GNU Linux-libre 4.9.322-gnu1
[releases.git] / drivers / iio / adc / ad7266.c
1 /*
2  * AD7266/65 SPI ADC driver
3  *
4  * Copyright 2012 Analog Devices Inc.
5  *
6  * Licensed under the GPL-2.
7  */
8
9 #include <linux/device.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/spi/spi.h>
13 #include <linux/regulator/consumer.h>
14 #include <linux/err.h>
15 #include <linux/gpio.h>
16 #include <linux/module.h>
17
18 #include <linux/interrupt.h>
19
20 #include <linux/iio/iio.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/iio/trigger_consumer.h>
23 #include <linux/iio/triggered_buffer.h>
24
25 #include <linux/platform_data/ad7266.h>
26
27 struct ad7266_state {
28         struct spi_device       *spi;
29         struct regulator        *reg;
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             gpios[3];
39
40         /*
41          * DMA (thus cache coherency maintenance) requires 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                 s64 timestamp;
49         } data ____cacheline_aligned;
50 };
51
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
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
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
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         .postenable = &iio_triggered_buffer_postenable,
79         .predisable = &iio_triggered_buffer_predisable,
80         .postdisable = &ad7266_postdisable,
81 };
82
83 static irqreturn_t ad7266_trigger_handler(int irq, void *p)
84 {
85         struct iio_poll_func *pf = p;
86         struct iio_dev *indio_dev = pf->indio_dev;
87         struct ad7266_state *st = iio_priv(indio_dev);
88         int ret;
89
90         ret = spi_read(st->spi, st->data.sample, 4);
91         if (ret == 0) {
92                 iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
93                             pf->timestamp);
94         }
95
96         iio_trigger_notify_done(indio_dev->trig);
97
98         return IRQ_HANDLED;
99 }
100
101 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
102 {
103         unsigned int i;
104
105         if (st->fixed_addr)
106                 return;
107
108         switch (st->mode) {
109         case AD7266_MODE_SINGLE_ENDED:
110                 nr >>= 1;
111                 break;
112         case AD7266_MODE_PSEUDO_DIFF:
113                 nr |= 1;
114                 break;
115         case AD7266_MODE_DIFF:
116                 nr &= ~1;
117                 break;
118         }
119
120         for (i = 0; i < 3; ++i)
121                 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
122 }
123
124 static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
125         const unsigned long *scan_mask)
126 {
127         struct ad7266_state *st = iio_priv(indio_dev);
128         unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);
129
130         ad7266_select_input(st, nr);
131
132         return 0;
133 }
134
135 static int ad7266_read_single(struct ad7266_state *st, int *val,
136         unsigned int address)
137 {
138         int ret;
139
140         ad7266_select_input(st, address);
141
142         ret = spi_sync(st->spi, &st->single_msg);
143         *val = be16_to_cpu(st->data.sample[address % 2]);
144
145         return ret;
146 }
147
148 static int ad7266_read_raw(struct iio_dev *indio_dev,
149         struct iio_chan_spec const *chan, int *val, int *val2, long m)
150 {
151         struct ad7266_state *st = iio_priv(indio_dev);
152         unsigned long scale_mv;
153         int ret;
154
155         switch (m) {
156         case IIO_CHAN_INFO_RAW:
157                 ret = iio_device_claim_direct_mode(indio_dev);
158                 if (ret)
159                         return ret;
160                 ret = ad7266_read_single(st, val, chan->address);
161                 iio_device_release_direct_mode(indio_dev);
162
163                 *val = (*val >> 2) & 0xfff;
164                 if (chan->scan_type.sign == 's')
165                         *val = sign_extend32(*val, 11);
166
167                 return IIO_VAL_INT;
168         case IIO_CHAN_INFO_SCALE:
169                 scale_mv = st->vref_mv;
170                 if (st->mode == AD7266_MODE_DIFF)
171                         scale_mv *= 2;
172                 if (st->range == AD7266_RANGE_2VREF)
173                         scale_mv *= 2;
174
175                 *val = scale_mv;
176                 *val2 = chan->scan_type.realbits;
177                 return IIO_VAL_FRACTIONAL_LOG2;
178         case IIO_CHAN_INFO_OFFSET:
179                 if (st->range == AD7266_RANGE_2VREF &&
180                         st->mode != AD7266_MODE_DIFF)
181                         *val = 2048;
182                 else
183                         *val = 0;
184                 return IIO_VAL_INT;
185         }
186         return -EINVAL;
187 }
188
189 #define AD7266_CHAN(_chan, _sign) {                     \
190         .type = IIO_VOLTAGE,                            \
191         .indexed = 1,                                   \
192         .channel = (_chan),                             \
193         .address = (_chan),                             \
194         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
195         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
196                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
197         .scan_index = (_chan),                          \
198         .scan_type = {                                  \
199                 .sign = (_sign),                        \
200                 .realbits = 12,                         \
201                 .storagebits = 16,                      \
202                 .shift = 2,                             \
203                 .endianness = IIO_BE,                   \
204         },                                              \
205 }
206
207 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
208 const struct iio_chan_spec ad7266_channels_##_name[] = { \
209         AD7266_CHAN(0, (_sign)), \
210         AD7266_CHAN(1, (_sign)), \
211         AD7266_CHAN(2, (_sign)), \
212         AD7266_CHAN(3, (_sign)), \
213         AD7266_CHAN(4, (_sign)), \
214         AD7266_CHAN(5, (_sign)), \
215         AD7266_CHAN(6, (_sign)), \
216         AD7266_CHAN(7, (_sign)), \
217         AD7266_CHAN(8, (_sign)), \
218         AD7266_CHAN(9, (_sign)), \
219         AD7266_CHAN(10, (_sign)), \
220         AD7266_CHAN(11, (_sign)), \
221         IIO_CHAN_SOFT_TIMESTAMP(13), \
222 }
223
224 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
225 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
226         AD7266_CHAN(0, (_sign)), \
227         AD7266_CHAN(1, (_sign)), \
228         IIO_CHAN_SOFT_TIMESTAMP(2), \
229 }
230
231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
234 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');
235
236 #define AD7266_CHAN_DIFF(_chan, _sign) {                        \
237         .type = IIO_VOLTAGE,                            \
238         .indexed = 1,                                   \
239         .channel = (_chan) * 2,                         \
240         .channel2 = (_chan) * 2 + 1,                    \
241         .address = (_chan),                             \
242         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
243         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE)    \
244                 | BIT(IIO_CHAN_INFO_OFFSET),                    \
245         .scan_index = (_chan),                          \
246         .scan_type = {                                  \
247                 .sign = _sign,                  \
248                 .realbits = 12,                         \
249                 .storagebits = 16,                      \
250                 .shift = 2,                             \
251                 .endianness = IIO_BE,                   \
252         },                                              \
253         .differential = 1,                              \
254 }
255
256 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
257 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
258         AD7266_CHAN_DIFF(0, (_sign)), \
259         AD7266_CHAN_DIFF(1, (_sign)), \
260         AD7266_CHAN_DIFF(2, (_sign)), \
261         AD7266_CHAN_DIFF(3, (_sign)), \
262         AD7266_CHAN_DIFF(4, (_sign)), \
263         AD7266_CHAN_DIFF(5, (_sign)), \
264         IIO_CHAN_SOFT_TIMESTAMP(6), \
265 }
266
267 static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
268 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');
269
270 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
271 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
272         AD7266_CHAN_DIFF(0, (_sign)), \
273         AD7266_CHAN_DIFF(1, (_sign)), \
274         IIO_CHAN_SOFT_TIMESTAMP(2), \
275 }
276
277 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
278 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');
279
280 static const struct iio_info ad7266_info = {
281         .read_raw = &ad7266_read_raw,
282         .update_scan_mode = &ad7266_update_scan_mode,
283         .driver_module = THIS_MODULE,
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
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         indio_dev->masklength = chan_info->num_channels - 1;
378 }
379
380 static const char * const ad7266_gpio_labels[] = {
381         "AD0", "AD1", "AD2",
382 };
383
384 static int ad7266_probe(struct spi_device *spi)
385 {
386         struct ad7266_platform_data *pdata = spi->dev.platform_data;
387         struct iio_dev *indio_dev;
388         struct ad7266_state *st;
389         unsigned int i;
390         int ret;
391
392         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
393         if (indio_dev == NULL)
394                 return -ENOMEM;
395
396         st = iio_priv(indio_dev);
397
398         st->reg = devm_regulator_get_optional(&spi->dev, "vref");
399         if (!IS_ERR(st->reg)) {
400                 ret = regulator_enable(st->reg);
401                 if (ret)
402                         return ret;
403
404                 ret = regulator_get_voltage(st->reg);
405                 if (ret < 0)
406                         goto error_disable_reg;
407
408                 st->vref_mv = ret / 1000;
409         } else {
410                 /* Any other error indicates that the regulator does exist */
411                 if (PTR_ERR(st->reg) != -ENODEV)
412                         return PTR_ERR(st->reg);
413                 /* Use internal reference */
414                 st->vref_mv = 2500;
415         }
416
417         if (pdata) {
418                 st->fixed_addr = pdata->fixed_addr;
419                 st->mode = pdata->mode;
420                 st->range = pdata->range;
421
422                 if (!st->fixed_addr) {
423                         for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
424                                 st->gpios[i].gpio = pdata->addr_gpios[i];
425                                 st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
426                                 st->gpios[i].label = ad7266_gpio_labels[i];
427                         }
428                         ret = gpio_request_array(st->gpios,
429                                 ARRAY_SIZE(st->gpios));
430                         if (ret)
431                                 goto error_disable_reg;
432                 }
433         } else {
434                 st->fixed_addr = true;
435                 st->range = AD7266_RANGE_VREF;
436                 st->mode = AD7266_MODE_DIFF;
437         }
438
439         spi_set_drvdata(spi, indio_dev);
440         st->spi = spi;
441
442         indio_dev->dev.parent = &spi->dev;
443         indio_dev->dev.of_node = spi->dev.of_node;
444         indio_dev->name = spi_get_device_id(spi)->name;
445         indio_dev->modes = INDIO_DIRECT_MODE;
446         indio_dev->info = &ad7266_info;
447
448         ad7266_init_channels(indio_dev);
449
450         /* wakeup */
451         st->single_xfer[0].rx_buf = &st->data.sample[0];
452         st->single_xfer[0].len = 2;
453         st->single_xfer[0].cs_change = 1;
454         /* conversion */
455         st->single_xfer[1].rx_buf = st->data.sample;
456         st->single_xfer[1].len = 4;
457         st->single_xfer[1].cs_change = 1;
458         /* powerdown */
459         st->single_xfer[2].tx_buf = &st->data.sample[0];
460         st->single_xfer[2].len = 1;
461
462         spi_message_init(&st->single_msg);
463         spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
464         spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
465         spi_message_add_tail(&st->single_xfer[2], &st->single_msg);
466
467         ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
468                 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
469         if (ret)
470                 goto error_free_gpios;
471
472         ret = iio_device_register(indio_dev);
473         if (ret)
474                 goto error_buffer_cleanup;
475
476         return 0;
477
478 error_buffer_cleanup:
479         iio_triggered_buffer_cleanup(indio_dev);
480 error_free_gpios:
481         if (!st->fixed_addr)
482                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
483 error_disable_reg:
484         if (!IS_ERR(st->reg))
485                 regulator_disable(st->reg);
486
487         return ret;
488 }
489
490 static int ad7266_remove(struct spi_device *spi)
491 {
492         struct iio_dev *indio_dev = spi_get_drvdata(spi);
493         struct ad7266_state *st = iio_priv(indio_dev);
494
495         iio_device_unregister(indio_dev);
496         iio_triggered_buffer_cleanup(indio_dev);
497         if (!st->fixed_addr)
498                 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
499         if (!IS_ERR(st->reg))
500                 regulator_disable(st->reg);
501
502         return 0;
503 }
504
505 static const struct spi_device_id ad7266_id[] = {
506         {"ad7265", 0},
507         {"ad7266", 0},
508         { }
509 };
510 MODULE_DEVICE_TABLE(spi, ad7266_id);
511
512 static struct spi_driver ad7266_driver = {
513         .driver = {
514                 .name   = "ad7266",
515         },
516         .probe          = ad7266_probe,
517         .remove         = ad7266_remove,
518         .id_table       = ad7266_id,
519 };
520 module_spi_driver(ad7266_driver);
521
522 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
523 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
524 MODULE_LICENSE("GPL v2");