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 | |
103 | static 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 | |
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: &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 | |
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(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 | |
201 | static const struct iio_info lmp91000_info = { |
202 | .read_raw = lmp91000_read_raw, |
203 | }; |
204 | |
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, 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 | |
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 | |
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(cb_buff: data->cb_buffer); |
279 | } |
280 | |
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(cb_buff: 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 | |
295 | static 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 | |
374 | error_unreg_cb_buffer: |
375 | iio_channel_release_all_cb(cb_buffer: data->cb_buffer); |
376 | |
377 | error_unreg_buffer: |
378 | iio_triggered_buffer_cleanup(indio_dev); |
379 | |
380 | error_unreg_trigger: |
381 | iio_trigger_unregister(trig_info: data->trig); |
382 | |
383 | return ret; |
384 | } |
385 | |
386 | static 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 | |
400 | static const struct of_device_id lmp91000_of_match[] = { |
401 | { .compatible = "ti,lmp91000" , }, |
402 | { .compatible = "ti,lmp91002" , }, |
403 | { }, |
404 | }; |
405 | MODULE_DEVICE_TABLE(of, lmp91000_of_match); |
406 | |
407 | static const struct i2c_device_id lmp91000_id[] = { |
408 | { "lmp91000" , 0 }, |
409 | { "lmp91002" , 0 }, |
410 | {} |
411 | }; |
412 | MODULE_DEVICE_TABLE(i2c, lmp91000_id); |
413 | |
414 | static 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 | }; |
423 | module_i2c_driver(lmp91000_driver); |
424 | |
425 | MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>" ); |
426 | MODULE_DESCRIPTION("LMP91000 digital potentiostat" ); |
427 | MODULE_LICENSE("GPL" ); |
428 | |