lmp91000.c 11 KB

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  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. #include <linux/module.h>
  11. #include <linux/i2c.h>
  12. #include <linux/delay.h>
  13. #include <linux/of.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. #define LMP91000_REG_LOCK 0x01
  22. #define LMP91000_REG_TIACN 0x10
  23. #define LMP91000_REG_TIACN_GAIN_SHIFT 2
  24. #define LMP91000_REG_REFCN 0x11
  25. #define LMP91000_REG_REFCN_EXT_REF 0x20
  26. #define LMP91000_REG_REFCN_50_ZERO 0x80
  27. #define LMP91000_REG_MODECN 0x12
  28. #define LMP91000_REG_MODECN_3LEAD 0x03
  29. #define LMP91000_REG_MODECN_TEMP 0x07
  30. #define LMP91000_DRV_NAME "lmp91000"
  31. static const int lmp91000_tia_gain[] = { 0, 2750, 3500, 7000, 14000, 35000,
  32. 120000, 350000 };
  33. static const int lmp91000_rload[] = { 10, 33, 50, 100 };
  34. #define LMP91000_TEMP_BASE -40
  35. static const u16 lmp91000_temp_lut[] = {
  36. 1875, 1867, 1860, 1852, 1844, 1836, 1828, 1821, 1813, 1805,
  37. 1797, 1789, 1782, 1774, 1766, 1758, 1750, 1742, 1734, 1727,
  38. 1719, 1711, 1703, 1695, 1687, 1679, 1671, 1663, 1656, 1648,
  39. 1640, 1632, 1624, 1616, 1608, 1600, 1592, 1584, 1576, 1568,
  40. 1560, 1552, 1544, 1536, 1528, 1520, 1512, 1504, 1496, 1488,
  41. 1480, 1472, 1464, 1456, 1448, 1440, 1432, 1424, 1415, 1407,
  42. 1399, 1391, 1383, 1375, 1367, 1359, 1351, 1342, 1334, 1326,
  43. 1318, 1310, 1302, 1293, 1285, 1277, 1269, 1261, 1253, 1244,
  44. 1236, 1228, 1220, 1212, 1203, 1195, 1187, 1179, 1170, 1162,
  45. 1154, 1146, 1137, 1129, 1121, 1112, 1104, 1096, 1087, 1079,
  46. 1071, 1063, 1054, 1046, 1038, 1029, 1021, 1012, 1004, 996,
  47. 987, 979, 971, 962, 954, 945, 937, 929, 920, 912,
  48. 903, 895, 886, 878, 870, 861 };
  49. static const struct regmap_config lmp91000_regmap_config = {
  50. .reg_bits = 8,
  51. .val_bits = 8,
  52. };
  53. struct lmp91000_data {
  54. struct regmap *regmap;
  55. struct device *dev;
  56. struct iio_trigger *trig;
  57. struct iio_cb_buffer *cb_buffer;
  58. struct iio_channel *adc_chan;
  59. struct completion completion;
  60. u8 chan_select;
  61. u32 buffer[4]; /* 64-bit data + 64-bit timestamp */
  62. };
  63. static const struct iio_chan_spec lmp91000_channels[] = {
  64. { /* chemical channel mV */
  65. .type = IIO_VOLTAGE,
  66. .channel = 0,
  67. .address = LMP91000_REG_MODECN_3LEAD,
  68. .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  69. BIT(IIO_CHAN_INFO_OFFSET) |
  70. BIT(IIO_CHAN_INFO_SCALE),
  71. .scan_index = 0,
  72. .scan_type = {
  73. .sign = 's',
  74. .realbits = 32,
  75. .storagebits = 32,
  76. },
  77. },
  78. IIO_CHAN_SOFT_TIMESTAMP(1),
  79. { /* temperature channel mV */
  80. .type = IIO_TEMP,
  81. .channel = 1,
  82. .address = LMP91000_REG_MODECN_TEMP,
  83. .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
  84. .scan_index = -1,
  85. },
  86. };
  87. static int lmp91000_read(struct lmp91000_data *data, int channel, int *val)
  88. {
  89. int state, ret;
  90. ret = regmap_read(data->regmap, LMP91000_REG_MODECN, &state);
  91. if (ret)
  92. return -EINVAL;
  93. ret = regmap_write(data->regmap, LMP91000_REG_MODECN, channel);
  94. if (ret)
  95. return -EINVAL;
  96. /* delay till first temperature reading is complete */
  97. if ((state != channel) && (channel == LMP91000_REG_MODECN_TEMP))
  98. usleep_range(3000, 4000);
  99. data->chan_select = channel != LMP91000_REG_MODECN_3LEAD;
  100. iio_trigger_poll_chained(data->trig);
  101. ret = wait_for_completion_timeout(&data->completion, HZ);
  102. reinit_completion(&data->completion);
  103. if (!ret)
  104. return -ETIMEDOUT;
  105. *val = data->buffer[data->chan_select];
  106. return 0;
  107. }
  108. static irqreturn_t lmp91000_buffer_handler(int irq, void *private)
  109. {
  110. struct iio_poll_func *pf = private;
  111. struct iio_dev *indio_dev = pf->indio_dev;
  112. struct lmp91000_data *data = iio_priv(indio_dev);
  113. int ret, val;
  114. memset(data->buffer, 0, sizeof(data->buffer));
  115. ret = lmp91000_read(data, LMP91000_REG_MODECN_3LEAD, &val);
  116. if (!ret) {
  117. data->buffer[0] = val;
  118. iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
  119. iio_get_time_ns(indio_dev));
  120. }
  121. iio_trigger_notify_done(indio_dev->trig);
  122. return IRQ_HANDLED;
  123. }
  124. static int lmp91000_read_raw(struct iio_dev *indio_dev,
  125. struct iio_chan_spec const *chan,
  126. int *val, int *val2, long mask)
  127. {
  128. struct lmp91000_data *data = iio_priv(indio_dev);
  129. switch (mask) {
  130. case IIO_CHAN_INFO_RAW:
  131. case IIO_CHAN_INFO_PROCESSED: {
  132. int ret = iio_channel_start_all_cb(data->cb_buffer);
  133. if (ret)
  134. return ret;
  135. ret = lmp91000_read(data, chan->address, val);
  136. iio_channel_stop_all_cb(data->cb_buffer);
  137. if (ret)
  138. return ret;
  139. if (mask == IIO_CHAN_INFO_PROCESSED) {
  140. int tmp, i;
  141. ret = iio_convert_raw_to_processed(data->adc_chan,
  142. *val, &tmp, 1);
  143. if (ret)
  144. return ret;
  145. for (i = 0; i < ARRAY_SIZE(lmp91000_temp_lut); i++)
  146. if (lmp91000_temp_lut[i] < tmp)
  147. break;
  148. *val = (LMP91000_TEMP_BASE + i) * 1000;
  149. }
  150. return IIO_VAL_INT;
  151. }
  152. case IIO_CHAN_INFO_OFFSET:
  153. return iio_read_channel_offset(data->adc_chan, val, val2);
  154. case IIO_CHAN_INFO_SCALE:
  155. return iio_read_channel_scale(data->adc_chan, val, val2);
  156. }
  157. return -EINVAL;
  158. }
  159. static const struct iio_info lmp91000_info = {
  160. .read_raw = lmp91000_read_raw,
  161. };
  162. static int lmp91000_read_config(struct lmp91000_data *data)
  163. {
  164. struct device *dev = data->dev;
  165. struct device_node *np = dev->of_node;
  166. unsigned int reg, val;
  167. int i, ret;
  168. ret = of_property_read_u32(np, "ti,tia-gain-ohm", &val);
  169. if (ret) {
  170. if (of_property_read_bool(np, "ti,external-tia-resistor"))
  171. val = 0;
  172. else {
  173. dev_err(dev, "no ti,tia-gain-ohm defined");
  174. return ret;
  175. }
  176. }
  177. ret = -EINVAL;
  178. for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) {
  179. if (lmp91000_tia_gain[i] == val) {
  180. reg = i << LMP91000_REG_TIACN_GAIN_SHIFT;
  181. ret = 0;
  182. break;
  183. }
  184. }
  185. if (ret) {
  186. dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val);
  187. return ret;
  188. }
  189. ret = of_property_read_u32(np, "ti,rload-ohm", &val);
  190. if (ret) {
  191. val = 100;
  192. dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val);
  193. }
  194. ret = -EINVAL;
  195. for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) {
  196. if (lmp91000_rload[i] == val) {
  197. reg |= i;
  198. ret = 0;
  199. break;
  200. }
  201. }
  202. if (ret) {
  203. dev_err(dev, "invalid ti,rload-ohm %d\n", val);
  204. return ret;
  205. }
  206. regmap_write(data->regmap, LMP91000_REG_LOCK, 0);
  207. regmap_write(data->regmap, LMP91000_REG_TIACN, reg);
  208. regmap_write(data->regmap, LMP91000_REG_REFCN, LMP91000_REG_REFCN_EXT_REF
  209. | LMP91000_REG_REFCN_50_ZERO);
  210. regmap_write(data->regmap, LMP91000_REG_LOCK, 1);
  211. return 0;
  212. }
  213. static int lmp91000_buffer_cb(const void *val, void *private)
  214. {
  215. struct iio_dev *indio_dev = private;
  216. struct lmp91000_data *data = iio_priv(indio_dev);
  217. data->buffer[data->chan_select] = *((int *)val);
  218. complete_all(&data->completion);
  219. return 0;
  220. }
  221. static const struct iio_trigger_ops lmp91000_trigger_ops = {
  222. };
  223. static int lmp91000_buffer_preenable(struct iio_dev *indio_dev)
  224. {
  225. struct lmp91000_data *data = iio_priv(indio_dev);
  226. return iio_channel_start_all_cb(data->cb_buffer);
  227. }
  228. static int lmp91000_buffer_predisable(struct iio_dev *indio_dev)
  229. {
  230. struct lmp91000_data *data = iio_priv(indio_dev);
  231. iio_channel_stop_all_cb(data->cb_buffer);
  232. return 0;
  233. }
  234. static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
  235. .preenable = lmp91000_buffer_preenable,
  236. .postenable = iio_triggered_buffer_postenable,
  237. .predisable = lmp91000_buffer_predisable,
  238. };
  239. static int lmp91000_probe(struct i2c_client *client,
  240. const struct i2c_device_id *id)
  241. {
  242. struct device *dev = &client->dev;
  243. struct lmp91000_data *data;
  244. struct iio_dev *indio_dev;
  245. int ret;
  246. indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
  247. if (!indio_dev)
  248. return -ENOMEM;
  249. indio_dev->info = &lmp91000_info;
  250. indio_dev->channels = lmp91000_channels;
  251. indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
  252. indio_dev->name = LMP91000_DRV_NAME;
  253. indio_dev->dev.parent = &client->dev;
  254. indio_dev->modes = INDIO_DIRECT_MODE;
  255. i2c_set_clientdata(client, indio_dev);
  256. data = iio_priv(indio_dev);
  257. data->dev = dev;
  258. data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
  259. if (IS_ERR(data->regmap)) {
  260. dev_err(dev, "regmap initialization failed.\n");
  261. return PTR_ERR(data->regmap);
  262. }
  263. data->trig = devm_iio_trigger_alloc(data->dev, "%s-mux%d",
  264. indio_dev->name, indio_dev->id);
  265. if (!data->trig) {
  266. dev_err(dev, "cannot allocate iio trigger.\n");
  267. return -ENOMEM;
  268. }
  269. data->trig->ops = &lmp91000_trigger_ops;
  270. data->trig->dev.parent = dev;
  271. init_completion(&data->completion);
  272. ret = lmp91000_read_config(data);
  273. if (ret)
  274. return ret;
  275. ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer),
  276. data->trig);
  277. if (ret) {
  278. dev_err(dev, "cannot set immutable trigger.\n");
  279. return ret;
  280. }
  281. ret = iio_trigger_register(data->trig);
  282. if (ret) {
  283. dev_err(dev, "cannot register iio trigger.\n");
  284. return ret;
  285. }
  286. ret = iio_triggered_buffer_setup(indio_dev, NULL,
  287. &lmp91000_buffer_handler,
  288. &lmp91000_buffer_setup_ops);
  289. if (ret)
  290. goto error_unreg_trigger;
  291. data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb,
  292. indio_dev);
  293. if (IS_ERR(data->cb_buffer)) {
  294. if (PTR_ERR(data->cb_buffer) == -ENODEV)
  295. ret = -EPROBE_DEFER;
  296. else
  297. ret = PTR_ERR(data->cb_buffer);
  298. goto error_unreg_buffer;
  299. }
  300. data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer);
  301. ret = iio_device_register(indio_dev);
  302. if (ret)
  303. goto error_unreg_cb_buffer;
  304. return 0;
  305. error_unreg_cb_buffer:
  306. iio_channel_release_all_cb(data->cb_buffer);
  307. error_unreg_buffer:
  308. iio_triggered_buffer_cleanup(indio_dev);
  309. error_unreg_trigger:
  310. iio_trigger_unregister(data->trig);
  311. return ret;
  312. }
  313. static int lmp91000_remove(struct i2c_client *client)
  314. {
  315. struct iio_dev *indio_dev = i2c_get_clientdata(client);
  316. struct lmp91000_data *data = iio_priv(indio_dev);
  317. iio_device_unregister(indio_dev);
  318. iio_channel_stop_all_cb(data->cb_buffer);
  319. iio_channel_release_all_cb(data->cb_buffer);
  320. iio_triggered_buffer_cleanup(indio_dev);
  321. iio_trigger_unregister(data->trig);
  322. return 0;
  323. }
  324. static const struct of_device_id lmp91000_of_match[] = {
  325. { .compatible = "ti,lmp91000", },
  326. { .compatible = "ti,lmp91002", },
  327. { },
  328. };
  329. MODULE_DEVICE_TABLE(of, lmp91000_of_match);
  330. static const struct i2c_device_id lmp91000_id[] = {
  331. { "lmp91000", 0 },
  332. { "lmp91002", 0 },
  333. {}
  334. };
  335. MODULE_DEVICE_TABLE(i2c, lmp91000_id);
  336. static struct i2c_driver lmp91000_driver = {
  337. .driver = {
  338. .name = LMP91000_DRV_NAME,
  339. .of_match_table = of_match_ptr(lmp91000_of_match),
  340. },
  341. .probe = lmp91000_probe,
  342. .remove = lmp91000_remove,
  343. .id_table = lmp91000_id,
  344. };
  345. module_i2c_driver(lmp91000_driver);
  346. MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
  347. MODULE_DESCRIPTION("LMP91000 digital potentiostat");
  348. MODULE_LICENSE("GPL");