adis16400_ring.c

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

#include <linux/iio/iio.h>
#include "../ring_sw.h"
#include <linux/iio/trigger_consumer.h>
#include "adis16400.h"

static int adis16400_spi_read_burst(struct iio_dev *indio_dev, u8 *rx)
{
    struct spi_message msg;
    struct adis16400_state *st = iio_priv(indio_dev);
    u32 old_speed_hz = st->us->max_speed_hz;
    int ret;

    struct spi_transfer xfers[] = {
        {
            .tx_buf = st->tx,
            .bits_per_word = 8,
            .len = 2,
        }, {
            .rx_buf = rx,
            .bits_per_word = 8,
            .len = 24,
        },
    };

    mutex_lock(&st->buf_lock);
    st->tx[0] = ADIS16400_READ_REG(ADIS16400_GLOB_CMD);
    st->tx[1] = 0;

    spi_message_init(&msg);
    spi_message_add_tail(&xfers[0], &msg);
    spi_message_add_tail(&xfers[1], &msg);

    st->us->max_speed_hz = min(ADIS16400_SPI_BURST, old_speed_hz);
    spi_setup(st->us);

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

    st->us->max_speed_hz = old_speed_hz;
    spi_setup(st->us);
    mutex_unlock(&st->buf_lock);
    return ret;
}

static const u16 read_all_tx_array[] = {
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_SUPPLY_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_XGYRO_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_YGYRO_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_ZGYRO_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_XACCL_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_YACCL_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_ZACCL_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16350_XTEMP_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16350_YTEMP_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16350_ZTEMP_OUT)),
    cpu_to_be16(ADIS16400_READ_REG(ADIS16400_AUX_ADC)),
};

static int adis16350_spi_read_all(struct iio_dev *indio_dev, u8 *rx)
{
    struct adis16400_state *st = iio_priv(indio_dev);

    struct spi_message msg;
    int i, j = 0, ret;
    struct spi_transfer *xfers;
    int scan_count = bitmap_weight(indio_dev->active_scan_mask,
                       indio_dev->masklength);

    xfers = kzalloc(sizeof(*xfers)*(scan_count + 1),
            GFP_KERNEL);
    if (xfers == NULL)
        return -ENOMEM;

    for (i = 0; i < ARRAY_SIZE(read_all_tx_array); i++)
        if (test_bit(i, indio_dev->active_scan_mask)) {
            xfers[j].tx_buf = &read_all_tx_array[i];
            xfers[j].bits_per_word = 16;
            xfers[j].len = 2;
            xfers[j + 1].rx_buf = rx + j*2;
            j++;
        }
    xfers[j].bits_per_word = 16;
    xfers[j].len = 2;

    spi_message_init(&msg);
    for (j = 0; j < scan_count + 1; j++)
        spi_message_add_tail(&xfers[j], &msg);

    ret = spi_sync(st->us, &msg);
    kfree(xfers);

    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 adis16400_trigger_handler(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct iio_dev *indio_dev = pf->indio_dev;
    struct adis16400_state *st = iio_priv(indio_dev);
    struct iio_buffer *ring = indio_dev->buffer;
    int i = 0, j, ret = 0;
    s16 *data;

    /* Asumption that long is enough for maximum channels */
    unsigned long mask = *indio_dev->active_scan_mask;
    int scan_count = bitmap_weight(indio_dev->active_scan_mask,
                       indio_dev->masklength);
    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 (scan_count) {
        if (st->variant->flags & ADIS16400_NO_BURST) {
            ret = adis16350_spi_read_all(indio_dev, st->rx);
            if (ret < 0)
                goto done;
            for (; i < scan_count; i++)
                data[i] = *(s16 *)(st->rx + i*2);
        } else {
            ret = adis16400_spi_read_burst(indio_dev, st->rx);
            if (ret < 0)
                goto done;
            for (; i < scan_count; i++) {
                j = __ffs(mask);
                mask &= ~(1 << j);
                data[i] = be16_to_cpup(
                    (__be16 *)&(st->rx[j*2]));
            }
        }
    }
    /* Guaranteed to be aligned with 8 byte boundary */
    if (ring->scan_timestamp)
        *((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
    iio_push_to_buffer(ring, (u8 *) data);

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

    return IRQ_HANDLED;
}

void adis16400_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 adis16400_ring_setup_ops = {
    .preenable = &iio_sw_buffer_preenable,
    .postenable = &iio_triggered_buffer_postenable,
    .predisable = &iio_triggered_buffer_predisable,
};

int adis16400_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 = &adis16400_ring_setup_ops;

    indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
                         &adis16400_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;
}