drivers/iio/proximity/sx_common.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2021 Google LLC.
   4  *
   5  * Common part of most Semtech SAR sensor.
   6  */
   7
   8 #include <linux/bitops.h>
   9 #include <linux/byteorder/generic.h>
  10 #include <linux/delay.h>
  11 #include <linux/device.h>
  12 #include <linux/err.h>
  13 #include <linux/export.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/irqreturn.h>
  16 #include <linux/i2c.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19 #include <linux/regmap.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <vdso/bits.h>
  22
  23 #include <linux/iio/buffer.h>
  24 #include <linux/iio/events.h>
  25 #include <linux/iio/iio.h>
  26 #include <linux/iio/trigger.h>
  27 #include <linux/iio/triggered_buffer.h>
  28 #include <linux/iio/trigger_consumer.h>
  29
  30 #include "sx_common.h"
  31
  32 /* All Semtech SAR sensors have IRQ bit in the same order. */
  33 #define   SX_COMMON_CONVDONE_IRQ                        BIT(0)
  34 #define   SX_COMMON_FAR_IRQ                             BIT(2)
  35 #define   SX_COMMON_CLOSE_IRQ                           BIT(3)
  36
  37 const struct iio_event_spec sx_common_events[3] = {
  38         {
  39                 .type = IIO_EV_TYPE_THRESH,
  40                 .dir = IIO_EV_DIR_RISING,
  41                 .mask_shared_by_all = BIT(IIO_EV_INFO_PERIOD),
  42         },
  43         {
  44                 .type = IIO_EV_TYPE_THRESH,
  45                 .dir = IIO_EV_DIR_FALLING,
  46                 .mask_shared_by_all = BIT(IIO_EV_INFO_PERIOD),
  47         },
  48         {
  49                 .type = IIO_EV_TYPE_THRESH,
  50                 .dir = IIO_EV_DIR_EITHER,
  51                 .mask_separate = BIT(IIO_EV_INFO_ENABLE) |
  52                                  BIT(IIO_EV_INFO_HYSTERESIS) |
  53                                  BIT(IIO_EV_INFO_VALUE),
  54         },
  55 };
  56 EXPORT_SYMBOL_NS_GPL(sx_common_events, SEMTECH_PROX);
  57
  58 static irqreturn_t sx_common_irq_handler(int irq, void *private)
  59 {
  60         struct iio_dev *indio_dev = private;
  61         struct sx_common_data *data = iio_priv(indio_dev);
  62
  63         if (data->trigger_enabled)
  64                 iio_trigger_poll(data->trig);
  65
  66         /*
  67          * Even if no event is enabled, we need to wake the thread to clear the
  68          * interrupt state by reading SX_COMMON_REG_IRQ_SRC.
  69          * It is not possible to do that here because regmap_read takes a mutex.
  70          */
  71         return IRQ_WAKE_THREAD;
  72 }
  73
  74 static void sx_common_push_events(struct iio_dev *indio_dev)
  75 {
  76         int ret;
  77         unsigned int val, chan;
  78         struct sx_common_data *data = iio_priv(indio_dev);
  79         s64 timestamp = iio_get_time_ns(indio_dev);
  80         unsigned long prox_changed;
  81
  82         /* Read proximity state on all channels */
  83         ret = regmap_read(data->regmap, data->chip_info->reg_stat, &val);
  84         if (ret) {
  85                 dev_err(&data->client->dev, "i2c transfer error in irq\n");
  86                 return;
  87         }
  88
  89         val >>= data->chip_info->stat_offset;
  90
  91         /*
  92          * Only iterate over channels with changes on proximity status that have
  93          * events enabled.
  94          */
  95         prox_changed = (data->chan_prox_stat ^ val) & data->chan_event;
  96
  97         for_each_set_bit(chan, &prox_changed, data->chip_info->num_channels) {
  98                 int dir;
  99                 u64 ev;
 100
 101                 dir = (val & BIT(chan)) ? IIO_EV_DIR_FALLING : IIO_EV_DIR_RISING;
 102                 ev = IIO_UNMOD_EVENT_CODE(IIO_PROXIMITY, chan,
 103                                           IIO_EV_TYPE_THRESH, dir);
 104
 105                 iio_push_event(indio_dev, ev, timestamp);
 106         }
 107         data->chan_prox_stat = val;
 108 }
 109
 110 static int sx_common_enable_irq(struct sx_common_data *data, unsigned int irq)
 111 {
 112         if (!data->client->irq)
 113                 return 0;
 114         return regmap_set_bits(data->regmap, data->chip_info->reg_irq_msk,
 115                                irq << data->chip_info->irq_msk_offset);
 116 }
 117
 118 static int sx_common_disable_irq(struct sx_common_data *data, unsigned int irq)
 119 {
 120         if (!data->client->irq)
 121                 return 0;
 122         return regmap_clear_bits(data->regmap, data->chip_info->reg_irq_msk,
 123                                  irq << data->chip_info->irq_msk_offset);
 124 }
 125
 126 static int sx_common_update_chan_en(struct sx_common_data *data,
 127                                     unsigned long chan_read,
 128                                     unsigned long chan_event)
 129 {
 130         int ret;
 131         unsigned long channels = chan_read | chan_event;
 132
 133         if ((data->chan_read | data->chan_event) != channels) {
 134                 ret = regmap_update_bits(data->regmap,
 135                                          data->chip_info->reg_enable_chan,
 136                                          data->chip_info->mask_enable_chan,
 137                                          channels);
 138                 if (ret)
 139                         return ret;
 140         }
 141         data->chan_read = chan_read;
 142         data->chan_event = chan_event;
 143         return 0;
 144 }
 145
 146 static int sx_common_get_read_channel(struct sx_common_data *data, int channel)
 147 {
 148         return sx_common_update_chan_en(data, data->chan_read | BIT(channel),
 149                                      data->chan_event);
 150 }
 151
 152 static int sx_common_put_read_channel(struct sx_common_data *data, int channel)
 153 {
 154         return sx_common_update_chan_en(data, data->chan_read & ~BIT(channel),
 155                                      data->chan_event);
 156 }
 157
 158 static int sx_common_get_event_channel(struct sx_common_data *data, int channel)
 159 {
 160         return sx_common_update_chan_en(data, data->chan_read,
 161                                      data->chan_event | BIT(channel));
 162 }
 163
 164 static int sx_common_put_event_channel(struct sx_common_data *data, int channel)
 165 {
 166         return sx_common_update_chan_en(data, data->chan_read,
 167                                      data->chan_event & ~BIT(channel));
 168 }
 169
 170 /**
 171  * sx_common_read_proximity() - Read raw proximity value.
 172  * @data:       Internal data
 173  * @chan:       Channel to read
 174  * @val:        pointer to return read value.
 175  *
 176  * Request a conversion, wait for the sensor to be ready and
 177  * return the raw proximity value.
 178  */
 179 int sx_common_read_proximity(struct sx_common_data *data,
 180                              const struct iio_chan_spec *chan, int *val)
 181 {
 182         int ret;
 183         __be16 rawval;
 184
 185         mutex_lock(&data->mutex);
 186
 187         ret = sx_common_get_read_channel(data, chan->channel);
 188         if (ret)
 189                 goto out;
 190
 191         ret = sx_common_enable_irq(data, SX_COMMON_CONVDONE_IRQ);
 192         if (ret)
 193                 goto out_put_channel;
 194
 195         mutex_unlock(&data->mutex);
 196
 197         if (data->client->irq) {
 198                 ret = wait_for_completion_interruptible(&data->completion);
 199                 reinit_completion(&data->completion);
 200         } else {
 201                 ret = data->chip_info->ops.wait_for_sample(data);
 202         }
 203
 204         mutex_lock(&data->mutex);
 205
 206         if (ret)
 207                 goto out_disable_irq;
 208
 209         ret = data->chip_info->ops.read_prox_data(data, chan, &rawval);
 210         if (ret)
 211                 goto out_disable_irq;
 212
 213         *val = sign_extend32(be16_to_cpu(rawval), chan->scan_type.realbits - 1);
 214
 215         ret = sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
 216         if (ret)
 217                 goto out_put_channel;
 218
 219         ret = sx_common_put_read_channel(data, chan->channel);
 220         if (ret)
 221                 goto out;
 222
 223         mutex_unlock(&data->mutex);
 224
 225         return IIO_VAL_INT;
 226
 227 out_disable_irq:
 228         sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
 229 out_put_channel:
 230         sx_common_put_read_channel(data, chan->channel);
 231 out:
 232         mutex_unlock(&data->mutex);
 233
 234         return ret;
 235 }
 236 EXPORT_SYMBOL_NS_GPL(sx_common_read_proximity, SEMTECH_PROX);
 237
 238 /**
 239  * sx_common_read_event_config() - Configure event setting.
 240  * @indio_dev:  iio device object
 241  * @chan:       Channel to read
 242  * @type:       Type of event (unused)
 243  * @dir:        Direction of event (unused)
 244  *
 245  * return if the given channel is used for event gathering.
 246  */
 247 int sx_common_read_event_config(struct iio_dev *indio_dev,
 248                                 const struct iio_chan_spec *chan,
 249                                 enum iio_event_type type,
 250                                 enum iio_event_direction dir)
 251 {
 252         struct sx_common_data *data = iio_priv(indio_dev);
 253
 254         return !!(data->chan_event & BIT(chan->channel));
 255 }
 256 EXPORT_SYMBOL_NS_GPL(sx_common_read_event_config, SEMTECH_PROX);
 257
 258 /**
 259  * sx_common_write_event_config() - Configure event setting.
 260  * @indio_dev:  iio device object
 261  * @chan:       Channel to enable
 262  * @type:       Type of event (unused)
 263  * @dir:        Direction of event (unused)
 264  * @state:      State of the event.
 265  *
 266  * Enable/Disable event on a given channel.
 267  */
 268 int sx_common_write_event_config(struct iio_dev *indio_dev,
 269                                  const struct iio_chan_spec *chan,
 270                                  enum iio_event_type type,
 271                                  enum iio_event_direction dir, bool state)
 272 {
 273         struct sx_common_data *data = iio_priv(indio_dev);
 274         unsigned int eventirq = SX_COMMON_FAR_IRQ | SX_COMMON_CLOSE_IRQ;
 275         int ret;
 276
 277         /* If the state hasn't changed, there's nothing to do. */
 278         if (!!(data->chan_event & BIT(chan->channel)) == state)
 279                 return 0;
 280
 281         mutex_lock(&data->mutex);
 282         if (state) {
 283                 ret = sx_common_get_event_channel(data, chan->channel);
 284                 if (ret)
 285                         goto out_unlock;
 286                 if (!(data->chan_event & ~BIT(chan->channel))) {
 287                         ret = sx_common_enable_irq(data, eventirq);
 288                         if (ret)
 289                                 sx_common_put_event_channel(data, chan->channel);
 290                 }
 291         } else {
 292                 ret = sx_common_put_event_channel(data, chan->channel);
 293                 if (ret)
 294                         goto out_unlock;
 295                 if (!data->chan_event) {
 296                         ret = sx_common_disable_irq(data, eventirq);
 297                         if (ret)
 298                                 sx_common_get_event_channel(data, chan->channel);
 299                 }
 300         }
 301
 302 out_unlock:
 303         mutex_unlock(&data->mutex);
 304         return ret;
 305 }
 306 EXPORT_SYMBOL_NS_GPL(sx_common_write_event_config, SEMTECH_PROX);
 307
 308 static int sx_common_set_trigger_state(struct iio_trigger *trig, bool state)
 309 {
 310         struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
 311         struct sx_common_data *data = iio_priv(indio_dev);
 312         int ret = 0;
 313
 314         mutex_lock(&data->mutex);
 315
 316         if (state)
 317                 ret = sx_common_enable_irq(data, SX_COMMON_CONVDONE_IRQ);
 318         else if (!data->chan_read)
 319                 ret = sx_common_disable_irq(data, SX_COMMON_CONVDONE_IRQ);
 320         if (ret)
 321                 goto out;
 322
 323         data->trigger_enabled = state;
 324
 325 out:
 326         mutex_unlock(&data->mutex);
 327
 328         return ret;
 329 }
 330
 331 static const struct iio_trigger_ops sx_common_trigger_ops = {
 332         .set_trigger_state = sx_common_set_trigger_state,
 333 };
 334
 335 static irqreturn_t sx_common_irq_thread_handler(int irq, void *private)
 336 {
 337         struct iio_dev *indio_dev = private;
 338         struct sx_common_data *data = iio_priv(indio_dev);
 339         int ret;
 340         unsigned int val;
 341
 342         mutex_lock(&data->mutex);
 343
 344         ret = regmap_read(data->regmap, SX_COMMON_REG_IRQ_SRC, &val);
 345         if (ret) {
 346                 dev_err(&data->client->dev, "i2c transfer error in irq\n");
 347                 goto out;
 348         }
 349
 350         if (val & ((SX_COMMON_FAR_IRQ | SX_COMMON_CLOSE_IRQ) << data->chip_info->irq_msk_offset))
 351                 sx_common_push_events(indio_dev);
 352
 353         if (val & (SX_COMMON_CONVDONE_IRQ << data->chip_info->irq_msk_offset))
 354                 complete(&data->completion);
 355
 356 out:
 357         mutex_unlock(&data->mutex);
 358
 359         return IRQ_HANDLED;
 360 }
 361
 362 static irqreturn_t sx_common_trigger_handler(int irq, void *private)
 363 {
 364         struct iio_poll_func *pf = private;
 365         struct iio_dev *indio_dev = pf->indio_dev;
 366         struct sx_common_data *data = iio_priv(indio_dev);
 367         __be16 val;
 368         int bit, ret, i = 0;
 369
 370         mutex_lock(&data->mutex);
 371
 372         iio_for_each_active_channel(indio_dev, bit) {
 373                 ret = data->chip_info->ops.read_prox_data(data,
 374                                                      &indio_dev->channels[bit],
 375                                                      &val);
 376                 if (ret)
 377                         goto out;
 378
 379                 data->buffer.channels[i++] = val;
 380         }
 381
 382         iio_push_to_buffers_with_timestamp(indio_dev, &data->buffer,
 383                                            pf->timestamp);
 384
 385 out:
 386         mutex_unlock(&data->mutex);
 387
 388         iio_trigger_notify_done(indio_dev->trig);
 389
 390         return IRQ_HANDLED;
 391 }
 392
 393 static int sx_common_buffer_preenable(struct iio_dev *indio_dev)
 394 {
 395         struct sx_common_data *data = iio_priv(indio_dev);
 396         unsigned long channels = 0;
 397         int bit, ret;
 398
 399         mutex_lock(&data->mutex);
 400         iio_for_each_active_channel(indio_dev, bit)
 401                 __set_bit(indio_dev->channels[bit].channel, &channels);
 402
 403         ret = sx_common_update_chan_en(data, channels, data->chan_event);
 404         mutex_unlock(&data->mutex);
 405         return ret;
 406 }
 407
 408 static int sx_common_buffer_postdisable(struct iio_dev *indio_dev)
 409 {
 410         struct sx_common_data *data = iio_priv(indio_dev);
 411         int ret;
 412
 413         mutex_lock(&data->mutex);
 414         ret = sx_common_update_chan_en(data, 0, data->chan_event);
 415         mutex_unlock(&data->mutex);
 416         return ret;
 417 }
 418
 419 static const struct iio_buffer_setup_ops sx_common_buffer_setup_ops = {
 420         .preenable = sx_common_buffer_preenable,
 421         .postdisable = sx_common_buffer_postdisable,
 422 };
 423
 424 #define SX_COMMON_SOFT_RESET                            0xde
 425
 426 static int sx_common_init_device(struct device *dev, struct iio_dev *indio_dev)
 427 {
 428         struct sx_common_data *data = iio_priv(indio_dev);
 429         struct sx_common_reg_default tmp;
 430         const struct sx_common_reg_default *initval;
 431         int ret;
 432         unsigned int i, val;
 433
 434         ret = regmap_write(data->regmap, data->chip_info->reg_reset,
 435                            SX_COMMON_SOFT_RESET);
 436         if (ret)
 437                 return ret;
 438
 439         usleep_range(1000, 2000); /* power-up time is ~1ms. */
 440
 441         /* Clear reset interrupt state by reading SX_COMMON_REG_IRQ_SRC. */
 442         ret = regmap_read(data->regmap, SX_COMMON_REG_IRQ_SRC, &val);
 443         if (ret)
 444                 return ret;
 445
 446         /* Program defaults from constant or BIOS. */
 447         for (i = 0; i < data->chip_info->num_default_regs; i++) {
 448                 initval = data->chip_info->ops.get_default_reg(dev, i, &tmp);
 449                 ret = regmap_write(data->regmap, initval->reg, initval->def);
 450                 if (ret)
 451                         return ret;
 452         }
 453
 454         return data->chip_info->ops.init_compensation(indio_dev);
 455 }
 456
 457 /**
 458  * sx_common_probe() - Common setup for Semtech SAR sensor
 459  * @client:             I2C client object
 460  * @chip_info:          Semtech sensor chip information.
 461  * @regmap_config:      Sensor registers map configuration.
 462  */
 463 int sx_common_probe(struct i2c_client *client,
 464                     const struct sx_common_chip_info *chip_info,
 465                     const struct regmap_config *regmap_config)
 466 {
 467         static const char * const regulator_names[] = { "vdd", "svdd" };
 468         struct device *dev = &client->dev;
 469         struct iio_dev *indio_dev;
 470         struct sx_common_data *data;
 471         int ret;
 472
 473         indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
 474         if (!indio_dev)
 475                 return -ENOMEM;
 476
 477         data = iio_priv(indio_dev);
 478
 479         data->chip_info = chip_info;
 480         data->client = client;
 481         mutex_init(&data->mutex);
 482         init_completion(&data->completion);
 483
 484         data->regmap = devm_regmap_init_i2c(client, regmap_config);
 485         if (IS_ERR(data->regmap))
 486                 return dev_err_probe(dev, PTR_ERR(data->regmap),
 487                                      "Could init register map\n");
 488
 489         ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulator_names),
 490                                              regulator_names);
 491         if (ret)
 492                 return dev_err_probe(dev, ret, "Unable to get regulators\n");
 493
 494         /* Must wait for Tpor time after initial power up */
 495         usleep_range(1000, 1100);
 496
 497         ret = data->chip_info->ops.check_whoami(dev, indio_dev);
 498         if (ret)
 499                 return dev_err_probe(dev, ret, "error reading WHOAMI\n");
 500
 501         indio_dev->modes = INDIO_DIRECT_MODE;
 502
 503         indio_dev->channels =  data->chip_info->iio_channels;
 504         indio_dev->num_channels = data->chip_info->num_iio_channels;
 505         indio_dev->info = &data->chip_info->iio_info;
 506
 507         i2c_set_clientdata(client, indio_dev);
 508
 509         ret = sx_common_init_device(dev, indio_dev);
 510         if (ret)
 511                 return dev_err_probe(dev, ret, "Unable to initialize sensor\n");
 512
 513         if (client->irq) {
 514                 ret = devm_request_threaded_irq(dev, client->irq,
 515                                                 sx_common_irq_handler,
 516                                                 sx_common_irq_thread_handler,
 517                                                 IRQF_ONESHOT,
 518                                                 "sx_event", indio_dev);
 519                 if (ret)
 520                         return dev_err_probe(dev, ret, "No IRQ\n");
 521
 522                 data->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
 523                                                     indio_dev->name,
 524                                                     iio_device_id(indio_dev));
 525                 if (!data->trig)
 526                         return -ENOMEM;
 527
 528                 data->trig->ops = &sx_common_trigger_ops;
 529                 iio_trigger_set_drvdata(data->trig, indio_dev);
 530
 531                 ret = devm_iio_trigger_register(dev, data->trig);
 532                 if (ret)
 533                         return ret;
 534         }
 535
 536         ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 537                                               iio_pollfunc_store_time,
 538                                               sx_common_trigger_handler,
 539                                               &sx_common_buffer_setup_ops);
 540         if (ret)
 541                 return ret;
 542
 543         return devm_iio_device_register(dev, indio_dev);
 544 }
 545 EXPORT_SYMBOL_NS_GPL(sx_common_probe, SEMTECH_PROX);
 546
 547 MODULE_AUTHOR("Gwendal Grignou <gwendal@chromium.org>");
 548 MODULE_DESCRIPTION("Common functions and structures for Semtech sensor");
 549 MODULE_LICENSE("GPL v2");