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/trigger_consumer.h>
  17#include <linux/iio/triggered_buffer.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        __u8 *buf;
  50        int ret;
  51
  52        buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
  53        if (!buf)
  54                return;
  55
  56        if (gpio_is_valid(st->pdata->gpio_frstdata)) {
  57                ret = st->bops->read_block(st->dev, 1, buf);
  58                if (ret)
  59                        goto done;
  60                if (!gpio_get_value(st->pdata->gpio_frstdata)) {
  61                        /* This should never happen. However
  62                         * some signal glitch caused by bad PCB desgin or
  63                         * electrostatic discharge, could cause an extra read
  64                         * or clock. This allows recovery.
  65                         */
  66                        ad7606_reset(st);
  67                        goto done;
  68                }
  69                ret = st->bops->read_block(st->dev,
  70                        st->chip_info->num_channels - 1, buf + 2);
  71                if (ret)
  72                        goto done;
  73        } else {
  74                ret = st->bops->read_block(st->dev,
  75                        st->chip_info->num_channels, buf);
  76                if (ret)
  77                        goto done;
  78        }
  79
  80        iio_push_to_buffers_with_timestamp(indio_dev, buf,
  81                                           iio_get_time_ns(indio_dev));
  82done:
  83        gpio_set_value(st->pdata->gpio_convst, 0);
  84        iio_trigger_notify_done(indio_dev->trig);
  85        kfree(buf);
  86}
  87
  88int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
  89{
  90        struct ad7606_state *st = iio_priv(indio_dev);
  91
  92        INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
  93
  94        return iio_triggered_buffer_setup(indio_dev,
  95                &ad7606_trigger_handler_th_bh, &ad7606_trigger_handler_th_bh,
  96                NULL);
  97}
  98
  99void ad7606_ring_cleanup(struct iio_dev *indio_dev)
 100{
 101        iio_triggered_buffer_cleanup(indio_dev);
 102}
 103