drivers/iio/adc/hi8435.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Holt Integrated Circuits HI-8435 threshold detector driver
   4  *
   5  * Copyright (C) 2015 Zodiac Inflight Innovations
   6  * Copyright (C) 2015 Cogent Embedded, Inc.
   7  */
   8
   9 #include <linux/delay.h>
  10 #include <linux/iio/events.h>
  11 #include <linux/iio/iio.h>
  12 #include <linux/iio/sysfs.h>
  13 #include <linux/iio/trigger.h>
  14 #include <linux/iio/trigger_consumer.h>
  15 #include <linux/iio/triggered_event.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_device.h>
  20 #include <linux/of_gpio.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/gpio/consumer.h>
  23
  24 #define DRV_NAME "hi8435"
  25
  26 /* Register offsets for HI-8435 */
  27 #define HI8435_CTRL_REG         0x02
  28 #define HI8435_PSEN_REG         0x04
  29 #define HI8435_TMDATA_REG       0x1E
  30 #define HI8435_GOCENHYS_REG     0x3A
  31 #define HI8435_SOCENHYS_REG     0x3C
  32 #define HI8435_SO7_0_REG        0x10
  33 #define HI8435_SO15_8_REG       0x12
  34 #define HI8435_SO23_16_REG      0x14
  35 #define HI8435_SO31_24_REG      0x16
  36 #define HI8435_SO31_0_REG       0x78
  37
  38 #define HI8435_WRITE_OPCODE     0x00
  39 #define HI8435_READ_OPCODE      0x80
  40
  41 /* CTRL register bits */
  42 #define HI8435_CTRL_TEST        0x01
  43 #define HI8435_CTRL_SRST        0x02
  44
  45 struct hi8435_priv {
  46         struct spi_device *spi;
  47         struct mutex lock;
  48
  49         unsigned long event_scan_mask; /* soft mask/unmask channels events */
  50         unsigned int event_prev_val;
  51
  52         unsigned threshold_lo[2]; /* GND-Open and Supply-Open thresholds */
  53         unsigned threshold_hi[2]; /* GND-Open and Supply-Open thresholds */
  54         u8 reg_buffer[3] ____cacheline_aligned;
  55 };
  56
  57 static int hi8435_readb(struct hi8435_priv *priv, u8 reg, u8 *val)
  58 {
  59         reg |= HI8435_READ_OPCODE;
  60         return spi_write_then_read(priv->spi, &reg, 1, val, 1);
  61 }
  62
  63 static int hi8435_readw(struct hi8435_priv *priv, u8 reg, u16 *val)
  64 {
  65         int ret;
  66         __be16 be_val;
  67
  68         reg |= HI8435_READ_OPCODE;
  69         ret = spi_write_then_read(priv->spi, &reg, 1, &be_val, 2);
  70         *val = be16_to_cpu(be_val);
  71
  72         return ret;
  73 }
  74
  75 static int hi8435_readl(struct hi8435_priv *priv, u8 reg, u32 *val)
  76 {
  77         int ret;
  78         __be32 be_val;
  79
  80         reg |= HI8435_READ_OPCODE;
  81         ret = spi_write_then_read(priv->spi, &reg, 1, &be_val, 4);
  82         *val = be32_to_cpu(be_val);
  83
  84         return ret;
  85 }
  86
  87 static int hi8435_writeb(struct hi8435_priv *priv, u8 reg, u8 val)
  88 {
  89         priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE;
  90         priv->reg_buffer[1] = val;
  91
  92         return spi_write(priv->spi, priv->reg_buffer, 2);
  93 }
  94
  95 static int hi8435_writew(struct hi8435_priv *priv, u8 reg, u16 val)
  96 {
  97         priv->reg_buffer[0] = reg | HI8435_WRITE_OPCODE;
  98         priv->reg_buffer[1] = (val >> 8) & 0xff;
  99         priv->reg_buffer[2] = val & 0xff;
 100
 101         return spi_write(priv->spi, priv->reg_buffer, 3);
 102 }
 103
 104 static int hi8435_read_raw(struct iio_dev *idev,
 105                            const struct iio_chan_spec *chan,
 106                            int *val, int *val2, long mask)
 107 {
 108         struct hi8435_priv *priv = iio_priv(idev);
 109         u32 tmp;
 110         int ret;
 111
 112         switch (mask) {
 113         case IIO_CHAN_INFO_RAW:
 114                 ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
 115                 if (ret < 0)
 116                         return ret;
 117                 *val = !!(tmp & BIT(chan->channel));
 118                 return IIO_VAL_INT;
 119         default:
 120                 return -EINVAL;
 121         }
 122 }
 123
 124 static int hi8435_read_event_config(struct iio_dev *idev,
 125                                     const struct iio_chan_spec *chan,
 126                                     enum iio_event_type type,
 127                                     enum iio_event_direction dir)
 128 {
 129         struct hi8435_priv *priv = iio_priv(idev);
 130
 131         return !!(priv->event_scan_mask & BIT(chan->channel));
 132 }
 133
 134 static int hi8435_write_event_config(struct iio_dev *idev,
 135                                      const struct iio_chan_spec *chan,
 136                                      enum iio_event_type type,
 137                                      enum iio_event_direction dir, int state)
 138 {
 139         struct hi8435_priv *priv = iio_priv(idev);
 140         int ret;
 141         u32 tmp;
 142
 143         if (state) {
 144                 ret = hi8435_readl(priv, HI8435_SO31_0_REG, &tmp);
 145                 if (ret < 0)
 146                         return ret;
 147                 if (tmp & BIT(chan->channel))
 148                         priv->event_prev_val |= BIT(chan->channel);
 149                 else
 150                         priv->event_prev_val &= ~BIT(chan->channel);
 151
 152                 priv->event_scan_mask |= BIT(chan->channel);
 153         } else
 154                 priv->event_scan_mask &= ~BIT(chan->channel);
 155
 156         return 0;
 157 }
 158
 159 static int hi8435_read_event_value(struct iio_dev *idev,
 160                                    const struct iio_chan_spec *chan,
 161                                    enum iio_event_type type,
 162                                    enum iio_event_direction dir,
 163                                    enum iio_event_info info,
 164                                    int *val, int *val2)
 165 {
 166         struct hi8435_priv *priv = iio_priv(idev);
 167         int ret;
 168         u8 mode, psen;
 169         u16 reg;
 170
 171         ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen);
 172         if (ret < 0)
 173                 return ret;
 174
 175         /* Supply-Open or GND-Open sensing mode */
 176         mode = !!(psen & BIT(chan->channel / 8));
 177
 178         ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
 179                                  HI8435_GOCENHYS_REG, &reg);
 180         if (ret < 0)
 181                 return ret;
 182
 183         if (dir == IIO_EV_DIR_FALLING)
 184                 *val = ((reg & 0xff) - (reg >> 8)) / 2;
 185         else if (dir == IIO_EV_DIR_RISING)
 186                 *val = ((reg & 0xff) + (reg >> 8)) / 2;
 187
 188         return IIO_VAL_INT;
 189 }
 190
 191 static int hi8435_write_event_value(struct iio_dev *idev,
 192                                     const struct iio_chan_spec *chan,
 193                                     enum iio_event_type type,
 194                                     enum iio_event_direction dir,
 195                                     enum iio_event_info info,
 196                                     int val, int val2)
 197 {
 198         struct hi8435_priv *priv = iio_priv(idev);
 199         int ret;
 200         u8 mode, psen;
 201         u16 reg;
 202
 203         ret = hi8435_readb(priv, HI8435_PSEN_REG, &psen);
 204         if (ret < 0)
 205                 return ret;
 206
 207         /* Supply-Open or GND-Open sensing mode */
 208         mode = !!(psen & BIT(chan->channel / 8));
 209
 210         ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
 211                                  HI8435_GOCENHYS_REG, &reg);
 212         if (ret < 0)
 213                 return ret;
 214
 215         if (dir == IIO_EV_DIR_FALLING) {
 216                 /* falling threshold range 2..21V, hysteresis minimum 2V */
 217                 if (val < 2 || val > 21 || (val + 2) > priv->threshold_hi[mode])
 218                         return -EINVAL;
 219
 220                 if (val == priv->threshold_lo[mode])
 221                         return 0;
 222
 223                 priv->threshold_lo[mode] = val;
 224
 225                 /* hysteresis must not be odd */
 226                 if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2)
 227                         priv->threshold_hi[mode]--;
 228         } else if (dir == IIO_EV_DIR_RISING) {
 229                 /* rising threshold range 3..22V, hysteresis minimum 2V */
 230                 if (val < 3 || val > 22 || val < (priv->threshold_lo[mode] + 2))
 231                         return -EINVAL;
 232
 233                 if (val == priv->threshold_hi[mode])
 234                         return 0;
 235
 236                 priv->threshold_hi[mode] = val;
 237
 238                 /* hysteresis must not be odd */
 239                 if ((priv->threshold_hi[mode] - priv->threshold_lo[mode]) % 2)
 240                         priv->threshold_lo[mode]++;
 241         }
 242
 243         /* program thresholds */
 244         mutex_lock(&priv->lock);
 245
 246         ret = hi8435_readw(priv, mode ? HI8435_SOCENHYS_REG :
 247                                  HI8435_GOCENHYS_REG, &reg);
 248         if (ret < 0) {
 249                 mutex_unlock(&priv->lock);
 250                 return ret;
 251         }
 252
 253         /* hysteresis */
 254         reg = priv->threshold_hi[mode] - priv->threshold_lo[mode];
 255         reg <<= 8;
 256         /* threshold center */
 257         reg |= (priv->threshold_hi[mode] + priv->threshold_lo[mode]);
 258
 259         ret = hi8435_writew(priv, mode ? HI8435_SOCENHYS_REG :
 260                                   HI8435_GOCENHYS_REG, reg);
 261
 262         mutex_unlock(&priv->lock);
 263
 264         return ret;
 265 }
 266
 267 static int hi8435_debugfs_reg_access(struct iio_dev *idev,
 268                                      unsigned reg, unsigned writeval,
 269                                      unsigned *readval)
 270 {
 271         struct hi8435_priv *priv = iio_priv(idev);
 272         int ret;
 273         u8 val;
 274
 275         if (readval != NULL) {
 276                 ret = hi8435_readb(priv, reg, &val);
 277                 *readval = val;
 278         } else {
 279                 val = (u8)writeval;
 280                 ret = hi8435_writeb(priv, reg, val);
 281         }
 282
 283         return ret;
 284 }
 285
 286 static const struct iio_event_spec hi8435_events[] = {
 287         {
 288                 .type = IIO_EV_TYPE_THRESH,
 289                 .dir = IIO_EV_DIR_RISING,
 290                 .mask_separate = BIT(IIO_EV_INFO_VALUE),
 291         }, {
 292                 .type = IIO_EV_TYPE_THRESH,
 293                 .dir = IIO_EV_DIR_FALLING,
 294                 .mask_separate = BIT(IIO_EV_INFO_VALUE),
 295         }, {
 296                 .type = IIO_EV_TYPE_THRESH,
 297                 .dir = IIO_EV_DIR_EITHER,
 298                 .mask_separate = BIT(IIO_EV_INFO_ENABLE),
 299         },
 300 };
 301
 302 static int hi8435_get_sensing_mode(struct iio_dev *idev,
 303                                    const struct iio_chan_spec *chan)
 304 {
 305         struct hi8435_priv *priv = iio_priv(idev);
 306         int ret;
 307         u8 reg;
 308
 309         ret = hi8435_readb(priv, HI8435_PSEN_REG, &reg);
 310         if (ret < 0)
 311                 return ret;
 312
 313         return !!(reg & BIT(chan->channel / 8));
 314 }
 315
 316 static int hi8435_set_sensing_mode(struct iio_dev *idev,
 317                                    const struct iio_chan_spec *chan,
 318                                    unsigned int mode)
 319 {
 320         struct hi8435_priv *priv = iio_priv(idev);
 321         int ret;
 322         u8 reg;
 323
 324         mutex_lock(&priv->lock);
 325
 326         ret = hi8435_readb(priv, HI8435_PSEN_REG, &reg);
 327         if (ret < 0) {
 328                 mutex_unlock(&priv->lock);
 329                 return ret;
 330         }
 331
 332         reg &= ~BIT(chan->channel / 8);
 333         if (mode)
 334                 reg |= BIT(chan->channel / 8);
 335
 336         ret = hi8435_writeb(priv, HI8435_PSEN_REG, reg);
 337
 338         mutex_unlock(&priv->lock);
 339
 340         return ret;
 341 }
 342
 343 static const char * const hi8435_sensing_modes[] = { "GND-Open",
 344                                                      "Supply-Open" };
 345
 346 static const struct iio_enum hi8435_sensing_mode = {
 347         .items = hi8435_sensing_modes,
 348         .num_items = ARRAY_SIZE(hi8435_sensing_modes),
 349         .get = hi8435_get_sensing_mode,
 350         .set = hi8435_set_sensing_mode,
 351 };
 352
 353 static const struct iio_chan_spec_ext_info hi8435_ext_info[] = {
 354         IIO_ENUM("sensing_mode", IIO_SEPARATE, &hi8435_sensing_mode),
 355         IIO_ENUM_AVAILABLE("sensing_mode", &hi8435_sensing_mode),
 356         {},
 357 };
 358
 359 #define HI8435_VOLTAGE_CHANNEL(num)                     \
 360 {                                                       \
 361         .type = IIO_VOLTAGE,                            \
 362         .indexed = 1,                                   \
 363         .channel = num,                                 \
 364         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 365         .event_spec = hi8435_events,                    \
 366         .num_event_specs = ARRAY_SIZE(hi8435_events),   \
 367         .ext_info = hi8435_ext_info,                    \
 368 }
 369
 370 static const struct iio_chan_spec hi8435_channels[] = {
 371         HI8435_VOLTAGE_CHANNEL(0),
 372         HI8435_VOLTAGE_CHANNEL(1),
 373         HI8435_VOLTAGE_CHANNEL(2),
 374         HI8435_VOLTAGE_CHANNEL(3),
 375         HI8435_VOLTAGE_CHANNEL(4),
 376         HI8435_VOLTAGE_CHANNEL(5),
 377         HI8435_VOLTAGE_CHANNEL(6),
 378         HI8435_VOLTAGE_CHANNEL(7),
 379         HI8435_VOLTAGE_CHANNEL(8),
 380         HI8435_VOLTAGE_CHANNEL(9),
 381         HI8435_VOLTAGE_CHANNEL(10),
 382         HI8435_VOLTAGE_CHANNEL(11),
 383         HI8435_VOLTAGE_CHANNEL(12),
 384         HI8435_VOLTAGE_CHANNEL(13),
 385         HI8435_VOLTAGE_CHANNEL(14),
 386         HI8435_VOLTAGE_CHANNEL(15),
 387         HI8435_VOLTAGE_CHANNEL(16),
 388         HI8435_VOLTAGE_CHANNEL(17),
 389         HI8435_VOLTAGE_CHANNEL(18),
 390         HI8435_VOLTAGE_CHANNEL(19),
 391         HI8435_VOLTAGE_CHANNEL(20),
 392         HI8435_VOLTAGE_CHANNEL(21),
 393         HI8435_VOLTAGE_CHANNEL(22),
 394         HI8435_VOLTAGE_CHANNEL(23),
 395         HI8435_VOLTAGE_CHANNEL(24),
 396         HI8435_VOLTAGE_CHANNEL(25),
 397         HI8435_VOLTAGE_CHANNEL(26),
 398         HI8435_VOLTAGE_CHANNEL(27),
 399         HI8435_VOLTAGE_CHANNEL(28),
 400         HI8435_VOLTAGE_CHANNEL(29),
 401         HI8435_VOLTAGE_CHANNEL(30),
 402         HI8435_VOLTAGE_CHANNEL(31),
 403         IIO_CHAN_SOFT_TIMESTAMP(32),
 404 };
 405
 406 static const struct iio_info hi8435_info = {
 407         .read_raw = hi8435_read_raw,
 408         .read_event_config = hi8435_read_event_config,
 409         .write_event_config = hi8435_write_event_config,
 410         .read_event_value = hi8435_read_event_value,
 411         .write_event_value = hi8435_write_event_value,
 412         .debugfs_reg_access = hi8435_debugfs_reg_access,
 413 };
 414
 415 static void hi8435_iio_push_event(struct iio_dev *idev, unsigned int val)
 416 {
 417         struct hi8435_priv *priv = iio_priv(idev);
 418         enum iio_event_direction dir;
 419         unsigned int i;
 420         unsigned int status = priv->event_prev_val ^ val;
 421
 422         if (!status)
 423                 return;
 424
 425         for_each_set_bit(i, &priv->event_scan_mask, 32) {
 426                 if (status & BIT(i)) {
 427                         dir = val & BIT(i) ? IIO_EV_DIR_RISING :
 428                                              IIO_EV_DIR_FALLING;
 429                         iio_push_event(idev,
 430                                        IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, i,
 431                                                     IIO_EV_TYPE_THRESH, dir),
 432                                        iio_get_time_ns(idev));
 433                 }
 434         }
 435
 436         priv->event_prev_val = val;
 437 }
 438
 439 static irqreturn_t hi8435_trigger_handler(int irq, void *private)
 440 {
 441         struct iio_poll_func *pf = private;
 442         struct iio_dev *idev = pf->indio_dev;
 443         struct hi8435_priv *priv = iio_priv(idev);
 444         u32 val;
 445         int ret;
 446
 447         ret = hi8435_readl(priv, HI8435_SO31_0_REG, &val);
 448         if (ret < 0)
 449                 goto err_read;
 450
 451         hi8435_iio_push_event(idev, val);
 452
 453 err_read:
 454         iio_trigger_notify_done(idev->trig);
 455
 456         return IRQ_HANDLED;
 457 }
 458
 459 static void hi8435_triggered_event_cleanup(void *data)
 460 {
 461         iio_triggered_event_cleanup(data);
 462 }
 463
 464 static int hi8435_probe(struct spi_device *spi)
 465 {
 466         struct iio_dev *idev;
 467         struct hi8435_priv *priv;
 468         struct gpio_desc *reset_gpio;
 469         int ret;
 470
 471         idev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
 472         if (!idev)
 473                 return -ENOMEM;
 474
 475         priv = iio_priv(idev);
 476         priv->spi = spi;
 477
 478         reset_gpio = devm_gpiod_get(&spi->dev, NULL, GPIOD_OUT_LOW);
 479         if (IS_ERR(reset_gpio)) {
 480                 /* chip s/w reset if h/w reset failed */
 481                 hi8435_writeb(priv, HI8435_CTRL_REG, HI8435_CTRL_SRST);
 482                 hi8435_writeb(priv, HI8435_CTRL_REG, 0);
 483         } else {
 484                 udelay(5);
 485                 gpiod_set_value_cansleep(reset_gpio, 1);
 486         }
 487
 488         spi_set_drvdata(spi, idev);
 489         mutex_init(&priv->lock);
 490
 491         idev->name              = spi_get_device_id(spi)->name;
 492         idev->modes             = INDIO_DIRECT_MODE;
 493         idev->info              = &hi8435_info;
 494         idev->channels          = hi8435_channels;
 495         idev->num_channels      = ARRAY_SIZE(hi8435_channels);
 496
 497         /* unmask all events */
 498         priv->event_scan_mask = ~(0);
 499         /*
 500          * There is a restriction in the chip - the hysteresis can not be odd.
 501          * If the hysteresis is set to odd value then chip gets into lock state
 502          * and not functional anymore.
 503          * After chip reset the thresholds are in undefined state, so we need to
 504          * initialize thresholds to some initial values and then prevent
 505          * userspace setting odd hysteresis.
 506          *
 507          * Set threshold low voltage to 2V, threshold high voltage to 4V
 508          * for both GND-Open and Supply-Open sensing modes.
 509          */
 510         priv->threshold_lo[0] = priv->threshold_lo[1] = 2;
 511         priv->threshold_hi[0] = priv->threshold_hi[1] = 4;
 512         hi8435_writew(priv, HI8435_GOCENHYS_REG, 0x206);
 513         hi8435_writew(priv, HI8435_SOCENHYS_REG, 0x206);
 514
 515         ret = iio_triggered_event_setup(idev, NULL, hi8435_trigger_handler);
 516         if (ret)
 517                 return ret;
 518
 519         ret = devm_add_action_or_reset(&spi->dev,
 520                                        hi8435_triggered_event_cleanup,
 521                                        idev);
 522         if (ret)
 523                 return ret;
 524
 525         return devm_iio_device_register(&spi->dev, idev);
 526 }
 527
 528 static const struct of_device_id hi8435_dt_ids[] = {
 529         { .compatible = "holt,hi8435" },
 530         {},
 531 };
 532 MODULE_DEVICE_TABLE(of, hi8435_dt_ids);
 533
 534 static const struct spi_device_id hi8435_id[] = {
 535         { "hi8435", 0},
 536         { }
 537 };
 538 MODULE_DEVICE_TABLE(spi, hi8435_id);
 539
 540 static struct spi_driver hi8435_driver = {
 541         .driver = {
 542                 .name           = DRV_NAME,
 543                 .of_match_table = of_match_ptr(hi8435_dt_ids),
 544         },
 545         .probe          = hi8435_probe,
 546         .id_table       = hi8435_id,
 547 };
 548 module_spi_driver(hi8435_driver);
 549
 550 MODULE_LICENSE("GPL");
 551 MODULE_AUTHOR("Vladimir Barinov");
 552 MODULE_DESCRIPTION("HI-8435 threshold detector");