max1363_ring.c

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/*
 * Copyright (C) 2008 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.
 *
 * max1363_ring.c
 */

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

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include "../ring_sw.h"
#include <linux/iio/trigger_consumer.h>

#include "max1363.h"

int max1363_update_scan_mode(struct iio_dev *indio_dev,
                 const unsigned long *scan_mask)
{
    struct max1363_state *st = iio_priv(indio_dev);

    /*
     * Need to figure out the current mode based upon the requested
     * scan mask in iio_dev
     */
    st->current_mode = max1363_match_mode(scan_mask, st->chip_info);
    if (!st->current_mode)
        return -EINVAL;
    max1363_set_scan_mode(st);
    return 0;
}

static irqreturn_t max1363_trigger_handler(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct iio_dev *indio_dev = pf->indio_dev;
    struct max1363_state *st = iio_priv(indio_dev);
    s64 time_ns;
    __u8 *rxbuf;
    int b_sent;
    size_t d_size;
    unsigned long numvals = bitmap_weight(st->current_mode->modemask,
                          MAX1363_MAX_CHANNELS);

    /* Ensure the timestamp is 8 byte aligned */
    if (st->chip_info->bits != 8)
        d_size = numvals*2;
    else
        d_size = numvals;
    if (indio_dev->scan_timestamp) {
        d_size += sizeof(s64);
        if (d_size % sizeof(s64))
            d_size += sizeof(s64) - (d_size % sizeof(s64));
    }
    /* Monitor mode prevents reading. Whilst not currently implemented
     * might as well have this test in here in the meantime as it does
     * no harm.
     */
    if (numvals == 0)
        goto done;

    rxbuf = kmalloc(d_size, GFP_KERNEL);
    if (rxbuf == NULL)
        goto done;
    if (st->chip_info->bits != 8)
        b_sent = i2c_master_recv(st->client, rxbuf, numvals*2);
    else
        b_sent = i2c_master_recv(st->client, rxbuf, numvals);
    if (b_sent < 0)
        goto done_free;

    time_ns = iio_get_time_ns();

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

done_free:
    kfree(rxbuf);
done:
    iio_trigger_notify_done(indio_dev->trig);

    return IRQ_HANDLED;
}

static const struct iio_buffer_setup_ops max1363_ring_setup_ops = {
    .postenable = &iio_triggered_buffer_postenable,
    .preenable = &iio_sw_buffer_preenable,
    .predisable = &iio_triggered_buffer_predisable,
};

int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
    struct max1363_state *st = iio_priv(indio_dev);
    int ret = 0;

    indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
    if (!indio_dev->buffer) {
        ret = -ENOMEM;
        goto error_ret;
    }
    indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
                         &max1363_trigger_handler,
                         IRQF_ONESHOT,
                         indio_dev,
                         "%s_consumer%d",
                         st->client->name,
                         indio_dev->id);
    if (indio_dev->pollfunc == NULL) {
        ret = -ENOMEM;
        goto error_deallocate_sw_rb;
    }
    /* Ring buffer functions - here trigger setup related */
    indio_dev->setup_ops = &max1363_ring_setup_ops;

    /* Flag that polled ring buffering is possible */
    indio_dev->modes |= INDIO_BUFFER_TRIGGERED;

    return 0;

error_deallocate_sw_rb:
    iio_sw_rb_free(indio_dev->buffer);
error_ret:
    return ret;
}

void max1363_ring_cleanup(struct iio_dev *indio_dev)
{
    /* ensure that the trigger has been detached */
    iio_dealloc_pollfunc(indio_dev->pollfunc);
    iio_sw_rb_free(indio_dev->buffer);
}