
207
208 switch (mask) {
209 case IIO_CHAN_INFO_SCALE:
210 ret = -EINVAL;
211 mutex_lock(&st->lock);
212 for (i = 0; i < ARRAY_SIZE(scale_avail); i++)
213 if (val2 == scale_avail[i][1]) {
214 gpiod_set_value(st->gpio_range, i);
215 st->range = i;
216
217 ret = 0;
218 break;
219 }
220 mutex_unlock(&st->lock);
221
222 return ret;
223 case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
224 if (val2)
225 return -EINVAL;
226 ret = ad7606_oversampling_get_index(val);
227 if (ret < 0)
228 return ret;
229
230 values[0] = (ret >> 0) & 1;
231 values[1] = (ret >> 1) & 1;
232 values[2] = (ret >> 2) & 1;
233
234 mutex_lock(&st->lock);
235 gpiod_set_array_value(ARRAY_SIZE(values), st->gpio_os->desc,
236 values);
237 st->oversampling = val;
238 mutex_unlock(&st->lock);
239
240 return 0;
241 default:
242 return -EINVAL;
243 }
244 }
245
246 static IIO_CONST_ATTR(oversampling_ratio_available, "1 2 4 8 16 32 64");
247
248 static struct attribute *ad7606_attributes_os_and_range[] = {
249 &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
250 &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
251 NULL,
252 };
253
254 static const struct attribute_group ad7606_attribute_group_os_and_range = {
255 .attrs = ad7606_attributes_os_and_range,
256 };
257
258 static struct attribute *ad7606_attributes_os[] = {
259 &iio_const_attr_oversampling_ratio_available.dev_attr.attr,
260 NULL,
261 };
262
263 static const struct attribute_group ad7606_attribute_group_os = {
264 .attrs = ad7606_attributes_os,
265 };
266
267 static struct attribute *ad7606_attributes_range[] = {
268 &iio_dev_attr_in_voltage_scale_available.dev_attr.attr,
269 NULL,
270 };
271
272 static const struct attribute_group ad7606_attribute_group_range = {
273 .attrs = ad7606_attributes_range,
274 };
275
276 #define AD7606_CHANNEL(num) \
277 { \
278 .type = IIO_VOLTAGE, \
279 .indexed = 1, \
280 .channel = num, \
281 .address = num, \
282 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
283 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
284 .info_mask_shared_by_all = \
285 BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
286 .scan_index = num, \
287 .scan_type = { \
288 .sign = 's', \
289 .realbits = 16, \
290 .storagebits = 16, \
291 .endianness = IIO_CPU, \
292 }, \
293 }
294
295 static const struct iio_chan_spec ad7606_channels[] = {
296 IIO_CHAN_SOFT_TIMESTAMP(8),
297 AD7606_CHANNEL(0),
298 AD7606_CHANNEL(1),
299 AD7606_CHANNEL(2),
300 AD7606_CHANNEL(3),
301 AD7606_CHANNEL(4),
302 AD7606_CHANNEL(5),
303 AD7606_CHANNEL(6),
304 AD7606_CHANNEL(7),
305 };
306
307 static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
308 /*
309 * More devices added in future
310 */
311 [ID_AD7606_8] = {
312 .channels = ad7606_channels,
313 .num_channels = 9,
314 },
315 [ID_AD7606_6] = {
316 .channels = ad7606_channels,
317 .num_channels = 7,
318 },
319 [ID_AD7606_4] = {
320 .channels = ad7606_channels,
321 .num_channels = 5,
322 },
323 };
324
ad7606_request_gpios(struct ad7606_state * st)325 static int ad7606_request_gpios(struct ad7606_state *st)
326 {
327 struct device *dev = st->dev;
328
329 st->gpio_convst = devm_gpiod_get(dev, "conversion-start",
330 GPIOD_OUT_LOW);
331 if (IS_ERR(st->gpio_convst))
332 return PTR_ERR(st->gpio_convst);
333
334 st->gpio_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
335 if (IS_ERR(st->gpio_reset))
336 return PTR_ERR(st->gpio_reset);
337
338 st->gpio_range = devm_gpiod_get_optional(dev, "range", GPIOD_OUT_LOW);
339 if (IS_ERR(st->gpio_range))
340 return PTR_ERR(st->gpio_range);
341
342 st->gpio_standby = devm_gpiod_get_optional(dev, "standby",
343 GPIOD_OUT_HIGH);
344 if (IS_ERR(st->gpio_standby))
345 return PTR_ERR(st->gpio_standby);
346
347 st->gpio_frstdata = devm_gpiod_get_optional(dev, "first-data",
348 GPIOD_IN);
349 if (IS_ERR(st->gpio_frstdata))
350 return PTR_ERR(st->gpio_frstdata);
351
352 st->gpio_os = devm_gpiod_get_array_optional(dev, "oversampling-ratio",
353 GPIOD_OUT_LOW);
354 return PTR_ERR_OR_ZERO(st->gpio_os);
355 }
356
357 /**
358 * Interrupt handler
359 */
ad7606_interrupt(int irq,void * dev_id)360 static irqreturn_t ad7606_interrupt(int irq, void *dev_id)
361 {
362 struct iio_dev *indio_dev = dev_id;
363 struct ad7606_state *st = iio_priv(indio_dev);
364
365 if (iio_buffer_enabled(indio_dev)) {
366 schedule_work(&st->poll_work);
367 } else {
368 st->done = true;
369 wake_up_interruptible(&st->wq_data_avail);
370 }
371
372 return IRQ_HANDLED;
373 };
374
375 static const struct iio_info ad7606_info_no_os_or_range = {
376 .read_raw = &ad7606_read_raw,
377 };
378
379 static const struct iio_info ad7606_info_os_and_range = {
380 .read_raw = &ad7606_read_raw,
381 .write_raw = &ad7606_write_raw,
382 .attrs = &ad7606_attribute_group_os_and_range,
383 };
384
385 static const struct iio_info ad7606_info_os = {
386 .read_raw = &ad7606_read_raw,
387 .write_raw = &ad7606_write_raw,
388 .attrs = &ad7606_attribute_group_os,
389 };
390
391 static const struct iio_info ad7606_info_range = {
392 .read_raw = &ad7606_read_raw,
393 .write_raw = &ad7606_write_raw,
394 .attrs = &ad7606_attribute_group_range,
395 };
396
ad7606_probe(struct device * dev,int irq,void __iomem * base_address,const char * name,unsigned int id,const struct ad7606_bus_ops * bops)397 int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
398 const char *name, unsigned int id,
399 const struct ad7606_bus_ops *bops)
400 {
401 struct ad7606_state *st;
402 int ret;
403 struct iio_dev *indio_dev;
404
405 indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
406 if (!indio_dev)
407 return -ENOMEM;
408
409 st = iio_priv(indio_dev);
410
411 st->dev = dev;
412 mutex_init(&st->lock);
413 st->bops = bops;
414 st->base_address = base_address;
415 /* tied to logic low, analog input range is +/- 5V */
416 st->range = 0;
417 st->oversampling = 1;
418 INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
419
420 st->reg = devm_regulator_get(dev, "avcc");
421 if (IS_ERR(st->reg))
422 return PTR_ERR(st->reg);
423
424 ret = regulator_enable(st->reg);
425 if (ret) {
426 dev_err(dev, "Failed to enable specified AVcc supply\n");
427 return ret;
428 }
429
430 ret = ad7606_request_gpios(st);
431 if (ret)
432 goto error_disable_reg;
433
434 st->chip_info = &ad7606_chip_info_tbl[id];
435
436 indio_dev->dev.parent = dev;
437 if (st->gpio_os) {
438 if (st->gpio_range)
439 indio_dev->info = &ad7606_info_os_and_range;
440 else
441 indio_dev->info = &ad7606_info_os;
442 } else {
443 if (st->gpio_range)
444 indio_dev->info = &ad7606_info_range;
445 else
446 indio_dev->info = &ad7606_info_no_os_or_range;
447 }
448 indio_dev->modes = INDIO_DIRECT_MODE;
449 indio_dev->name = name;
450 indio_dev->channels = st->chip_info->channels;
451 indio_dev->num_channels = st->chip_info->num_channels;
452
453 init_waitqueue_head(&st->wq_data_avail);
454
455 ret = ad7606_reset(st);
456 if (ret)
457 dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n");
458
459 ret = request_irq(irq, ad7606_interrupt, IRQF_TRIGGER_FALLING, name,
460 indio_dev);
461 if (ret)
462 goto error_disable_reg;
463
464 ret = iio_triggered_buffer_setup(indio_dev, &ad7606_trigger_handler,
465 NULL, NULL);
466 if (ret)
467 goto error_free_irq;
468
469 ret = iio_device_register(indio_dev);
470 if (ret)
471 goto error_unregister_ring;
472
473 dev_set_drvdata(dev, indio_dev);
474
475 return 0;
476 error_unregister_ring:
477 iio_triggered_buffer_cleanup(indio_dev);
478
479 error_free_irq:
480 free_irq(irq, indio_dev);
481
482 error_disable_reg:
483 regulator_disable(st->reg);
484 return ret;
485 }
486 EXPORT_SYMBOL_GPL(ad7606_probe);
487
ad7606_remove(struct device * dev,int irq)488 int ad7606_remove(struct device *dev, int irq)
489 {
490 struct iio_dev *indio_dev = dev_get_drvdata(dev);
491 struct ad7606_state *st = iio_priv(indio_dev);
492
493 iio_device_unregister(indio_dev);
494 iio_triggered_buffer_cleanup(indio_dev);
495
496 free_irq(irq, indio_dev);
497 regulator_disable(st->reg);
498
499 return 0;
500 }
501 EXPORT_SYMBOL_GPL(ad7606_remove);
502
503 #ifdef CONFIG_PM_SLEEP
504
ad7606_suspend(struct device * dev)505 static int ad7606_suspend(struct device *dev)
506 {
507 struct iio_dev *indio_dev = dev_get_drvdata(dev);
508 struct ad7606_state *st = iio_priv(indio_dev);
509
510 if (st->gpio_standby) {
511 gpiod_set_value(st->gpio_range, 1);
512 gpiod_set_value(st->gpio_standby, 0);
513 }
514
515 return 0;
516 }
517
ad7606_resume(struct device * dev)518 static int ad7606_resume(struct device *dev)
519 {
520 struct iio_dev *indio_dev = dev_get_drvdata(dev);
521 struct ad7606_state *st = iio_priv(indio_dev);
522
523 if (st->gpio_standby) {
524 gpiod_set_value(st->gpio_range, st->range);
525 gpiod_set_value(st->gpio_standby, 1);
526 ad7606_reset(st);
527 }
528
529 return 0;
530 }
531
532 SIMPLE_DEV_PM_OPS(ad7606_pm_ops, ad7606_suspend, ad7606_resume);
533 EXPORT_SYMBOL_GPL(ad7606_pm_ops);
534
535 #endif
536
537 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
538 MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
539 MODULE_LICENSE("GPL v2");
540
