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
  12 #include "../iio.h"
  13 #include "../sysfs.h"
  14 #include "../ring_sw.h"
  15 #include "accel.h"
  16 #include "../trigger.h"
  17 #include "lis3l02dq.h"
  18
  19 /**
  20  * combine_8_to_16() utility function to munge to u8s into u16
  21  **/
  22 static inline u16 combine_8_to_16(u8 lower, u8 upper)
  23 {
  24         u16 _lower = lower;
  25         u16 _upper = upper;
  26         return _lower | (_upper << 8);
  27 }
  28
  29 /**
  30  * lis3l02dq_scan_el_set_state() set whether a scan contains a given channel
  31  * @scan_el:    associtate iio scan element attribute
  32  * @indio_dev:  the device structure
  33  * @bool:       desired state
  34  *
  35  * mlock already held when this is called.
  36  **/
  37 static int lis3l02dq_scan_el_set_state(struct iio_scan_el *scan_el,
  38                                        struct iio_dev *indio_dev,
  39                                        bool state)
  40 {
  41         u8 t, mask;
  42         int ret;
  43
  44         ret = lis3l02dq_spi_read_reg_8(&indio_dev->dev,
  45                                        LIS3L02DQ_REG_CTRL_1_ADDR,
  46                                        &t);
  47         if (ret)
  48                 goto error_ret;
  49         switch (scan_el->label) {
  50         case LIS3L02DQ_REG_OUT_X_L_ADDR:
  51                 mask = LIS3L02DQ_REG_CTRL_1_AXES_X_ENABLE;
  52                 break;
  53         case LIS3L02DQ_REG_OUT_Y_L_ADDR:
  54                 mask = LIS3L02DQ_REG_CTRL_1_AXES_Y_ENABLE;
  55                 break;
  56         case LIS3L02DQ_REG_OUT_Z_L_ADDR:
  57                 mask = LIS3L02DQ_REG_CTRL_1_AXES_Z_ENABLE;
  58                 break;
  59         default:
  60                 ret = -EINVAL;
  61                 goto error_ret;
  62         }
  63
  64         if (!(mask & t) == state) {
  65                 if (state)
  66                         t |= mask;
  67                 else
  68                         t &= ~mask;
  69                 ret = lis3l02dq_spi_write_reg_8(&indio_dev->dev,
  70                                                 LIS3L02DQ_REG_CTRL_1_ADDR,
  71                                                 &t);
  72         }
  73 error_ret:
  74         return ret;
  75
  76 }
  77 static IIO_SCAN_EL_C(accel_x, LIS3L02DQ_SCAN_ACC_X, IIO_SIGNED(16),
  78                      LIS3L02DQ_REG_OUT_X_L_ADDR,
  79                      &lis3l02dq_scan_el_set_state);
  80 static IIO_SCAN_EL_C(accel_y, LIS3L02DQ_SCAN_ACC_Y, IIO_SIGNED(16),
  81                      LIS3L02DQ_REG_OUT_Y_L_ADDR,
  82                      &lis3l02dq_scan_el_set_state);
  83 static IIO_SCAN_EL_C(accel_z, LIS3L02DQ_SCAN_ACC_Z, IIO_SIGNED(16),
  84                      LIS3L02DQ_REG_OUT_Z_L_ADDR,
  85                      &lis3l02dq_scan_el_set_state);
  86 static IIO_SCAN_EL_TIMESTAMP;
  87
  88 static struct attribute *lis3l02dq_scan_el_attrs[] = {
  89         &iio_scan_el_accel_x.dev_attr.attr,
  90         &iio_scan_el_accel_y.dev_attr.attr,
  91         &iio_scan_el_accel_z.dev_attr.attr,
  92         &iio_scan_el_timestamp.dev_attr.attr,
  93         NULL,
  94 };
  95
  96 static struct attribute_group lis3l02dq_scan_el_group = {
  97         .attrs = lis3l02dq_scan_el_attrs,
  98         .name = "scan_elements",
  99 };
 100
 101 /**
 102  * lis3l02dq_poll_func_th() top half interrupt handler called by trigger
 103  * @private_data:       iio_dev
 104  **/
 105 static void lis3l02dq_poll_func_th(struct iio_dev *indio_dev)
 106 {
 107   struct lis3l02dq_state *st = iio_dev_get_devdata(indio_dev);
 108         st->last_timestamp = indio_dev->trig->timestamp;
 109         schedule_work(&st->work_trigger_to_ring);
 110         /* Indicate that this interrupt is being handled */
 111
 112         /* Technically this is trigger related, but without this
 113          * handler running there is currently now way for the interrupt
 114          * to clear.
 115          */
 116         st->inter = 1;
 117 }
 118
 119 /**
 120  * lis3l02dq_data_rdy_trig_poll() the event handler for the data rdy trig
 121  **/
 122 static int lis3l02dq_data_rdy_trig_poll(struct iio_dev *dev_info,
 123                                        int index,
 124                                        s64 timestamp,
 125                                        int no_test)
 126 {
 127         struct lis3l02dq_state *st = iio_dev_get_devdata(dev_info);
 128         struct iio_trigger *trig = st->trig;
 129
 130         trig->timestamp = timestamp;
 131         iio_trigger_poll(trig);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 /* This is an event as it is a response to a physical interrupt */
 137 IIO_EVENT_SH(data_rdy_trig, &lis3l02dq_data_rdy_trig_poll);
 138
 139 /**
 140  * lis3l02dq_read_accel_from_ring() individual acceleration read from ring
 141  **/
 142 ssize_t lis3l02dq_read_accel_from_ring(struct device *dev,
 143                                        struct device_attribute *attr,
 144                                        char *buf)
 145 {
 146         struct iio_scan_el *el = NULL;
 147         int ret, len = 0, i = 0;
 148         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 149         struct iio_dev *dev_info = dev_get_drvdata(dev);
 150         s16 *data;
 151
 152         while (dev_info->scan_el_attrs->attrs[i]) {
 153                 el = to_iio_scan_el((struct device_attribute *)
 154                                     (dev_info->scan_el_attrs->attrs[i]));
 155                 /* label is in fact the address */
 156                 if (el->label == this_attr->address)
 157                         break;
 158                 i++;
 159         }
 160         if (!dev_info->scan_el_attrs->attrs[i]) {
 161                 ret = -EINVAL;
 162                 goto error_ret;
 163         }
 164         /* If this element is in the scan mask */
 165         ret = iio_scan_mask_query(dev_info, el->number);
 166         if (ret < 0)
 167                 goto error_ret;
 168         if (ret) {
 169                 data = kmalloc(dev_info->ring->access.get_bpd(dev_info->ring),
 170                                GFP_KERNEL);
 171                 if (data == NULL)
 172                         return -ENOMEM;
 173                 ret = dev_info->ring->access.read_last(dev_info->ring,
 174                                                       (u8 *)data);
 175                 if (ret)
 176                         goto error_free_data;
 177         } else {
 178                 ret = -EINVAL;
 179                 goto error_ret;
 180         }
 181         len = iio_scan_mask_count_to_right(dev_info, el->number);
 182         if (len < 0) {
 183                 ret = len;
 184                 goto error_free_data;
 185         }
 186         len = sprintf(buf, "ring %d\n", data[len]);
 187 error_free_data:
 188         kfree(data);
 189 error_ret:
 190         return ret ? ret : len;
 191
 192 }
 193
 194 static const u8 read_all_tx_array[] =
 195 {
 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                 return;
 290         }
 291
 292         /* whilst trigger specific, if this read does nto occur the data
 293            ready interrupt will not be cleared.  Need to add a mechanism
 294            to provide a dummy read function if this is not triggering on
 295            the data ready function but something else is.
 296         */
 297         st->inter = 0;
 298
 299         if (st->indio_dev->scan_count)
 300                 if (lis3l02dq_read_all(st, rx_array) >= 0)
 301                         for (; i < st->indio_dev->scan_count; i++)
 302                                 data[i] = combine_8_to_16(rx_array[i*4+1],
 303                                                           rx_array[i*4+3]);
 304         /* Guaranteed to be aligned with 8 byte boundary */
 305         if (st->indio_dev->scan_timestamp)
 306                 *((s64 *)(data + ((i + 3)/4)*4)) = st->last_timestamp;
 307
 308         st->indio_dev->ring->access.store_to(st->indio_dev->ring,
 309                                             (u8 *)data,
 310                                             st->last_timestamp);
 311
 312         iio_trigger_notify_done(st->indio_dev->trig);
 313         kfree(rx_array);
 314         kfree(data);
 315
 316         return;
 317 }
 318 /* in these circumstances is it better to go with unaligned packing and
 319  * deal with the cost?*/
 320 static int lis3l02dq_data_rdy_ring_preenable(struct iio_dev *indio_dev)
 321 {
 322         size_t size;
 323         /* Check if there are any scan elements enabled, if not fail*/
 324         if (!(indio_dev->scan_count || indio_dev->scan_timestamp))
 325                 return -EINVAL;
 326
 327         if (indio_dev->ring->access.set_bpd) {
 328                 if (indio_dev->scan_timestamp)
 329                         if (indio_dev->scan_count) /* Timestamp and data */
 330                                 size = 2*sizeof(s64);
 331                         else /* Timestamp only  */
 332                                 size = sizeof(s64);
 333                 else /* Data only */
 334                         size = indio_dev->scan_count*sizeof(s16);
 335                 indio_dev->ring->access.set_bpd(indio_dev->ring, size);
 336         }
 337
 338         return 0;
 339 }
 340
 341 static int lis3l02dq_data_rdy_ring_postenable(struct iio_dev *indio_dev)
 342 {
 343         return indio_dev->trig
 344                 ? iio_trigger_attach_poll_func(indio_dev->trig,
 345                                                indio_dev->pollfunc)
 346                 : 0;
 347 }
 348
 349 static int lis3l02dq_data_rdy_ring_predisable(struct iio_dev *indio_dev)
 350 {
 351         return indio_dev->trig
 352                 ? iio_trigger_dettach_poll_func(indio_dev->trig,
 353                                                 indio_dev->pollfunc)
 354                 : 0;
 355 }
 356
 357
 358 /* Caller responsible for locking as necessary. */
 359 static int __lis3l02dq_write_data_ready_config(struct device *dev,
 360                                                struct
 361                                                iio_event_handler_list *list,
 362                                                bool state)
 363 {
 364         int ret;
 365         u8 valold;
 366         bool currentlyset;
 367         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 368
 369 /* Get the current event mask register */
 370         ret = lis3l02dq_spi_read_reg_8(dev,
 371                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 372                                        &valold);
 373         if (ret)
 374                 goto error_ret;
 375 /* Find out if data ready is already on */
 376         currentlyset
 377                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 378
 379 /* Disable requested */
 380         if (!state && currentlyset) {
 381
 382                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 383                 /* The double write is to overcome a hardware bug?*/
 384                 ret = lis3l02dq_spi_write_reg_8(dev,
 385                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 386                                                 &valold);
 387                 if (ret)
 388                         goto error_ret;
 389                 ret = lis3l02dq_spi_write_reg_8(dev,
 390                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 391                                                 &valold);
 392                 if (ret)
 393                         goto error_ret;
 394
 395                 iio_remove_event_from_list(list,
 396                                            &indio_dev->interrupts[0]
 397                                            ->ev_list);
 398
 399 /* Enable requested */
 400         } else if (state && !currentlyset) {
 401                 /* if not set, enable requested */
 402                 valold |= LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 403                 iio_add_event_to_list(list, &indio_dev->interrupts[0]->ev_list);
 404                 ret = lis3l02dq_spi_write_reg_8(dev,
 405                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 406                                                 &valold);
 407                 if (ret)
 408                         goto error_ret;
 409         }
 410
 411         return 0;
 412 error_ret:
 413         return ret;
 414 }
 415
 416 /**
 417  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 418  *
 419  * If disabling the interrupt also does a final read to ensure it is clear.
 420  * This is only important in some cases where the scan enable elements are
 421  * switched before the ring is reenabled.
 422  **/
 423 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 424                                                 bool state)
 425 {
 426         struct lis3l02dq_state *st = trig->private_data;
 427         int ret = 0;
 428         u8 t;
 429         __lis3l02dq_write_data_ready_config(&st->indio_dev->dev,
 430                                             &iio_event_data_rdy_trig,
 431                                             state);
 432         if (state == false) {
 433                 /* possible quirk with handler currently worked around
 434                    by ensuring the work queue is empty */
 435                 flush_scheduled_work();
 436                 /* Clear any outstanding ready events */
 437                 ret = lis3l02dq_read_all(st, NULL);
 438         }
 439         lis3l02dq_spi_read_reg_8(&st->indio_dev->dev,
 440                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 441                                  &t);
 442         return ret;
 443 }
 444 DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
 445
 446 static struct attribute *lis3l02dq_trigger_attrs[] = {
 447         &dev_attr_name.attr,
 448         NULL,
 449 };
 450
 451 static const struct attribute_group lis3l02dq_trigger_attr_group = {
 452         .attrs = lis3l02dq_trigger_attrs,
 453 };
 454
 455 /**
 456  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 457  * @trig:       the datardy trigger
 458  *
 459  * As the trigger may occur on any data element being updated it is
 460  * really rather likely to occur during the read from the previous
 461  * trigger event.  The only way to discover if this has occured on
 462  * boards not supporting level interrupts is to take a look at the line.
 463  * If it is indicating another interrupt and we don't seem to have a
 464  * handler looking at it, then we need to notify the core that we need
 465  * to tell the triggering core to try reading all these again.
 466  **/
 467 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 468 {
 469         struct lis3l02dq_state *st = trig->private_data;
 470         enable_irq(st->us->irq);
 471         /* If gpio still high (or high again) */
 472         if (gpio_get_value(irq_to_gpio(st->us->irq)))
 473                 if (st->inter == 0) {
 474                         /* already interrupt handler dealing with it */
 475                         disable_irq_nosync(st->us->irq);
 476                         if (st->inter == 1) {
 477                                 /* interrupt handler snuck in between test
 478                                  * and disable */
 479                                 enable_irq(st->us->irq);
 480                                 return 0;
 481                         }
 482                         return -EAGAIN;
 483                 }
 484         /* irq reenabled so success! */
 485         return 0;
 486 }
 487
 488 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 489 {
 490         int ret;
 491         struct lis3l02dq_state *state = indio_dev->dev_data;
 492
 493         state->trig = iio_allocate_trigger();
 494         state->trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
 495         if (!state->trig->name) {
 496                 ret = -ENOMEM;
 497                 goto error_free_trig;
 498         }
 499         snprintf((char *)state->trig->name,
 500                  IIO_TRIGGER_NAME_LENGTH,
 501                  "lis3l02dq-dev%d", indio_dev->id);
 502         state->trig->dev.parent = &state->us->dev;
 503         state->trig->owner = THIS_MODULE;
 504         state->trig->private_data = state;
 505         state->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 506         state->trig->try_reenable = &lis3l02dq_trig_try_reen;
 507         state->trig->control_attrs = &lis3l02dq_trigger_attr_group;
 508         ret = iio_trigger_register(state->trig);
 509         if (ret)
 510                 goto error_free_trig_name;
 511
 512         return 0;
 513
 514 error_free_trig_name:
 515         kfree(state->trig->name);
 516 error_free_trig:
 517         iio_free_trigger(state->trig);
 518
 519         return ret;
 520 }
 521
 522 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 523 {
 524         struct lis3l02dq_state *state = indio_dev->dev_data;
 525
 526         iio_trigger_unregister(state->trig);
 527         kfree(state->trig->name);
 528         iio_free_trigger(state->trig);
 529 }
 530
 531 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 532 {
 533         kfree(indio_dev->pollfunc);
 534         iio_sw_rb_free(indio_dev->ring);
 535 }
 536
 537 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 538 {
 539         int ret = 0;
 540         struct lis3l02dq_state *st = indio_dev->dev_data;
 541         struct iio_ring_buffer *ring;
 542         INIT_WORK(&st->work_trigger_to_ring, lis3l02dq_trigger_bh_to_ring);
 543         /* Set default scan mode */
 544
 545         iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
 546         iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
 547         iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
 548         indio_dev->scan_timestamp = true;
 549
 550         indio_dev->scan_el_attrs = &lis3l02dq_scan_el_group;
 551
 552         ring = iio_sw_rb_allocate(indio_dev);
 553         if (!ring) {
 554                 ret = -ENOMEM;
 555                 return ret;
 556         }
 557         indio_dev->ring = ring;
 558         /* Effectively select the ring buffer implementation */
 559         iio_ring_sw_register_funcs(&ring->access);
 560         ring->preenable = &lis3l02dq_data_rdy_ring_preenable;
 561         ring->postenable = &lis3l02dq_data_rdy_ring_postenable;
 562         ring->predisable = &lis3l02dq_data_rdy_ring_predisable;
 563         ring->owner = THIS_MODULE;
 564
 565         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 566         if (indio_dev->pollfunc == NULL) {
 567                 ret = -ENOMEM;
 568                 goto error_iio_sw_rb_free;;
 569         }
 570         indio_dev->pollfunc->poll_func_main = &lis3l02dq_poll_func_th;
 571         indio_dev->pollfunc->private_data = indio_dev;
 572         indio_dev->modes |= INDIO_RING_TRIGGERED;
 573         return 0;
 574
 575 error_iio_sw_rb_free:
 576         iio_sw_rb_free(indio_dev->ring);
 577         return ret;
 578 }
 579
 580 int lis3l02dq_initialize_ring(struct iio_ring_buffer *ring)
 581 {
 582         return iio_ring_buffer_register(ring);
 583 }
 584
 585 void lis3l02dq_uninitialize_ring(struct iio_ring_buffer *ring)
 586 {
 587         iio_ring_buffer_unregister(ring);
 588 }
 589
 590
 591 int lis3l02dq_set_ring_length(struct iio_dev *indio_dev, int length)
 592 {
 593         /* Set sensible defaults for the ring buffer */
 594         if (indio_dev->ring->access.set_length)
 595                 return indio_dev->ring->access.set_length(indio_dev->ring, 500);
 596         return 0;
 597 }
 598
 599