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5691b234 LPC |
1 | /* |
2 | * AD5421 Digital to analog converters driver | |
3 | * | |
4 | * Copyright 2011 Analog Devices Inc. | |
5 | * | |
6 | * Licensed under the GPL-2. | |
7 | */ | |
8 | ||
9 | #include <linux/device.h> | |
10 | #include <linux/delay.h> | |
11 | #include <linux/err.h> | |
12 | #include <linux/module.h> | |
13 | #include <linux/interrupt.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/spi/spi.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/sysfs.h> | |
18 | ||
06458e27 JC |
19 | #include <linux/iio/iio.h> |
20 | #include <linux/iio/sysfs.h> | |
21 | #include <linux/iio/events.h> | |
dbdc025b | 22 | #include <linux/iio/dac/ad5421.h> |
5691b234 LPC |
23 | |
24 | ||
25 | #define AD5421_REG_DAC_DATA 0x1 | |
26 | #define AD5421_REG_CTRL 0x2 | |
27 | #define AD5421_REG_OFFSET 0x3 | |
28 | #define AD5421_REG_GAIN 0x4 | |
29 | /* load dac and fault shared the same register number. Writing to it will cause | |
30 | * a dac load command, reading from it will return the fault status register */ | |
31 | #define AD5421_REG_LOAD_DAC 0x5 | |
32 | #define AD5421_REG_FAULT 0x5 | |
33 | #define AD5421_REG_FORCE_ALARM_CURRENT 0x6 | |
34 | #define AD5421_REG_RESET 0x7 | |
35 | #define AD5421_REG_START_CONVERSION 0x8 | |
36 | #define AD5421_REG_NOOP 0x9 | |
37 | ||
38 | #define AD5421_CTRL_WATCHDOG_DISABLE BIT(12) | |
39 | #define AD5421_CTRL_AUTO_FAULT_READBACK BIT(11) | |
40 | #define AD5421_CTRL_MIN_CURRENT BIT(9) | |
41 | #define AD5421_CTRL_ADC_SOURCE_TEMP BIT(8) | |
42 | #define AD5421_CTRL_ADC_ENABLE BIT(7) | |
43 | #define AD5421_CTRL_PWR_DOWN_INT_VREF BIT(6) | |
44 | ||
45 | #define AD5421_FAULT_SPI BIT(15) | |
46 | #define AD5421_FAULT_PEC BIT(14) | |
47 | #define AD5421_FAULT_OVER_CURRENT BIT(13) | |
48 | #define AD5421_FAULT_UNDER_CURRENT BIT(12) | |
49 | #define AD5421_FAULT_TEMP_OVER_140 BIT(11) | |
50 | #define AD5421_FAULT_TEMP_OVER_100 BIT(10) | |
51 | #define AD5421_FAULT_UNDER_VOLTAGE_6V BIT(9) | |
52 | #define AD5421_FAULT_UNDER_VOLTAGE_12V BIT(8) | |
53 | ||
54 | /* These bits will cause the fault pin to go high */ | |
55 | #define AD5421_FAULT_TRIGGER_IRQ \ | |
56 | (AD5421_FAULT_SPI | AD5421_FAULT_PEC | AD5421_FAULT_OVER_CURRENT | \ | |
57 | AD5421_FAULT_UNDER_CURRENT | AD5421_FAULT_TEMP_OVER_140) | |
58 | ||
59 | /** | |
60 | * struct ad5421_state - driver instance specific data | |
61 | * @spi: spi_device | |
62 | * @ctrl: control register cache | |
63 | * @current_range: current range which the device is configured for | |
64 | * @data: spi transfer buffers | |
65 | * @fault_mask: software masking of events | |
66 | */ | |
67 | struct ad5421_state { | |
68 | struct spi_device *spi; | |
69 | unsigned int ctrl; | |
70 | enum ad5421_current_range current_range; | |
71 | unsigned int fault_mask; | |
72 | ||
73 | /* | |
74 | * DMA (thus cache coherency maintenance) requires the | |
75 | * transfer buffers to live in their own cache lines. | |
76 | */ | |
77 | union { | |
78 | u32 d32; | |
79 | u8 d8[4]; | |
80 | } data[2] ____cacheline_aligned; | |
81 | }; | |
82 | ||
83 | static const struct iio_chan_spec ad5421_channels[] = { | |
84 | { | |
85 | .type = IIO_CURRENT, | |
86 | .indexed = 1, | |
87 | .output = 1, | |
88 | .channel = 0, | |
31311c2a JC |
89 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | |
90 | BIT(IIO_CHAN_INFO_CALIBSCALE) | | |
91 | BIT(IIO_CHAN_INFO_CALIBBIAS), | |
92 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | | |
93 | BIT(IIO_CHAN_INFO_OFFSET), | |
5691b234 LPC |
94 | .scan_type = IIO_ST('u', 16, 16, 0), |
95 | .event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING) | | |
96 | IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_FALLING), | |
97 | }, | |
98 | { | |
99 | .type = IIO_TEMP, | |
100 | .channel = -1, | |
101 | .event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, IIO_EV_DIR_RISING), | |
102 | }, | |
103 | }; | |
104 | ||
105 | static int ad5421_write_unlocked(struct iio_dev *indio_dev, | |
106 | unsigned int reg, unsigned int val) | |
107 | { | |
108 | struct ad5421_state *st = iio_priv(indio_dev); | |
109 | ||
110 | st->data[0].d32 = cpu_to_be32((reg << 16) | val); | |
111 | ||
112 | return spi_write(st->spi, &st->data[0].d8[1], 3); | |
113 | } | |
114 | ||
115 | static int ad5421_write(struct iio_dev *indio_dev, unsigned int reg, | |
116 | unsigned int val) | |
117 | { | |
118 | int ret; | |
119 | ||
120 | mutex_lock(&indio_dev->mlock); | |
121 | ret = ad5421_write_unlocked(indio_dev, reg, val); | |
122 | mutex_unlock(&indio_dev->mlock); | |
123 | ||
124 | return ret; | |
125 | } | |
126 | ||
127 | static int ad5421_read(struct iio_dev *indio_dev, unsigned int reg) | |
128 | { | |
129 | struct ad5421_state *st = iio_priv(indio_dev); | |
5691b234 LPC |
130 | int ret; |
131 | struct spi_transfer t[] = { | |
132 | { | |
133 | .tx_buf = &st->data[0].d8[1], | |
134 | .len = 3, | |
135 | .cs_change = 1, | |
136 | }, { | |
137 | .rx_buf = &st->data[1].d8[1], | |
138 | .len = 3, | |
139 | }, | |
140 | }; | |
141 | ||
5691b234 LPC |
142 | mutex_lock(&indio_dev->mlock); |
143 | ||
144 | st->data[0].d32 = cpu_to_be32((1 << 23) | (reg << 16)); | |
145 | ||
14543a00 | 146 | ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t)); |
5691b234 LPC |
147 | if (ret >= 0) |
148 | ret = be32_to_cpu(st->data[1].d32) & 0xffff; | |
149 | ||
150 | mutex_unlock(&indio_dev->mlock); | |
151 | ||
152 | return ret; | |
153 | } | |
154 | ||
155 | static int ad5421_update_ctrl(struct iio_dev *indio_dev, unsigned int set, | |
156 | unsigned int clr) | |
157 | { | |
158 | struct ad5421_state *st = iio_priv(indio_dev); | |
159 | unsigned int ret; | |
160 | ||
161 | mutex_lock(&indio_dev->mlock); | |
162 | ||
163 | st->ctrl &= ~clr; | |
164 | st->ctrl |= set; | |
165 | ||
166 | ret = ad5421_write_unlocked(indio_dev, AD5421_REG_CTRL, st->ctrl); | |
167 | ||
168 | mutex_unlock(&indio_dev->mlock); | |
169 | ||
170 | return ret; | |
171 | } | |
172 | ||
173 | static irqreturn_t ad5421_fault_handler(int irq, void *data) | |
174 | { | |
175 | struct iio_dev *indio_dev = data; | |
176 | struct ad5421_state *st = iio_priv(indio_dev); | |
177 | unsigned int fault; | |
178 | unsigned int old_fault = 0; | |
179 | unsigned int events; | |
180 | ||
181 | fault = ad5421_read(indio_dev, AD5421_REG_FAULT); | |
182 | if (!fault) | |
183 | return IRQ_NONE; | |
184 | ||
185 | /* If we had a fault, this might mean that the DAC has lost its state | |
186 | * and has been reset. Make sure that the control register actually | |
187 | * contains what we expect it to contain. Otherwise the watchdog might | |
188 | * be enabled and we get watchdog timeout faults, which will render the | |
189 | * DAC unusable. */ | |
190 | ad5421_update_ctrl(indio_dev, 0, 0); | |
191 | ||
192 | ||
193 | /* The fault pin stays high as long as a fault condition is present and | |
194 | * it is not possible to mask fault conditions. For certain fault | |
195 | * conditions for example like over-temperature it takes some time | |
196 | * until the fault condition disappears. If we would exit the interrupt | |
197 | * handler immediately after handling the event it would be entered | |
198 | * again instantly. Thus we fall back to polling in case we detect that | |
199 | * a interrupt condition is still present. | |
200 | */ | |
201 | do { | |
202 | /* 0xffff is a invalid value for the register and will only be | |
203 | * read if there has been a communication error */ | |
204 | if (fault == 0xffff) | |
205 | fault = 0; | |
206 | ||
207 | /* we are only interested in new events */ | |
208 | events = (old_fault ^ fault) & fault; | |
209 | events &= st->fault_mask; | |
210 | ||
211 | if (events & AD5421_FAULT_OVER_CURRENT) { | |
212 | iio_push_event(indio_dev, | |
213 | IIO_UNMOD_EVENT_CODE(IIO_CURRENT, | |
214 | 0, | |
215 | IIO_EV_TYPE_THRESH, | |
216 | IIO_EV_DIR_RISING), | |
217 | iio_get_time_ns()); | |
218 | } | |
219 | ||
220 | if (events & AD5421_FAULT_UNDER_CURRENT) { | |
221 | iio_push_event(indio_dev, | |
222 | IIO_UNMOD_EVENT_CODE(IIO_CURRENT, | |
223 | 0, | |
224 | IIO_EV_TYPE_THRESH, | |
225 | IIO_EV_DIR_FALLING), | |
226 | iio_get_time_ns()); | |
227 | } | |
228 | ||
229 | if (events & AD5421_FAULT_TEMP_OVER_140) { | |
230 | iio_push_event(indio_dev, | |
231 | IIO_UNMOD_EVENT_CODE(IIO_TEMP, | |
232 | 0, | |
233 | IIO_EV_TYPE_MAG, | |
234 | IIO_EV_DIR_RISING), | |
235 | iio_get_time_ns()); | |
236 | } | |
237 | ||
238 | old_fault = fault; | |
239 | fault = ad5421_read(indio_dev, AD5421_REG_FAULT); | |
240 | ||
241 | /* still active? go to sleep for some time */ | |
242 | if (fault & AD5421_FAULT_TRIGGER_IRQ) | |
243 | msleep(1000); | |
244 | ||
245 | } while (fault & AD5421_FAULT_TRIGGER_IRQ); | |
246 | ||
247 | ||
248 | return IRQ_HANDLED; | |
249 | } | |
250 | ||
251 | static void ad5421_get_current_min_max(struct ad5421_state *st, | |
252 | unsigned int *min, unsigned int *max) | |
253 | { | |
254 | /* The current range is configured using external pins, which are | |
255 | * usually hard-wired and not run-time switchable. */ | |
256 | switch (st->current_range) { | |
257 | case AD5421_CURRENT_RANGE_4mA_20mA: | |
258 | *min = 4000; | |
259 | *max = 20000; | |
260 | break; | |
261 | case AD5421_CURRENT_RANGE_3mA8_21mA: | |
262 | *min = 3800; | |
263 | *max = 21000; | |
264 | break; | |
265 | case AD5421_CURRENT_RANGE_3mA2_24mA: | |
266 | *min = 3200; | |
267 | *max = 24000; | |
268 | break; | |
269 | default: | |
270 | *min = 0; | |
271 | *max = 1; | |
272 | break; | |
273 | } | |
274 | } | |
275 | ||
276 | static inline unsigned int ad5421_get_offset(struct ad5421_state *st) | |
277 | { | |
278 | unsigned int min, max; | |
279 | ||
280 | ad5421_get_current_min_max(st, &min, &max); | |
281 | return (min * (1 << 16)) / (max - min); | |
282 | } | |
283 | ||
284 | static inline unsigned int ad5421_get_scale(struct ad5421_state *st) | |
285 | { | |
286 | unsigned int min, max; | |
287 | ||
288 | ad5421_get_current_min_max(st, &min, &max); | |
289 | return ((max - min) * 1000) / (1 << 16); | |
290 | } | |
291 | ||
292 | static int ad5421_read_raw(struct iio_dev *indio_dev, | |
293 | struct iio_chan_spec const *chan, int *val, int *val2, long m) | |
294 | { | |
295 | struct ad5421_state *st = iio_priv(indio_dev); | |
296 | int ret; | |
297 | ||
298 | if (chan->type != IIO_CURRENT) | |
299 | return -EINVAL; | |
300 | ||
301 | switch (m) { | |
09f4eb40 | 302 | case IIO_CHAN_INFO_RAW: |
5691b234 LPC |
303 | ret = ad5421_read(indio_dev, AD5421_REG_DAC_DATA); |
304 | if (ret < 0) | |
305 | return ret; | |
306 | *val = ret; | |
307 | return IIO_VAL_INT; | |
308 | case IIO_CHAN_INFO_SCALE: | |
309 | *val = 0; | |
310 | *val2 = ad5421_get_scale(st); | |
311 | return IIO_VAL_INT_PLUS_MICRO; | |
312 | case IIO_CHAN_INFO_OFFSET: | |
313 | *val = ad5421_get_offset(st); | |
314 | return IIO_VAL_INT; | |
315 | case IIO_CHAN_INFO_CALIBBIAS: | |
316 | ret = ad5421_read(indio_dev, AD5421_REG_OFFSET); | |
317 | if (ret < 0) | |
318 | return ret; | |
319 | *val = ret - 32768; | |
320 | return IIO_VAL_INT; | |
321 | case IIO_CHAN_INFO_CALIBSCALE: | |
322 | ret = ad5421_read(indio_dev, AD5421_REG_GAIN); | |
323 | if (ret < 0) | |
324 | return ret; | |
325 | *val = ret; | |
326 | return IIO_VAL_INT; | |
327 | } | |
328 | ||
329 | return -EINVAL; | |
330 | } | |
331 | ||
332 | static int ad5421_write_raw(struct iio_dev *indio_dev, | |
333 | struct iio_chan_spec const *chan, int val, int val2, long mask) | |
334 | { | |
335 | const unsigned int max_val = 1 << 16; | |
336 | ||
337 | switch (mask) { | |
09f4eb40 | 338 | case IIO_CHAN_INFO_RAW: |
5691b234 LPC |
339 | if (val >= max_val || val < 0) |
340 | return -EINVAL; | |
341 | ||
342 | return ad5421_write(indio_dev, AD5421_REG_DAC_DATA, val); | |
343 | case IIO_CHAN_INFO_CALIBBIAS: | |
344 | val += 32768; | |
345 | if (val >= max_val || val < 0) | |
346 | return -EINVAL; | |
347 | ||
348 | return ad5421_write(indio_dev, AD5421_REG_OFFSET, val); | |
349 | case IIO_CHAN_INFO_CALIBSCALE: | |
350 | if (val >= max_val || val < 0) | |
351 | return -EINVAL; | |
352 | ||
353 | return ad5421_write(indio_dev, AD5421_REG_GAIN, val); | |
354 | default: | |
355 | break; | |
356 | } | |
357 | ||
358 | return -EINVAL; | |
359 | } | |
360 | ||
361 | static int ad5421_write_event_config(struct iio_dev *indio_dev, | |
362 | u64 event_code, int state) | |
363 | { | |
364 | struct ad5421_state *st = iio_priv(indio_dev); | |
365 | unsigned int mask; | |
366 | ||
367 | switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { | |
368 | case IIO_CURRENT: | |
369 | if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) == | |
370 | IIO_EV_DIR_RISING) | |
371 | mask = AD5421_FAULT_OVER_CURRENT; | |
372 | else | |
373 | mask = AD5421_FAULT_UNDER_CURRENT; | |
374 | break; | |
375 | case IIO_TEMP: | |
376 | mask = AD5421_FAULT_TEMP_OVER_140; | |
377 | break; | |
378 | default: | |
379 | return -EINVAL; | |
380 | } | |
381 | ||
382 | mutex_lock(&indio_dev->mlock); | |
383 | if (state) | |
384 | st->fault_mask |= mask; | |
385 | else | |
386 | st->fault_mask &= ~mask; | |
387 | mutex_unlock(&indio_dev->mlock); | |
388 | ||
389 | return 0; | |
390 | } | |
391 | ||
392 | static int ad5421_read_event_config(struct iio_dev *indio_dev, | |
393 | u64 event_code) | |
394 | { | |
395 | struct ad5421_state *st = iio_priv(indio_dev); | |
396 | unsigned int mask; | |
397 | ||
398 | switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { | |
399 | case IIO_CURRENT: | |
400 | if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) == | |
401 | IIO_EV_DIR_RISING) | |
402 | mask = AD5421_FAULT_OVER_CURRENT; | |
403 | else | |
404 | mask = AD5421_FAULT_UNDER_CURRENT; | |
405 | break; | |
406 | case IIO_TEMP: | |
407 | mask = AD5421_FAULT_TEMP_OVER_140; | |
408 | break; | |
409 | default: | |
410 | return -EINVAL; | |
411 | } | |
412 | ||
413 | return (bool)(st->fault_mask & mask); | |
414 | } | |
415 | ||
416 | static int ad5421_read_event_value(struct iio_dev *indio_dev, u64 event_code, | |
417 | int *val) | |
418 | { | |
419 | int ret; | |
420 | ||
421 | switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) { | |
422 | case IIO_CURRENT: | |
423 | ret = ad5421_read(indio_dev, AD5421_REG_DAC_DATA); | |
424 | if (ret < 0) | |
425 | return ret; | |
426 | *val = ret; | |
427 | break; | |
428 | case IIO_TEMP: | |
429 | *val = 140000; | |
430 | break; | |
431 | default: | |
432 | return -EINVAL; | |
433 | } | |
434 | ||
435 | return 0; | |
436 | } | |
437 | ||
438 | static const struct iio_info ad5421_info = { | |
439 | .read_raw = ad5421_read_raw, | |
440 | .write_raw = ad5421_write_raw, | |
441 | .read_event_config = ad5421_read_event_config, | |
442 | .write_event_config = ad5421_write_event_config, | |
443 | .read_event_value = ad5421_read_event_value, | |
444 | .driver_module = THIS_MODULE, | |
445 | }; | |
446 | ||
fc52692c | 447 | static int ad5421_probe(struct spi_device *spi) |
5691b234 LPC |
448 | { |
449 | struct ad5421_platform_data *pdata = dev_get_platdata(&spi->dev); | |
450 | struct iio_dev *indio_dev; | |
451 | struct ad5421_state *st; | |
452 | int ret; | |
453 | ||
7cbb7537 | 454 | indio_dev = iio_device_alloc(sizeof(*st)); |
5691b234 LPC |
455 | if (indio_dev == NULL) { |
456 | dev_err(&spi->dev, "Failed to allocate iio device\n"); | |
457 | return -ENOMEM; | |
458 | } | |
459 | ||
460 | st = iio_priv(indio_dev); | |
461 | spi_set_drvdata(spi, indio_dev); | |
462 | ||
463 | st->spi = spi; | |
464 | ||
465 | indio_dev->dev.parent = &spi->dev; | |
466 | indio_dev->name = "ad5421"; | |
467 | indio_dev->info = &ad5421_info; | |
468 | indio_dev->modes = INDIO_DIRECT_MODE; | |
469 | indio_dev->channels = ad5421_channels; | |
470 | indio_dev->num_channels = ARRAY_SIZE(ad5421_channels); | |
471 | ||
472 | st->ctrl = AD5421_CTRL_WATCHDOG_DISABLE | | |
473 | AD5421_CTRL_AUTO_FAULT_READBACK; | |
474 | ||
475 | if (pdata) { | |
476 | st->current_range = pdata->current_range; | |
477 | if (pdata->external_vref) | |
478 | st->ctrl |= AD5421_CTRL_PWR_DOWN_INT_VREF; | |
479 | } else { | |
480 | st->current_range = AD5421_CURRENT_RANGE_4mA_20mA; | |
481 | } | |
482 | ||
483 | /* write initial ctrl register value */ | |
484 | ad5421_update_ctrl(indio_dev, 0, 0); | |
485 | ||
486 | if (spi->irq) { | |
487 | ret = request_threaded_irq(spi->irq, | |
488 | NULL, | |
489 | ad5421_fault_handler, | |
490 | IRQF_TRIGGER_HIGH | IRQF_ONESHOT, | |
491 | "ad5421 fault", | |
492 | indio_dev); | |
493 | if (ret) | |
494 | goto error_free; | |
495 | } | |
496 | ||
497 | ret = iio_device_register(indio_dev); | |
498 | if (ret) { | |
499 | dev_err(&spi->dev, "Failed to register iio device: %d\n", ret); | |
500 | goto error_free_irq; | |
501 | } | |
502 | ||
503 | return 0; | |
504 | ||
505 | error_free_irq: | |
506 | if (spi->irq) | |
507 | free_irq(spi->irq, indio_dev); | |
508 | error_free: | |
7cbb7537 | 509 | iio_device_free(indio_dev); |
5691b234 LPC |
510 | |
511 | return ret; | |
512 | } | |
513 | ||
fc52692c | 514 | static int ad5421_remove(struct spi_device *spi) |
5691b234 LPC |
515 | { |
516 | struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
517 | ||
518 | iio_device_unregister(indio_dev); | |
519 | if (spi->irq) | |
520 | free_irq(spi->irq, indio_dev); | |
7cbb7537 | 521 | iio_device_free(indio_dev); |
5691b234 LPC |
522 | |
523 | return 0; | |
524 | } | |
525 | ||
526 | static struct spi_driver ad5421_driver = { | |
527 | .driver = { | |
528 | .name = "ad5421", | |
529 | .owner = THIS_MODULE, | |
530 | }, | |
531 | .probe = ad5421_probe, | |
fc52692c | 532 | .remove = ad5421_remove, |
5691b234 | 533 | }; |
519ff1d2 | 534 | module_spi_driver(ad5421_driver); |
5691b234 LPC |
535 | |
536 | MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); | |
537 | MODULE_DESCRIPTION("Analog Devices AD5421 DAC"); | |
538 | MODULE_LICENSE("GPL v2"); | |
539 | MODULE_ALIAS("spi:ad5421"); |