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,
  79                      LIS3L02DQ_REG_OUT_X_L_ADDR,
  80                      &lis3l02dq_scan_el_set_state);
  81 static IIO_SCAN_EL_C(accel_y, 1,
  82                      LIS3L02DQ_REG_OUT_Y_L_ADDR,
  83                      &lis3l02dq_scan_el_set_state);
  84 static IIO_SCAN_EL_C(accel_z, 2,
  85                      LIS3L02DQ_REG_OUT_Z_L_ADDR,
  86                      &lis3l02dq_scan_el_set_state);
  87 static IIO_CONST_ATTR_SCAN_EL_TYPE(accel, s, 12, 16);
  88 static IIO_SCAN_EL_TIMESTAMP(3);
  89 static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
  90
  91 static struct attribute *lis3l02dq_scan_el_attrs[] = {
  92         &iio_scan_el_accel_x.dev_attr.attr,
  93         &iio_const_attr_accel_x_index.dev_attr.attr,
  94         &iio_scan_el_accel_y.dev_attr.attr,
  95         &iio_const_attr_accel_y_index.dev_attr.attr,
  96         &iio_scan_el_accel_z.dev_attr.attr,
  97         &iio_const_attr_accel_z_index.dev_attr.attr,
  98         &iio_const_attr_accel_type.dev_attr.attr,
  99         &iio_scan_el_timestamp.dev_attr.attr,
 100         &iio_const_attr_timestamp_index.dev_attr.attr,
 101         &iio_const_attr_timestamp_type.dev_attr.attr,
 102         NULL,
 103 };
 104
 105 static struct attribute_group lis3l02dq_scan_el_group = {
 106         .attrs = lis3l02dq_scan_el_attrs,
 107         .name = "scan_elements",
 108 };
 109
 110 /**
 111  * lis3l02dq_poll_func_th() top half interrupt handler called by trigger
 112  * @private_data:       iio_dev
 113  **/
 114 static void lis3l02dq_poll_func_th(struct iio_dev *indio_dev, s64 time)
 115 {
 116         struct iio_sw_ring_helper_state *h
 117                 = iio_dev_get_devdata(indio_dev);
 118         struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
 119         /* in this case we need to slightly extend the helper function */
 120         iio_sw_poll_func_th(indio_dev, time);
 121
 122         /* Indicate that this interrupt is being handled */
 123         /* Technically this is trigger related, but without this
 124          * handler running there is currently now way for the interrupt
 125          * to clear.
 126          */
 127         st->inter = 1;
 128 }
 129
 130 /**
 131  * lis3l02dq_data_rdy_trig_poll() the event handler for the data rdy trig
 132  **/
 133 static int lis3l02dq_data_rdy_trig_poll(struct iio_dev *indio_dev,
 134                                        int index,
 135                                        s64 timestamp,
 136                                        int no_test)
 137 {
 138         struct iio_sw_ring_helper_state *h
 139                 = iio_dev_get_devdata(indio_dev);
 140         struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
 141
 142         iio_trigger_poll(st->trig, timestamp);
 143
 144         return IRQ_HANDLED;
 145 }
 146
 147 /* This is an event as it is a response to a physical interrupt */
 148 IIO_EVENT_SH(data_rdy_trig, &lis3l02dq_data_rdy_trig_poll);
 149
 150 /**
 151  * lis3l02dq_read_accel_from_ring() individual acceleration read from ring
 152  **/
 153 ssize_t lis3l02dq_read_accel_from_ring(struct device *dev,
 154                                        struct device_attribute *attr,
 155                                        char *buf)
 156 {
 157         struct iio_scan_el *el = NULL;
 158         int ret, len = 0, i = 0;
 159         struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 160         struct iio_dev *dev_info = dev_get_drvdata(dev);
 161         struct iio_ring_buffer *ring = dev_info->ring;
 162         struct attribute_group *scan_el_attrs = ring->scan_el_attrs;
 163         s16 *data;
 164
 165         while (scan_el_attrs->attrs[i]) {
 166                 el = to_iio_scan_el((struct device_attribute *)
 167                                     (scan_el_attrs->attrs[i]));
 168                 /* label is in fact the address */
 169                 if (el->label == this_attr->address)
 170                         break;
 171                 i++;
 172         }
 173         if (!scan_el_attrs->attrs[i]) {
 174                 ret = -EINVAL;
 175                 goto error_ret;
 176         }
 177         /* If this element is in the scan mask */
 178         ret = iio_scan_mask_query(ring, el->number);
 179         if (ret < 0)
 180                 goto error_ret;
 181         if (ret) {
 182                 data = kmalloc(ring->access.get_bytes_per_datum(ring),
 183                                GFP_KERNEL);
 184                 if (data == NULL)
 185                         return -ENOMEM;
 186                 ret = ring->access.read_last(ring,
 187                                         (u8 *)data);
 188                 if (ret)
 189                         goto error_free_data;
 190         } else {
 191                 ret = -EINVAL;
 192                 goto error_ret;
 193         }
 194         len = iio_scan_mask_count_to_right(ring, el->number);
 195         if (len < 0) {
 196                 ret = len;
 197                 goto error_free_data;
 198         }
 199         len = sprintf(buf, "ring %d\n", data[len]);
 200 error_free_data:
 201         kfree(data);
 202 error_ret:
 203         return ret ? ret : len;
 204
 205 }
 206
 207 static const u8 read_all_tx_array[] = {
 208         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
 209         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
 210         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
 211         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
 212         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
 213         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
 214 };
 215
 216 /**
 217  * lis3l02dq_read_all() Reads all channels currently selected
 218  * @st:         device specific state
 219  * @rx_array:   (dma capable) recieve array, must be at least
 220  *              4*number of channels
 221  **/
 222 static int lis3l02dq_read_all(struct lis3l02dq_state *st, u8 *rx_array)
 223 {
 224         struct iio_ring_buffer *ring = st->help.indio_dev->ring;
 225         struct spi_transfer *xfers;
 226         struct spi_message msg;
 227         int ret, i, j = 0;
 228
 229         xfers = kzalloc((ring->scan_count) * 2
 230                         * sizeof(*xfers), GFP_KERNEL);
 231         if (!xfers)
 232                 return -ENOMEM;
 233
 234         mutex_lock(&st->buf_lock);
 235
 236         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++) {
 237                 if (ring->scan_mask & (1 << i)) {
 238                         /* lower byte */
 239                         xfers[j].tx_buf = st->tx + 2*j;
 240                         st->tx[2*j] = read_all_tx_array[i*4];
 241                         st->tx[2*j + 1] = 0;
 242                         if (rx_array)
 243                                 xfers[j].rx_buf = rx_array + j*2;
 244                         xfers[j].bits_per_word = 8;
 245                         xfers[j].len = 2;
 246                         xfers[j].cs_change = 1;
 247                         j++;
 248
 249                         /* upper byte */
 250                         xfers[j].tx_buf = st->tx + 2*j;
 251                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 252                         st->tx[2*j + 1] = 0;
 253                         if (rx_array)
 254                                 xfers[j].rx_buf = rx_array + j*2;
 255                         xfers[j].bits_per_word = 8;
 256                         xfers[j].len = 2;
 257                         xfers[j].cs_change = 1;
 258                         j++;
 259                 }
 260         }
 261         /* After these are transmitted, the rx_buff should have
 262          * values in alternate bytes
 263          */
 264         spi_message_init(&msg);
 265         for (j = 0; j < ring->scan_count * 2; j++)
 266                 spi_message_add_tail(&xfers[j], &msg);
 267
 268         ret = spi_sync(st->us, &msg);
 269         mutex_unlock(&st->buf_lock);
 270         kfree(xfers);
 271
 272         return ret;
 273 }
 274
 275 static void lis3l02dq_trigger_bh_to_ring(struct work_struct *work_s)
 276 {
 277         struct iio_sw_ring_helper_state *h
 278                 = container_of(work_s, struct iio_sw_ring_helper_state,
 279                         work_trigger_to_ring);
 280         struct lis3l02dq_state *st = lis3l02dq_h_to_s(h);
 281
 282         st->inter = 0;
 283         iio_sw_trigger_bh_to_ring(work_s);
 284 }
 285
 286 static int lis3l02dq_get_ring_element(struct iio_sw_ring_helper_state *h,
 287                                 u8 *buf)
 288 {
 289         int ret, i;
 290         u8 *rx_array ;
 291         s16 *data = (s16 *)buf;
 292
 293         rx_array = kzalloc(4 * (h->indio_dev->ring->scan_count), GFP_KERNEL);
 294         if (rx_array == NULL)
 295                 return -ENOMEM;
 296         ret = lis3l02dq_read_all(lis3l02dq_h_to_s(h), rx_array);
 297         if (ret < 0)
 298                 return ret;
 299         for (i = 0; i < h->indio_dev->ring->scan_count; i++)
 300                 data[i] = combine_8_to_16(rx_array[i*4+1],
 301                                         rx_array[i*4+3]);
 302         kfree(rx_array);
 303
 304         return i*sizeof(data[0]);
 305 }
 306
 307 /* Caller responsible for locking as necessary. */
 308 static int
 309 __lis3l02dq_write_data_ready_config(struct device *dev,
 310                                     struct iio_event_handler_list *list,
 311                                     bool state)
 312 {
 313         int ret;
 314         u8 valold;
 315         bool currentlyset;
 316         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 317
 318 /* Get the current event mask register */
 319         ret = lis3l02dq_spi_read_reg_8(dev,
 320                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 321                                        &valold);
 322         if (ret)
 323                 goto error_ret;
 324 /* Find out if data ready is already on */
 325         currentlyset
 326                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 327
 328 /* Disable requested */
 329         if (!state && currentlyset) {
 330
 331                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 332                 /* The double write is to overcome a hardware bug?*/
 333                 ret = lis3l02dq_spi_write_reg_8(dev,
 334                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 335                                                 &valold);
 336                 if (ret)
 337                         goto error_ret;
 338                 ret = lis3l02dq_spi_write_reg_8(dev,
 339                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 340                                                 &valold);
 341                 if (ret)
 342                         goto error_ret;
 343
 344                 iio_remove_event_from_list(list,
 345                                            &indio_dev->interrupts[0]
 346                                            ->ev_list);
 347
 348 /* Enable requested */
 349         } else if (state && !currentlyset) {
 350                 /* if not set, enable requested */
 351                 valold |= LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 352                 iio_add_event_to_list(list, &indio_dev->interrupts[0]->ev_list);
 353                 ret = lis3l02dq_spi_write_reg_8(dev,
 354                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 355                                                 &valold);
 356                 if (ret)
 357                         goto error_ret;
 358         }
 359
 360         return 0;
 361 error_ret:
 362         return ret;
 363 }
 364
 365 /**
 366  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 367  *
 368  * If disabling the interrupt also does a final read to ensure it is clear.
 369  * This is only important in some cases where the scan enable elements are
 370  * switched before the ring is reenabled.
 371  **/
 372 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 373                                                 bool state)
 374 {
 375         struct lis3l02dq_state *st = trig->private_data;
 376         int ret = 0;
 377         u8 t;
 378         __lis3l02dq_write_data_ready_config(&st->help.indio_dev->dev,
 379                                             &iio_event_data_rdy_trig,
 380                                             state);
 381         if (state == false) {
 382                 /* possible quirk with handler currently worked around
 383                    by ensuring the work queue is empty */
 384                 flush_scheduled_work();
 385                 /* Clear any outstanding ready events */
 386                 ret = lis3l02dq_read_all(st, NULL);
 387         }
 388         lis3l02dq_spi_read_reg_8(&st->help.indio_dev->dev,
 389                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 390                                  &t);
 391         return ret;
 392 }
 393
 394 static IIO_TRIGGER_NAME_ATTR;
 395
 396 static struct attribute *lis3l02dq_trigger_attrs[] = {
 397         &dev_attr_name.attr,
 398         NULL,
 399 };
 400
 401 static const struct attribute_group lis3l02dq_trigger_attr_group = {
 402         .attrs = lis3l02dq_trigger_attrs,
 403 };
 404
 405 /**
 406  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 407  * @trig:       the datardy trigger
 408  *
 409  * As the trigger may occur on any data element being updated it is
 410  * really rather likely to occur during the read from the previous
 411  * trigger event.  The only way to discover if this has occured on
 412  * boards not supporting level interrupts is to take a look at the line.
 413  * If it is indicating another interrupt and we don't seem to have a
 414  * handler looking at it, then we need to notify the core that we need
 415  * to tell the triggering core to try reading all these again.
 416  **/
 417 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 418 {
 419         struct lis3l02dq_state *st = trig->private_data;
 420         enable_irq(st->us->irq);
 421         /* If gpio still high (or high again) */
 422         if (gpio_get_value(irq_to_gpio(st->us->irq)))
 423                 if (st->inter == 0) {
 424                         /* already interrupt handler dealing with it */
 425                         disable_irq_nosync(st->us->irq);
 426                         if (st->inter == 1) {
 427                                 /* interrupt handler snuck in between test
 428                                  * and disable */
 429                                 enable_irq(st->us->irq);
 430                                 return 0;
 431                         }
 432                         return -EAGAIN;
 433                 }
 434         /* irq reenabled so success! */
 435         return 0;
 436 }
 437
 438 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 439 {
 440         int ret;
 441         struct lis3l02dq_state *state = indio_dev->dev_data;
 442
 443         state->trig = iio_allocate_trigger();
 444         if (!state->trig)
 445                 return -ENOMEM;
 446
 447         state->trig->name = kasprintf(GFP_KERNEL,
 448                                       "lis3l02dq-dev%d",
 449                                       indio_dev->id);
 450         if (!state->trig->name) {
 451                 ret = -ENOMEM;
 452                 goto error_free_trig;
 453         }
 454
 455         state->trig->dev.parent = &state->us->dev;
 456         state->trig->owner = THIS_MODULE;
 457         state->trig->private_data = state;
 458         state->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 459         state->trig->try_reenable = &lis3l02dq_trig_try_reen;
 460         state->trig->control_attrs = &lis3l02dq_trigger_attr_group;
 461         ret = iio_trigger_register(state->trig);
 462         if (ret)
 463                 goto error_free_trig_name;
 464
 465         return 0;
 466
 467 error_free_trig_name:
 468         kfree(state->trig->name);
 469 error_free_trig:
 470         iio_free_trigger(state->trig);
 471
 472         return ret;
 473 }
 474
 475 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 476 {
 477         struct lis3l02dq_state *state = indio_dev->dev_data;
 478
 479         iio_trigger_unregister(state->trig);
 480         kfree(state->trig->name);
 481         iio_free_trigger(state->trig);
 482 }
 483
 484 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 485 {
 486         kfree(indio_dev->pollfunc);
 487         iio_sw_rb_free(indio_dev->ring);
 488 }
 489
 490 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 491 {
 492         int ret;
 493         struct iio_sw_ring_helper_state *h = iio_dev_get_devdata(indio_dev);
 494         struct iio_ring_buffer *ring;
 495         INIT_WORK(&h->work_trigger_to_ring, lis3l02dq_trigger_bh_to_ring);
 496         h->get_ring_element = &lis3l02dq_get_ring_element;
 497
 498         ring = iio_sw_rb_allocate(indio_dev);
 499         if (!ring)
 500                 return -ENOMEM;
 501
 502         indio_dev->ring = ring;
 503         /* Effectively select the ring buffer implementation */
 504         iio_ring_sw_register_funcs(&ring->access);
 505         ring->bpe = 2;
 506         ring->scan_el_attrs = &lis3l02dq_scan_el_group;
 507         ring->scan_timestamp = true;
 508         ring->preenable = &iio_sw_ring_preenable;
 509         ring->postenable = &iio_triggered_ring_postenable;
 510         ring->predisable = &iio_triggered_ring_predisable;
 511         ring->owner = THIS_MODULE;
 512
 513         /* Set default scan mode */
 514         iio_scan_mask_set(ring, iio_scan_el_accel_x.number);
 515         iio_scan_mask_set(ring, iio_scan_el_accel_y.number);
 516         iio_scan_mask_set(ring, iio_scan_el_accel_z.number);
 517
 518         ret = iio_alloc_pollfunc(indio_dev, NULL, &lis3l02dq_poll_func_th);
 519         if (ret)
 520                 goto error_iio_sw_rb_free;;
 521         indio_dev->modes |= INDIO_RING_TRIGGERED;
 522         return 0;
 523
 524 error_iio_sw_rb_free:
 525         iio_sw_rb_free(indio_dev->ring);
 526         return ret;
 527 }