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