ad7606_ring.c

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/*
 * Copyright 2011-2012 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 *
 */

#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include "ad7606.h"

static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct ad7606_state *st = iio_priv(pf->indio_dev);

    gpio_set_value(st->pdata->gpio_convst, 1);

    return IRQ_HANDLED;
}

static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
{
    struct ad7606_state *st = container_of(work_s, struct ad7606_state,
                        poll_work);
    struct iio_dev *indio_dev = iio_priv_to_dev(st);
    s64 time_ns;
    __u8 *buf;
    int ret;

    buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
    if (buf == NULL)
        return;

    if (gpio_is_valid(st->pdata->gpio_frstdata)) {
        ret = st->bops->read_block(st->dev, 1, buf);
        if (ret)
            goto done;
        if (!gpio_get_value(st->pdata->gpio_frstdata)) {
            /* This should never happen. However
             * some signal glitch caused by bad PCB desgin or
             * electrostatic discharge, could cause an extra read
             * or clock. This allows recovery.
             */
            ad7606_reset(st);
            goto done;
        }
        ret = st->bops->read_block(st->dev,
            st->chip_info->num_channels - 1, buf + 2);
        if (ret)
            goto done;
    } else {
        ret = st->bops->read_block(st->dev,
            st->chip_info->num_channels, buf);
        if (ret)
            goto done;
    }

    time_ns = iio_get_time_ns();

    if (indio_dev->scan_timestamp)
        *((s64 *)(buf + indio_dev->scan_bytes - sizeof(s64))) = time_ns;

    iio_push_to_buffer(indio_dev->buffer, buf);
done:
    gpio_set_value(st->pdata->gpio_convst, 0);
    iio_trigger_notify_done(indio_dev->trig);
    kfree(buf);
}

int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
    struct ad7606_state *st = iio_priv(indio_dev);

    INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);

    return iio_triggered_buffer_setup(indio_dev,
        &ad7606_trigger_handler_th_bh, &ad7606_trigger_handler_th_bh,
        NULL);
}

void ad7606_ring_cleanup(struct iio_dev *indio_dev)
{
    iio_triggered_buffer_cleanup(indio_dev);
}