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 = st->indio_dev->ring;
  27         int ret;
  28         u16 *ring_data;
  29
  30         ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), 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 = indio_dev->dev_data;
  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 = indio_dev->dev_data;
  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 = st->indio_dev;
 107         struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
 108         struct iio_ring_buffer *ring = indio_dev->ring;
 109         s64 time_ns;
 110         __u8 *buf;
 111         int ret;
 112
 113         buf = kzalloc(st->d_size, GFP_KERNEL);
 114         if (buf == NULL)
 115                 return;
 116
 117         if (st->have_frstdata) {
 118                 ret = st->bops->read_block(st->dev, 1, buf);
 119                 if (ret)
 120                         goto done;
 121                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
 122                         /* This should never happen. However
 123                          * some signal glitch caused by bad PCB desgin or
 124                          * electrostatic discharge, could cause an extra read
 125                          * or clock. This allows recovery.
 126                          */
 127                         ad7606_reset(st);
 128                         goto done;
 129                 }
 130                 ret = st->bops->read_block(st->dev,
 131                         st->chip_info->num_channels - 1, buf + 2);
 132                 if (ret)
 133                         goto done;
 134         } else {
 135                 ret = st->bops->read_block(st->dev,
 136                         st->chip_info->num_channels, buf);
 137                 if (ret)
 138                         goto done;
 139         }
 140
 141         time_ns = iio_get_time_ns();
 142
 143         if (ring->scan_timestamp)
 144                 memcpy(buf + st->d_size - sizeof(s64),
 145                         &time_ns, sizeof(time_ns));
 146
 147         ring->access.store_to(&sw_ring->buf, buf, time_ns);
 148 done:
 149         gpio_set_value(st->pdata->gpio_convst, 0);
 150         iio_trigger_notify_done(indio_dev->trig);
 151         kfree(buf);
 152 }
 153
 154 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 155 {
 156         struct ad7606_state *st = indio_dev->dev_data;
 157         int ret;
 158
 159         indio_dev->ring = iio_sw_rb_allocate(indio_dev);
 160         if (!indio_dev->ring) {
 161                 ret = -ENOMEM;
 162                 goto error_ret;
 163         }
 164
 165         /* Effectively select the ring buffer implementation */
 166         iio_ring_sw_register_funcs(&indio_dev->ring->access);
 167         indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
 168         if (indio_dev->pollfunc == NULL) {
 169                 ret = -ENOMEM;
 170                 goto error_deallocate_sw_rb;
 171         }
 172
 173         indio_dev->pollfunc->private_data = indio_dev;
 174         indio_dev->pollfunc->h = &ad7606_trigger_handler_th_bh;
 175         indio_dev->pollfunc->thread = &ad7606_trigger_handler_th_bh;
 176         indio_dev->pollfunc->name =
 177                 kasprintf(GFP_KERNEL, "%s_consumer%d", indio_dev->name,
 178                           indio_dev->id);
 179         if (indio_dev->pollfunc->name == NULL) {
 180                 ret = -ENOMEM;
 181                 goto error_free_poll_func;
 182         }
 183         /* Ring buffer functions - here trigger setup related */
 184
 185         indio_dev->ring->preenable = &ad7606_ring_preenable;
 186         indio_dev->ring->postenable = &iio_triggered_ring_postenable;
 187         indio_dev->ring->predisable = &iio_triggered_ring_predisable;
 188         indio_dev->ring->scan_timestamp = true ;
 189
 190         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 191
 192         /* Flag that polled ring buffering is possible */
 193         indio_dev->modes |= INDIO_RING_TRIGGERED;
 194         return 0;
 195 error_free_poll_func:
 196         kfree(indio_dev->pollfunc);
 197 error_deallocate_sw_rb:
 198         iio_sw_rb_free(indio_dev->ring);
 199 error_ret:
 200         return ret;
 201 }
 202
 203 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 204 {
 205         if (indio_dev->trig) {
 206                 iio_put_trigger(indio_dev->trig);
 207                 iio_trigger_dettach_poll_func(indio_dev->trig,
 208                                               indio_dev->pollfunc);
 209         }
 210         kfree(indio_dev->pollfunc->name);
 211         kfree(indio_dev->pollfunc);
 212         iio_sw_rb_free(indio_dev->ring);
 213 }