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/*
* AD7298 SPI ADC driver
*
* Copyright 2011-2012 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/trigger_consumer.h>
#include "ad7298.h"
/**
* ad7298_ring_preenable() setup the parameters of the ring before enabling
*
* The complex nature of the setting of the number of bytes per datum is due
* to this driver currently ensuring that the timestamp is stored at an 8
* byte boundary.
**/
static int ad7298_ring_preenable(struct iio_dev *indio_dev)
{
struct ad7298_state *st = iio_priv(indio_dev);
int i, m;
unsigned short command;
int scan_count, ret;
ret = iio_sw_buffer_preenable(indio_dev);
if (ret < 0)
return ret;
/* Now compute overall size */
scan_count = bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength);
command = AD7298_WRITE | st->ext_ref;
for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
if (test_bit(i, indio_dev->active_scan_mask))
command |= m;
st->tx_buf[0] = cpu_to_be16(command);
/* build spi ring message */
st->ring_xfer[0].tx_buf = &st->tx_buf[0];
st->ring_xfer[0].len = 2;
st->ring_xfer[0].cs_change = 1;
st->ring_xfer[1].tx_buf = &st->tx_buf[1];
st->ring_xfer[1].len = 2;
st->ring_xfer[1].cs_change = 1;
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);
for (i = 0; i < scan_count; i++) {
st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
st->ring_xfer[i + 2].len = 2;
st->ring_xfer[i + 2].cs_change = 1;
spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
}
/* make sure last transfer cs_change is not set */
st->ring_xfer[i + 1].cs_change = 0;
return 0;
}
/**
* ad7298_trigger_handler() bh of trigger launched polling to ring buffer
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
**/
static irqreturn_t ad7298_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7298_state *st = iio_priv(indio_dev);
struct iio_buffer *ring = indio_dev->buffer;
s64 time_ns;
__u16 buf[16];
int b_sent, i;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
return b_sent;
if (indio_dev->scan_timestamp) {
time_ns = iio_get_time_ns();
memcpy((u8 *)buf + indio_dev->scan_bytes - sizeof(s64),
&time_ns, sizeof(time_ns));
}
for (i = 0; i < bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength); i++)
buf[i] = be16_to_cpu(st->rx_buf[i]);
indio_dev->buffer->access->store_to(ring, (u8 *)buf, time_ns);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_buffer_setup_ops ad7298_ring_setup_ops = {
.preenable = &ad7298_ring_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
};
int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
int ret;
indio_dev->buffer = iio_kfifo_allocate(indio_dev);
if (!indio_dev->buffer) {
ret = -ENOMEM;
goto error_ret;
}
indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
&ad7298_trigger_handler,
IRQF_ONESHOT,
indio_dev,
"ad7298_consumer%d",
indio_dev->id);
if (indio_dev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_deallocate_kfifo;
}
/* Ring buffer functions - here trigger setup related */
indio_dev->setup_ops = &ad7298_ring_setup_ops;
indio_dev->buffer->scan_timestamp = true;
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
return 0;
error_deallocate_kfifo:
iio_kfifo_free(indio_dev->buffer);
error_ret:
return ret;
}
void ad7298_ring_cleanup(struct iio_dev *indio_dev)
{
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_kfifo_free(indio_dev->buffer);
}
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