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/of.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 75 u32 buffer[4]; /* 64-bit data + 64-bit timestamp */ 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(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 } 133 134 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 } 154 155 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 }; 204 205 static int lmp91000_read_config(struct lmp91000_data *data) 206 { 207 struct device *dev = data->dev; 208 struct device_node *np = dev->of_node; 209 unsigned int reg, val; 210 int i, ret; 211 212 ret = of_property_read_u32(np, "ti,tia-gain-ohm", &val); 213 if (ret) { 214 if (!of_property_read_bool(np, "ti,external-tia-resistor")) { 215 dev_err(dev, "no ti,tia-gain-ohm defined and external resistor not specified\n"); 216 return ret; 217 } 218 val = 0; 219 } 220 221 ret = -EINVAL; 222 for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) { 223 if (lmp91000_tia_gain[i] == val) { 224 reg = i << LMP91000_REG_TIACN_GAIN_SHIFT; 225 ret = 0; 226 break; 227 } 228 } 229 230 if (ret) { 231 dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val); 232 return ret; 233 } 234 235 ret = of_property_read_u32(np, "ti,rload-ohm", &val); 236 if (ret) { 237 val = 100; 238 dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val); 239 } 240 241 ret = -EINVAL; 242 for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) { 243 if (lmp91000_rload[i] == val) { 244 reg |= i; 245 ret = 0; 246 break; 247 } 248 } 249 250 if (ret) { 251 dev_err(dev, "invalid ti,rload-ohm %d\n", val); 252 return ret; 253 } 254 255 regmap_write(data->regmap, LMP91000_REG_LOCK, 0); 256 regmap_write(data->regmap, LMP91000_REG_TIACN, reg); 257 regmap_write(data->regmap, LMP91000_REG_REFCN, 258 LMP91000_REG_REFCN_EXT_REF | LMP91000_REG_REFCN_50_ZERO); 259 regmap_write(data->regmap, LMP91000_REG_LOCK, 1); 260 261 return 0; 262 } 263 264 static int lmp91000_buffer_cb(const void *val, void *private) 265 { 266 struct iio_dev *indio_dev = private; 267 struct lmp91000_data *data = iio_priv(indio_dev); 268 269 data->buffer[data->chan_select] = *((int *)val); 270 complete_all(&data->completion); 271 272 return 0; 273 } 274 275 static const struct iio_trigger_ops lmp91000_trigger_ops = { 276 }; 277 278 static int lmp91000_buffer_postenable(struct iio_dev *indio_dev) 279 { 280 struct lmp91000_data *data = iio_priv(indio_dev); 281 int err; 282 283 err = iio_triggered_buffer_postenable(indio_dev); 284 if (err) 285 return err; 286 287 err = iio_channel_start_all_cb(data->cb_buffer); 288 if (err) 289 iio_triggered_buffer_predisable(indio_dev); 290 291 return err; 292 } 293 294 static int lmp91000_buffer_predisable(struct iio_dev *indio_dev) 295 { 296 struct lmp91000_data *data = iio_priv(indio_dev); 297 298 iio_channel_stop_all_cb(data->cb_buffer); 299 300 return iio_triggered_buffer_predisable(indio_dev); 301 } 302 303 static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = { 304 .postenable = lmp91000_buffer_postenable, 305 .predisable = lmp91000_buffer_predisable, 306 }; 307 308 static int lmp91000_probe(struct i2c_client *client, 309 const struct i2c_device_id *id) 310 { 311 struct device *dev = &client->dev; 312 struct lmp91000_data *data; 313 struct iio_dev *indio_dev; 314 int ret; 315 316 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 317 if (!indio_dev) 318 return -ENOMEM; 319 320 indio_dev->info = &lmp91000_info; 321 indio_dev->channels = lmp91000_channels; 322 indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels); 323 indio_dev->name = LMP91000_DRV_NAME; 324 indio_dev->dev.parent = &client->dev; 325 indio_dev->modes = INDIO_DIRECT_MODE; 326 i2c_set_clientdata(client, indio_dev); 327 328 data = iio_priv(indio_dev); 329 data->dev = dev; 330 data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config); 331 if (IS_ERR(data->regmap)) { 332 dev_err(dev, "regmap initialization failed.\n"); 333 return PTR_ERR(data->regmap); 334 } 335 336 data->trig = devm_iio_trigger_alloc(data->dev, "%s-mux%d", 337 indio_dev->name, indio_dev->id); 338 if (!data->trig) { 339 dev_err(dev, "cannot allocate iio trigger.\n"); 340 return -ENOMEM; 341 } 342 343 data->trig->ops = &lmp91000_trigger_ops; 344 data->trig->dev.parent = dev; 345 init_completion(&data->completion); 346 347 ret = lmp91000_read_config(data); 348 if (ret) 349 return ret; 350 351 ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer), 352 data->trig); 353 if (ret) { 354 dev_err(dev, "cannot set immutable trigger.\n"); 355 return ret; 356 } 357 358 ret = iio_trigger_register(data->trig); 359 if (ret) { 360 dev_err(dev, "cannot register iio trigger.\n"); 361 return ret; 362 } 363 364 ret = iio_triggered_buffer_setup(indio_dev, NULL, 365 &lmp91000_buffer_handler, 366 &lmp91000_buffer_setup_ops); 367 if (ret) 368 goto error_unreg_trigger; 369 370 data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb, 371 indio_dev); 372 373 if (IS_ERR(data->cb_buffer)) { 374 if (PTR_ERR(data->cb_buffer) == -ENODEV) 375 ret = -EPROBE_DEFER; 376 else 377 ret = PTR_ERR(data->cb_buffer); 378 379 goto error_unreg_buffer; 380 } 381 382 data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer); 383 384 ret = iio_device_register(indio_dev); 385 if (ret) 386 goto error_unreg_cb_buffer; 387 388 return 0; 389 390 error_unreg_cb_buffer: 391 iio_channel_release_all_cb(data->cb_buffer); 392 393 error_unreg_buffer: 394 iio_triggered_buffer_cleanup(indio_dev); 395 396 error_unreg_trigger: 397 iio_trigger_unregister(data->trig); 398 399 return ret; 400 } 401 402 static int lmp91000_remove(struct i2c_client *client) 403 { 404 struct iio_dev *indio_dev = i2c_get_clientdata(client); 405 struct lmp91000_data *data = iio_priv(indio_dev); 406 407 iio_device_unregister(indio_dev); 408 409 iio_channel_stop_all_cb(data->cb_buffer); 410 iio_channel_release_all_cb(data->cb_buffer); 411 412 iio_triggered_buffer_cleanup(indio_dev); 413 iio_trigger_unregister(data->trig); 414 415 return 0; 416 } 417 418 static const struct of_device_id lmp91000_of_match[] = { 419 { .compatible = "ti,lmp91000", }, 420 { .compatible = "ti,lmp91002", }, 421 { }, 422 }; 423 MODULE_DEVICE_TABLE(of, lmp91000_of_match); 424 425 static const struct i2c_device_id lmp91000_id[] = { 426 { "lmp91000", 0 }, 427 { "lmp91002", 0 }, 428 {} 429 }; 430 MODULE_DEVICE_TABLE(i2c, lmp91000_id); 431 432 static struct i2c_driver lmp91000_driver = { 433 .driver = { 434 .name = LMP91000_DRV_NAME, 435 .of_match_table = of_match_ptr(lmp91000_of_match), 436 }, 437 .probe = lmp91000_probe, 438 .remove = lmp91000_remove, 439 .id_table = lmp91000_id, 440 }; 441 module_i2c_driver(lmp91000_driver); 442 443 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); 444 MODULE_DESCRIPTION("LMP91000 digital potentiostat"); 445 MODULE_LICENSE("GPL"); 446