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
  14 #include "../iio.h"
  15 #include "../buffer.h"
  16 #include "../ring_sw.h"
  17 #include "../trigger_consumer.h"
  18
  19 #include "ad7606.h"
  20
  21 int ad7606_scan_from_ring(struct iio_dev *indio_dev, unsigned ch)
  22 {
  23         struct iio_buffer *ring = indio_dev->buffer;
  24         int ret;
  25         u16 *ring_data;
  26
  27         ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
  28                             GFP_KERNEL);
  29         if (ring_data == NULL) {
  30                 ret = -ENOMEM;
  31                 goto error_ret;
  32         }
  33         ret = ring->access->read_last(ring, (u8 *) ring_data);
  34         if (ret)
  35                 goto error_free_ring_data;
  36
  37         ret = ring_data[ch];
  38
  39 error_free_ring_data:
  40         kfree(ring_data);
  41 error_ret:
  42         return ret;
  43 }
  44
  45 /**
  46  * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  47  *
  48  **/
  49 static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
  50 {
  51         struct iio_poll_func *pf = p;
  52         struct ad7606_state *st = iio_priv(pf->indio_dev);
  53
  54         gpio_set_value(st->pdata->gpio_convst, 1);
  55
  56         return IRQ_HANDLED;
  57 }
  58
  59 /**
  60  * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  61  * @work_s:     the work struct through which this was scheduled
  62  *
  63  * Currently there is no option in this driver to disable the saving of
  64  * timestamps within the ring.
  65  * I think the one copy of this at a time was to avoid problems if the
  66  * trigger was set far too high and the reads then locked up the computer.
  67  **/
  68 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
  69 {
  70         struct ad7606_state *st = container_of(work_s, struct ad7606_state,
  71                                                 poll_work);
  72         struct iio_dev *indio_dev = iio_priv_to_dev(st);
  73         struct iio_buffer *ring = indio_dev->buffer;
  74         s64 time_ns;
  75         __u8 *buf;
  76         int ret;
  77
  78         buf = kzalloc(ring->access->get_bytes_per_datum(ring),
  79                       GFP_KERNEL);
  80         if (buf == NULL)
  81                 return;
  82
  83         if (gpio_is_valid(st->pdata->gpio_frstdata)) {
  84                 ret = st->bops->read_block(st->dev, 1, buf);
  85                 if (ret)
  86                         goto done;
  87                 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
  88                         /* This should never happen. However
  89                          * some signal glitch caused by bad PCB desgin or
  90                          * electrostatic discharge, could cause an extra read
  91                          * or clock. This allows recovery.
  92                          */
  93                         ad7606_reset(st);
  94                         goto done;
  95                 }
  96                 ret = st->bops->read_block(st->dev,
  97                         st->chip_info->num_channels - 1, buf + 2);
  98                 if (ret)
  99                         goto done;
 100         } else {
 101                 ret = st->bops->read_block(st->dev,
 102                         st->chip_info->num_channels, buf);
 103                 if (ret)
 104                         goto done;
 105         }
 106
 107         time_ns = iio_get_time_ns();
 108
 109         if (ring->scan_timestamp)
 110                 *((s64 *)(buf + ring->access->get_bytes_per_datum(ring) -
 111                           sizeof(s64))) = time_ns;
 112
 113         ring->access->store_to(indio_dev->buffer, buf, time_ns);
 114 done:
 115         gpio_set_value(st->pdata->gpio_convst, 0);
 116         iio_trigger_notify_done(indio_dev->trig);
 117         kfree(buf);
 118 }
 119
 120 static const struct iio_buffer_setup_ops ad7606_ring_setup_ops = {
 121         .preenable = &iio_sw_buffer_preenable,
 122         .postenable = &iio_triggered_buffer_postenable,
 123         .predisable = &iio_triggered_buffer_predisable,
 124 };
 125
 126 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 127 {
 128         struct ad7606_state *st = iio_priv(indio_dev);
 129         int ret;
 130
 131         indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
 132         if (!indio_dev->buffer) {
 133                 ret = -ENOMEM;
 134                 goto error_ret;
 135         }
 136
 137         /* Effectively select the ring buffer implementation */
 138         indio_dev->buffer->access = &ring_sw_access_funcs;
 139         indio_dev->buffer->bpe =
 140                 st->chip_info->channels[0].scan_type.storagebits / 8;
 141         indio_dev->pollfunc = iio_alloc_pollfunc(&ad7606_trigger_handler_th_bh,
 142                                                  &ad7606_trigger_handler_th_bh,
 143                                                  0,
 144                                                  indio_dev,
 145                                                  "%s_consumer%d",
 146                                                  indio_dev->name,
 147                                                  indio_dev->id);
 148         if (indio_dev->pollfunc == NULL) {
 149                 ret = -ENOMEM;
 150                 goto error_deallocate_sw_rb;
 151         }
 152
 153         /* Ring buffer functions - here trigger setup related */
 154
 155         indio_dev->buffer->setup_ops = &ad7606_ring_setup_ops;
 156         indio_dev->buffer->scan_timestamp = true ;
 157
 158         INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 159
 160         /* Flag that polled ring buffering is possible */
 161         indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
 162         return 0;
 163
 164 error_deallocate_sw_rb:
 165         iio_sw_rb_free(indio_dev->buffer);
 166 error_ret:
 167         return ret;
 168 }
 169
 170 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 171 {
 172         iio_dealloc_pollfunc(indio_dev->pollfunc);
 173         iio_sw_rb_free(indio_dev->buffer);
 174 }