1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * AD7887 SPI ADC driver
4 *
5 * Copyright 2010-2011 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/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/bitops.h>
18
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.h>
21 #include <linux/iio/buffer.h>
22
23 #include <linux/iio/trigger_consumer.h>
24 #include <linux/iio/triggered_buffer.h>
25
26 #include <linux/platform_data/ad7887.h>
27
28 #define AD7887_REF_DIS BIT(5) /* on-chip reference disable */
29 #define AD7887_DUAL BIT(4) /* dual-channel mode */
30 #define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */
31 #define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */
32 #define AD7887_PM_MODE1 0 /* CS based shutdown */
33 #define AD7887_PM_MODE2 1 /* full on */
34 #define AD7887_PM_MODE3 2 /* auto shutdown after conversion */
35 #define AD7887_PM_MODE4 3 /* standby mode */
36
37 enum ad7887_channels {
38 AD7887_CH0,
39 AD7887_CH0_CH1,
40 AD7887_CH1,
41 };
42
43 /**
44 * struct ad7887_chip_info - chip specifc information
45 * @int_vref_mv: the internal reference voltage
46 * @channels: channels specification
47 * @num_channels: number of channels
48 * @dual_channels: channels specification in dual mode
49 * @num_dual_channels: number of channels in dual mode
50 */
51 struct ad7887_chip_info {
52 u16 int_vref_mv;
53 const struct iio_chan_spec *channels;
54 unsigned int num_channels;
55 const struct iio_chan_spec *dual_channels;
56 unsigned int num_dual_channels;
57 };
58
59 struct ad7887_state {
60 struct spi_device *spi;
61 const struct ad7887_chip_info *chip_info;
62 struct regulator *reg;
63 struct spi_transfer xfer[4];
64 struct spi_message msg[3];
65 struct spi_message *ring_msg;
66 unsigned char tx_cmd_buf[4];
67
68 /*
69 * DMA (thus cache coherency maintenance) requires the
70 * transfer buffers to live in their own cache lines.
71 * Buffer needs to be large enough to hold two 16 bit samples and a
72 * 64 bit aligned 64 bit timestamp.
73 */
74 unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
75 ____cacheline_aligned;
76 };
77
78 enum ad7887_supported_device_ids {
79 ID_AD7887
80 };
81
ad7887_ring_preenable(struct iio_dev * indio_dev)82 static int ad7887_ring_preenable(struct iio_dev *indio_dev)
83 {
84 struct ad7887_state *st = iio_priv(indio_dev);
85
86 /* We know this is a single long so can 'cheat' */
87 switch (*indio_dev->active_scan_mask) {
88 case (1 << 0):
89 st->ring_msg = &st->msg[AD7887_CH0];
90 break;
91 case (1 << 1):
92 st->ring_msg = &st->msg[AD7887_CH1];
93 /* Dummy read: push CH1 setting down to hardware */
94 spi_sync(st->spi, st->ring_msg);
95 break;
96 case ((1 << 1) | (1 << 0)):
97 st->ring_msg = &st->msg[AD7887_CH0_CH1];
98 break;
99 }
100
101 return 0;
102 }
103
ad7887_ring_postdisable(struct iio_dev * indio_dev)104 static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
105 {
106 struct ad7887_state *st = iio_priv(indio_dev);
107
108 /* dummy read: restore default CH0 settin */
109 return spi_sync(st->spi, &st->msg[AD7887_CH0]);
110 }
111
112 /*
113 * ad7887_trigger_handler() bh of trigger launched polling to ring buffer
114 *
115 * Currently there is no option in this driver to disable the saving of
116 * timestamps within the ring.
117 **/
ad7887_trigger_handler(int irq,void * p)118 static irqreturn_t ad7887_trigger_handler(int irq, void *p)
119 {
120 struct iio_poll_func *pf = p;
121 struct iio_dev *indio_dev = pf->indio_dev;
122 struct ad7887_state *st = iio_priv(indio_dev);
123 int b_sent;
124
125 b_sent = spi_sync(st->spi, st->ring_msg);
126 if (b_sent)
127 goto done;
128
129 iio_push_to_buffers_with_timestamp(indio_dev, st->data,
130 iio_get_time_ns(indio_dev));
131 done:
132 iio_trigger_notify_done(indio_dev->trig);
133
134 return IRQ_HANDLED;
135 }
136
137 static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
138 .preenable = &ad7887_ring_preenable,
139 .postdisable = &ad7887_ring_postdisable,
140 };
141
ad7887_scan_direct(struct ad7887_state * st,unsigned ch)142 static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
143 {
144 int ret = spi_sync(st->spi, &st->msg[ch]);
145 if (ret)
146 return ret;
147
148 return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
149 }
150
ad7887_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)151 static int ad7887_read_raw(struct iio_dev *indio_dev,
152 struct iio_chan_spec const *chan,
153 int *val,
154 int *val2,
155 long m)
156 {
157 int ret;
158 struct ad7887_state *st = iio_priv(indio_dev);
159
160 switch (m) {
161 case IIO_CHAN_INFO_RAW:
162 ret = iio_device_claim_direct_mode(indio_dev);
163 if (ret)
164 return ret;
165 ret = ad7887_scan_direct(st, chan->address);
166 iio_device_release_direct_mode(indio_dev);
167
168 if (ret < 0)
169 return ret;
170 *val = ret >> chan->scan_type.shift;
171 *val &= GENMASK(chan->scan_type.realbits - 1, 0);
172 return IIO_VAL_INT;
173 case IIO_CHAN_INFO_SCALE:
174 if (st->reg) {
175 *val = regulator_get_voltage(st->reg);
176 if (*val < 0)
177 return *val;
178 *val /= 1000;
179 } else {
180 *val = st->chip_info->int_vref_mv;
181 }
182
183 *val2 = chan->scan_type.realbits;
184
185 return IIO_VAL_FRACTIONAL_LOG2;
186 }
187 return -EINVAL;
188 }
189
190 #define AD7887_CHANNEL(x) { \
191 .type = IIO_VOLTAGE, \
192 .indexed = 1, \
193 .channel = (x), \
194 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
195 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
196 .address = (x), \
197 .scan_index = (x), \
198 .scan_type = { \
199 .sign = 'u', \
200 .realbits = 12, \
201 .storagebits = 16, \
202 .shift = 0, \
203 .endianness = IIO_BE, \
204 }, \
205 }
206
207 static const struct iio_chan_spec ad7887_channels[] = {
208 AD7887_CHANNEL(0),
209 IIO_CHAN_SOFT_TIMESTAMP(1),
210 };
211
212 static const struct iio_chan_spec ad7887_dual_channels[] = {
213 AD7887_CHANNEL(0),
214 AD7887_CHANNEL(1),
215 IIO_CHAN_SOFT_TIMESTAMP(2),
216 };
217
218 static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
219 /*
220 * More devices added in future
221 */
222 [ID_AD7887] = {
223 .channels = ad7887_channels,
224 .num_channels = ARRAY_SIZE(ad7887_channels),
225 .dual_channels = ad7887_dual_channels,
226 .num_dual_channels = ARRAY_SIZE(ad7887_dual_channels),
227 .int_vref_mv = 2500,
228 },
229 };
230
231 static const struct iio_info ad7887_info = {
232 .read_raw = &ad7887_read_raw,
233 };
234
ad7887_probe(struct spi_device * spi)235 static int ad7887_probe(struct spi_device *spi)
236 {
237 struct ad7887_platform_data *pdata = spi->dev.platform_data;
238 struct ad7887_state *st;
239 struct iio_dev *indio_dev;
240 uint8_t mode;
241 int ret;
242
243 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
244 if (indio_dev == NULL)
245 return -ENOMEM;
246
247 st = iio_priv(indio_dev);
248
249 if (!pdata || !pdata->use_onchip_ref) {
250 st->reg = devm_regulator_get(&spi->dev, "vref");
251 if (IS_ERR(st->reg))
252 return PTR_ERR(st->reg);
253
254 ret = regulator_enable(st->reg);
255 if (ret)
256 return ret;
257 }
258
259 st->chip_info =
260 &ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
261
262 spi_set_drvdata(spi, indio_dev);
263 st->spi = spi;
264
265 indio_dev->name = spi_get_device_id(spi)->name;
266 indio_dev->info = &ad7887_info;
267 indio_dev->modes = INDIO_DIRECT_MODE;
268
269 /* Setup default message */
270
271 mode = AD7887_PM_MODE4;
272 if (!pdata || !pdata->use_onchip_ref)
273 mode |= AD7887_REF_DIS;
274 if (pdata && pdata->en_dual)
275 mode |= AD7887_DUAL;
276
277 st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
278
279 st->xfer[0].rx_buf = &st->data[0];
280 st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
281 st->xfer[0].len = 2;
282
283 spi_message_init(&st->msg[AD7887_CH0]);
284 spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
285
286 if (pdata && pdata->en_dual) {
287 st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
288
289 st->xfer[1].rx_buf = &st->data[0];
290 st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
291 st->xfer[1].len = 2;
292
293 st->xfer[2].rx_buf = &st->data[2];
294 st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
295 st->xfer[2].len = 2;
296
297 spi_message_init(&st->msg[AD7887_CH0_CH1]);
298 spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
299 spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
300
301 st->xfer[3].rx_buf = &st->data[2];
302 st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
303 st->xfer[3].len = 2;
304
305 spi_message_init(&st->msg[AD7887_CH1]);
306 spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
307
308 indio_dev->channels = st->chip_info->dual_channels;
309 indio_dev->num_channels = st->chip_info->num_dual_channels;
310 } else {
311 indio_dev->channels = st->chip_info->channels;
312 indio_dev->num_channels = st->chip_info->num_channels;
313 }
314
315 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
316 &ad7887_trigger_handler, &ad7887_ring_setup_ops);
317 if (ret)
318 goto error_disable_reg;
319
320 ret = iio_device_register(indio_dev);
321 if (ret)
322 goto error_unregister_ring;
323
324 return 0;
325 error_unregister_ring:
326 iio_triggered_buffer_cleanup(indio_dev);
327 error_disable_reg:
328 if (st->reg)
329 regulator_disable(st->reg);
330
331 return ret;
332 }
333
ad7887_remove(struct spi_device * spi)334 static int ad7887_remove(struct spi_device *spi)
335 {
336 struct iio_dev *indio_dev = spi_get_drvdata(spi);
337 struct ad7887_state *st = iio_priv(indio_dev);
338
339 iio_device_unregister(indio_dev);
340 iio_triggered_buffer_cleanup(indio_dev);
341 if (st->reg)
342 regulator_disable(st->reg);
343
344 return 0;
345 }
346
347 static const struct spi_device_id ad7887_id[] = {
348 {"ad7887", ID_AD7887},
349 {}
350 };
351 MODULE_DEVICE_TABLE(spi, ad7887_id);
352
353 static struct spi_driver ad7887_driver = {
354 .driver = {
355 .name = "ad7887",
356 },
357 .probe = ad7887_probe,
358 .remove = ad7887_remove,
359 .id_table = ad7887_id,
360 };
361 module_spi_driver(ad7887_driver);
362
363 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
364 MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
365 MODULE_LICENSE("GPL v2");
366