drivers/iio/potentiostat/lmp91000.c

   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_preenable(struct iio_dev *indio_dev)
 279 {
 280         struct lmp91000_data *data = iio_priv(indio_dev);
 281
 282         return iio_channel_start_all_cb(data->cb_buffer);
 283 }
 284
 285 static int lmp91000_buffer_predisable(struct iio_dev *indio_dev)
 286 {
 287         struct lmp91000_data *data = iio_priv(indio_dev);
 288
 289         iio_channel_stop_all_cb(data->cb_buffer);
 290
 291         return 0;
 292 }
 293
 294 static const struct iio_buffer_setup_ops lmp91000_buffer_setup_ops = {
 295         .preenable = lmp91000_buffer_preenable,
 296         .postenable = iio_triggered_buffer_postenable,
 297         .predisable = lmp91000_buffer_predisable,
 298 };
 299
 300 static int lmp91000_probe(struct i2c_client *client,
 301                           const struct i2c_device_id *id)
 302 {
 303         struct device *dev = &client->dev;
 304         struct lmp91000_data *data;
 305         struct iio_dev *indio_dev;
 306         int ret;
 307
 308         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 309         if (!indio_dev)
 310                 return -ENOMEM;
 311
 312         indio_dev->info = &lmp91000_info;
 313         indio_dev->channels = lmp91000_channels;
 314         indio_dev->num_channels = ARRAY_SIZE(lmp91000_channels);
 315         indio_dev->name = LMP91000_DRV_NAME;
 316         indio_dev->dev.parent = &client->dev;
 317         indio_dev->modes = INDIO_DIRECT_MODE;
 318         i2c_set_clientdata(client, indio_dev);
 319
 320         data = iio_priv(indio_dev);
 321         data->dev = dev;
 322         data->regmap = devm_regmap_init_i2c(client, &lmp91000_regmap_config);
 323         if (IS_ERR(data->regmap)) {
 324                 dev_err(dev, "regmap initialization failed.\n");
 325                 return PTR_ERR(data->regmap);
 326         }
 327
 328         data->trig = devm_iio_trigger_alloc(data->dev, "%s-mux%d",
 329                                             indio_dev->name, indio_dev->id);
 330         if (!data->trig) {
 331                 dev_err(dev, "cannot allocate iio trigger.\n");
 332                 return -ENOMEM;
 333         }
 334
 335         data->trig->ops = &lmp91000_trigger_ops;
 336         data->trig->dev.parent = dev;
 337         init_completion(&data->completion);
 338
 339         ret = lmp91000_read_config(data);
 340         if (ret)
 341                 return ret;
 342
 343         ret = iio_trigger_set_immutable(iio_channel_cb_get_iio_dev(data->cb_buffer),
 344                                         data->trig);
 345         if (ret) {
 346                 dev_err(dev, "cannot set immutable trigger.\n");
 347                 return ret;
 348         }
 349
 350         ret = iio_trigger_register(data->trig);
 351         if (ret) {
 352                 dev_err(dev, "cannot register iio trigger.\n");
 353                 return ret;
 354         }
 355
 356         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 357                                          &lmp91000_buffer_handler,
 358                                          &lmp91000_buffer_setup_ops);
 359         if (ret)
 360                 goto error_unreg_trigger;
 361
 362         data->cb_buffer = iio_channel_get_all_cb(dev, &lmp91000_buffer_cb,
 363                                                  indio_dev);
 364
 365         if (IS_ERR(data->cb_buffer)) {
 366                 if (PTR_ERR(data->cb_buffer) == -ENODEV)
 367                         ret = -EPROBE_DEFER;
 368                 else
 369                         ret = PTR_ERR(data->cb_buffer);
 370
 371                 goto error_unreg_buffer;
 372         }
 373
 374         data->adc_chan = iio_channel_cb_get_channels(data->cb_buffer);
 375
 376         ret = iio_device_register(indio_dev);
 377         if (ret)
 378                 goto error_unreg_cb_buffer;
 379
 380         return 0;
 381
 382 error_unreg_cb_buffer:
 383         iio_channel_release_all_cb(data->cb_buffer);
 384
 385 error_unreg_buffer:
 386         iio_triggered_buffer_cleanup(indio_dev);
 387
 388 error_unreg_trigger:
 389         iio_trigger_unregister(data->trig);
 390
 391         return ret;
 392 }
 393
 394 static int lmp91000_remove(struct i2c_client *client)
 395 {
 396         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 397         struct lmp91000_data *data = iio_priv(indio_dev);
 398
 399         iio_device_unregister(indio_dev);
 400
 401         iio_channel_stop_all_cb(data->cb_buffer);
 402         iio_channel_release_all_cb(data->cb_buffer);
 403
 404         iio_triggered_buffer_cleanup(indio_dev);
 405         iio_trigger_unregister(data->trig);
 406
 407         return 0;
 408 }
 409
 410 static const struct of_device_id lmp91000_of_match[] = {
 411         { .compatible = "ti,lmp91000", },
 412         { .compatible = "ti,lmp91002", },
 413         { },
 414 };
 415 MODULE_DEVICE_TABLE(of, lmp91000_of_match);
 416
 417 static const struct i2c_device_id lmp91000_id[] = {
 418         { "lmp91000", 0 },
 419         { "lmp91002", 0 },
 420         {}
 421 };
 422 MODULE_DEVICE_TABLE(i2c, lmp91000_id);
 423
 424 static struct i2c_driver lmp91000_driver = {
 425         .driver = {
 426                 .name = LMP91000_DRV_NAME,
 427                 .of_match_table = of_match_ptr(lmp91000_of_match),
 428         },
 429         .probe = lmp91000_probe,
 430         .remove = lmp91000_remove,
 431         .id_table = lmp91000_id,
 432 };
 433 module_i2c_driver(lmp91000_driver);
 434
 435 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 436 MODULE_DESCRIPTION("LMP91000 digital potentiostat");
 437 MODULE_LICENSE("GPL");