drivers/staging/iio/meter/ade7758_ring.c

   1 /*
   2  * ADE7758 Poly Phase Multifunction Energy Metering IC driver
   3  *
   4  * Copyright 2010-2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8 #include <linux/interrupt.h>
   9 #include <linux/kernel.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/slab.h>
  12 #include <asm/unaligned.h>
  13
  14 #include "../iio.h"
  15 #include "../ring_sw.h"
  16 #include "../trigger_consumer.h"
  17 #include "ade7758.h"
  18
  19 /**
  20  * ade7758_spi_read_burst() - read data registers
  21  * @dev: device associated with child of actual device (iio_dev or iio_trig)
  22  **/
  23 static int ade7758_spi_read_burst(struct device *dev)
  24 {
  25         struct iio_dev *indio_dev = dev_get_drvdata(dev);
  26         struct ade7758_state *st = iio_priv(indio_dev);
  27         int ret;
  28
  29         ret = spi_sync(st->us, &st->ring_msg);
  30         if (ret)
  31                 dev_err(&st->us->dev, "problem when reading WFORM value\n");
  32
  33         return ret;
  34 }
  35
  36 static int ade7758_write_waveform_type(struct device *dev, unsigned type)
  37 {
  38         int ret;
  39         u8 reg;
  40
  41         ret = ade7758_spi_read_reg_8(dev,
  42                         ADE7758_WAVMODE,
  43                         &reg);
  44         if (ret)
  45                 goto out;
  46
  47         reg &= ~0x1F;
  48         reg |= type & 0x1F;
  49
  50         ret = ade7758_spi_write_reg_8(dev,
  51                         ADE7758_WAVMODE,
  52                         reg);
  53 out:
  54         return ret;
  55 }
  56
  57 /* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
  58  * specific to be rolled into the core.
  59  */
  60 static irqreturn_t ade7758_trigger_handler(int irq, void *p)
  61 {
  62         struct iio_poll_func *pf = p;
  63         struct iio_dev *indio_dev = pf->indio_dev;
  64         struct iio_ring_buffer *ring = indio_dev->ring;
  65         struct ade7758_state *st = iio_priv(indio_dev);
  66         s64 dat64[2];
  67         u32 *dat32 = (u32 *)dat64;
  68
  69         if (ring->scan_count)
  70                 if (ade7758_spi_read_burst(&indio_dev->dev) >= 0)
  71                         *dat32 = get_unaligned_be32(&st->rx_buf[5]) & 0xFFFFFF;
  72
  73         /* Guaranteed to be aligned with 8 byte boundary */
  74         if (ring->scan_timestamp)
  75                 dat64[1] = pf->timestamp;
  76
  77         ring->access->store_to(ring, (u8 *)dat64, pf->timestamp);
  78
  79         iio_trigger_notify_done(indio_dev->trig);
  80
  81         return IRQ_HANDLED;
  82 }
  83
  84 /**
  85  * ade7758_ring_preenable() setup the parameters of the ring before enabling
  86  *
  87  * The complex nature of the setting of the nuber of bytes per datum is due
  88  * to this driver currently ensuring that the timestamp is stored at an 8
  89  * byte boundary.
  90  **/
  91 static int ade7758_ring_preenable(struct iio_dev *indio_dev)
  92 {
  93         struct ade7758_state *st = iio_priv(indio_dev);
  94         struct iio_ring_buffer *ring = indio_dev->ring;
  95         size_t d_size;
  96         unsigned channel;
  97
  98         if (!ring->scan_count)
  99                 return -EINVAL;
 100
 101         channel = __ffs(ring->scan_mask);
 102
 103         d_size = st->ade7758_ring_channels[channel].scan_type.storagebits / 8;
 104
 105         if (ring->scan_timestamp) {
 106                 d_size += sizeof(s64);
 107
 108                 if (d_size % sizeof(s64))
 109                         d_size += sizeof(s64) - (d_size % sizeof(s64));
 110         }
 111
 112         if (indio_dev->ring->access->set_bytes_per_datum)
 113                 indio_dev->ring->access->set_bytes_per_datum(indio_dev->ring,
 114                                                             d_size);
 115
 116         ade7758_write_waveform_type(&indio_dev->dev,
 117                 st->ade7758_ring_channels[channel].address);
 118
 119         return 0;
 120 }
 121
 122 static const struct iio_ring_setup_ops ade7758_ring_setup_ops = {
 123         .preenable = &ade7758_ring_preenable,
 124         .postenable = &iio_triggered_ring_postenable,
 125         .predisable = &iio_triggered_ring_predisable,
 126 };
 127
 128 void ade7758_unconfigure_ring(struct iio_dev *indio_dev)
 129 {
 130         iio_dealloc_pollfunc(indio_dev->pollfunc);
 131         iio_sw_rb_free(indio_dev->ring);
 132 }
 133
 134 int ade7758_configure_ring(struct iio_dev *indio_dev)
 135 {
 136         struct ade7758_state *st = iio_priv(indio_dev);
 137         int ret = 0;
 138
 139         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 140         if (!indio_dev->ring) {
 141                 ret = -ENOMEM;
 142                 return ret;
 143         }
 144
 145         /* Effectively select the ring buffer implementation */
 146         indio_dev->ring->access = &ring_sw_access_funcs;
 147         indio_dev->ring->setup_ops = &ade7758_ring_setup_ops;
 148         indio_dev->ring->owner = THIS_MODULE;
 149
 150         indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
 151                                                  &ade7758_trigger_handler,
 152                                                  0,
 153                                                  indio_dev,
 154                                                  "ade7759_consumer%d",
 155                                                  indio_dev->id);
 156         if (indio_dev->pollfunc == NULL) {
 157                 ret = -ENOMEM;
 158                 goto error_iio_sw_rb_free;
 159         }
 160
 161         indio_dev->modes |= INDIO_RING_TRIGGERED;
 162
 163         st->tx_buf[0] = ADE7758_READ_REG(ADE7758_RSTATUS);
 164         st->tx_buf[1] = 0;
 165         st->tx_buf[2] = 0;
 166         st->tx_buf[3] = 0;
 167         st->tx_buf[4] = ADE7758_READ_REG(ADE7758_WFORM);
 168         st->tx_buf[5] = 0;
 169         st->tx_buf[6] = 0;
 170         st->tx_buf[7] = 0;
 171
 172         /* build spi ring message */
 173         st->ring_xfer[0].tx_buf = &st->tx_buf[0];
 174         st->ring_xfer[0].len = 1;
 175         st->ring_xfer[0].bits_per_word = 8;
 176         st->ring_xfer[0].delay_usecs = 4;
 177         st->ring_xfer[1].rx_buf = &st->rx_buf[1];
 178         st->ring_xfer[1].len = 3;
 179         st->ring_xfer[1].bits_per_word = 8;
 180         st->ring_xfer[1].cs_change = 1;
 181
 182         st->ring_xfer[2].tx_buf = &st->tx_buf[4];
 183         st->ring_xfer[2].len = 1;
 184         st->ring_xfer[2].bits_per_word = 8;
 185         st->ring_xfer[2].delay_usecs = 1;
 186         st->ring_xfer[3].rx_buf = &st->rx_buf[5];
 187         st->ring_xfer[3].len = 3;
 188         st->ring_xfer[3].bits_per_word = 8;
 189
 190         spi_message_init(&st->ring_msg);
 191         spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
 192         spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
 193         spi_message_add_tail(&st->ring_xfer[2], &st->ring_msg);
 194         spi_message_add_tail(&st->ring_xfer[3], &st->ring_msg);
 195
 196         return 0;
 197
 198 error_iio_sw_rb_free:
 199         iio_sw_rb_free(indio_dev->ring);
 200         return ret;
 201 }
 202
 203 void ade7758_uninitialize_ring(struct iio_ring_buffer *ring)
 204 {
 205         iio_ring_buffer_unregister(ring);
 206 }