drivers/staging/iio/imu/adis16400_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 #include <linux/bitops.h>
   7
   8 #include "../iio.h"
   9 #include "../ring_sw.h"
  10 #include "../trigger_consumer.h"
  11 #include "adis16400.h"
  12
  13 /**
  14  * adis16400_spi_read_burst() - read all data registers
  15  * @dev: device associated with child of actual device (iio_dev or iio_trig)
  16  * @rx: somewhere to pass back the value read (min size is 24 bytes)
  17  **/
  18 static int adis16400_spi_read_burst(struct device *dev, u8 *rx)
  19 {
  20         struct spi_message msg;
  21         struct iio_dev *indio_dev = dev_get_drvdata(dev);
  22         struct adis16400_state *st = iio_priv(indio_dev);
  23         u32 old_speed_hz = st->us->max_speed_hz;
  24         int ret;
  25
  26         struct spi_transfer xfers[] = {
  27                 {
  28                         .tx_buf = st->tx,
  29                         .bits_per_word = 8,
  30                         .len = 2,
  31                 }, {
  32                         .rx_buf = rx,
  33                         .bits_per_word = 8,
  34                         .len = 24,
  35                 },
  36         };
  37
  38         mutex_lock(&st->buf_lock);
  39         st->tx[0] = ADIS16400_READ_REG(ADIS16400_GLOB_CMD);
  40         st->tx[1] = 0;
  41
  42         spi_message_init(&msg);
  43         spi_message_add_tail(&xfers[0], &msg);
  44         spi_message_add_tail(&xfers[1], &msg);
  45
  46         st->us->max_speed_hz = min(ADIS16400_SPI_BURST, old_speed_hz);
  47         spi_setup(st->us);
  48
  49         ret = spi_sync(st->us, &msg);
  50         if (ret)
  51                 dev_err(&st->us->dev, "problem when burst reading");
  52
  53         st->us->max_speed_hz = old_speed_hz;
  54         spi_setup(st->us);
  55         mutex_unlock(&st->buf_lock);
  56         return ret;
  57 }
  58
  59 static const u16 read_all_tx_array[] = {
  60         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_SUPPLY_OUT)),
  61         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_XGYRO_OUT)),
  62         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_YGYRO_OUT)),
  63         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_ZGYRO_OUT)),
  64         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_XACCL_OUT)),
  65         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_YACCL_OUT)),
  66         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_ZACCL_OUT)),
  67         cpu_to_be16(ADIS16400_READ_REG(ADIS16350_XTEMP_OUT)),
  68         cpu_to_be16(ADIS16400_READ_REG(ADIS16350_YTEMP_OUT)),
  69         cpu_to_be16(ADIS16400_READ_REG(ADIS16350_ZTEMP_OUT)),
  70         cpu_to_be16(ADIS16400_READ_REG(ADIS16400_AUX_ADC)),
  71 };
  72
  73 static int adis16350_spi_read_all(struct device *dev, u8 *rx)
  74 {
  75         struct iio_dev *indio_dev = dev_get_drvdata(dev);
  76         struct adis16400_state *st = iio_priv(indio_dev);
  77
  78         struct spi_message msg;
  79         int i, j = 0, ret;
  80         struct spi_transfer *xfers;
  81
  82         xfers = kzalloc(sizeof(*xfers)*indio_dev->ring->scan_count + 1,
  83                         GFP_KERNEL);
  84         if (xfers == NULL)
  85                 return -ENOMEM;
  86
  87         for (i = 0; i < ARRAY_SIZE(read_all_tx_array); i++)
  88                 if (test_bit(i, indio_dev->ring->scan_mask)) {
  89                         xfers[j].tx_buf = &read_all_tx_array[i];
  90                         xfers[j].bits_per_word = 16;
  91                         xfers[j].len = 2;
  92                         xfers[j + 1].rx_buf = rx + j*2;
  93                         j++;
  94                 }
  95         xfers[j].bits_per_word = 16;
  96         xfers[j].len = 2;
  97
  98         spi_message_init(&msg);
  99         for (j = 0; j < indio_dev->ring->scan_count + 1; j++)
 100                 spi_message_add_tail(&xfers[j], &msg);
 101
 102         ret = spi_sync(st->us, &msg);
 103         kfree(xfers);
 104
 105         return ret;
 106 }
 107
 108 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
 109  * specific to be rolled into the core.
 110  */
 111 static irqreturn_t adis16400_trigger_handler(int irq, void *p)
 112 {
 113         struct iio_poll_func *pf = p;
 114         struct iio_dev *indio_dev = pf->indio_dev;
 115         struct adis16400_state *st = iio_priv(indio_dev);
 116         struct iio_ring_buffer *ring = indio_dev->ring;
 117         int i = 0, j, ret = 0;
 118         s16 *data;
 119         size_t datasize = ring->access->get_bytes_per_datum(ring);
 120         /* Asumption that long is enough for maximum channels */
 121         unsigned long mask = *ring->scan_mask;
 122
 123         data = kmalloc(datasize , GFP_KERNEL);
 124         if (data == NULL) {
 125                 dev_err(&st->us->dev, "memory alloc failed in ring bh");
 126                 return -ENOMEM;
 127         }
 128
 129         if (ring->scan_count) {
 130                 if (st->variant->flags & ADIS16400_NO_BURST) {
 131                         ret = adis16350_spi_read_all(&indio_dev->dev, st->rx);
 132                         if (ret < 0)
 133                                 goto err;
 134                         for (; i < ring->scan_count; i++)
 135                                 data[i] = *(s16 *)(st->rx + i*2);
 136                 } else {
 137                         ret = adis16400_spi_read_burst(&indio_dev->dev, st->rx);
 138                         if (ret < 0)
 139                                 goto err;
 140                         for (; i < indio_dev->ring->scan_count; i++) {
 141                                 j = __ffs(mask);
 142                                 mask &= ~(1 << j);
 143                                 data[i] = be16_to_cpup(
 144                                         (__be16 *)&(st->rx[j*2]));
 145                         }
 146                 }
 147         }
 148         /* Guaranteed to be aligned with 8 byte boundary */
 149         if (ring->scan_timestamp)
 150                 *((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 151         ring->access->store_to(indio_dev->ring, (u8 *) data, pf->timestamp);
 152
 153         iio_trigger_notify_done(indio_dev->trig);
 154
 155         kfree(data);
 156         return IRQ_HANDLED;
 157
 158 err:
 159         kfree(data);
 160         return ret;
 161 }
 162
 163 void adis16400_unconfigure_ring(struct iio_dev *indio_dev)
 164 {
 165         iio_dealloc_pollfunc(indio_dev->pollfunc);
 166         iio_sw_rb_free(indio_dev->ring);
 167 }
 168
 169 static const struct iio_ring_setup_ops adis16400_ring_setup_ops = {
 170         .preenable = &iio_sw_ring_preenable,
 171         .postenable = &iio_triggered_buffer_postenable,
 172         .predisable = &iio_triggered_buffer_predisable,
 173 };
 174
 175 int adis16400_configure_ring(struct iio_dev *indio_dev)
 176 {
 177         int ret = 0;
 178         struct adis16400_state *st = iio_priv(indio_dev);
 179         struct iio_ring_buffer *ring;
 180
 181         ring = iio_sw_rb_allocate(indio_dev);
 182         if (!ring) {
 183                 ret = -ENOMEM;
 184                 return ret;
 185         }
 186         indio_dev->ring = ring;
 187         /* Effectively select the ring buffer implementation */
 188         ring->access = &ring_sw_access_funcs;
 189         ring->bpe = 2;
 190         ring->scan_timestamp = true;
 191         ring->setup_ops = &adis16400_ring_setup_ops;
 192         ring->owner = THIS_MODULE;
 193
 194         indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
 195                                                  &adis16400_trigger_handler,
 196                                                  IRQF_ONESHOT,
 197                                                  indio_dev,
 198                                                  "%s_consumer%d",
 199                                                  indio_dev->name,
 200                                                  indio_dev->id);
 201         if (indio_dev->pollfunc == NULL) {
 202                 ret = -ENOMEM;
 203                 goto error_iio_sw_rb_free;
 204         }
 205
 206         indio_dev->modes |= INDIO_RING_TRIGGERED;
 207         return 0;
 208 error_iio_sw_rb_free:
 209         iio_sw_rb_free(indio_dev->ring);
 210         return ret;
 211 }