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/workqueue.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/sysfs.h>
  15
  16 #include "../iio.h"
  17 #include "../ring_generic.h"
  18 #include "../ring_sw.h"
  19 #include "../trigger.h"
  20 #include "../sysfs.h"
  21
  22 #include "ad7606.h"
  23
  24 int ad7606_scan_from_ring(struct ad7606_state *st, unsigned ch)
  25 {
  26         struct iio_ring_buffer *ring = iio_priv_to_dev(st)->ring;
  27         int ret;
  28         u16 *ring_data;
  29
  30         ring_data = kmalloc(ring->access.get_bytes_per_datum(ring),
  31                             GFP_KERNEL);
  32         if (ring_data == NULL) {
  33                 ret = -ENOMEM;
  34                 goto error_ret;
  35         }
  36         ret = ring->access.read_last(ring, (u8 *) ring_data);
  37         if (ret)
  38                 goto error_free_ring_data;
  39
  40         ret = ring_data[ch];
  41
  42 error_free_ring_data:
  43         kfree(ring_data);
  44 error_ret:
  45         return ret;
  46 }
  47
  48 /**
  49  * ad7606_ring_preenable() setup the parameters of the ring before enabling
  50  *
  51  * The complex nature of the setting of the nuber of bytes per datum is due
  52  * to this driver currently ensuring that the timestamp is stored at an 8
  53  * byte boundary.
  54  **/
  55 static int ad7606_ring_preenable(struct iio_dev *indio_dev)
  56 {
  57         struct ad7606_state *st = indio_dev->dev_data;
  58         struct iio_ring_buffer *ring = indio_dev->ring;
  59         size_t d_size;
  60
  61         d_size = st->chip_info->num_channels *
  62                  st->chip_info->channels[0].scan_type.storagebits / 8;
  63
  64         if (ring->scan_timestamp) {
  65                 d_size += sizeof(s64);
  66
  67                 if (d_size % sizeof(s64))
  68                         d_size += sizeof(s64) - (d_size % sizeof(s64));
  69         }
  70
  71         if (ring->access.set_bytes_per_datum)
  72                 ring->access.set_bytes_per_datum(ring, d_size);
  73
  74         st->d_size = d_size;
  75
  76         return 0;
  77 }
  78
  79 /**
  80  * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  81  *
  82  **/
  83 static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
  84 {
  85         struct iio_poll_func *pf = p;
  86         struct iio_dev *indio_dev = pf->private_data;
  87         struct ad7606_state *st = indio_dev->dev_data;
  88
  89         gpio_set_value(st->pdata->gpio_convst, 1);
  90
  91         return IRQ_HANDLED;
  92 }
  93
  94 /**
  95  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  96  * @work_s:     the work struct through which this was scheduled
  97  *
  98  * Currently there is no option in this driver to disable the saving of
  99  * timestamps within the ring.
 100  * I think the one copy of this at a time was to avoid problems if the
 101  * trigger was set far too high and the reads then locked up the computer.
 102  **/
 103 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
 104 {
 105         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
 106                                                 poll_work);
 107         struct iio_dev *indio_dev = iio_priv_to_dev(st);
 108         struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
 109         struct iio_ring_buffer *ring = indio_dev->ring;
 110         s64 time_ns;
 111         __u8 *buf;
 112         int ret;
 113
 114         buf = kzalloc(st->d_size, GFP_KERNEL);
 115         if (buf == NULL)
 116                 return;
 117
 118         if (st->have_frstdata) {
 119                 ret = st->bops->read_block(st->dev, 1, buf);
 120                 if (ret)
 121                         goto done;
 122                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
 123                         /* This should never happen. However
 124                          * some signal glitch caused by bad PCB desgin or
 125                          * electrostatic discharge, could cause an extra read
 126                          * or clock. This allows recovery.
 127                          */
 128                         ad7606_reset(st);
 129                         goto done;
 130                 }
 131                 ret = st->bops->read_block(st->dev,
 132                         st->chip_info->num_channels - 1, buf + 2);
 133                 if (ret)
 134                         goto done;
 135         } else {
 136                 ret = st->bops->read_block(st->dev,
 137                         st->chip_info->num_channels, buf);
 138                 if (ret)
 139                         goto done;
 140         }
 141
 142         time_ns = iio_get_time_ns();
 143
 144         if (ring->scan_timestamp)
 145                 memcpy(buf + st->d_size - sizeof(s64),
 146                         &time_ns, sizeof(time_ns));
 147
 148         ring->access.store_to(&sw_ring->buf, buf, time_ns);
 149 done:
 150         gpio_set_value(st->pdata->gpio_convst, 0);
 151         iio_trigger_notify_done(indio_dev->trig);
 152         kfree(buf);
 153 }
 154
 155 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 156 {
 157         struct ad7606_state *st = indio_dev->dev_data;
 158         int ret;
 159
 160         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 161         if (!indio_dev->ring) {
 162                 ret = -ENOMEM;
 163                 goto error_ret;
 164         }
 165
 166         /* Effectively select the ring buffer implementation */
 167         iio_ring_sw_register_funcs(&indio_dev->ring->access);
 168         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 169         if (indio_dev->pollfunc == NULL) {
 170                 ret = -ENOMEM;
 171                 goto error_deallocate_sw_rb;
 172         }
 173
 174         indio_dev->pollfunc->private_data = indio_dev;
 175         indio_dev->pollfunc->h = &ad7606_trigger_handler_th_bh;
 176         indio_dev->pollfunc->thread = &ad7606_trigger_handler_th_bh;
 177         indio_dev->pollfunc->name =
 178                 kasprintf(GFP_KERNEL, "%s_consumer%d", indio_dev->name,
 179                           indio_dev->id);
 180         if (indio_dev->pollfunc->name == NULL) {
 181                 ret = -ENOMEM;
 182                 goto error_free_poll_func;
 183         }
 184         /* Ring buffer functions - here trigger setup related */
 185
 186         indio_dev->ring->preenable = &ad7606_ring_preenable;
 187         indio_dev->ring->postenable = &iio_triggered_ring_postenable;
 188         indio_dev->ring->predisable = &iio_triggered_ring_predisable;
 189         indio_dev->ring->scan_timestamp = true ;
 190
 191         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 192
 193         /* Flag that polled ring buffering is possible */
 194         indio_dev->modes |= INDIO_RING_TRIGGERED;
 195         return 0;
 196 error_free_poll_func:
 197         kfree(indio_dev->pollfunc);
 198 error_deallocate_sw_rb:
 199         iio_sw_rb_free(indio_dev->ring);
 200 error_ret:
 201         return ret;
 202 }
 203
 204 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 205 {
 206         if (indio_dev->trig) {
 207                 iio_put_trigger(indio_dev->trig);
 208                 iio_trigger_dettach_poll_func(indio_dev->trig,
 209                                               indio_dev->pollfunc);
 210         }
 211         kfree(indio_dev->pollfunc->name);
 212         kfree(indio_dev->pollfunc);
 213         iio_sw_rb_free(indio_dev->ring);
 214 }