ad799x_ring.c

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/*
 * Copyright (C) 2010-2012 Michael Hennerich, Analog Devices Inc.
 * Copyright (C) 2008-2010 Jonathan Cameron
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * ad799x_ring.c
 */

#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/i2c.h>
#include <linux/bitops.h>

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

#include "ad799x.h"

static irqreturn_t ad799x_trigger_handler(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct iio_dev *indio_dev = pf->indio_dev;
    struct ad799x_state *st = iio_priv(indio_dev);
    s64 time_ns;
    __u8 *rxbuf;
    int b_sent;
    u8 cmd;

    rxbuf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
    if (rxbuf == NULL)
        goto out;

    switch (st->id) {
    case ad7991:
    case ad7995:
    case ad7999:
        cmd = st->config |
            (*indio_dev->active_scan_mask << AD799X_CHANNEL_SHIFT);
        break;
    case ad7992:
    case ad7993:
    case ad7994:
        cmd = (*indio_dev->active_scan_mask << AD799X_CHANNEL_SHIFT) |
            AD7998_CONV_RES_REG;
        break;
    case ad7997:
    case ad7998:
        cmd = AD7997_8_READ_SEQUENCE | AD7998_CONV_RES_REG;
        break;
    default:
        cmd = 0;
    }

    b_sent = i2c_smbus_read_i2c_block_data(st->client,
            cmd, bitmap_weight(indio_dev->active_scan_mask,
                       indio_dev->masklength) * 2, rxbuf);
    if (b_sent < 0)
        goto done;

    time_ns = iio_get_time_ns();

    if (indio_dev->scan_timestamp)
        memcpy(rxbuf + indio_dev->scan_bytes - sizeof(s64),
            &time_ns, sizeof(time_ns));

    iio_push_to_buffer(indio_dev->buffer, rxbuf);
done:
    kfree(rxbuf);
out:
    iio_trigger_notify_done(indio_dev->trig);

    return IRQ_HANDLED;
}

int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
    return iio_triggered_buffer_setup(indio_dev, NULL,
        &ad799x_trigger_handler, NULL);
}

void ad799x_ring_cleanup(struct iio_dev *indio_dev)
{
    iio_triggered_buffer_cleanup(indio_dev);
}