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
37 static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000,
38 120000, 350000 };
39
40 static const int lmp91000_rload[] = { 10, 33, 50, 100 };
41
42 #define LMP91000_TEMP_BASE -40
43
44 static 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
59 static const struct regmap_config lmp91000_regmap_config = {
60 .reg_bits = 8,
61 .val_bits = 8,
62 };
63
64 struct 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
78 static 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
lmp91000_read(struct lmp91000_data * data,int channel,int * val)103 static int lmp91000_read(struct lmp91000_data *data, int channel, int *val)
104 {
105 int state, ret;
106
107 ret = regmap_read(data->regmap, LMP91000_REG_MODECN, &state);
108 if (ret)
109 return -EINVAL;
110
111 ret = regmap_write(data->regmap, LMP91000_REG_MODECN, 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(3000, 4000);
118
119 data->chan_select = channel != LMP91000_REG_MODECN_3LEAD;
120
121 iio_trigger_poll_chained(data->trig);
122
123 ret = wait_for_completion_timeout(&data->completion, HZ);
124 reinit_completion(&data->completion);
125
126 if (!ret)
127 return -ETIMEDOUT;
128
129 *val = data->buffer[data->chan_select];
130
131 return 0;
132 }
133
lmp91000_buffer_handler(int irq,void * private)134 static 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);
144 if (!ret) {
145 data->buffer[0] = val;
146 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
147 iio_get_time_ns(indio_dev));
148 }
149
150 iio_trigger_notify_done(indio_dev->trig);
151
152 return IRQ_HANDLED;
153 }
154
lmp91000_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)155 static 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(data->cb_buffer);
165
166 if (ret)
167 return ret;
168
169 ret = lmp91000_read(data, chan->address, val);
170
171 iio_channel_stop_all_cb(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(data->adc_chan,
180 *val, &tmp, 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(data->adc_chan, val, val2);
194 case IIO_CHAN_INFO_SCALE:
195 return iio_read_channel_scale(data->adc_chan, val, val2);
196 }
197
198 return -EINVAL;
199 }
200
201 static const struct iio_info lmp91000_info = {
202 .read_raw = lmp91000_read_raw,
203 };
204
lmp91000_read_config(struct lmp91000_data * data)205 static 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, "ti,tia-gain-ohm", &val);
212 if (ret) {
213 if (!device_property_read_bool(dev, "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, "ti,rload-ohm", &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(data->regmap, LMP91000_REG_LOCK, 0);
255 regmap_write(data->regmap, LMP91000_REG_TIACN, reg);
256 regmap_write(data->regmap, LMP91000_REG_REFCN,
257 LMP91000_REG_REFCN_EXT_REF | LMP91000_REG_REFCN_50_ZERO);
258 regmap_write(data->regmap, LMP91000_REG_LOCK, 1);
259
260 return 0;
261 }
262
lmp91000_buffer_cb(const void * val,void * private)263 static 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
lmp91000_buffer_postenable(struct iio_dev * indio_dev)274 static 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(data->cb_buffer);
279 }
280
lmp91000_buffer_predisable(struct iio_dev * indio_dev)281 static 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(data->cb_buffer);
286
287 return 0;
288 }
289
290 static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
291 .postenable = lmp91000_buffer_postenable,
292 .predisable = lmp91000_buffer_predisable,
293 };
294
lmp91000_probe(struct i2c_client * client,const struct i2c_device_id * id)295 static int lmp91000_probe(struct i2c_client *client,
296 const struct i2c_device_id *id)
297 {
298 struct device *dev = &client->dev;
299 struct lmp91000_data *data;
300 struct iio_dev *indio_dev;
301 int ret;
302
303 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
304 if (!indio_dev)
305 return -ENOMEM;
306
307 indio_dev->info = &lmp91000_info;
308 indio_dev->channels = lmp91000_channels;
309 indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
310 indio_dev->name = LMP91000_DRV_NAME;
311 indio_dev->modes = INDIO_DIRECT_MODE;
312 i2c_set_clientdata(client, indio_dev);
313
314 data = iio_priv(indio_dev);
315 data->dev = dev;
316 data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
317 if (IS_ERR(data->regmap)) {
318 dev_err(dev, "regmap initialization failed.\n");
319 return PTR_ERR(data->regmap);
320 }
321
322 data->trig = devm_iio_trigger_alloc(dev, "%s-mux%d",
323 indio_dev->name,
324 iio_device_id(indio_dev));
325 if (!data->trig) {
326 dev_err(dev, "cannot allocate iio trigger.\n");
327 return -ENOMEM;
328 }
329
330 init_completion(&data->completion);
331
332 ret = lmp91000_read_config(data);
333 if (ret)
334 return ret;
335
336 ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer),
337 data->trig);
338 if (ret) {
339 dev_err(dev, "cannot set immutable trigger.\n");
340 return ret;
341 }
342
343 ret = iio_trigger_register(data->trig);
344 if (ret) {
345 dev_err(dev, "cannot register iio trigger.\n");
346 return ret;
347 }
348
349 ret = iio_triggered_buffer_setup(indio_dev, NULL,
350 &lmp91000_buffer_handler,
351 &lmp91000_buffer_setup_ops);
352 if (ret)
353 goto error_unreg_trigger;
354
355 data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb,
356 indio_dev);
357
358 if (IS_ERR(data->cb_buffer)) {
359 if (PTR_ERR(data->cb_buffer) == -ENODEV)
360 ret = -EPROBE_DEFER;
361 else
362 ret = PTR_ERR(data->cb_buffer);
363
364 goto error_unreg_buffer;
365 }
366
367 data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer);
368
369 ret = iio_device_register(indio_dev);
370 if (ret)
371 goto error_unreg_cb_buffer;
372
373 return 0;
374
375 error_unreg_cb_buffer:
376 iio_channel_release_all_cb(data->cb_buffer);
377
378 error_unreg_buffer:
379 iio_triggered_buffer_cleanup(indio_dev);
380
381 error_unreg_trigger:
382 iio_trigger_unregister(data->trig);
383
384 return ret;
385 }
386
lmp91000_remove(struct i2c_client * client)387 static void lmp91000_remove(struct i2c_client *client)
388 {
389 struct iio_dev *indio_dev = i2c_get_clientdata(client);
390 struct lmp91000_data *data = iio_priv(indio_dev);
391
392 iio_device_unregister(indio_dev);
393
394 iio_channel_stop_all_cb(data->cb_buffer);
395 iio_channel_release_all_cb(data->cb_buffer);
396
397 iio_triggered_buffer_cleanup(indio_dev);
398 iio_trigger_unregister(data->trig);
399 }
400
401 static const struct of_device_id lmp91000_of_match[] = {
402 { .compatible = "ti,lmp91000", },
403 { .compatible = "ti,lmp91002", },
404 { },
405 };
406 MODULE_DEVICE_TABLE(of, lmp91000_of_match);
407
408 static const struct i2c_device_id lmp91000_id[] = {
409 { "lmp91000", 0 },
410 { "lmp91002", 0 },
411 {}
412 };
413 MODULE_DEVICE_TABLE(i2c, lmp91000_id);
414
415 static struct i2c_driver lmp91000_driver = {
416 .driver = {
417 .name = LMP91000_DRV_NAME,
418 .of_match_table = lmp91000_of_match,
419 },
420 .probe = lmp91000_probe,
421 .remove = lmp91000_remove,
422 .id_table = lmp91000_id,
423 };
424 module_i2c_driver(lmp91000_driver);
425
426 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
427 MODULE_DESCRIPTION("LMP91000 digital potentiostat");
428 MODULE_LICENSE("GPL");
429
