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(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_nested(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 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 } 262 263 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(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(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(dev, 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, 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(data->regmap)) { 317 dev_err(dev, "regmap initialization failed.\n"); 318 return PTR_ERR(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(&data->completion); 330 331 ret = lmp91000_read_config(data); 332 if (ret) 333 return ret; 334 335 ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer), 336 data->trig); 337 if (ret) { 338 dev_err(dev, "cannot set immutable trigger.\n"); 339 return ret; 340 } 341 342 ret = iio_trigger_register(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, &lmp91000_buffer_cb, 355 indio_dev); 356 357 if (IS_ERR(data->cb_buffer)) { 358 if (PTR_ERR(data->cb_buffer) == -ENODEV) 359 ret = -EPROBE_DEFER; 360 else 361 ret = PTR_ERR(data->cb_buffer); 362 363 goto error_unreg_buffer; 364 } 365 366 data->adc_chan = iio_channel_cb_get_channels(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(data->cb_buffer); 376 377 error_unreg_buffer: 378 iio_triggered_buffer_cleanup(indio_dev); 379 380 error_unreg_trigger: 381 iio_trigger_unregister(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(data->cb_buffer); 394 iio_channel_release_all_cb(data->cb_buffer); 395 396 iio_triggered_buffer_cleanup(indio_dev); 397 iio_trigger_unregister(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" }, 409 { "lmp91002" }, 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