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