drivers/staging/iio/adc/ad7606_ring.c

   1 /*
   2  * Copyright 2011 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2.
   5  *
   6  */
   7
   8 #include <linux/interrupt.h>
   9 #include <linux/gpio.h>
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysfs.h>
  14
  15 #include "../iio.h"
  16 #include "../ring_generic.h"
  17 #include "../ring_sw.h"
  18 #include "../trigger.h"
  19 #include "../sysfs.h"
  20
  21 #include "ad7606.h"
  22
  23 int ad7606_scan_from_ring(struct iio_dev *indio_dev, unsigned ch)
  24 {
  25         struct iio_ring_buffer *ring = indio_dev->ring;
  26         int ret;
  27         u16 *ring_data;
  28
  29         ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
  30                             GFP_KERNEL);
  31         if (ring_data == NULL) {
  32                 ret = -ENOMEM;
  33                 goto error_ret;
  34         }
  35         ret = ring->access->read_last(ring, (u8 *) ring_data);
  36         if (ret)
  37                 goto error_free_ring_data;
  38
  39         ret = ring_data[ch];
  40
  41 error_free_ring_data:
  42         kfree(ring_data);
  43 error_ret:
  44         return ret;
  45 }
  46
  47 /**
  48  * ad7606_ring_preenable() setup the parameters of the ring before enabling
  49  *
  50  * The complex nature of the setting of the nuber of bytes per datum is due
  51  * to this driver currently ensuring that the timestamp is stored at an 8
  52  * byte boundary.
  53  **/
  54 static int ad7606_ring_preenable(struct iio_dev *indio_dev)
  55 {
  56         struct ad7606_state *st = iio_priv(indio_dev);
  57         struct iio_ring_buffer *ring = indio_dev->ring;
  58         size_t d_size;
  59
  60         d_size = st->chip_info->num_channels *
  61                  st->chip_info->channels[0].scan_type.storagebits / 8;
  62
  63         if (ring->scan_timestamp) {
  64                 d_size += sizeof(s64);
  65
  66                 if (d_size % sizeof(s64))
  67                         d_size += sizeof(s64) - (d_size % sizeof(s64));
  68         }
  69
  70         if (ring->access->set_bytes_per_datum)
  71                 ring->access->set_bytes_per_datum(ring, d_size);
  72
  73         st->d_size = d_size;
  74
  75         return 0;
  76 }
  77
  78 /**
  79  * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  80  *
  81  **/
  82 static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
  83 {
  84         struct iio_poll_func *pf = p;
  85         struct iio_dev *indio_dev = pf->private_data;
  86         struct ad7606_state *st = iio_priv(indio_dev);
  87
  88         gpio_set_value(st->pdata->gpio_convst, 1);
  89
  90         return IRQ_HANDLED;
  91 }
  92
  93 /**
  94  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  95  * @work_s:     the work struct through which this was scheduled
  96  *
  97  * Currently there is no option in this driver to disable the saving of
  98  * timestamps within the ring.
  99  * I think the one copy of this at a time was to avoid problems if the
 100  * trigger was set far too high and the reads then locked up the computer.
 101  **/
 102 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
 103 {
 104         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
 105                                                 poll_work);
 106         struct iio_dev *indio_dev = iio_priv_to_dev(st);
 107         struct iio_ring_buffer *ring = indio_dev->ring;
 108         s64 time_ns;
 109         __u8 *buf;
 110         int ret;
 111
 112         buf = kzalloc(st->d_size, GFP_KERNEL);
 113         if (buf == NULL)
 114                 return;
 115
 116         if (st->have_frstdata) {
 117                 ret = st->bops->read_block(st->dev, 1, buf);
 118                 if (ret)
 119                         goto done;
 120                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
 121                         /* This should never happen. However
 122                          * some signal glitch caused by bad PCB desgin or
 123                          * electrostatic discharge, could cause an extra read
 124                          * or clock. This allows recovery.
 125                          */
 126                         ad7606_reset(st);
 127                         goto done;
 128                 }
 129                 ret = st->bops->read_block(st->dev,
 130                         st->chip_info->num_channels - 1, buf + 2);
 131                 if (ret)
 132                         goto done;
 133         } else {
 134                 ret = st->bops->read_block(st->dev,
 135                         st->chip_info->num_channels, buf);
 136                 if (ret)
 137                         goto done;
 138         }
 139
 140         time_ns = iio_get_time_ns();
 141
 142         if (ring->scan_timestamp)
 143                 memcpy(buf + st->d_size - sizeof(s64),
 144                         &time_ns, sizeof(time_ns));
 145
 146         ring->access->store_to(indio_dev->ring, buf, time_ns);
 147 done:
 148         gpio_set_value(st->pdata->gpio_convst, 0);
 149         iio_trigger_notify_done(indio_dev->trig);
 150         kfree(buf);
 151 }
 152
 153 static const struct iio_ring_setup_ops ad7606_ring_setup_ops = {
 154         .preenable = &ad7606_ring_preenable,
 155         .postenable = &iio_triggered_ring_postenable,
 156         .predisable = &iio_triggered_ring_predisable,
 157 };
 158
 159 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 160 {
 161         struct ad7606_state *st = iio_priv(indio_dev);
 162         int ret;
 163
 164         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 165         if (!indio_dev->ring) {
 166                 ret = -ENOMEM;
 167                 goto error_ret;
 168         }
 169
 170         /* Effectively select the ring buffer implementation */
 171         indio_dev->ring->access = &ring_sw_access_funcs;
 172         indio_dev->pollfunc = iio_alloc_pollfunc(&ad7606_trigger_handler_th_bh,
 173                                                  &ad7606_trigger_handler_th_bh,
 174                                                  0,
 175                                                  indio_dev,
 176                                                  "%s_consumer%d",
 177                                                  indio_dev->name,
 178                                                  indio_dev->id);
 179         if (indio_dev->pollfunc == NULL) {
 180                 ret = -ENOMEM;
 181                 goto error_deallocate_sw_rb;
 182         }
 183
 184         /* Ring buffer functions - here trigger setup related */
 185
 186         indio_dev->ring->setup_ops = &ad7606_ring_setup_ops;
 187         indio_dev->ring->scan_timestamp = true ;
 188
 189         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 190
 191         /* Flag that polled ring buffering is possible */
 192         indio_dev->modes |= INDIO_RING_TRIGGERED;
 193         return 0;
 194
 195 error_deallocate_sw_rb:
 196         iio_sw_rb_free(indio_dev->ring);
 197 error_ret:
 198         return ret;
 199 }
 200
 201 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 202 {
 203         if (indio_dev->trig) {
 204                 iio_put_trigger(indio_dev->trig);
 205                 iio_trigger_dettach_poll_func(indio_dev->trig,
 206                                               indio_dev->pollfunc);
 207         }
 208         iio_dealloc_pollfunc(indio_dev->pollfunc);
 209         iio_sw_rb_free(indio_dev->ring);
 210 }