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

   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/**
  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(ring->access->get_bytes_per_datum(ring),
  55                      GFP_KERNEL);
  56        if (buf == NULL)
  57                return;
  58
  59        if (gpio_is_valid(st->pdata->gpio_frstdata)) {
  60                ret = st->bops->read_block(st->dev, 1, buf);
  61                if (ret)
  62                        goto done;
  63                if (!gpio_get_value(st->pdata->gpio_frstdata)) {
  64                        /* This should never happen. However
  65                         * some signal glitch caused by bad PCB desgin or
  66                         * electrostatic discharge, could cause an extra read
  67                         * or clock. This allows recovery.
  68                         */
  69                        ad7606_reset(st);
  70                        goto done;
  71                }
  72                ret = st->bops->read_block(st->dev,
  73                        st->chip_info->num_channels - 1, buf + 2);
  74                if (ret)
  75                        goto done;
  76        } else {
  77                ret = st->bops->read_block(st->dev,
  78                        st->chip_info->num_channels, buf);
  79                if (ret)
  80                        goto done;
  81        }
  82
  83        time_ns = iio_get_time_ns();
  84
  85        if (ring->scan_timestamp)
  86                *((s64 *)(buf + ring->access->get_bytes_per_datum(ring) -
  87                          sizeof(s64))) = time_ns;
  88
  89        ring->access->store_to(indio_dev->buffer, buf, time_ns);
  90done:
  91        gpio_set_value(st->pdata->gpio_convst, 0);
  92        iio_trigger_notify_done(indio_dev->trig);
  93        kfree(buf);
  94}
  95
  96static const struct iio_buffer_setup_ops ad7606_ring_setup_ops = {
  97        .preenable = &iio_sw_buffer_preenable,
  98        .postenable = &iio_triggered_buffer_postenable,
  99        .predisable = &iio_triggered_buffer_predisable,
 100};
 101
 102int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 103{
 104        struct ad7606_state *st = iio_priv(indio_dev);
 105        int ret;
 106
 107        indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
 108        if (!indio_dev->buffer) {
 109                ret = -ENOMEM;
 110                goto error_ret;
 111        }
 112
 113        indio_dev->pollfunc = iio_alloc_pollfunc(&ad7606_trigger_handler_th_bh,
 114                                                 &ad7606_trigger_handler_th_bh,
 115                                                 0,
 116                                                 indio_dev,
 117                                                 "%s_consumer%d",
 118                                                 indio_dev->name,
 119                                                 indio_dev->id);
 120        if (indio_dev->pollfunc == NULL) {
 121                ret = -ENOMEM;
 122                goto error_deallocate_sw_rb;
 123        }
 124
 125        /* Ring buffer functions - here trigger setup related */
 126
 127        indio_dev->setup_ops = &ad7606_ring_setup_ops;
 128        indio_dev->buffer->scan_timestamp = true ;
 129
 130        INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
 131
 132        /* Flag that polled ring buffering is possible */
 133        indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
 134        return 0;
 135
 136error_deallocate_sw_rb:
 137        iio_sw_rb_free(indio_dev->buffer);
 138error_ret:
 139        return ret;
 140}
 141
 142void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 143{
 144        iio_dealloc_pollfunc(indio_dev->pollfunc);
 145        iio_sw_rb_free(indio_dev->buffer);
 146}
 147