ade7758_ring.c

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/*
 * ADE7758 Poly Phase Multifunction Energy Metering IC driver
 *
 * Copyright 2010-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <asm/unaligned.h>

#include <linux/iio/iio.h>
#include "../ring_sw.h"
#include <linux/iio/trigger_consumer.h>
#include "ade7758.h"

static int ade7758_spi_read_burst(struct iio_dev *indio_dev)
{
    struct ade7758_state *st = iio_priv(indio_dev);
    int ret;

    ret = spi_sync(st->us, &st->ring_msg);
    if (ret)
        dev_err(&st->us->dev, "problem when reading WFORM value\n");

    return ret;
}

static int ade7758_write_waveform_type(struct device *dev, unsigned type)
{
    int ret;
    u8 reg;

    ret = ade7758_spi_read_reg_8(dev,
            ADE7758_WAVMODE,
            &reg);
    if (ret)
        goto out;

    reg &= ~0x1F;
    reg |= type & 0x1F;

    ret = ade7758_spi_write_reg_8(dev,
            ADE7758_WAVMODE,
            reg);
out:
    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 ade7758_trigger_handler(int irq, void *p)
{
    struct iio_poll_func *pf = p;
    struct iio_dev *indio_dev = pf->indio_dev;
    struct ade7758_state *st = iio_priv(indio_dev);
    s64 dat64[2];
    u32 *dat32 = (u32 *)dat64;

    if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength))
        if (ade7758_spi_read_burst(indio_dev) >= 0)
            *dat32 = get_unaligned_be32(&st->rx_buf[5]) & 0xFFFFFF;

    /* Guaranteed to be aligned with 8 byte boundary */
    if (indio_dev->scan_timestamp)
        dat64[1] = pf->timestamp;

    iio_push_to_buffer(indio_dev->buffer, (u8 *)dat64);

    iio_trigger_notify_done(indio_dev->trig);

    return IRQ_HANDLED;
}

static int ade7758_ring_preenable(struct iio_dev *indio_dev)
{
    struct ade7758_state *st = iio_priv(indio_dev);
    unsigned channel;
    int ret;

    if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength))
        return -EINVAL;

    ret = iio_sw_buffer_preenable(indio_dev);
    if (ret < 0)
        return ret;

    channel = find_first_bit(indio_dev->active_scan_mask,
                 indio_dev->masklength);

    ade7758_write_waveform_type(&indio_dev->dev,
        st->ade7758_ring_channels[channel].address);

    return 0;
}

static const struct iio_buffer_setup_ops ade7758_ring_setup_ops = {
    .preenable = &ade7758_ring_preenable,
    .postenable = &iio_triggered_buffer_postenable,
    .predisable = &iio_triggered_buffer_predisable,
    .validate_scan_mask = &iio_validate_scan_mask_onehot,
};

void ade7758_unconfigure_ring(struct iio_dev *indio_dev)
{
    iio_dealloc_pollfunc(indio_dev->pollfunc);
    iio_sw_rb_free(indio_dev->buffer);
}

int ade7758_configure_ring(struct iio_dev *indio_dev)
{
    struct ade7758_state *st = iio_priv(indio_dev);
    int ret = 0;

    indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
    if (!indio_dev->buffer) {
        ret = -ENOMEM;
        return ret;
    }

    indio_dev->setup_ops = &ade7758_ring_setup_ops;

    indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
                         &ade7758_trigger_handler,
                         0,
                         indio_dev,
                         "ade7759_consumer%d",
                         indio_dev->id);
    if (indio_dev->pollfunc == NULL) {
        ret = -ENOMEM;
        goto error_iio_sw_rb_free;
    }

    indio_dev->modes |= INDIO_BUFFER_TRIGGERED;

    st->tx_buf[0] = ADE7758_READ_REG(ADE7758_RSTATUS);
    st->tx_buf[1] = 0;
    st->tx_buf[2] = 0;
    st->tx_buf[3] = 0;
    st->tx_buf[4] = ADE7758_READ_REG(ADE7758_WFORM);
    st->tx_buf[5] = 0;
    st->tx_buf[6] = 0;
    st->tx_buf[7] = 0;

    /* build spi ring message */
    st->ring_xfer[0].tx_buf = &st->tx_buf[0];
    st->ring_xfer[0].len = 1;
    st->ring_xfer[0].bits_per_word = 8;
    st->ring_xfer[0].delay_usecs = 4;
    st->ring_xfer[1].rx_buf = &st->rx_buf[1];
    st->ring_xfer[1].len = 3;
    st->ring_xfer[1].bits_per_word = 8;
    st->ring_xfer[1].cs_change = 1;

    st->ring_xfer[2].tx_buf = &st->tx_buf[4];
    st->ring_xfer[2].len = 1;
    st->ring_xfer[2].bits_per_word = 8;
    st->ring_xfer[2].delay_usecs = 1;
    st->ring_xfer[3].rx_buf = &st->rx_buf[5];
    st->ring_xfer[3].len = 3;
    st->ring_xfer[3].bits_per_word = 8;

    spi_message_init(&st->ring_msg);
    spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
    spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
    spi_message_add_tail(&st->ring_xfer[2], &st->ring_msg);
    spi_message_add_tail(&st->ring_xfer[3], &st->ring_msg);

    return 0;

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

void ade7758_uninitialize_ring(struct iio_dev *indio_dev)
{
    iio_buffer_unregister(indio_dev);
}