drivers/staging/iio/accel/lis3l02dq_ring.c

   1 #include <linux/interrupt.h>
   2 #include <linux/gpio.h>
   3 #include <linux/mutex.h>
   4 #include <linux/kernel.h>
   5 #include <linux/spi/spi.h>
   6 #include <linux/slab.h>
   7
   8 #include "../iio.h"
   9 #include "../ring_sw.h"
  10 #include "../kfifo_buf.h"
  11 #include "../trigger.h"
  12 #include "../trigger_consumer.h"
  13 #include "lis3l02dq.h"
  14
  15 /**
  16  * combine_8_to_16() utility function to munge to u8s into u16
  17  **/
  18 static inline u16 combine_8_to_16(u8 lower, u8 upper)
  19 {
  20         u16 _lower = lower;
  21         u16 _upper = upper;
  22         return _lower | (_upper << 8);
  23 }
  24
  25 /**
  26  * lis3l02dq_data_rdy_trig_poll() the event handler for the data rdy trig
  27  **/
  28 irqreturn_t lis3l02dq_data_rdy_trig_poll(int irq, void *private)
  29 {
  30         struct iio_dev *indio_dev = private;
  31         struct lis3l02dq_state *st = iio_priv(indio_dev);
  32
  33         if (st->trigger_on) {
  34                 iio_trigger_poll(st->trig, iio_get_time_ns());
  35                 return IRQ_HANDLED;
  36         } else
  37                 return IRQ_WAKE_THREAD;
  38 }
  39
  40 /**
  41  * lis3l02dq_read_accel_from_ring() individual acceleration read from ring
  42  **/
  43 ssize_t lis3l02dq_read_accel_from_ring(struct iio_ring_buffer *ring,
  44                                        int index,
  45                                        int *val)
  46 {
  47         int ret;
  48         s16 *data;
  49
  50         if (!iio_scan_mask_query(ring, index))
  51                 return -EINVAL;
  52
  53         if (!ring->access->read_last)
  54                 return -EBUSY;
  55
  56         data = kmalloc(ring->access->get_bytes_per_datum(ring),
  57                        GFP_KERNEL);
  58         if (data == NULL)
  59                 return -ENOMEM;
  60
  61         ret = ring->access->read_last(ring, (u8 *)data);
  62         if (ret)
  63                 goto error_free_data;
  64         *val = data[bitmap_weight(ring->scan_mask, index)];
  65 error_free_data:
  66
  67         kfree(data);
  68
  69         return ret;
  70 }
  71
  72 static const u8 read_all_tx_array[] = {
  73         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
  74         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
  75         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
  76         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
  77         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
  78         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
  79 };
  80
  81 /**
  82  * lis3l02dq_read_all() Reads all channels currently selected
  83  * @st:         device specific state
  84  * @rx_array:   (dma capable) receive array, must be at least
  85  *              4*number of channels
  86  **/
  87 static int lis3l02dq_read_all(struct iio_dev *indio_dev, u8 *rx_array)
  88 {
  89         struct iio_ring_buffer *ring = indio_dev->ring;
  90         struct lis3l02dq_state *st = iio_priv(indio_dev);
  91         struct spi_transfer *xfers;
  92         struct spi_message msg;
  93         int ret, i, j = 0;
  94
  95         xfers = kzalloc((ring->scan_count) * 2
  96                         * sizeof(*xfers), GFP_KERNEL);
  97         if (!xfers)
  98                 return -ENOMEM;
  99
 100         mutex_lock(&st->buf_lock);
 101
 102         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++)
 103                 if (test_bit(i, ring->scan_mask)) {
 104                         /* lower byte */
 105                         xfers[j].tx_buf = st->tx + 2*j;
 106                         st->tx[2*j] = read_all_tx_array[i*4];
 107                         st->tx[2*j + 1] = 0;
 108                         if (rx_array)
 109                                 xfers[j].rx_buf = rx_array + j*2;
 110                         xfers[j].bits_per_word = 8;
 111                         xfers[j].len = 2;
 112                         xfers[j].cs_change = 1;
 113                         j++;
 114
 115                         /* upper byte */
 116                         xfers[j].tx_buf = st->tx + 2*j;
 117                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 118                         st->tx[2*j + 1] = 0;
 119                         if (rx_array)
 120                                 xfers[j].rx_buf = rx_array + j*2;
 121                         xfers[j].bits_per_word = 8;
 122                         xfers[j].len = 2;
 123                         xfers[j].cs_change = 1;
 124                         j++;
 125                 }
 126
 127         /* After these are transmitted, the rx_buff should have
 128          * values in alternate bytes
 129          */
 130         spi_message_init(&msg);
 131         for (j = 0; j < ring->scan_count * 2; j++)
 132                 spi_message_add_tail(&xfers[j], &msg);
 133
 134         ret = spi_sync(st->us, &msg);
 135         mutex_unlock(&st->buf_lock);
 136         kfree(xfers);
 137
 138         return ret;
 139 }
 140
 141 static int lis3l02dq_get_ring_element(struct iio_dev *indio_dev,
 142                                 u8 *buf)
 143 {
 144         int ret, i;
 145         u8 *rx_array ;
 146         s16 *data = (s16 *)buf;
 147
 148         rx_array = kzalloc(4 * (indio_dev->ring->scan_count), GFP_KERNEL);
 149         if (rx_array == NULL)
 150                 return -ENOMEM;
 151         ret = lis3l02dq_read_all(indio_dev, rx_array);
 152         if (ret < 0)
 153                 return ret;
 154         for (i = 0; i < indio_dev->ring->scan_count; i++)
 155                 data[i] = combine_8_to_16(rx_array[i*4+1],
 156                                         rx_array[i*4+3]);
 157         kfree(rx_array);
 158
 159         return i*sizeof(data[0]);
 160 }
 161
 162 static irqreturn_t lis3l02dq_trigger_handler(int irq, void *p)
 163 {
 164         struct iio_poll_func *pf = p;
 165         struct iio_dev *indio_dev = pf->indio_dev;
 166         struct iio_ring_buffer *ring = indio_dev->ring;
 167         int len = 0;
 168         size_t datasize = ring->access->get_bytes_per_datum(ring);
 169         char *data = kmalloc(datasize, GFP_KERNEL);
 170
 171         if (data == NULL) {
 172                 dev_err(indio_dev->dev.parent,
 173                         "memory alloc failed in ring bh");
 174                 return -ENOMEM;
 175         }
 176
 177         if (ring->scan_count)
 178                 len = lis3l02dq_get_ring_element(indio_dev, data);
 179
 180           /* Guaranteed to be aligned with 8 byte boundary */
 181         if (ring->scan_timestamp)
 182                 *(s64 *)(((phys_addr_t)data + len
 183                                 + sizeof(s64) - 1) & ~(sizeof(s64) - 1))
 184                         = pf->timestamp;
 185         ring->access->store_to(ring, (u8 *)data, pf->timestamp);
 186
 187         iio_trigger_notify_done(indio_dev->trig);
 188         kfree(data);
 189         return IRQ_HANDLED;
 190 }
 191
 192 /* Caller responsible for locking as necessary. */
 193 static int
 194 __lis3l02dq_write_data_ready_config(struct device *dev, bool state)
 195 {
 196         int ret;
 197         u8 valold;
 198         bool currentlyset;
 199         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 200         struct lis3l02dq_state *st = iio_priv(indio_dev);
 201
 202 /* Get the current event mask register */
 203         ret = lis3l02dq_spi_read_reg_8(indio_dev,
 204                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 205                                        &valold);
 206         if (ret)
 207                 goto error_ret;
 208 /* Find out if data ready is already on */
 209         currentlyset
 210                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 211
 212 /* Disable requested */
 213         if (!state && currentlyset) {
 214                 /* disable the data ready signal */
 215                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 216
 217                 /* The double write is to overcome a hardware bug?*/
 218                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 219                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 220                                                 valold);
 221                 if (ret)
 222                         goto error_ret;
 223                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 224                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 225                                                 valold);
 226                 if (ret)
 227                         goto error_ret;
 228                 st->trigger_on = false;
 229 /* Enable requested */
 230         } else if (state && !currentlyset) {
 231                 /* if not set, enable requested */
 232                 /* first disable all events */
 233                 ret = lis3l02dq_disable_all_events(indio_dev);
 234                 if (ret < 0)
 235                         goto error_ret;
 236
 237                 valold = ret |
 238                         LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 239
 240                 st->trigger_on = true;
 241                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 242                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 243                                                 valold);
 244                 if (ret)
 245                         goto error_ret;
 246         }
 247
 248         return 0;
 249 error_ret:
 250         return ret;
 251 }
 252
 253 /**
 254  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 255  *
 256  * If disabling the interrupt also does a final read to ensure it is clear.
 257  * This is only important in some cases where the scan enable elements are
 258  * switched before the ring is reenabled.
 259  **/
 260 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 261                                                 bool state)
 262 {
 263         struct iio_dev *indio_dev = trig->private_data;
 264         int ret = 0;
 265         u8 t;
 266
 267         __lis3l02dq_write_data_ready_config(&indio_dev->dev, state);
 268         if (state == false) {
 269                 /*
 270                  * A possible quirk with teh handler is currently worked around
 271                  *  by ensuring outstanding read events are cleared.
 272                  */
 273                 ret = lis3l02dq_read_all(indio_dev, NULL);
 274         }
 275         lis3l02dq_spi_read_reg_8(indio_dev,
 276                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 277                                  &t);
 278         return ret;
 279 }
 280
 281 /**
 282  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 283  * @trig:       the datardy trigger
 284  */
 285 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 286 {
 287         struct iio_dev *indio_dev = trig->private_data;
 288         struct lis3l02dq_state *st = iio_priv(indio_dev);
 289         int i;
 290
 291         /* If gpio still high (or high again) */
 292         /* In theory possible we will need to do this several times */
 293         for (i = 0; i < 5; i++)
 294                 if (gpio_get_value(irq_to_gpio(st->us->irq)))
 295                         lis3l02dq_read_all(indio_dev, NULL);
 296                 else
 297                         break;
 298         if (i == 5)
 299                 printk(KERN_INFO
 300                        "Failed to clear the interrupt for lis3l02dq\n");
 301
 302         /* irq reenabled so success! */
 303         return 0;
 304 }
 305
 306 static const struct iio_trigger_ops lis3l02dq_trigger_ops = {
 307         .owner = THIS_MODULE,
 308         .set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state,
 309         .try_reenable = &lis3l02dq_trig_try_reen,
 310 };
 311
 312 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 313 {
 314         int ret;
 315         struct lis3l02dq_state *st = iio_priv(indio_dev);
 316
 317         st->trig = iio_allocate_trigger("lis3l02dq-dev%d", indio_dev->id);
 318         if (!st->trig) {
 319                 ret = -ENOMEM;
 320                 goto error_ret;
 321         }
 322
 323         st->trig->dev.parent = &st->us->dev;
 324         st->trig->ops = &lis3l02dq_trigger_ops;
 325         st->trig->private_data = indio_dev;
 326         ret = iio_trigger_register(st->trig);
 327         if (ret)
 328                 goto error_free_trig;
 329
 330         return 0;
 331
 332 error_free_trig:
 333         iio_free_trigger(st->trig);
 334 error_ret:
 335         return ret;
 336 }
 337
 338 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 339 {
 340         struct lis3l02dq_state *st = iio_priv(indio_dev);
 341
 342         iio_trigger_unregister(st->trig);
 343         iio_free_trigger(st->trig);
 344 }
 345
 346 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 347 {
 348         iio_dealloc_pollfunc(indio_dev->pollfunc);
 349         lis3l02dq_free_buf(indio_dev->ring);
 350 }
 351
 352 static int lis3l02dq_ring_postenable(struct iio_dev *indio_dev)
 353 {
 354         /* Disable unwanted channels otherwise the interrupt will not clear */
 355         u8 t;
 356         int ret;
 357         bool oneenabled = false;
 358
 359         ret = lis3l02dq_spi_read_reg_8(indio_dev,
 360                                        LIS3L02DQ_REG_CTRL_1_ADDR,
 361                                        &t);
 362         if (ret)
 363                 goto error_ret;
 364
 365         if (iio_scan_mask_query(indio_dev->ring, 0)) {
 366                 t |= LIS3L02DQ_REG_CTRL_1_AXES_X_ENABLE;
 367                 oneenabled = true;
 368         } else
 369                 t &= ~LIS3L02DQ_REG_CTRL_1_AXES_X_ENABLE;
 370         if (iio_scan_mask_query(indio_dev->ring, 1)) {
 371                 t |= LIS3L02DQ_REG_CTRL_1_AXES_Y_ENABLE;
 372                 oneenabled = true;
 373         } else
 374                 t &= ~LIS3L02DQ_REG_CTRL_1_AXES_Y_ENABLE;
 375         if (iio_scan_mask_query(indio_dev->ring, 2)) {
 376                 t |= LIS3L02DQ_REG_CTRL_1_AXES_Z_ENABLE;
 377                 oneenabled = true;
 378         } else
 379                 t &= ~LIS3L02DQ_REG_CTRL_1_AXES_Z_ENABLE;
 380
 381         if (!oneenabled) /* what happens in this case is unknown */
 382                 return -EINVAL;
 383         ret = lis3l02dq_spi_write_reg_8(indio_dev,
 384                                         LIS3L02DQ_REG_CTRL_1_ADDR,
 385                                         t);
 386         if (ret)
 387                 goto error_ret;
 388
 389         return iio_triggered_buffer_postenable(indio_dev);
 390 error_ret:
 391         return ret;
 392 }
 393
 394 /* Turn all channels on again */
 395 static int lis3l02dq_ring_predisable(struct iio_dev *indio_dev)
 396 {
 397         u8 t;
 398         int ret;
 399
 400         ret = iio_triggered_buffer_predisable(indio_dev);
 401         if (ret)
 402                 goto error_ret;
 403
 404         ret = lis3l02dq_spi_read_reg_8(indio_dev,
 405                                        LIS3L02DQ_REG_CTRL_1_ADDR,
 406                                        &t);
 407         if (ret)
 408                 goto error_ret;
 409         t |= LIS3L02DQ_REG_CTRL_1_AXES_X_ENABLE |
 410                 LIS3L02DQ_REG_CTRL_1_AXES_Y_ENABLE |
 411                 LIS3L02DQ_REG_CTRL_1_AXES_Z_ENABLE;
 412
 413         ret = lis3l02dq_spi_write_reg_8(indio_dev,
 414                                         LIS3L02DQ_REG_CTRL_1_ADDR,
 415                                         t);
 416
 417 error_ret:
 418         return ret;
 419 }
 420
 421 static const struct iio_ring_setup_ops lis3l02dq_ring_setup_ops = {
 422         .preenable = &iio_sw_ring_preenable,
 423         .postenable = &lis3l02dq_ring_postenable,
 424         .predisable = &lis3l02dq_ring_predisable,
 425 };
 426
 427 int lis3l02dq_configure_ring(struct iio_dev *indio_dev)
 428 {
 429         int ret;
 430         struct iio_ring_buffer *ring;
 431
 432         ring = lis3l02dq_alloc_buf(indio_dev);
 433         if (!ring)
 434                 return -ENOMEM;
 435
 436         indio_dev->ring = ring;
 437         /* Effectively select the ring buffer implementation */
 438         indio_dev->ring->access = &lis3l02dq_access_funcs;
 439         ring->bpe = 2;
 440
 441         ring->scan_timestamp = true;
 442         ring->setup_ops = &lis3l02dq_ring_setup_ops;
 443         ring->owner = THIS_MODULE;
 444
 445         /* Functions are NULL as we set handler below */
 446         indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
 447                                                  &lis3l02dq_trigger_handler,
 448                                                  0,
 449                                                  indio_dev,
 450                                                  "lis3l02dq_consumer%d",
 451                                                  indio_dev->id);
 452
 453         if (indio_dev->pollfunc == NULL) {
 454                 ret = -ENOMEM;
 455                 goto error_iio_sw_rb_free;
 456         }
 457
 458         indio_dev->modes |= INDIO_RING_TRIGGERED;
 459         return 0;
 460
 461 error_iio_sw_rb_free:
 462         lis3l02dq_free_buf(indio_dev->ring);
 463         return ret;
 464 }