drivers/staging/iio/accel/lis3l02dq_ring.c

   1 #include <linux/interrupt.h>
   2 #include <linux/irq.h>
   3 #include <linux/gpio.h>
   4 #include <linux/workqueue.h>
   5 #include <linux/mutex.h>
   6 #include <linux/device.h>
   7 #include <linux/kernel.h>
   8 #include <linux/spi/spi.h>
   9 #include <linux/sysfs.h>
  10 #include <linux/list.h>
  11 #include <linux/slab.h>
  12
  13 #include "../iio.h"
  14 #include "../sysfs.h"
  15 #include "../ring_sw.h"
  16 #include "accel.h"
  17 #include "../trigger.h"
  18 #include "lis3l02dq.h"
  19
  20 /**
  21  * combine_8_to_16() utility function to munge to u8s into u16
  22  **/
  23 static inline u16 combine_8_to_16(u8 lower, u8 upper)
  24 {
  25         u16 _lower = lower;
  26         u16 _upper = upper;
  27         return _lower | (_upper << 8);
  28 }
  29
  30 /**
  31  * lis3l02dq_scan_el_set_state() set whether a scan contains a given channel
  32  * @scan_el:    associtate iio scan element attribute
  33  * @indio_dev:  the device structure
  34  * @bool:       desired state
  35  *
  36  * mlock already held when this is called.
  37  **/
  38 static int lis3l02dq_scan_el_set_state(struct iio_scan_el *scan_el,
  39                                        struct iio_dev *indio_dev,
  40                                        bool state)
  41 {
  42         u8 t, mask;
  43         int ret;
  44
  45         ret = lis3l02dq_spi_read_reg_8(&indio_dev->dev,
  46                                        LIS3L02DQ_REG_CTRL_1_ADDR,
  47                                        &t);
  48         if (ret)
  49                 goto error_ret;
  50         switch (scan_el->label) {
  51         case LIS3L02DQ_REG_OUT_X_L_ADDR:
  52                 mask = LIS3L02DQ_REG_CTRL_1_AXES_X_ENABLE;
  53                 break;
  54         case LIS3L02DQ_REG_OUT_Y_L_ADDR:
  55                 mask = LIS3L02DQ_REG_CTRL_1_AXES_Y_ENABLE;
  56                 break;
  57         case LIS3L02DQ_REG_OUT_Z_L_ADDR:
  58                 mask = LIS3L02DQ_REG_CTRL_1_AXES_Z_ENABLE;
  59                 break;
  60         default:
  61                 ret = -EINVAL;
  62                 goto error_ret;
  63         }
  64
  65         if (!(mask & t) == state) {
  66                 if (state)
  67                         t |= mask;
  68                 else
  69                         t &= ~mask;
  70                 ret = lis3l02dq_spi_write_reg_8(&indio_dev->dev,
  71                                                 LIS3L02DQ_REG_CTRL_1_ADDR,
  72                                                 &t);
  73         }
  74 error_ret:
  75         return ret;
  76
  77 }
  78 static IIO_SCAN_EL_C(accel_x, 0, IIO_SIGNED(16),
  79                      LIS3L02DQ_REG_OUT_X_L_ADDR,
  80                      &lis3l02dq_scan_el_set_state);
  81 static IIO_SCAN_EL_C(accel_y, 1, IIO_SIGNED(16),
  82                      LIS3L02DQ_REG_OUT_Y_L_ADDR,
  83                      &lis3l02dq_scan_el_set_state);
  84 static IIO_SCAN_EL_C(accel_z, 2, IIO_SIGNED(16),
  85                      LIS3L02DQ_REG_OUT_Z_L_ADDR,
  86                      &lis3l02dq_scan_el_set_state);
  87 static IIO_SCAN_EL_TIMESTAMP(3);
  88
  89 static struct attribute *lis3l02dq_scan_el_attrs[] = {
  90         &iio_scan_el_accel_x.dev_attr.attr,
  91         &iio_scan_el_accel_y.dev_attr.attr,
  92         &iio_scan_el_accel_z.dev_attr.attr,
  93         &iio_scan_el_timestamp.dev_attr.attr,
  94         NULL,
  95 };
  96
  97 static struct attribute_group lis3l02dq_scan_el_group = {
  98         .attrs = lis3l02dq_scan_el_attrs,
  99         .name = "scan_elements",
 100 };
 101
 102 /**
 103  * lis3l02dq_poll_func_th() top half interrupt handler called by trigger
 104  * @private_data:       iio_dev
 105  **/
 106 static void lis3l02dq_poll_func_th(struct iio_dev *indio_dev)
 107 {
 108   struct lis3l02dq_state *st = iio_dev_get_devdata(indio_dev);
 109         st->last_timestamp = indio_dev->trig->timestamp;
 110         schedule_work(&st->work_trigger_to_ring);
 111         /* Indicate that this interrupt is being handled */
 112
 113         /* Technically this is trigger related, but without this
 114          * handler running there is currently now way for the interrupt
 115          * to clear.
 116          */
 117         st->inter = 1;
 118 }
 119
 120 /**
 121  * lis3l02dq_data_rdy_trig_poll() the event handler for the data rdy trig
 122  **/
 123 static int lis3l02dq_data_rdy_trig_poll(struct iio_dev *dev_info,
 124                                        int index,
 125                                        s64 timestamp,
 126                                        int no_test)
 127 {
 128         struct lis3l02dq_state *st = iio_dev_get_devdata(dev_info);
 129         struct iio_trigger *trig = st->trig;
 130
 131         trig->timestamp = timestamp;
 132         iio_trigger_poll(trig);
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 /* This is an event as it is a response to a physical interrupt */
 138 IIO_EVENT_SH(data_rdy_trig, &lis3l02dq_data_rdy_trig_poll);
 139
 140 /**
 141  * lis3l02dq_read_accel_from_ring() individual acceleration read from ring
 142  **/
 143 ssize_t lis3l02dq_read_accel_from_ring(struct device *dev,
 144                                        struct device_attribute *attr,
 145                                        char *buf)
 146 {
 147         struct iio_scan_el *el = NULL;
 148         int ret, len = 0, i = 0;
 149         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 150         struct iio_dev *dev_info = dev_get_drvdata(dev);
 151         s16 *data;
 152
 153         while (dev_info->scan_el_attrs->attrs[i]) {
 154                 el = to_iio_scan_el((struct device_attribute *)
 155                                     (dev_info->scan_el_attrs->attrs[i]));
 156                 /* label is in fact the address */
 157                 if (el->label == this_attr->address)
 158                         break;
 159                 i++;
 160         }
 161         if (!dev_info->scan_el_attrs->attrs[i]) {
 162                 ret = -EINVAL;
 163                 goto error_ret;
 164         }
 165         /* If this element is in the scan mask */
 166         ret = iio_scan_mask_query(dev_info, el->number);
 167         if (ret < 0)
 168                 goto error_ret;
 169         if (ret) {
 170                 data = kmalloc(dev_info->ring->access.get_bpd(dev_info->ring),
 171                                GFP_KERNEL);
 172                 if (data == NULL)
 173                         return -ENOMEM;
 174                 ret = dev_info->ring->access.read_last(dev_info->ring,
 175                                                       (u8 *)data);
 176                 if (ret)
 177                         goto error_free_data;
 178         } else {
 179                 ret = -EINVAL;
 180                 goto error_ret;
 181         }
 182         len = iio_scan_mask_count_to_right(dev_info, el->number);
 183         if (len < 0) {
 184                 ret = len;
 185                 goto error_free_data;
 186         }
 187         len = sprintf(buf, "ring %d\n", data[len]);
 188 error_free_data:
 189         kfree(data);
 190 error_ret:
 191         return ret ? ret : len;
 192
 193 }
 194
 195 static const u8 read_all_tx_array[] = {
 196         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
 197         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
 198         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
 199         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
 200         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
 201         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
 202 };
 203
 204 /**
 205  * lis3l02dq_read_all() Reads all channels currently selected
 206  * @st:         device specific state
 207  * @rx_array:   (dma capable) recieve array, must be at least
 208  *              4*number of channels
 209  **/
 210 int lis3l02dq_read_all(struct lis3l02dq_state *st, u8 *rx_array)
 211 {
 212         struct spi_transfer *xfers;
 213         struct spi_message msg;
 214         int ret, i, j = 0;
 215
 216         xfers = kzalloc((st->indio_dev->scan_count) * 2
 217                         * sizeof(*xfers), GFP_KERNEL);
 218         if (!xfers)
 219                 return -ENOMEM;
 220
 221         mutex_lock(&st->buf_lock);
 222
 223         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++) {
 224                 if (st->indio_dev->scan_mask & (1 << i)) {
 225                         /* lower byte */
 226                         xfers[j].tx_buf = st->tx + 2*j;
 227                         st->tx[2*j] = read_all_tx_array[i*4];
 228                         st->tx[2*j + 1] = 0;
 229                         if (rx_array)
 230                                 xfers[j].rx_buf = rx_array + j*2;
 231                         xfers[j].bits_per_word = 8;
 232                         xfers[j].len = 2;
 233                         xfers[j].cs_change = 1;
 234                         j++;
 235
 236                         /* upper byte */
 237                         xfers[j].tx_buf = st->tx + 2*j;
 238                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 239                         st->tx[2*j + 1] = 0;
 240                         if (rx_array)
 241                                 xfers[j].rx_buf = rx_array + j*2;
 242                         xfers[j].bits_per_word = 8;
 243                         xfers[j].len = 2;
 244                         xfers[j].cs_change = 1;
 245                         j++;
 246                 }
 247         }
 248         /* After these are transmitted, the rx_buff should have
 249          * values in alternate bytes
 250          */
 251         spi_message_init(&msg);
 252         for (j = 0; j < st->indio_dev->scan_count * 2; j++)
 253                 spi_message_add_tail(&xfers[j], &msg);
 254
 255         ret = spi_sync(st->us, &msg);
 256         mutex_unlock(&st->buf_lock);
 257         kfree(xfers);
 258
 259         return ret;
 260 }
 261
 262
 263 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
 264  * specific to be rolled into the core.
 265  */
 266 static void lis3l02dq_trigger_bh_to_ring(struct work_struct *work_s)
 267 {
 268         struct lis3l02dq_state *st
 269                 = container_of(work_s, struct lis3l02dq_state,
 270                                work_trigger_to_ring);
 271
 272         u8 *rx_array;
 273         int i = 0;
 274         u16 *data;
 275         size_t datasize = st->indio_dev
 276                 ->ring->access.get_bpd(st->indio_dev->ring);
 277
 278         data = kmalloc(datasize , GFP_KERNEL);
 279         if (data == NULL) {
 280                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 281                 return;
 282         }
 283         /* Due to interleaved nature of transmission this buffer must be
 284          * twice the number of bytes, or 4 times the number of channels
 285          */
 286         rx_array = kmalloc(4 * (st->indio_dev->scan_count), GFP_KERNEL);
 287         if (rx_array == NULL) {
 288                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 289                 kfree(data);
 290                 return;
 291         }
 292
 293         /* whilst trigger specific, if this read does nto occur the data
 294            ready interrupt will not be cleared.  Need to add a mechanism
 295            to provide a dummy read function if this is not triggering on
 296            the data ready function but something else is.
 297         */
 298         st->inter = 0;
 299
 300         if (st->indio_dev->scan_count)
 301                 if (lis3l02dq_read_all(st, rx_array) >= 0)
 302                         for (; i < st->indio_dev->scan_count; i++)
 303                                 data[i] = combine_8_to_16(rx_array[i*4+1],
 304                                                           rx_array[i*4+3]);
 305         /* Guaranteed to be aligned with 8 byte boundary */
 306         if (st->indio_dev->scan_timestamp)
 307                 *((s64 *)(data + ((i + 3)/4)*4)) = st->last_timestamp;
 308
 309         st->indio_dev->ring->access.store_to(st->indio_dev->ring,
 310                                             (u8 *)data,
 311                                             st->last_timestamp);
 312
 313         iio_trigger_notify_done(st->indio_dev->trig);
 314         kfree(rx_array);
 315         kfree(data);
 316
 317         return;
 318 }
 319 /* in these circumstances is it better to go with unaligned packing and
 320  * deal with the cost?*/
 321 static int lis3l02dq_data_rdy_ring_preenable(struct iio_dev *indio_dev)
 322 {
 323         size_t size;
 324         /* Check if there are any scan elements enabled, if not fail*/
 325         if (!(indio_dev->scan_count || indio_dev->scan_timestamp))
 326                 return -EINVAL;
 327
 328         if (indio_dev->ring->access.set_bpd) {
 329                 if (indio_dev->scan_timestamp)
 330                         if (indio_dev->scan_count) /* Timestamp and data */
 331                                 size = 2*sizeof(s64);
 332                         else /* Timestamp only  */
 333                                 size = sizeof(s64);
 334                 else /* Data only */
 335                         size = indio_dev->scan_count*sizeof(s16);
 336                 indio_dev->ring->access.set_bpd(indio_dev->ring, size);
 337         }
 338
 339         return 0;
 340 }
 341
 342 static int lis3l02dq_data_rdy_ring_postenable(struct iio_dev *indio_dev)
 343 {
 344         return indio_dev->trig
 345                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 346                                                indio_dev->pollfunc)
 347                 : 0;
 348 }
 349
 350 static int lis3l02dq_data_rdy_ring_predisable(struct iio_dev *indio_dev)
 351 {
 352         return indio_dev->trig
 353                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 354                                                 indio_dev->pollfunc)
 355                 : 0;
 356 }
 357
 358
 359 /* Caller responsible for locking as necessary. */
 360 static int
 361 __lis3l02dq_write_data_ready_config(struct device *dev,
 362                                     struct iio_event_handler_list *list,
 363                                     bool state)
 364 {
 365         int ret;
 366         u8 valold;
 367         bool currentlyset;
 368         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 369
 370 /* Get the current event mask register */
 371         ret = lis3l02dq_spi_read_reg_8(dev,
 372                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 373                                        &valold);
 374         if (ret)
 375                 goto error_ret;
 376 /* Find out if data ready is already on */
 377         currentlyset
 378                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 379
 380 /* Disable requested */
 381         if (!state && currentlyset) {
 382
 383                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 384                 /* The double write is to overcome a hardware bug?*/
 385                 ret = lis3l02dq_spi_write_reg_8(dev,
 386                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 387                                                 &valold);
 388                 if (ret)
 389                         goto error_ret;
 390                 ret = lis3l02dq_spi_write_reg_8(dev,
 391                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 392                                                 &valold);
 393                 if (ret)
 394                         goto error_ret;
 395
 396                 iio_remove_event_from_list(list,
 397                                            &indio_dev->interrupts[0]
 398                                            ->ev_list);
 399
 400 /* Enable requested */
 401         } else if (state && !currentlyset) {
 402                 /* if not set, enable requested */
 403                 valold |= LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 404                 iio_add_event_to_list(list, &indio_dev->interrupts[0]->ev_list);
 405                 ret = lis3l02dq_spi_write_reg_8(dev,
 406                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 407                                                 &valold);
 408                 if (ret)
 409                         goto error_ret;
 410         }
 411
 412         return 0;
 413 error_ret:
 414         return ret;
 415 }
 416
 417 /**
 418  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 419  *
 420  * If disabling the interrupt also does a final read to ensure it is clear.
 421  * This is only important in some cases where the scan enable elements are
 422  * switched before the ring is reenabled.
 423  **/
 424 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 425                                                 bool state)
 426 {
 427         struct lis3l02dq_state *st = trig->private_data;
 428         int ret = 0;
 429         u8 t;
 430         __lis3l02dq_write_data_ready_config(&st->indio_dev->dev,
 431                                             &iio_event_data_rdy_trig,
 432                                             state);
 433         if (state == false) {
 434                 /* possible quirk with handler currently worked around
 435                    by ensuring the work queue is empty */
 436                 flush_scheduled_work();
 437                 /* Clear any outstanding ready events */
 438                 ret = lis3l02dq_read_all(st, NULL);
 439         }
 440         lis3l02dq_spi_read_reg_8(&st->indio_dev->dev,
 441                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 442                                  &t);
 443         return ret;
 444 }
 445 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
 446
 447 static struct attribute *lis3l02dq_trigger_attrs[] = {
 448         &dev_attr_name.attr,
 449         NULL,
 450 };
 451
 452 static const struct attribute_group lis3l02dq_trigger_attr_group = {
 453         .attrs = lis3l02dq_trigger_attrs,
 454 };
 455
 456 /**
 457  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 458  * @trig:       the datardy trigger
 459  *
 460  * As the trigger may occur on any data element being updated it is
 461  * really rather likely to occur during the read from the previous
 462  * trigger event.  The only way to discover if this has occured on
 463  * boards not supporting level interrupts is to take a look at the line.
 464  * If it is indicating another interrupt and we don't seem to have a
 465  * handler looking at it, then we need to notify the core that we need
 466  * to tell the triggering core to try reading all these again.
 467  **/
 468 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 469 {
 470         struct lis3l02dq_state *st = trig->private_data;
 471         enable_irq(st->us->irq);
 472         /* If gpio still high (or high again) */
 473         if (gpio_get_value(irq_to_gpio(st->us->irq)))
 474                 if (st->inter == 0) {
 475                         /* already interrupt handler dealing with it */
 476                         disable_irq_nosync(st->us->irq);
 477                         if (st->inter == 1) {
 478                                 /* interrupt handler snuck in between test
 479                                  * and disable */
 480                                 enable_irq(st->us->irq);
 481                                 return 0;
 482                         }
 483                         return -EAGAIN;
 484                 }
 485         /* irq reenabled so success! */
 486         return 0;
 487 }
 488
 489 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 490 {
 491         int ret;
 492         struct lis3l02dq_state *state = indio_dev->dev_data;
 493
 494         state->trig = iio_allocate_trigger();
 495         state->trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
 496         if (!state->trig->name) {
 497                 ret = -ENOMEM;
 498                 goto error_free_trig;
 499         }
 500         snprintf((char *)state->trig->name,
 501                  IIO_TRIGGER_NAME_LENGTH,
 502                  "lis3l02dq-dev%d", indio_dev->id);
 503         state->trig->dev.parent = &state->us->dev;
 504         state->trig->owner = THIS_MODULE;
 505         state->trig->private_data = state;
 506         state->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 507         state->trig->try_reenable = &lis3l02dq_trig_try_reen;
 508         state->trig->control_attrs = &lis3l02dq_trigger_attr_group;
 509         ret = iio_trigger_register(state->trig);
 510         if (ret)
 511                 goto error_free_trig_name;
 512
 513         return 0;
 514
 515 error_free_trig_name:
 516         kfree(state->trig->name);
 517 error_free_trig:
 518         iio_free_trigger(state->trig);
 519
 520         return ret;
 521 }
 522
 523 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 524 {
 525         struct lis3l02dq_state *state = indio_dev->dev_data;
 526
 527         iio_trigger_unregister(state->trig);
 528         kfree(state->trig->name);
 529         iio_free_trigger(state->trig);
 530 }
 531
 532 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 533 {
 534         kfree(indio_dev->pollfunc);
 535         iio_sw_rb_free(indio_dev->ring);
 536 }
 537
 538 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 539 {
 540         int ret = 0;
 541         struct lis3l02dq_state *st = indio_dev->dev_data;
 542         struct iio_ring_buffer *ring;
 543         INIT_WORK(&st->work_trigger_to_ring, lis3l02dq_trigger_bh_to_ring);
 544         /* Set default scan mode */
 545
 546         iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
 547         iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
 548         iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
 549         indio_dev->scan_timestamp = true;
 550
 551         indio_dev->scan_el_attrs = &lis3l02dq_scan_el_group;
 552
 553         ring = iio_sw_rb_allocate(indio_dev);
 554         if (!ring) {
 555                 ret = -ENOMEM;
 556                 return ret;
 557         }
 558         indio_dev->ring = ring;
 559         /* Effectively select the ring buffer implementation */
 560         iio_ring_sw_register_funcs(&ring->access);
 561         ring->preenable = &lis3l02dq_data_rdy_ring_preenable;
 562         ring->postenable = &lis3l02dq_data_rdy_ring_postenable;
 563         ring->predisable = &lis3l02dq_data_rdy_ring_predisable;
 564         ring->owner = THIS_MODULE;
 565
 566         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 567         if (indio_dev->pollfunc == NULL) {
 568                 ret = -ENOMEM;
 569                 goto error_iio_sw_rb_free;;
 570         }
 571         indio_dev->pollfunc->poll_func_main = &lis3l02dq_poll_func_th;
 572         indio_dev->pollfunc->private_data = indio_dev;
 573         indio_dev->modes |= INDIO_RING_TRIGGERED;
 574         return 0;
 575
 576 error_iio_sw_rb_free:
 577         iio_sw_rb_free(indio_dev->ring);
 578         return ret;
 579 }
 580
 581 int lis3l02dq_initialize_ring(struct iio_ring_buffer *ring)
 582 {
 583         return iio_ring_buffer_register(ring, 0);
 584 }
 585
 586 void lis3l02dq_uninitialize_ring(struct iio_ring_buffer *ring)
 587 {
 588         iio_ring_buffer_unregister(ring);
 589 }
 590
 591
 592 int lis3l02dq_set_ring_length(struct iio_dev *indio_dev, int length)
 593 {
 594         /* Set sensible defaults for the ring buffer */
 595         if (indio_dev->ring->access.set_length)
 596                 return indio_dev->ring->access.set_length(indio_dev->ring, 500);
 597         return 0;
 598 }
 599
 600