1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * lmp91000.c - Support for Texas Instruments digital potentiostats
4 *
5 * Copyright (C) 2016, 2018
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7 *
8 * TODO: bias voltage + polarity control, and multiple chip support
9 */
10
11#include <linux/module.h>
12#include <linux/i2c.h>
13#include <linux/delay.h>
14#include <linux/mod_devicetable.h>
15#include <linux/regmap.h>
16#include <linux/iio/iio.h>
17#include <linux/iio/buffer.h>
18#include <linux/iio/consumer.h>
19#include <linux/iio/trigger.h>
20#include <linux/iio/trigger_consumer.h>
21#include <linux/iio/triggered_buffer.h>
22
23#define LMP91000_REG_LOCK 0x01
24#define LMP91000_REG_TIACN 0x10
25#define LMP91000_REG_TIACN_GAIN_SHIFT 2
26
27#define LMP91000_REG_REFCN 0x11
28#define LMP91000_REG_REFCN_EXT_REF 0x20
29#define LMP91000_REG_REFCN_50_ZERO 0x80
30
31#define LMP91000_REG_MODECN 0x12
32#define LMP91000_REG_MODECN_3LEAD 0x03
33#define LMP91000_REG_MODECN_TEMP 0x07
34
35#define LMP91000_DRV_NAME "lmp91000"
36
37static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000,
38 120000, 350000 };
39
40static const int lmp91000_rload[] = { 10, 33, 50, 100 };
41
42#define LMP91000_TEMP_BASE -40
43
44static const u16 lmp91000_temp_lut[] = {
45 1875, 1867, 1860, 1852, 1844, 1836, 1828, 1821, 1813, 1805,
46 1797, 1789, 1782, 1774, 1766, 1758, 1750, 1742, 1734, 1727,
47 1719, 1711, 1703, 1695, 1687, 1679, 1671, 1663, 1656, 1648,
48 1640, 1632, 1624, 1616, 1608, 1600, 1592, 1584, 1576, 1568,
49 1560, 1552, 1544, 1536, 1528, 1520, 1512, 1504, 1496, 1488,
50 1480, 1472, 1464, 1456, 1448, 1440, 1432, 1424, 1415, 1407,
51 1399, 1391, 1383, 1375, 1367, 1359, 1351, 1342, 1334, 1326,
52 1318, 1310, 1302, 1293, 1285, 1277, 1269, 1261, 1253, 1244,
53 1236, 1228, 1220, 1212, 1203, 1195, 1187, 1179, 1170, 1162,
54 1154, 1146, 1137, 1129, 1121, 1112, 1104, 1096, 1087, 1079,
55 1071, 1063, 1054, 1046, 1038, 1029, 1021, 1012, 1004, 996,
56 987, 979, 971, 962, 954, 945, 937, 929, 920, 912,
57 903, 895, 886, 878, 870, 861 };
58
59static const struct regmap_config lmp91000_regmap_config = {
60 .reg_bits = 8,
61 .val_bits = 8,
62};
63
64struct lmp91000_data {
65 struct regmap *regmap;
66 struct device *dev;
67
68 struct iio_trigger *trig;
69 struct iio_cb_buffer *cb_buffer;
70 struct iio_channel *adc_chan;
71
72 struct completion completion;
73 u8 chan_select;
74 /* 64-bit data + 64-bit naturally aligned timestamp */
75 u32 buffer[4] __aligned(8);
76};
77
78static const struct iio_chan_spec lmp91000_channels[] = {
79 { /* chemical channel mV */
80 .type = IIO_VOLTAGE,
81 .channel = 0,
82 .address = LMP91000_REG_MODECN_3LEAD,
83 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
84 BIT(IIO_CHAN_INFO_OFFSET) |
85 BIT(IIO_CHAN_INFO_SCALE),
86 .scan_index = 0,
87 .scan_type = {
88 .sign = 's',
89 .realbits = 32,
90 .storagebits = 32,
91 },
92 },
93 IIO_CHAN_SOFT_TIMESTAMP(1),
94 { /* temperature channel mV */
95 .type = IIO_TEMP,
96 .channel = 1,
97 .address = LMP91000_REG_MODECN_TEMP,
98 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
99 .scan_index = -1,
100 },
101};
102
103static int lmp91000_read(struct lmp91000_data *data, int channel, int *val)
104{
105 int state, ret;
106
107 ret = regmap_read(map: data->regmap, LMP91000_REG_MODECN, val: &state);
108 if (ret)
109 return -EINVAL;
110
111 ret = regmap_write(map: data->regmap, LMP91000_REG_MODECN, val: channel);
112 if (ret)
113 return -EINVAL;
114
115 /* delay till first temperature reading is complete */
116 if (state != channel && channel == LMP91000_REG_MODECN_TEMP)
117 usleep_range(min: 3000, max: 4000);
118
119 data->chan_select = channel != LMP91000_REG_MODECN_3LEAD;
120
121 iio_trigger_poll_nested(trig: data->trig);
122
123 ret = wait_for_completion_timeout(x: &data->completion, HZ);
124 reinit_completion(x: &data->completion);
125
126 if (!ret)
127 return -ETIMEDOUT;
128
129 *val = data->buffer[data->chan_select];
130
131 return 0;
132}
133
134static irqreturn_t lmp91000_buffer_handler(int irq, void *private)
135{
136 struct iio_poll_func *pf = private;
137 struct iio_dev *indio_dev = pf->indio_dev;
138 struct lmp91000_data *data = iio_priv(indio_dev);
139 int ret, val;
140
141 memset(data->buffer, 0, sizeof(data->buffer));
142
143 ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, val: &val);
144 if (!ret) {
145 data->buffer[0] = val;
146 iio_push_to_buffers_with_timestamp(indio_dev, data: data->buffer,
147 timestamp: iio_get_time_ns(indio_dev));
148 }
149
150 iio_trigger_notify_done(trig: indio_dev->trig);
151
152 return IRQ_HANDLED;
153}
154
155static int lmp91000_read_raw(struct iio_dev *indio_dev,
156 struct iio_chan_spec const *chan,
157 int *val, int *val2, long mask)
158{
159 struct lmp91000_data *data = iio_priv(indio_dev);
160
161 switch (mask) {
162 case IIO_CHAN_INFO_RAW:
163 case IIO_CHAN_INFO_PROCESSED: {
164 int ret = iio_channel_start_all_cb(cb_buff: data->cb_buffer);
165
166 if (ret)
167 return ret;
168
169 ret = lmp91000_read(data, channel: chan->address, val);
170
171 iio_channel_stop_all_cb(cb_buff: data->cb_buffer);
172
173 if (ret)
174 return ret;
175
176 if (mask == IIO_CHAN_INFO_PROCESSED) {
177 int tmp, i;
178
179 ret = iio_convert_raw_to_processed(chan: data->adc_chan,
180 raw: *val, processed: &tmp, scale: 1);
181 if (ret)
182 return ret;
183
184 for (i = 0; i < ARRAY_SIZE(lmp91000_temp_lut); i++)
185 if (lmp91000_temp_lut[i] < tmp)
186 break;
187
188 *val = (LMP91000_TEMP_BASE + i) * 1000;
189 }
190 return IIO_VAL_INT;
191 }
192 case IIO_CHAN_INFO_OFFSET:
193 return iio_read_channel_offset(chan: data->adc_chan, val, val2);
194 case IIO_CHAN_INFO_SCALE:
195 return iio_read_channel_scale(chan: data->adc_chan, val, val2);
196 }
197
198 return -EINVAL;
199}
200
201static const struct iio_info lmp91000_info = {
202 .read_raw = lmp91000_read_raw,
203};
204
205static int lmp91000_read_config(struct lmp91000_data *data)
206{
207 struct device *dev = data->dev;
208 unsigned int reg, val;
209 int i, ret;
210
211 ret = device_property_read_u32(dev, propname: "ti,tia-gain-ohm", val: &val);
212 if (ret) {
213 if (!device_property_read_bool(dev, propname: "ti,external-tia-resistor")) {
214 dev_err(dev, "no ti,tia-gain-ohm defined and external resistor not specified\n");
215 return ret;
216 }
217 val = 0;
218 }
219
220 ret = -EINVAL;
221 for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) {
222 if (lmp91000_tia_gain[i] == val) {
223 reg = i << LMP91000_REG_TIACN_GAIN_SHIFT;
224 ret = 0;
225 break;
226 }
227 }
228
229 if (ret) {
230 dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val);
231 return ret;
232 }
233
234 ret = device_property_read_u32(dev, propname: "ti,rload-ohm", val: &val);
235 if (ret) {
236 val = 100;
237 dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val);
238 }
239
240 ret = -EINVAL;
241 for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) {
242 if (lmp91000_rload[i] == val) {
243 reg |= i;
244 ret = 0;
245 break;
246 }
247 }
248
249 if (ret) {
250 dev_err(dev, "invalid ti,rload-ohm %d\n", val);
251 return ret;
252 }
253
254 regmap_write(map: data->regmap, LMP91000_REG_LOCK, val: 0);
255 regmap_write(map: data->regmap, LMP91000_REG_TIACN, val: reg);
256 regmap_write(map: data->regmap, LMP91000_REG_REFCN,
257 LMP91000_REG_REFCN_EXT_REF | LMP91000_REG_REFCN_50_ZERO);
258 regmap_write(map: data->regmap, LMP91000_REG_LOCK, val: 1);
259
260 return 0;
261}
262
263static int lmp91000_buffer_cb(const void *val, void *private)
264{
265 struct iio_dev *indio_dev = private;
266 struct lmp91000_data *data = iio_priv(indio_dev);
267
268 data->buffer[data->chan_select] = *((int *)val);
269 complete_all(&data->completion);
270
271 return 0;
272}
273
274static int lmp91000_buffer_postenable(struct iio_dev *indio_dev)
275{
276 struct lmp91000_data *data = iio_priv(indio_dev);
277
278 return iio_channel_start_all_cb(cb_buff: data->cb_buffer);
279}
280
281static int lmp91000_buffer_predisable(struct iio_dev *indio_dev)
282{
283 struct lmp91000_data *data = iio_priv(indio_dev);
284
285 iio_channel_stop_all_cb(cb_buff: data->cb_buffer);
286
287 return 0;
288}
289
290static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
291 .postenable = lmp91000_buffer_postenable,
292 .predisable = lmp91000_buffer_predisable,
293};
294
295static int lmp91000_probe(struct i2c_client *client)
296{
297 struct device *dev = &client->dev;
298 struct lmp91000_data *data;
299 struct iio_dev *indio_dev;
300 int ret;
301
302 indio_dev = devm_iio_device_alloc(parent: dev, sizeof_priv: sizeof(*data));
303 if (!indio_dev)
304 return -ENOMEM;
305
306 indio_dev->info = &lmp91000_info;
307 indio_dev->channels = lmp91000_channels;
308 indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
309 indio_dev->name = LMP91000_DRV_NAME;
310 indio_dev->modes = INDIO_DIRECT_MODE;
311 i2c_set_clientdata(client, data: indio_dev);
312
313 data = iio_priv(indio_dev);
314 data->dev = dev;
315 data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
316 if (IS_ERR(ptr: data->regmap)) {
317 dev_err(dev, "regmap initialization failed.\n");
318 return PTR_ERR(ptr: data->regmap);
319 }
320
321 data->trig = devm_iio_trigger_alloc(dev, "%s-mux%d",
322 indio_dev->name,
323 iio_device_id(indio_dev));
324 if (!data->trig) {
325 dev_err(dev, "cannot allocate iio trigger.\n");
326 return -ENOMEM;
327 }
328
329 init_completion(x: &data->completion);
330
331 ret = lmp91000_read_config(data);
332 if (ret)
333 return ret;
334
335 ret = iio_trigger_set_immutable(indio_dev: iio_channel_cb_get_iio_dev(cb_buffer: data->cb_buffer),
336 trig: data->trig);
337 if (ret) {
338 dev_err(dev, "cannot set immutable trigger.\n");
339 return ret;
340 }
341
342 ret = iio_trigger_register(trig_info: data->trig);
343 if (ret) {
344 dev_err(dev, "cannot register iio trigger.\n");
345 return ret;
346 }
347
348 ret = iio_triggered_buffer_setup(indio_dev, NULL,
349 &lmp91000_buffer_handler,
350 &lmp91000_buffer_setup_ops);
351 if (ret)
352 goto error_unreg_trigger;
353
354 data->cb_buffer = iio_channel_get_all_cb(dev, cb: &lmp91000_buffer_cb,
355 private: indio_dev);
356
357 if (IS_ERR(ptr: data->cb_buffer)) {
358 if (PTR_ERR(ptr: data->cb_buffer) == -ENODEV)
359 ret = -EPROBE_DEFER;
360 else
361 ret = PTR_ERR(ptr: data->cb_buffer);
362
363 goto error_unreg_buffer;
364 }
365
366 data->adc_chan = iio_channel_cb_get_channels(cb_buffer: data->cb_buffer);
367
368 ret = iio_device_register(indio_dev);
369 if (ret)
370 goto error_unreg_cb_buffer;
371
372 return 0;
373
374error_unreg_cb_buffer:
375 iio_channel_release_all_cb(cb_buffer: data->cb_buffer);
376
377error_unreg_buffer:
378 iio_triggered_buffer_cleanup(indio_dev);
379
380error_unreg_trigger:
381 iio_trigger_unregister(trig_info: data->trig);
382
383 return ret;
384}
385
386static void lmp91000_remove(struct i2c_client *client)
387{
388 struct iio_dev *indio_dev = i2c_get_clientdata(client);
389 struct lmp91000_data *data = iio_priv(indio_dev);
390
391 iio_device_unregister(indio_dev);
392
393 iio_channel_stop_all_cb(cb_buff: data->cb_buffer);
394 iio_channel_release_all_cb(cb_buffer: data->cb_buffer);
395
396 iio_triggered_buffer_cleanup(indio_dev);
397 iio_trigger_unregister(trig_info: data->trig);
398}
399
400static const struct of_device_id lmp91000_of_match[] = {
401 { .compatible = "ti,lmp91000", },
402 { .compatible = "ti,lmp91002", },
403 { },
404};
405MODULE_DEVICE_TABLE(of, lmp91000_of_match);
406
407static const struct i2c_device_id lmp91000_id[] = {
408 { "lmp91000", 0 },
409 { "lmp91002", 0 },
410 {}
411};
412MODULE_DEVICE_TABLE(i2c, lmp91000_id);
413
414static struct i2c_driver lmp91000_driver = {
415 .driver = {
416 .name = LMP91000_DRV_NAME,
417 .of_match_table = lmp91000_of_match,
418 },
419 .probe = lmp91000_probe,
420 .remove = lmp91000_remove,
421 .id_table = lmp91000_id,
422};
423module_i2c_driver(lmp91000_driver);
424
425MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
426MODULE_DESCRIPTION("LMP91000 digital potentiostat");
427MODULE_LICENSE("GPL");
428

source code of linux/drivers/iio/potentiostat/lmp91000.c