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, s64 time)
 107 {
 108         struct lis3l02dq_state *st = iio_dev_get_devdata(indio_dev);
 109         st->last_timestamp = time;
 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         iio_trigger_poll(trig, timestamp);
 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         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
 196         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
 197         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
 198         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
 199         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
 200         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
 201 };
 202
 203 /**
 204  * lis3l02dq_read_all() Reads all channels currently selected
 205  * @st:         device specific state
 206  * @rx_array:   (dma capable) recieve array, must be at least
 207  *              4*number of channels
 208  **/
 209 static int lis3l02dq_read_all(struct lis3l02dq_state *st, u8 *rx_array)
 210 {
 211         struct spi_transfer *xfers;
 212         struct spi_message msg;
 213         int ret, i, j = 0;
 214
 215         xfers = kzalloc((st->indio_dev->scan_count) * 2
 216                         * sizeof(*xfers), GFP_KERNEL);
 217         if (!xfers)
 218                 return -ENOMEM;
 219
 220         mutex_lock(&st->buf_lock);
 221
 222         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++) {
 223                 if (st->indio_dev->scan_mask & (1 << i)) {
 224                         /* lower byte */
 225                         xfers[j].tx_buf = st->tx + 2*j;
 226                         st->tx[2*j] = read_all_tx_array[i*4];
 227                         st->tx[2*j + 1] = 0;
 228                         if (rx_array)
 229                                 xfers[j].rx_buf = rx_array + j*2;
 230                         xfers[j].bits_per_word = 8;
 231                         xfers[j].len = 2;
 232                         xfers[j].cs_change = 1;
 233                         j++;
 234
 235                         /* upper byte */
 236                         xfers[j].tx_buf = st->tx + 2*j;
 237                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 238                         st->tx[2*j + 1] = 0;
 239                         if (rx_array)
 240                                 xfers[j].rx_buf = rx_array + j*2;
 241                         xfers[j].bits_per_word = 8;
 242                         xfers[j].len = 2;
 243                         xfers[j].cs_change = 1;
 244                         j++;
 245                 }
 246         }
 247         /* After these are transmitted, the rx_buff should have
 248          * values in alternate bytes
 249          */
 250         spi_message_init(&msg);
 251         for (j = 0; j < st->indio_dev->scan_count * 2; j++)
 252                 spi_message_add_tail(&xfers[j], &msg);
 253
 254         ret = spi_sync(st->us, &msg);
 255         mutex_unlock(&st->buf_lock);
 256         kfree(xfers);
 257
 258         return ret;
 259 }
 260
 261
 262 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
 263  * specific to be rolled into the core.
 264  */
 265 static void lis3l02dq_trigger_bh_to_ring(struct work_struct *work_s)
 266 {
 267         struct lis3l02dq_state *st
 268                 = container_of(work_s, struct lis3l02dq_state,
 269                                work_trigger_to_ring);
 270
 271         u8 *rx_array;
 272         int i = 0;
 273         u16 *data;
 274         size_t datasize = st->indio_dev
 275                 ->ring->access.get_bpd(st->indio_dev->ring);
 276
 277         data = kmalloc(datasize , GFP_KERNEL);
 278         if (data == NULL) {
 279                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 280                 return;
 281         }
 282         /* Due to interleaved nature of transmission this buffer must be
 283          * twice the number of bytes, or 4 times the number of channels
 284          */
 285         rx_array = kmalloc(4 * (st->indio_dev->scan_count), GFP_KERNEL);
 286         if (rx_array == NULL) {
 287                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 288                 kfree(data);
 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
 319 /* Caller responsible for locking as necessary. */
 320 static int
 321 __lis3l02dq_write_data_ready_config(struct device *dev,
 322                                     struct iio_event_handler_list *list,
 323                                     bool state)
 324 {
 325         int ret;
 326         u8 valold;
 327         bool currentlyset;
 328         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 329
 330 /* Get the current event mask register */
 331         ret = lis3l02dq_spi_read_reg_8(dev,
 332                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 333                                        &valold);
 334         if (ret)
 335                 goto error_ret;
 336 /* Find out if data ready is already on */
 337         currentlyset
 338                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 339
 340 /* Disable requested */
 341         if (!state && currentlyset) {
 342
 343                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 344                 /* The double write is to overcome a hardware bug?*/
 345                 ret = lis3l02dq_spi_write_reg_8(dev,
 346                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 347                                                 &valold);
 348                 if (ret)
 349                         goto error_ret;
 350                 ret = lis3l02dq_spi_write_reg_8(dev,
 351                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 352                                                 &valold);
 353                 if (ret)
 354                         goto error_ret;
 355
 356                 iio_remove_event_from_list(list,
 357                                            &indio_dev->interrupts[0]
 358                                            ->ev_list);
 359
 360 /* Enable requested */
 361         } else if (state && !currentlyset) {
 362                 /* if not set, enable requested */
 363                 valold |= LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 364                 iio_add_event_to_list(list, &indio_dev->interrupts[0]->ev_list);
 365                 ret = lis3l02dq_spi_write_reg_8(dev,
 366                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 367                                                 &valold);
 368                 if (ret)
 369                         goto error_ret;
 370         }
 371
 372         return 0;
 373 error_ret:
 374         return ret;
 375 }
 376
 377 /**
 378  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 379  *
 380  * If disabling the interrupt also does a final read to ensure it is clear.
 381  * This is only important in some cases where the scan enable elements are
 382  * switched before the ring is reenabled.
 383  **/
 384 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 385                                                 bool state)
 386 {
 387         struct lis3l02dq_state *st = trig->private_data;
 388         int ret = 0;
 389         u8 t;
 390         __lis3l02dq_write_data_ready_config(&st->indio_dev->dev,
 391                                             &iio_event_data_rdy_trig,
 392                                             state);
 393         if (state == false) {
 394                 /* possible quirk with handler currently worked around
 395                    by ensuring the work queue is empty */
 396                 flush_scheduled_work();
 397                 /* Clear any outstanding ready events */
 398                 ret = lis3l02dq_read_all(st, NULL);
 399         }
 400         lis3l02dq_spi_read_reg_8(&st->indio_dev->dev,
 401                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 402                                  &t);
 403         return ret;
 404 }
 405 static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
 406
 407 static struct attribute *lis3l02dq_trigger_attrs[] = {
 408         &dev_attr_name.attr,
 409         NULL,
 410 };
 411
 412 static const struct attribute_group lis3l02dq_trigger_attr_group = {
 413         .attrs = lis3l02dq_trigger_attrs,
 414 };
 415
 416 /**
 417  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 418  * @trig:       the datardy trigger
 419  *
 420  * As the trigger may occur on any data element being updated it is
 421  * really rather likely to occur during the read from the previous
 422  * trigger event.  The only way to discover if this has occured on
 423  * boards not supporting level interrupts is to take a look at the line.
 424  * If it is indicating another interrupt and we don't seem to have a
 425  * handler looking at it, then we need to notify the core that we need
 426  * to tell the triggering core to try reading all these again.
 427  **/
 428 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 429 {
 430         struct lis3l02dq_state *st = trig->private_data;
 431         enable_irq(st->us->irq);
 432         /* If gpio still high (or high again) */
 433         if (gpio_get_value(irq_to_gpio(st->us->irq)))
 434                 if (st->inter == 0) {
 435                         /* already interrupt handler dealing with it */
 436                         disable_irq_nosync(st->us->irq);
 437                         if (st->inter == 1) {
 438                                 /* interrupt handler snuck in between test
 439                                  * and disable */
 440                                 enable_irq(st->us->irq);
 441                                 return 0;
 442                         }
 443                         return -EAGAIN;
 444                 }
 445         /* irq reenabled so success! */
 446         return 0;
 447 }
 448
 449 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 450 {
 451         int ret;
 452         struct lis3l02dq_state *state = indio_dev->dev_data;
 453
 454         state->trig = iio_allocate_trigger();
 455         if (!state->trig)
 456                 return -ENOMEM;
 457
 458         state->trig->name = kasprintf(GFP_KERNEL,
 459                                       "lis3l02dq-dev%d",
 460                                       indio_dev->id);
 461         if (!state->trig->name) {
 462                 ret = -ENOMEM;
 463                 goto error_free_trig;
 464         }
 465
 466         state->trig->dev.parent = &state->us->dev;
 467         state->trig->owner = THIS_MODULE;
 468         state->trig->private_data = state;
 469         state->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 470         state->trig->try_reenable = &lis3l02dq_trig_try_reen;
 471         state->trig->control_attrs = &lis3l02dq_trigger_attr_group;
 472         ret = iio_trigger_register(state->trig);
 473         if (ret)
 474                 goto error_free_trig_name;
 475
 476         return 0;
 477
 478 error_free_trig_name:
 479         kfree(state->trig->name);
 480 error_free_trig:
 481         iio_free_trigger(state->trig);
 482
 483         return ret;
 484 }
 485
 486 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 487 {
 488         struct lis3l02dq_state *state = indio_dev->dev_data;
 489
 490         iio_trigger_unregister(state->trig);
 491         kfree(state->trig->name);
 492         iio_free_trigger(state->trig);
 493 }
 494
 495 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 496 {
 497         kfree(indio_dev->pollfunc);
 498         iio_sw_rb_free(indio_dev->ring);
 499 }
 500
 501 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 502 {
 503         int ret = 0;
 504         struct lis3l02dq_state *st = indio_dev->dev_data;
 505         struct iio_ring_buffer *ring;
 506         INIT_WORK(&st->work_trigger_to_ring, lis3l02dq_trigger_bh_to_ring);
 507         /* Set default scan mode */
 508
 509         iio_scan_mask_set(indio_dev, iio_scan_el_accel_x.number);
 510         iio_scan_mask_set(indio_dev, iio_scan_el_accel_y.number);
 511         iio_scan_mask_set(indio_dev, iio_scan_el_accel_z.number);
 512         indio_dev->scan_timestamp = true;
 513
 514         indio_dev->scan_el_attrs = &lis3l02dq_scan_el_group;
 515
 516         ring = iio_sw_rb_allocate(indio_dev);
 517         if (!ring) {
 518                 ret = -ENOMEM;
 519                 return ret;
 520         }
 521         indio_dev->ring = ring;
 522         /* Effectively select the ring buffer implementation */
 523         iio_ring_sw_register_funcs(&ring->access);
 524         ring->bpe = 2;
 525         ring->preenable = &iio_sw_ring_preenable;
 526         ring->postenable = &iio_triggered_ring_postenable;
 527         ring->predisable = &iio_triggered_ring_predisable;
 528         ring->owner = THIS_MODULE;
 529
 530         ret = iio_alloc_pollfunc(indio_dev, NULL, &lis3l02dq_poll_func_th);
 531         if (ret)
 532                 goto error_iio_sw_rb_free;;
 533         indio_dev->modes |= INDIO_RING_TRIGGERED;
 534         return 0;
 535
 536 error_iio_sw_rb_free:
 537         iio_sw_rb_free(indio_dev->ring);
 538         return ret;
 539 }
 540
 541
 542