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 val = 0; 216 else { 217 dev_err(dev, "no ti,tia-gain-ohm defined"); 218 return ret; 219 } 220 } 221 222 ret = -EINVAL; 223 for (i = 0; i < ARRAY_SIZE(lmp91000_tia_gain); i++) { 224 if (lmp91000_tia_gain[i] == val) { 225 reg = i << LMP91000_REG_TIACN_GAIN_SHIFT; 226 ret = 0; 227 break; 228 } 229 } 230 231 if (ret) { 232 dev_err(dev, "invalid ti,tia-gain-ohm %d\n", val); 233 return ret; 234 } 235 236 ret = of_property_read_u32(np, "ti,rload-ohm", &val); 237 if (ret) { 238 val = 100; 239 dev_info(dev, "no ti,rload-ohm defined, default to %d\n", val); 240 } 241 242 ret = -EINVAL; 243 for (i = 0; i < ARRAY_SIZE(lmp91000_rload); i++) { 244 if (lmp91000_rload[i] == val) { 245 reg |= i; 246 ret = 0; 247 break; 248 } 249 } 250 251 if (ret) { 252 dev_err(dev, "invalid ti,rload-ohm %d\n", val); 253 return ret; 254 } 255 256 regmap_write(data->regmap, LMP91000_REG_LOCK, 0); 257 regmap_write(data->regmap, LMP91000_REG_TIACN, reg); 258 regmap_write(data->regmap, LMP91000_REG_REFCN, LMP91000_REG_REFCN_EXT_REF 259 | LMP91000_REG_REFCN_50_ZERO); 260 regmap_write(data->regmap, LMP91000_REG_LOCK, 1); 261 262 return 0; 263 } 264 265 static int lmp91000_buffer_cb(const void *val, void *private) 266 { 267 struct iio_dev *indio_dev = private; 268 struct lmp91000_data *data = iio_priv(indio_dev); 269 270 data->buffer[data->chan_select] = *((int *)val); 271 complete_all(&data->completion); 272 273 return 0; 274 } 275 276 static const struct iio_trigger_ops lmp91000_trigger_ops = { 277 }; 278 279 280 static int lmp91000_buffer_preenable(struct iio_dev *indio_dev) 281 { 282 struct lmp91000_data *data = iio_priv(indio_dev); 283 284 return iio_channel_start_all_cb(data->cb_buffer); 285 } 286 287 static int lmp91000_buffer_predisable(struct iio_dev *indio_dev) 288 { 289 struct lmp91000_data *data = iio_priv(indio_dev); 290 291 iio_channel_stop_all_cb(data->cb_buffer); 292 293 return 0; 294 } 295 296 static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = { 297 .preenable = lmp91000_buffer_preenable, 298 .postenable = iio_triggered_buffer_postenable, 299 .predisable = lmp91000_buffer_predisable, 300 }; 301 302 static int lmp91000_probe(struct i2c_client *client, 303 const struct i2c_device_id *id) 304 { 305 struct device *dev = &client->dev; 306 struct lmp91000_data *data; 307 struct iio_dev *indio_dev; 308 int ret; 309 310 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 311 if (!indio_dev) 312 return -ENOMEM; 313 314 indio_dev->info = &lmp91000_info; 315 indio_dev->channels = lmp91000_channels; 316 indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels); 317 indio_dev->name = LMP91000_DRV_NAME; 318 indio_dev->dev.parent = &client->dev; 319 indio_dev->modes = INDIO_DIRECT_MODE; 320 i2c_set_clientdata(client, indio_dev); 321 322 data = iio_priv(indio_dev); 323 data->dev = dev; 324 data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config); 325 if (IS_ERR(data->regmap)) { 326 dev_err(dev, "regmap initialization failed.\n"); 327 return PTR_ERR(data->regmap); 328 } 329 330 data->trig = devm_iio_trigger_alloc(data->dev, "%s-mux%d", 331 indio_dev->name, indio_dev->id); 332 if (!data->trig) { 333 dev_err(dev, "cannot allocate iio trigger.\n"); 334 return -ENOMEM; 335 } 336 337 data->trig->ops = &lmp91000_trigger_ops; 338 data->trig->dev.parent = dev; 339 init_completion(&data->completion); 340 341 ret = lmp91000_read_config(data); 342 if (ret) 343 return ret; 344 345 ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer), 346 data->trig); 347 if (ret) { 348 dev_err(dev, "cannot set immutable trigger.\n"); 349 return ret; 350 } 351 352 ret = iio_trigger_register(data->trig); 353 if (ret) { 354 dev_err(dev, "cannot register iio trigger.\n"); 355 return ret; 356 } 357 358 ret = iio_triggered_buffer_setup(indio_dev, NULL, 359 &lmp91000_buffer_handler, 360 &lmp91000_buffer_setup_ops); 361 if (ret) 362 goto error_unreg_trigger; 363 364 data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb, 365 indio_dev); 366 367 if (IS_ERR(data->cb_buffer)) { 368 if (PTR_ERR(data->cb_buffer) == -ENODEV) 369 ret = -EPROBE_DEFER; 370 else 371 ret = PTR_ERR(data->cb_buffer); 372 373 goto error_unreg_buffer; 374 } 375 376 data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer); 377 378 ret = iio_device_register(indio_dev); 379 if (ret) 380 goto error_unreg_cb_buffer; 381 382 return 0; 383 384 error_unreg_cb_buffer: 385 iio_channel_release_all_cb(data->cb_buffer); 386 387 error_unreg_buffer: 388 iio_triggered_buffer_cleanup(indio_dev); 389 390 error_unreg_trigger: 391 iio_trigger_unregister(data->trig); 392 393 return ret; 394 } 395 396 static int lmp91000_remove(struct i2c_client *client) 397 { 398 struct iio_dev *indio_dev = i2c_get_clientdata(client); 399 struct lmp91000_data *data = iio_priv(indio_dev); 400 401 iio_device_unregister(indio_dev); 402 403 iio_channel_stop_all_cb(data->cb_buffer); 404 iio_channel_release_all_cb(data->cb_buffer); 405 406 iio_triggered_buffer_cleanup(indio_dev); 407 iio_trigger_unregister(data->trig); 408 409 return 0; 410 } 411 412 static const struct of_device_id lmp91000_of_match[] = { 413 { .compatible = "ti,lmp91000", }, 414 { .compatible = "ti,lmp91002", }, 415 { }, 416 }; 417 MODULE_DEVICE_TABLE(of, lmp91000_of_match); 418 419 static const struct i2c_device_id lmp91000_id[] = { 420 { "lmp91000", 0 }, 421 { "lmp91002", 0 }, 422 {} 423 }; 424 MODULE_DEVICE_TABLE(i2c, lmp91000_id); 425 426 static struct i2c_driver lmp91000_driver = { 427 .driver = { 428 .name = LMP91000_DRV_NAME, 429 .of_match_table = of_match_ptr(lmp91000_of_match), 430 }, 431 .probe = lmp91000_probe, 432 .remove = lmp91000_remove, 433 .id_table = lmp91000_id, 434 }; 435 module_i2c_driver(lmp91000_driver); 436 437 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); 438 MODULE_DESCRIPTION("LMP91000 digital potentiostat"); 439 MODULE_LICENSE("GPL"); 440