adis16204_ring.c

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#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>

#include <linux/iio/iio.h>
#include "../ring_sw.h"
#include <linux/iio/trigger_consumer.h>
#include "adis16204.h"

static int adis16204_read_ring_data(struct iio_dev *indio_dev, u8 *rx)
{
    struct spi_message msg;
    struct adis16204_state *st = iio_priv(indio_dev);
    struct spi_transfer xfers[ADIS16204_OUTPUTS + 1];
    int ret;
    int i;

    mutex_lock(&st->buf_lock);

    spi_message_init(&msg);

    memset(xfers, 0, sizeof(xfers));
    for (i = 0; i <= ADIS16204_OUTPUTS; i++) {
        xfers[i].bits_per_word = 8;
        xfers[i].cs_change = 1;
        xfers[i].len = 2;
        xfers[i].delay_usecs = 20;
        xfers[i].tx_buf = st->tx + 2 * i;
        st->tx[2 * i]
            = ADIS16204_READ_REG(ADIS16204_SUPPLY_OUT + 2 * i);
        st->tx[2 * i + 1] = 0;
        if (i >= 1)
            xfers[i].rx_buf = rx + 2 * (i - 1);
        spi_message_add_tail(&xfers[i], &msg);
    }

    ret = spi_sync(st->us, &msg);
    if (ret)
        dev_err(&st->us->dev, "problem when burst reading");

    mutex_unlock(&st->buf_lock);

    return ret;
}

/* Whilst this makes a lot of calls to iio_sw_ring functions - it is to device
 * specific to be rolled into the core.
 */
static irqreturn_t adis16204_trigger_handler(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct iio_dev *indio_dev = pf->indio_dev;
    struct adis16204_state *st = iio_priv(indio_dev);
    int i = 0;
    s16 *data;

    data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
    if (data == NULL) {
        dev_err(&st->us->dev, "memory alloc failed in ring bh");
        goto done;
    }

    if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength) &&
        adis16204_read_ring_data(indio_dev, st->rx) >= 0)
        for (; i < bitmap_weight(indio_dev->active_scan_mask,
                     indio_dev->masklength); i++)
            data[i] = be16_to_cpup((__be16 *)&(st->rx[i*2]));

    /* Guaranteed to be aligned with 8 byte boundary */
    if (indio_dev->scan_timestamp)
        *((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;

    iio_push_to_buffer(indio_dev->buffer, (u8 *)data);

    kfree(data);
done:
    iio_trigger_notify_done(indio_dev->trig);

    return IRQ_HANDLED;
}

void adis16204_unconfigure_ring(struct iio_dev *indio_dev)
{
    iio_dealloc_pollfunc(indio_dev->pollfunc);
    iio_sw_rb_free(indio_dev->buffer);
}

static const struct iio_buffer_setup_ops adis16204_ring_setup_ops = {
    .preenable = &iio_sw_buffer_preenable,
    .postenable = &iio_triggered_buffer_postenable,
    .predisable = &iio_triggered_buffer_predisable,
};

int adis16204_configure_ring(struct iio_dev *indio_dev)
{
    int ret = 0;
    struct iio_buffer *ring;

    ring = iio_sw_rb_allocate(indio_dev);
    if (!ring) {
        ret = -ENOMEM;
        return ret;
    }
    indio_dev->buffer = ring;
    ring->scan_timestamp = true;
    indio_dev->setup_ops = &adis16204_ring_setup_ops;

    indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
                         &adis16204_trigger_handler,
                         IRQF_ONESHOT,
                         indio_dev,
                         "%s_consumer%d",
                         indio_dev->name,
                         indio_dev->id);
    if (indio_dev->pollfunc == NULL) {
        ret = -ENOMEM;
        goto error_iio_sw_rb_free;
    }

    indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
    return 0;

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