1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AD7298 SPI ADC driver
4 *
5 * Copyright 2011 Analog Devices Inc.
6 */
7
8 #include <linux/device.h>
9 #include <linux/kernel.h>
10 #include <linux/slab.h>
11 #include <linux/sysfs.h>
12 #include <linux/spi/spi.h>
13 #include <linux/regulator/consumer.h>
14 #include <linux/err.h>
15 #include <linux/delay.h>
16 #include <linux/module.h>
17 #include <linux/interrupt.h>
18 #include <linux/bitops.h>
19
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/trigger_consumer.h>
24 #include <linux/iio/triggered_buffer.h>
25
26 #include <linux/platform_data/ad7298.h>
27
28 #define AD7298_WRITE BIT(15) /* write to the control register */
29 #define AD7298_REPEAT BIT(14) /* repeated conversion enable */
30 #define AD7298_CH(x) BIT(13 - (x)) /* channel select */
31 #define AD7298_TSENSE BIT(5) /* temperature conversion enable */
32 #define AD7298_EXTREF BIT(2) /* external reference enable */
33 #define AD7298_TAVG BIT(1) /* temperature sensor averaging enable */
34 #define AD7298_PDD BIT(0) /* partial power down enable */
35
36 #define AD7298_MAX_CHAN 8
37 #define AD7298_INTREF_mV 2500
38
39 #define AD7298_CH_TEMP 9
40
41 struct ad7298_state {
42 struct spi_device *spi;
43 struct regulator *reg;
44 unsigned ext_ref;
45 struct spi_transfer ring_xfer[10];
46 struct spi_transfer scan_single_xfer[3];
47 struct spi_message ring_msg;
48 struct spi_message scan_single_msg;
49 /*
50 * DMA (thus cache coherency maintenance) requires the
51 * transfer buffers to live in their own cache lines.
52 */
53 __be16 rx_buf[12] ____cacheline_aligned;
54 __be16 tx_buf[2];
55 };
56
57 #define AD7298_V_CHAN(index) \
58 { \
59 .type = IIO_VOLTAGE, \
60 .indexed = 1, \
61 .channel = index, \
62 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
63 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
64 .address = index, \
65 .scan_index = index, \
66 .scan_type = { \
67 .sign = 'u', \
68 .realbits = 12, \
69 .storagebits = 16, \
70 .endianness = IIO_BE, \
71 }, \
72 }
73
74 static const struct iio_chan_spec ad7298_channels[] = {
75 {
76 .type = IIO_TEMP,
77 .indexed = 1,
78 .channel = 0,
79 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
80 BIT(IIO_CHAN_INFO_SCALE) |
81 BIT(IIO_CHAN_INFO_OFFSET),
82 .address = AD7298_CH_TEMP,
83 .scan_index = -1,
84 .scan_type = {
85 .sign = 's',
86 .realbits = 32,
87 .storagebits = 32,
88 },
89 },
90 AD7298_V_CHAN(0),
91 AD7298_V_CHAN(1),
92 AD7298_V_CHAN(2),
93 AD7298_V_CHAN(3),
94 AD7298_V_CHAN(4),
95 AD7298_V_CHAN(5),
96 AD7298_V_CHAN(6),
97 AD7298_V_CHAN(7),
98 IIO_CHAN_SOFT_TIMESTAMP(8),
99 };
100
101 /**
102 * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
103 **/
ad7298_update_scan_mode(struct iio_dev * indio_dev,const unsigned long * active_scan_mask)104 static int ad7298_update_scan_mode(struct iio_dev *indio_dev,
105 const unsigned long *active_scan_mask)
106 {
107 struct ad7298_state *st = iio_priv(indio_dev);
108 int i, m;
109 unsigned short command;
110 int scan_count;
111
112 /* Now compute overall size */
113 scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength);
114
115 command = AD7298_WRITE | st->ext_ref;
116
117 for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
118 if (test_bit(i, active_scan_mask))
119 command |= m;
120
121 st->tx_buf[0] = cpu_to_be16(command);
122
123 /* build spi ring message */
124 st->ring_xfer[0].tx_buf = &st->tx_buf[0];
125 st->ring_xfer[0].len = 2;
126 st->ring_xfer[0].cs_change = 1;
127 st->ring_xfer[1].tx_buf = &st->tx_buf[1];
128 st->ring_xfer[1].len = 2;
129 st->ring_xfer[1].cs_change = 1;
130
131 spi_message_init(&st->ring_msg);
132 spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
133 spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
134
135 for (i = 0; i < scan_count; i++) {
136 st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
137 st->ring_xfer[i + 2].len = 2;
138 st->ring_xfer[i + 2].cs_change = 1;
139 spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
140 }
141 /* make sure last transfer cs_change is not set */
142 st->ring_xfer[i + 1].cs_change = 0;
143
144 return 0;
145 }
146
147 /**
148 * ad7298_trigger_handler() bh of trigger launched polling to ring buffer
149 *
150 * Currently there is no option in this driver to disable the saving of
151 * timestamps within the ring.
152 **/
ad7298_trigger_handler(int irq,void * p)153 static irqreturn_t ad7298_trigger_handler(int irq, void *p)
154 {
155 struct iio_poll_func *pf = p;
156 struct iio_dev *indio_dev = pf->indio_dev;
157 struct ad7298_state *st = iio_priv(indio_dev);
158 int b_sent;
159
160 b_sent = spi_sync(st->spi, &st->ring_msg);
161 if (b_sent)
162 goto done;
163
164 iio_push_to_buffers_with_timestamp(indio_dev, st->rx_buf,
165 iio_get_time_ns(indio_dev));
166
167 done:
168 iio_trigger_notify_done(indio_dev->trig);
169
170 return IRQ_HANDLED;
171 }
172
ad7298_scan_direct(struct ad7298_state * st,unsigned ch)173 static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
174 {
175 int ret;
176 st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
177 (AD7298_CH(0) >> ch));
178
179 ret = spi_sync(st->spi, &st->scan_single_msg);
180 if (ret)
181 return ret;
182
183 return be16_to_cpu(st->rx_buf[0]);
184 }
185
ad7298_scan_temp(struct ad7298_state * st,int * val)186 static int ad7298_scan_temp(struct ad7298_state *st, int *val)
187 {
188 int ret;
189 __be16 buf;
190
191 buf = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
192 AD7298_TAVG | st->ext_ref);
193
194 ret = spi_write(st->spi, (u8 *)&buf, 2);
195 if (ret)
196 return ret;
197
198 buf = cpu_to_be16(0);
199
200 ret = spi_write(st->spi, (u8 *)&buf, 2);
201 if (ret)
202 return ret;
203
204 usleep_range(101, 1000); /* sleep > 100us */
205
206 ret = spi_read(st->spi, (u8 *)&buf, 2);
207 if (ret)
208 return ret;
209
210 *val = sign_extend32(be16_to_cpu(buf), 11);
211
212 return 0;
213 }
214
ad7298_get_ref_voltage(struct ad7298_state * st)215 static int ad7298_get_ref_voltage(struct ad7298_state *st)
216 {
217 int vref;
218
219 if (st->ext_ref) {
220 vref = regulator_get_voltage(st->reg);
221 if (vref < 0)
222 return vref;
223
224 return vref / 1000;
225 } else {
226 return AD7298_INTREF_mV;
227 }
228 }
229
ad7298_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)230 static int ad7298_read_raw(struct iio_dev *indio_dev,
231 struct iio_chan_spec const *chan,
232 int *val,
233 int *val2,
234 long m)
235 {
236 int ret;
237 struct ad7298_state *st = iio_priv(indio_dev);
238
239 switch (m) {
240 case IIO_CHAN_INFO_RAW:
241 ret = iio_device_claim_direct_mode(indio_dev);
242 if (ret)
243 return ret;
244
245 if (chan->address == AD7298_CH_TEMP)
246 ret = ad7298_scan_temp(st, val);
247 else
248 ret = ad7298_scan_direct(st, chan->address);
249
250 iio_device_release_direct_mode(indio_dev);
251
252 if (ret < 0)
253 return ret;
254
255 if (chan->address != AD7298_CH_TEMP)
256 *val = ret & GENMASK(chan->scan_type.realbits - 1, 0);
257
258 return IIO_VAL_INT;
259 case IIO_CHAN_INFO_SCALE:
260 switch (chan->type) {
261 case IIO_VOLTAGE:
262 *val = ad7298_get_ref_voltage(st);
263 *val2 = chan->scan_type.realbits;
264 return IIO_VAL_FRACTIONAL_LOG2;
265 case IIO_TEMP:
266 *val = ad7298_get_ref_voltage(st);
267 *val2 = 10;
268 return IIO_VAL_FRACTIONAL;
269 default:
270 return -EINVAL;
271 }
272 case IIO_CHAN_INFO_OFFSET:
273 *val = 1093 - 2732500 / ad7298_get_ref_voltage(st);
274 return IIO_VAL_INT;
275 }
276 return -EINVAL;
277 }
278
279 static const struct iio_info ad7298_info = {
280 .read_raw = &ad7298_read_raw,
281 .update_scan_mode = ad7298_update_scan_mode,
282 };
283
ad7298_probe(struct spi_device * spi)284 static int ad7298_probe(struct spi_device *spi)
285 {
286 struct ad7298_platform_data *pdata = spi->dev.platform_data;
287 struct ad7298_state *st;
288 struct iio_dev *indio_dev;
289 int ret;
290
291 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
292 if (indio_dev == NULL)
293 return -ENOMEM;
294
295 st = iio_priv(indio_dev);
296
297 if (pdata && pdata->ext_ref)
298 st->ext_ref = AD7298_EXTREF;
299
300 if (st->ext_ref) {
301 st->reg = devm_regulator_get(&spi->dev, "vref");
302 if (IS_ERR(st->reg))
303 return PTR_ERR(st->reg);
304
305 ret = regulator_enable(st->reg);
306 if (ret)
307 return ret;
308 }
309
310 spi_set_drvdata(spi, indio_dev);
311
312 st->spi = spi;
313
314 indio_dev->name = spi_get_device_id(spi)->name;
315 indio_dev->dev.parent = &spi->dev;
316 indio_dev->dev.of_node = spi->dev.of_node;
317 indio_dev->modes = INDIO_DIRECT_MODE;
318 indio_dev->channels = ad7298_channels;
319 indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
320 indio_dev->info = &ad7298_info;
321
322 /* Setup default message */
323
324 st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
325 st->scan_single_xfer[0].len = 2;
326 st->scan_single_xfer[0].cs_change = 1;
327 st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
328 st->scan_single_xfer[1].len = 2;
329 st->scan_single_xfer[1].cs_change = 1;
330 st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
331 st->scan_single_xfer[2].len = 2;
332
333 spi_message_init(&st->scan_single_msg);
334 spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
335 spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
336 spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
337
338 ret = iio_triggered_buffer_setup(indio_dev, NULL,
339 &ad7298_trigger_handler, NULL);
340 if (ret)
341 goto error_disable_reg;
342
343 ret = iio_device_register(indio_dev);
344 if (ret)
345 goto error_cleanup_ring;
346
347 return 0;
348
349 error_cleanup_ring:
350 iio_triggered_buffer_cleanup(indio_dev);
351 error_disable_reg:
352 if (st->ext_ref)
353 regulator_disable(st->reg);
354
355 return ret;
356 }
357
ad7298_remove(struct spi_device * spi)358 static int ad7298_remove(struct spi_device *spi)
359 {
360 struct iio_dev *indio_dev = spi_get_drvdata(spi);
361 struct ad7298_state *st = iio_priv(indio_dev);
362
363 iio_device_unregister(indio_dev);
364 iio_triggered_buffer_cleanup(indio_dev);
365 if (st->ext_ref)
366 regulator_disable(st->reg);
367
368 return 0;
369 }
370
371 static const struct spi_device_id ad7298_id[] = {
372 {"ad7298", 0},
373 {}
374 };
375 MODULE_DEVICE_TABLE(spi, ad7298_id);
376
377 static struct spi_driver ad7298_driver = {
378 .driver = {
379 .name = "ad7298",
380 },
381 .probe = ad7298_probe,
382 .remove = ad7298_remove,
383 .id_table = ad7298_id,
384 };
385 module_spi_driver(ad7298_driver);
386
387 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
388 MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
389 MODULE_LICENSE("GPL v2");
390
