drivers/staging/iio/accel/adis16204_ring.c

   1 #include <linux/interrupt.h>
   2 #include <linux/mutex.h>
   3 #include <linux/kernel.h>
   4 #include <linux/spi/spi.h>
   5 #include <linux/slab.h>
   6
   7 #include "../iio.h"
   8 #include "../ring_sw.h"
   9 #include "../trigger_consumer.h"
  10 #include "adis16204.h"
  11
  12 /**
  13  * adis16204_read_ring_data() read data registers which will be placed into ring
  14  * @dev: device associated with child of actual device (iio_dev or iio_trig)
  15  * @rx: somewhere to pass back the value read
  16  **/
  17 static int adis16204_read_ring_data(struct device *dev, u8 *rx)
  18 {
  19         struct spi_message msg;
  20         struct iio_dev *indio_dev = dev_get_drvdata(dev);
  21         struct adis16204_state *st = iio_priv(indio_dev);
  22         struct spi_transfer xfers[ADIS16204_OUTPUTS + 1];
  23         int ret;
  24         int i;
  25
  26         mutex_lock(&st->buf_lock);
  27
  28         spi_message_init(&msg);
  29
  30         memset(xfers, 0, sizeof(xfers));
  31         for (i = 0; i <= ADIS16204_OUTPUTS; i++) {
  32                 xfers[i].bits_per_word = 8;
  33                 xfers[i].cs_change = 1;
  34                 xfers[i].len = 2;
  35                 xfers[i].delay_usecs = 20;
  36                 xfers[i].tx_buf = st->tx + 2 * i;
  37                 st->tx[2 * i]
  38                         = ADIS16204_READ_REG(ADIS16204_SUPPLY_OUT + 2 * i);
  39                 st->tx[2 * i + 1] = 0;
  40                 if (i >= 1)
  41                         xfers[i].rx_buf = rx + 2 * (i - 1);
  42                 spi_message_add_tail(&xfers[i], &msg);
  43         }
  44
  45         ret = spi_sync(st->us, &msg);
  46         if (ret)
  47                 dev_err(&st->us->dev, "problem when burst reading");
  48
  49         mutex_unlock(&st->buf_lock);
  50
  51         return ret;
  52 }
  53
  54 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
  55  * specific to be rolled into the core.
  56  */
  57 static irqreturn_t adis16204_trigger_handler(int irq, void *p)
  58 {
  59         struct iio_poll_func *pf = p;
  60         struct iio_dev *indio_dev = pf->indio_dev;
  61         struct adis16204_state *st = iio_priv(indio_dev);
  62         struct iio_ring_buffer *ring = indio_dev->ring;
  63         int i = 0;
  64         s16 *data;
  65         size_t datasize = ring->access->get_bytes_per_datum(ring);
  66
  67         data = kmalloc(datasize, GFP_KERNEL);
  68         if (data == NULL) {
  69                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
  70                 return -ENOMEM;
  71         }
  72
  73         if (ring->scan_count)
  74                 if (adis16204_read_ring_data(&indio_dev->dev, st->rx) >= 0)
  75                         for (; i < ring->scan_count; i++)
  76                                 data[i] = be16_to_cpup(
  77                                         (__be16 *)&(st->rx[i*2]));
  78
  79         /* Guaranteed to be aligned with 8 byte boundary */
  80         if (ring->scan_timestamp)
  81                 *((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
  82
  83         ring->access->store_to(ring, (u8 *)data, pf->timestamp);
  84
  85         iio_trigger_notify_done(indio_dev->trig);
  86         kfree(data);
  87
  88         return IRQ_HANDLED;
  89 }
  90
  91 void adis16204_unconfigure_ring(struct iio_dev *indio_dev)
  92 {
  93         iio_dealloc_pollfunc(indio_dev->pollfunc);
  94         iio_sw_rb_free(indio_dev->ring);
  95 }
  96
  97 static const struct iio_ring_setup_ops adis16204_ring_setup_ops = {
  98         .preenable = &iio_sw_ring_preenable,
  99         .postenable = &iio_triggered_buffer_postenable,
 100         .predisable = &iio_triggered_buffer_predisable,
 101 };
 102
 103 int adis16204_configure_ring(struct iio_dev *indio_dev)
 104 {
 105         int ret = 0;
 106         struct iio_ring_buffer *ring;
 107
 108         ring = iio_sw_rb_allocate(indio_dev);
 109         if (!ring) {
 110                 ret = -ENOMEM;
 111                 return ret;
 112         }
 113         indio_dev->ring = ring;
 114         /* Effectively select the ring buffer implementation */
 115         ring->access = &ring_sw_access_funcs;
 116         ring->bpe = 2;
 117         ring->scan_timestamp = true;
 118         ring->setup_ops = &adis16204_ring_setup_ops;
 119         ring->owner = THIS_MODULE;
 120
 121         indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
 122                                                  &adis16204_trigger_handler,
 123                                                  IRQF_ONESHOT,
 124                                                  indio_dev,
 125                                                  "%s_consumer%d",
 126                                                  indio_dev->name,
 127                                                  indio_dev->id);
 128         if (indio_dev->pollfunc == NULL) {
 129                 ret = -ENOMEM;
 130                 goto error_iio_sw_rb_free;
 131         }
 132
 133         indio_dev->modes |= INDIO_RING_TRIGGERED;
 134         return 0;
 135
 136 error_iio_sw_rb_free:
 137         iio_sw_rb_free(indio_dev->ring);
 138         return ret;
 139 }