LXR linux/drivers/staging/iio/adc/ad7606

   1/*
   2 * Copyright 2011-2012 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 <linux/iio/iio.h>
  15#include <linux/iio/buffer.h>
  16#include <linux/iio/kfifo_buf.h>
  17#include <linux/iio/trigger_consumer.h>
  18
  19#include "ad7606.h"
  20
  21/**
  22 * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  23 *
  24 **/
  25static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
  26{
  27        struct iio_poll_func *pf = p;
  28        struct ad7606_state *st = iio_priv(pf->indio_dev);
  29
  30        gpio_set_value(st->pdata->gpio_convst, 1);
  31
  32        return IRQ_HANDLED;
  33}
  34
  35/**
  36 * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
  37 * @work_s:     the work struct through which this was scheduled
  38 *
  39 * Currently there is no option in this driver to disable the saving of
  40 * timestamps within the ring.
  41 * I think the one copy of this at a time was to avoid problems if the
  42 * trigger was set far too high and the reads then locked up the computer.
  43 **/
  44static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
  45{
  46        struct ad7606_state *st = container_of(work_s, struct ad7606_state,
  47                                                poll_work);
  48        struct iio_dev *indio_dev = iio_priv_to_dev(st);
  49        struct iio_buffer *ring = indio_dev->buffer;
  50        s64 time_ns;
  51        __u8 *buf;
  52        int ret;
  53
  54        buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
  55        if (buf == NULL)
  56                return;
  57
  58        if (gpio_is_valid(st->pdata->gpio_frstdata)) {
  59                ret = st->bops->read_block(st->dev, 1, buf);
  60                if (ret)
  61                        goto done;
  62                if (!gpio_get_value(st->pdata->gpio_frstdata)) {
  63                        /* This should never happen. However
  64                         * some signal glitch caused by bad PCB desgin or
  65                         * electrostatic discharge, could cause an extra read
  66                         * or clock. This allows recovery.
  67                         */
  68                        ad7606_reset(st);
  69                        goto done;
  70                }
  71                ret = st->bops->read_block(st->dev,
  72                        st->chip_info->num_channels - 1, buf + 2);
  73                if (ret)
  74                        goto done;
  75        } else {
  76                ret = st->bops->read_block(st->dev,
  77                        st->chip_info->num_channels, buf);
  78                if (ret)
  79                        goto done;
  80        }
  81
  82        time_ns = iio_get_time_ns();
  83
  84        if (indio_dev->scan_timestamp)
  85                *((s64 *)(buf + indio_dev->scan_bytes - sizeof(s64))) = time_ns;
  86
  87        ring->access->store_to(indio_dev->buffer, buf, time_ns);
  88done:
  89        gpio_set_value(st->pdata->gpio_convst, 0);
  90        iio_trigger_notify_done(indio_dev->trig);
  91        kfree(buf);
  92}
  93
  94static const struct iio_buffer_setup_ops ad7606_ring_setup_ops = {
  95        .preenable = &iio_sw_buffer_preenable,
  96        .postenable = &iio_triggered_buffer_postenable,
  97        .predisable = &iio_triggered_buffer_predisable,
  98};
  99
 100int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 101{
 102        struct ad7606_state *st = iio_priv(indio_dev);
 103        int ret;
 104
 105        indio_dev->buffer = iio_kfifo_allocate(indio_dev);
 106        if (!indio_dev->buffer) {
 107                ret = -ENOMEM;
 108                goto error_ret;
 109        }
 110
 111        indio_dev->pollfunc = iio_alloc_pollfunc(&ad7606_trigger_handler_th_bh,
 112                                                 &ad7606_trigger_handler_th_bh,
 113                                                 0,
 114                                                 indio_dev,
 115                                                 "%s_consumer%d",
 116                                                 indio_dev->name,
 117                                                 indio_dev->id);
 118        if (indio_dev->pollfunc == NULL) {
 119                ret = -ENOMEM;
 120                goto error_deallocate_kfifo;
 121        }
 122
 123        /* Ring buffer functions - here trigger setup related */
 124
 125        indio_dev->setup_ops = &ad7606_ring_setup_ops;
 126        indio_dev->buffer->scan_timestamp = true;
 127
 128        INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 129
 130        /* Flag that polled ring buffering is possible */
 131        indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
 132        return 0;
 133
 134error_deallocate_kfifo:
 135        iio_kfifo_free(indio_dev->buffer);
 136error_ret:
 137        return ret;
 138}
 139
 140void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 141{
 142        iio_dealloc_pollfunc(indio_dev->pollfunc);
 143        iio_kfifo_free(indio_dev->buffer);
 144}
 145