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, LIS3L02DQ_SCAN_ACC_X, IIO_SIGNED(16),
  79                      LIS3L02DQ_REG_OUT_X_L_ADDR,
  80                      &lis3l02dq_scan_el_set_state);
  81 static IIO_SCAN_EL_C(accel_y, LIS3L02DQ_SCAN_ACC_Y, IIO_SIGNED(16),
  82                      LIS3L02DQ_REG_OUT_Y_L_ADDR,
  83                      &lis3l02dq_scan_el_set_state);
  84 static IIO_SCAN_EL_C(accel_z, LIS3L02DQ_SCAN_ACC_Z, IIO_SIGNED(16),
  85                      LIS3L02DQ_REG_OUT_Z_L_ADDR,
  86                      &lis3l02dq_scan_el_set_state);
  87 static IIO_SCAN_EL_TIMESTAMP;
  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 {
 197         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
 198         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
 199         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
 200         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
 201         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
 202         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
 203 };
 204
 205 /**
 206  * lis3l02dq_read_all() Reads all channels currently selected
 207  * @st:         device specific state
 208  * @rx_array:   (dma capable) recieve array, must be at least
 209  *              4*number of channels
 210  **/
 211 int lis3l02dq_read_all(struct lis3l02dq_state *st, u8 *rx_array)
 212 {
 213         struct spi_transfer *xfers;
 214         struct spi_message msg;
 215         int ret, i, j = 0;
 216
 217         xfers = kzalloc((st->indio_dev->scan_count) * 2
 218                         * sizeof(*xfers), GFP_KERNEL);
 219         if (!xfers)
 220                 return -ENOMEM;
 221
 222         mutex_lock(&st->buf_lock);
 223
 224         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++) {
 225                 if (st->indio_dev->scan_mask & (1 << i)) {
 226                         /* lower byte */
 227                         xfers[j].tx_buf = st->tx + 2*j;
 228                         st->tx[2*j] = read_all_tx_array[i*4];
 229                         st->tx[2*j + 1] = 0;
 230                         if (rx_array)
 231                                 xfers[j].rx_buf = rx_array + j*2;
 232                         xfers[j].bits_per_word = 8;
 233                         xfers[j].len = 2;
 234                         xfers[j].cs_change = 1;
 235                         j++;
 236
 237                         /* upper byte */
 238                         xfers[j].tx_buf = st->tx + 2*j;
 239                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 240                         st->tx[2*j + 1] = 0;
 241                         if (rx_array)
 242                                 xfers[j].rx_buf = rx_array + j*2;
 243                         xfers[j].bits_per_word = 8;
 244                         xfers[j].len = 2;
 245                         xfers[j].cs_change = 1;
 246                         j++;
 247                 }
 248         }
 249         /* After these are transmitted, the rx_buff should have
 250          * values in alternate bytes
 251          */
 252         spi_message_init(&msg);
 253         for (j = 0; j < st->indio_dev->scan_count * 2; j++)
 254                 spi_message_add_tail(&xfers[j], &msg);
 255
 256         ret = spi_sync(st->us, &msg);
 257         mutex_unlock(&st->buf_lock);
 258         kfree(xfers);
 259
 260         return ret;
 261 }
 262
 263
 264 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
 265  * specific to be rolled into the core.
 266  */
 267 static void lis3l02dq_trigger_bh_to_ring(struct work_struct *work_s)
 268 {
 269         struct lis3l02dq_state *st
 270                 = container_of(work_s, struct lis3l02dq_state,
 271                                work_trigger_to_ring);
 272
 273         u8 *rx_array;
 274         int i = 0;
 275         u16 *data;
 276         size_t datasize = st->indio_dev
 277                 ->ring->access.get_bpd(st->indio_dev->ring);
 278
 279         data = kmalloc(datasize , GFP_KERNEL);
 280         if (data == NULL) {
 281                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 282                 return;
 283         }
 284         /* Due to interleaved nature of transmission this buffer must be
 285          * twice the number of bytes, or 4 times the number of channels
 286          */
 287         rx_array = kmalloc(4 * (st->indio_dev->scan_count), GFP_KERNEL);
 288         if (rx_array == NULL) {
 289                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 290                 kfree(data);
 291                 return;
 292         }
 293
 294         /* whilst trigger specific, if this read does nto occur the data
 295            ready interrupt will not be cleared.  Need to add a mechanism
 296            to provide a dummy read function if this is not triggering on
 297            the data ready function but something else is.
 298         */
 299         st->inter = 0;
 300
 301         if (st->indio_dev->scan_count)
 302                 if (lis3l02dq_read_all(st, rx_array) >= 0)
 303                         for (; i < st->indio_dev->scan_count; i++)
 304                                 data[i] = combine_8_to_16(rx_array[i*4+1],
 305                                                           rx_array[i*4+3]);
 306         /* Guaranteed to be aligned with 8 byte boundary */
 307         if (st->indio_dev->scan_timestamp)
 308                 *((s64 *)(data + ((i + 3)/4)*4)) = st->last_timestamp;
 309
 310         st->indio_dev->ring->access.store_to(st->indio_dev->ring,
 311                                             (u8 *)data,
 312                                             st->last_timestamp);
 313
 314         iio_trigger_notify_done(st->indio_dev->trig);
 315         kfree(rx_array);
 316         kfree(data);
 317
 318         return;
 319 }
 320 /* in these circumstances is it better to go with unaligned packing and
 321  * deal with the cost?*/
 322 static int lis3l02dq_data_rdy_ring_preenable(struct iio_dev *indio_dev)
 323 {
 324         size_t size;
 325         /* Check if there are any scan elements enabled, if not fail*/
 326         if (!(indio_dev->scan_count || indio_dev->scan_timestamp))
 327                 return -EINVAL;
 328
 329         if (indio_dev->ring->access.set_bpd) {
 330                 if (indio_dev->scan_timestamp)
 331                         if (indio_dev->scan_count) /* Timestamp and data */
 332                                 size = 2*sizeof(s64);
 333                         else /* Timestamp only  */
 334                                 size = sizeof(s64);
 335                 else /* Data only */
 336                         size = indio_dev->scan_count*sizeof(s16);
 337                 indio_dev->ring->access.set_bpd(indio_dev->ring, size);
 338         }
 339
 340         return 0;
 341 }
 342
 343 static int lis3l02dq_data_rdy_ring_postenable(struct iio_dev *indio_dev)
 344 {
 345         return indio_dev->trig
 346                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 347                                                indio_dev->pollfunc)
 348                 : 0;
 349 }
 350
 351 static int lis3l02dq_data_rdy_ring_predisable(struct iio_dev *indio_dev)
 352 {
 353         return indio_dev->trig
 354                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 355                                                 indio_dev->pollfunc)
 356                 : 0;
 357 }
 358
 359
 360 /* Caller responsible for locking as necessary. */
 361 static int __lis3l02dq_write_data_ready_config(struct device *dev,
 362                                                struct
 363                                                iio_event_handler_list *list,
 364                                                bool state)
 365 {
 366         int ret;
 367         u8 valold;
 368         bool currentlyset;
 369         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 370
 371 /* Get the current event mask register */
 372         ret = lis3l02dq_spi_read_reg_8(dev,
 373                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 374                                        &valold);
 375         if (ret)
 376                 goto error_ret;
 377 /* Find out if data ready is already on */
 378         currentlyset
 379                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 380
 381 /* Disable requested */
 382         if (!state && currentlyset) {
 383
 384                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 385                 /* The double write is to overcome a hardware bug?*/
 386                 ret = lis3l02dq_spi_write_reg_8(dev,
 387                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 388                                                 &valold);
 389                 if (ret)
 390                         goto error_ret;
 391                 ret = lis3l02dq_spi_write_reg_8(dev,
 392                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 393                                                 &valold);
 394                 if (ret)
 395                         goto error_ret;
 396
 397                 iio_remove_event_from_list(list,
 398                                            &indio_dev->interrupts[0]
 399                                            ->ev_list);
 400
 401 /* Enable requested */
 402         } else if (state && !currentlyset) {
 403                 /* if not set, enable requested */
 404                 valold |= LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 405                 iio_add_event_to_list(list, &indio_dev->interrupts[0]->ev_list);
 406                 ret = lis3l02dq_spi_write_reg_8(dev,
 407                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 408                                                 &valold);
 409                 if (ret)
 410                         goto error_ret;
 411         }
 412
 413         return 0;
 414 error_ret:
 415         return ret;
 416 }
 417
 418 /**
 419  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 420  *
 421  * If disabling the interrupt also does a final read to ensure it is clear.
 422  * This is only important in some cases where the scan enable elements are
 423  * switched before the ring is reenabled.
 424  **/
 425 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 426                                                 bool state)
 427 {
 428         struct lis3l02dq_state *st = trig->private_data;
 429         int ret = 0;
 430         u8 t;
 431         __lis3l02dq_write_data_ready_config(&st->indio_dev->dev,
 432                                             &iio_event_data_rdy_trig,
 433                                             state);
 434         if (state == false) {
 435                 /* possible quirk with handler currently worked around
 436                    by ensuring the work queue is empty */
 437                 flush_scheduled_work();
 438                 /* Clear any outstanding ready events */
 439                 ret = lis3l02dq_read_all(st, NULL);
 440         }
 441         lis3l02dq_spi_read_reg_8(&st->indio_dev->dev,
 442                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 443                                  &t);
 444         return ret;
 445 }
 446 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
 447
 448 static struct attribute *lis3l02dq_trigger_attrs[] = {
 449         &dev_attr_name.attr,
 450         NULL,
 451 };
 452
 453 static const struct attribute_group lis3l02dq_trigger_attr_group = {
 454         .attrs = lis3l02dq_trigger_attrs,
 455 };
 456
 457 /**
 458  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 459  * @trig:       the datardy trigger
 460  *
 461  * As the trigger may occur on any data element being updated it is
 462  * really rather likely to occur during the read from the previous
 463  * trigger event.  The only way to discover if this has occured on
 464  * boards not supporting level interrupts is to take a look at the line.
 465  * If it is indicating another interrupt and we don't seem to have a
 466  * handler looking at it, then we need to notify the core that we need
 467  * to tell the triggering core to try reading all these again.
 468  **/
 469 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 470 {
 471         struct lis3l02dq_state *st = trig->private_data;
 472         enable_irq(st->us->irq);
 473         /* If gpio still high (or high again) */
 474         if (gpio_get_value(irq_to_gpio(st->us->irq)))
 475                 if (st->inter == 0) {
 476                         /* already interrupt handler dealing with it */
 477                         disable_irq_nosync(st->us->irq);
 478                         if (st->inter == 1) {
 479                                 /* interrupt handler snuck in between test
 480                                  * and disable */
 481                                 enable_irq(st->us->irq);
 482                                 return 0;
 483                         }
 484                         return -EAGAIN;
 485                 }
 486         /* irq reenabled so success! */
 487         return 0;
 488 }
 489
 490 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 491 {
 492         int ret;
 493         struct lis3l02dq_state *state = indio_dev->dev_data;
 494
 495         state->trig = iio_allocate_trigger();
 496         state->trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
 497         if (!state->trig->name) {
 498                 ret = -ENOMEM;
 499                 goto error_free_trig;
 500         }
 501         snprintf((char *)state->trig->name,
 502                  IIO_TRIGGER_NAME_LENGTH,
 503                  "lis3l02dq-dev%d", indio_dev->id);
 504         state->trig->dev.parent = &state->us->dev;
 505         state->trig->owner = THIS_MODULE;
 506         state->trig->private_data = state;
 507         state->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 508         state->trig->try_reenable = &lis3l02dq_trig_try_reen;
 509         state->trig->control_attrs = &lis3l02dq_trigger_attr_group;
 510         ret = iio_trigger_register(state->trig);
 511         if (ret)
 512                 goto error_free_trig_name;
 513
 514         return 0;
 515
 516 error_free_trig_name:
 517         kfree(state->trig->name);
 518 error_free_trig:
 519         iio_free_trigger(state->trig);
 520
 521         return ret;
 522 }
 523
 524 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 525 {
 526         struct lis3l02dq_state *state = indio_dev->dev_data;
 527
 528         iio_trigger_unregister(state->trig);
 529         kfree(state->trig->name);
 530         iio_free_trigger(state->trig);
 531 }
 532
 533 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 534 {
 535         kfree(indio_dev->pollfunc);
 536         iio_sw_rb_free(indio_dev->ring);
 537 }
 538
 539 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 540 {
 541         int ret = 0;
 542         struct lis3l02dq_state *st = indio_dev->dev_data;
 543         struct iio_ring_buffer *ring;
 544         INIT_WORK(&st->work_trigger_to_ring, lis3l02dq_trigger_bh_to_ring);
 545         /* Set default scan mode */
 546
 547         iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
 548         iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
 549         iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
 550         indio_dev->scan_timestamp = true;
 551
 552         indio_dev->scan_el_attrs = &lis3l02dq_scan_el_group;
 553
 554         ring = iio_sw_rb_allocate(indio_dev);
 555         if (!ring) {
 556                 ret = -ENOMEM;
 557                 return ret;
 558         }
 559         indio_dev->ring = ring;
 560         /* Effectively select the ring buffer implementation */
 561         iio_ring_sw_register_funcs(&ring->access);
 562         ring->preenable = &lis3l02dq_data_rdy_ring_preenable;
 563         ring->postenable = &lis3l02dq_data_rdy_ring_postenable;
 564         ring->predisable = &lis3l02dq_data_rdy_ring_predisable;
 565         ring->owner = THIS_MODULE;
 566
 567         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 568         if (indio_dev->pollfunc == NULL) {
 569                 ret = -ENOMEM;
 570                 goto error_iio_sw_rb_free;;
 571         }
 572         indio_dev->pollfunc->poll_func_main = &lis3l02dq_poll_func_th;
 573         indio_dev->pollfunc->private_data = indio_dev;
 574         indio_dev->modes |= INDIO_RING_TRIGGERED;
 575         return 0;
 576
 577 error_iio_sw_rb_free:
 578         iio_sw_rb_free(indio_dev->ring);
 579         return ret;
 580 }
 581
 582 int lis3l02dq_initialize_ring(struct iio_ring_buffer *ring)
 583 {
 584         return iio_ring_buffer_register(ring);
 585 }
 586
 587 void lis3l02dq_uninitialize_ring(struct iio_ring_buffer *ring)
 588 {
 589         iio_ring_buffer_unregister(ring);
 590 }
 591
 592
 593 int lis3l02dq_set_ring_length(struct iio_dev *indio_dev, int length)
 594 {
 595         /* Set sensible defaults for the ring buffer */
 596         if (indio_dev->ring->access.set_length)
 597                 return indio_dev->ring->access.set_length(indio_dev->ring, 500);
 598         return 0;
 599 }
 600
 601