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/mutex.h>
   5 #include <linux/device.h>
   6 #include <linux/kernel.h>
   7 #include <linux/spi/spi.h>
   8 #include <linux/sysfs.h>
   9 #include <linux/slab.h>
  10
  11 #include "../iio.h"
  12 #include "../sysfs.h"
  13 #include "../ring_sw.h"
  14 #include "../kfifo_buf.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_data_rdy_trig_poll() the event handler for the data rdy trig
  31  **/
  32 irqreturn_t lis3l02dq_data_rdy_trig_poll(int irq, void *private)
  33 {
  34         struct iio_dev *indio_dev = private;
  35         struct lis3l02dq_state *st = iio_priv(indio_dev);
  36
  37         if (st->trigger_on) {
  38                 iio_trigger_poll(st->trig, iio_get_time_ns());
  39                 return IRQ_HANDLED;
  40         } else
  41                 return IRQ_WAKE_THREAD;
  42 }
  43
  44 /**
  45  * lis3l02dq_read_accel_from_ring() individual acceleration read from ring
  46  **/
  47 ssize_t lis3l02dq_read_accel_from_ring(struct iio_ring_buffer *ring,
  48                                        int index,
  49                                        int *val)
  50 {
  51         int ret;
  52         s16 *data;
  53
  54         if (!iio_scan_mask_query(ring, index))
  55                 return -EINVAL;
  56
  57         if (!ring->access->read_last)
  58                 return -EBUSY;
  59
  60         data = kmalloc(ring->access->get_bytes_per_datum(ring),
  61                        GFP_KERNEL);
  62         if (data == NULL)
  63                 return -ENOMEM;
  64
  65         ret = ring->access->read_last(ring, (u8 *)data);
  66         if (ret)
  67                 goto error_free_data;
  68         *val = data[bitmap_weight(&ring->scan_mask, index)];
  69 error_free_data:
  70         kfree(data);
  71
  72         return ret;
  73 }
  74
  75 static const u8 read_all_tx_array[] = {
  76         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_L_ADDR), 0,
  77         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_X_H_ADDR), 0,
  78         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_L_ADDR), 0,
  79         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Y_H_ADDR), 0,
  80         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_L_ADDR), 0,
  81         LIS3L02DQ_READ_REG(LIS3L02DQ_REG_OUT_Z_H_ADDR), 0,
  82 };
  83
  84 /**
  85  * lis3l02dq_read_all() Reads all channels currently selected
  86  * @st:         device specific state
  87  * @rx_array:   (dma capable) receive array, must be at least
  88  *              4*number of channels
  89  **/
  90 static int lis3l02dq_read_all(struct iio_dev *indio_dev, u8 *rx_array)
  91 {
  92         struct iio_ring_buffer *ring = indio_dev->ring;
  93         struct lis3l02dq_state *st = iio_priv(indio_dev);
  94         struct spi_transfer *xfers;
  95         struct spi_message msg;
  96         int ret, i, j = 0;
  97
  98         xfers = kzalloc((ring->scan_count) * 2
  99                         * sizeof(*xfers), GFP_KERNEL);
 100         if (!xfers)
 101                 return -ENOMEM;
 102
 103         mutex_lock(&st->buf_lock);
 104
 105         for (i = 0; i < ARRAY_SIZE(read_all_tx_array)/4; i++)
 106                 if (ring->scan_mask & (1 << i)) {
 107                         /* lower byte */
 108                         xfers[j].tx_buf = st->tx + 2*j;
 109                         st->tx[2*j] = read_all_tx_array[i*4];
 110                         st->tx[2*j + 1] = 0;
 111                         if (rx_array)
 112                                 xfers[j].rx_buf = rx_array + j*2;
 113                         xfers[j].bits_per_word = 8;
 114                         xfers[j].len = 2;
 115                         xfers[j].cs_change = 1;
 116                         j++;
 117
 118                         /* upper byte */
 119                         xfers[j].tx_buf = st->tx + 2*j;
 120                         st->tx[2*j] = read_all_tx_array[i*4 + 2];
 121                         st->tx[2*j + 1] = 0;
 122                         if (rx_array)
 123                                 xfers[j].rx_buf = rx_array + j*2;
 124                         xfers[j].bits_per_word = 8;
 125                         xfers[j].len = 2;
 126                         xfers[j].cs_change = 1;
 127                         j++;
 128                 }
 129
 130         /* After these are transmitted, the rx_buff should have
 131          * values in alternate bytes
 132          */
 133         spi_message_init(&msg);
 134         for (j = 0; j < ring->scan_count * 2; j++)
 135                 spi_message_add_tail(&xfers[j], &msg);
 136
 137         ret = spi_sync(st->us, &msg);
 138         mutex_unlock(&st->buf_lock);
 139         kfree(xfers);
 140
 141         return ret;
 142 }
 143
 144 static int lis3l02dq_get_ring_element(struct iio_dev *indio_dev,
 145                                 u8 *buf)
 146 {
 147         int ret, i;
 148         u8 *rx_array ;
 149         s16 *data = (s16 *)buf;
 150
 151         rx_array = kzalloc(4 * (indio_dev->ring->scan_count), GFP_KERNEL);
 152         if (rx_array == NULL)
 153                 return -ENOMEM;
 154         ret = lis3l02dq_read_all(indio_dev, rx_array);
 155         if (ret < 0)
 156                 return ret;
 157         for (i = 0; i < indio_dev->ring->scan_count; i++)
 158                 data[i] = combine_8_to_16(rx_array[i*4+1],
 159                                         rx_array[i*4+3]);
 160         kfree(rx_array);
 161
 162         return i*sizeof(data[0]);
 163 }
 164
 165 static irqreturn_t lis3l02dq_trigger_handler(int irq, void *p)
 166 {
 167         struct iio_poll_func *pf = p;
 168         struct iio_dev *indio_dev = pf->private_data;
 169         struct iio_ring_buffer *ring = indio_dev->ring;
 170         int len = 0;
 171         size_t datasize = ring->access->get_bytes_per_datum(ring);
 172         char *data = kmalloc(datasize, GFP_KERNEL);
 173
 174         if (data == NULL) {
 175                 dev_err(indio_dev->dev.parent,
 176                         "memory alloc failed in ring bh");
 177                 return -ENOMEM;
 178         }
 179
 180         if (ring->scan_count)
 181                 len = lis3l02dq_get_ring_element(indio_dev, data);
 182
 183           /* Guaranteed to be aligned with 8 byte boundary */
 184         if (ring->scan_timestamp)
 185                 *(s64 *)(((phys_addr_t)data + len
 186                                 + sizeof(s64) - 1) & ~(sizeof(s64) - 1))
 187                         = pf->timestamp;
 188         ring->access->store_to(ring, (u8 *)data, pf->timestamp);
 189
 190         iio_trigger_notify_done(indio_dev->trig);
 191         kfree(data);
 192         return IRQ_HANDLED;
 193 }
 194
 195 /* Caller responsible for locking as necessary. */
 196 static int
 197 __lis3l02dq_write_data_ready_config(struct device *dev, bool state)
 198 {
 199         int ret;
 200         u8 valold;
 201         bool currentlyset;
 202         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 203         struct lis3l02dq_state *st = iio_priv(indio_dev);
 204
 205 /* Get the current event mask register */
 206         ret = lis3l02dq_spi_read_reg_8(indio_dev,
 207                                        LIS3L02DQ_REG_CTRL_2_ADDR,
 208                                        &valold);
 209         if (ret)
 210                 goto error_ret;
 211 /* Find out if data ready is already on */
 212         currentlyset
 213                 = valold & LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 214
 215 /* Disable requested */
 216         if (!state && currentlyset) {
 217                 /* disable the data ready signal */
 218                 valold &= ~LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 219
 220                 /* The double write is to overcome a hardware bug?*/
 221                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 222                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 223                                                 &valold);
 224                 if (ret)
 225                         goto error_ret;
 226                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 227                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 228                                                 &valold);
 229                 if (ret)
 230                         goto error_ret;
 231                 st->trigger_on = false;
 232 /* Enable requested */
 233         } else if (state && !currentlyset) {
 234                 /* if not set, enable requested */
 235                 /* first disable all events */
 236                 ret = lis3l02dq_disable_all_events(indio_dev);
 237                 if (ret < 0)
 238                         goto error_ret;
 239
 240                 valold = ret |
 241                         LIS3L02DQ_REG_CTRL_2_ENABLE_DATA_READY_GENERATION;
 242
 243                 st->trigger_on = true;
 244                 ret = lis3l02dq_spi_write_reg_8(indio_dev,
 245                                                 LIS3L02DQ_REG_CTRL_2_ADDR,
 246                                                 &valold);
 247                 if (ret)
 248                         goto error_ret;
 249         }
 250
 251         return 0;
 252 error_ret:
 253         return ret;
 254 }
 255
 256 /**
 257  * lis3l02dq_data_rdy_trigger_set_state() set datardy interrupt state
 258  *
 259  * If disabling the interrupt also does a final read to ensure it is clear.
 260  * This is only important in some cases where the scan enable elements are
 261  * switched before the ring is reenabled.
 262  **/
 263 static int lis3l02dq_data_rdy_trigger_set_state(struct iio_trigger *trig,
 264                                                 bool state)
 265 {
 266         struct iio_dev *indio_dev = trig->private_data;
 267         int ret = 0;
 268         u8 t;
 269
 270         __lis3l02dq_write_data_ready_config(&indio_dev->dev, state);
 271         if (state == false) {
 272                 /*
 273                  * A possible quirk with teh handler is currently worked around
 274                  *  by ensuring outstanding read events are cleared.
 275                  */
 276                 ret = lis3l02dq_read_all(indio_dev, NULL);
 277         }
 278         lis3l02dq_spi_read_reg_8(indio_dev,
 279                                  LIS3L02DQ_REG_WAKE_UP_SRC_ADDR,
 280                                  &t);
 281         return ret;
 282 }
 283
 284 /**
 285  * lis3l02dq_trig_try_reen() try renabling irq for data rdy trigger
 286  * @trig:       the datardy trigger
 287  */
 288 static int lis3l02dq_trig_try_reen(struct iio_trigger *trig)
 289 {
 290         struct iio_dev *indio_dev = trig->private_data;
 291         struct lis3l02dq_state *st = iio_priv(indio_dev);
 292         int i;
 293
 294         /* If gpio still high (or high again) */
 295         /* In theory possible we will need to do this several times */
 296         for (i = 0; i < 5; i++)
 297                 if (gpio_get_value(irq_to_gpio(st->us->irq)))
 298                         lis3l02dq_read_all(indio_dev, NULL);
 299                 else
 300                         break;
 301         if (i == 5)
 302                 printk(KERN_INFO
 303                        "Failed to clear the interrupt for lis3l02dq\n");
 304
 305         /* irq reenabled so success! */
 306         return 0;
 307 }
 308
 309 int lis3l02dq_probe_trigger(struct iio_dev *indio_dev)
 310 {
 311         int ret;
 312         struct lis3l02dq_state *st = iio_priv(indio_dev);
 313
 314         st->trig = iio_allocate_trigger("lis3l02dq-dev%d", indio_dev->id);
 315         if (!st->trig) {
 316                 ret = -ENOMEM;
 317                 goto error_ret;
 318         }
 319
 320         st->trig->dev.parent = &st->us->dev;
 321         st->trig->owner = THIS_MODULE;
 322         st->trig->private_data = indio_dev;
 323         st->trig->set_trigger_state = &lis3l02dq_data_rdy_trigger_set_state;
 324         st->trig->try_reenable = &lis3l02dq_trig_try_reen;
 325         ret = iio_trigger_register(st->trig);
 326         if (ret)
 327                 goto error_free_trig;
 328
 329         return 0;
 330
 331 error_free_trig:
 332         iio_free_trigger(st->trig);
 333 error_ret:
 334         return ret;
 335 }
 336
 337 void lis3l02dq_remove_trigger(struct iio_dev *indio_dev)
 338 {
 339         struct lis3l02dq_state *st = iio_priv(indio_dev);
 340
 341         iio_trigger_unregister(st->trig);
 342         iio_free_trigger(st->trig);
 343 }
 344
 345 void lis3l02dq_unconfigure_ring(struct iio_dev *indio_dev)
 346 {
 347         kfree(indio_dev->pollfunc->name);
 348         kfree(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_ring_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_ring_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         /* Set default scan mode */
 446         iio_scan_mask_set(ring, 0);
 447         iio_scan_mask_set(ring, 1);
 448         iio_scan_mask_set(ring, 2);
 449
 450         /* Functions are NULL as we set handler below */
 451         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 452
 453         if (indio_dev->pollfunc == NULL) {
 454                 ret = -ENOMEM;
 455                 goto error_iio_sw_rb_free;
 456         }
 457         indio_dev->pollfunc->private_data = indio_dev;
 458         indio_dev->pollfunc->thread = &lis3l02dq_trigger_handler;
 459         indio_dev->pollfunc->h = &iio_pollfunc_store_time;
 460         indio_dev->pollfunc->type = 0;
 461         indio_dev->pollfunc->name
 462                 = kasprintf(GFP_KERNEL, "lis3l02dq_consumer%d", indio_dev->id);
 463
 464         indio_dev->modes |= INDIO_RING_TRIGGERED;
 465         return 0;
 466
 467 error_iio_sw_rb_free:
 468         lis3l02dq_free_buf(indio_dev->ring);
 469         return ret;
 470 }