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/*
* Copyright 2010-2012 Analog Devices Inc.
* Copyright (C) 2008 Jonathan Cameron
*
* Licensed under the GPL-2.
*
* ad7887_ring.c
*/
#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 "ad7887.h"
/**
* ad7887_ring_preenable() setup the parameters of the ring before enabling
*
* The complex nature of the setting of the nuber of bytes per datum is due
* to this driver currently ensuring that the timestamp is stored at an 8
* byte boundary.
**/
static int ad7887_ring_preenable(struct iio_dev *indio_dev)
{
struct ad7887_state *st = iio_priv(indio_dev);
int ret;
ret = iio_sw_buffer_preenable(indio_dev);
if (ret < 0)
return ret;
/* We know this is a single long so can 'cheat' */
switch (*indio_dev->active_scan_mask) {
case (1 << 0):
st->ring_msg = &st->msg[AD7887_CH0];
break;
case (1 << 1):
st->ring_msg = &st->msg[AD7887_CH1];
/* Dummy read: push CH1 setting down to hardware */
spi_sync(st->spi, st->ring_msg);
break;
case ((1 << 1) | (1 << 0)):
st->ring_msg = &st->msg[AD7887_CH0_CH1];
break;
}
return 0;
}
static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
{
struct ad7887_state *st = iio_priv(indio_dev);
/* dummy read: restore default CH0 settin */
return spi_sync(st->spi, &st->msg[AD7887_CH0]);
}
/**
* ad7887_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 ad7887_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7887_state *st = iio_priv(indio_dev);
s64 time_ns;
__u8 *buf;
int b_sent;
unsigned int bytes = bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength) *
st->chip_info->channel[0].scan_type.storagebits / 8;
buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
if (buf == NULL)
return -ENOMEM;
b_sent = spi_sync(st->spi, st->ring_msg);
if (b_sent)
goto done;
time_ns = iio_get_time_ns();
memcpy(buf, st->data, bytes);
if (indio_dev->scan_timestamp)
memcpy(buf + indio_dev->scan_bytes - sizeof(s64),
&time_ns, sizeof(time_ns));
indio_dev->buffer->access->store_to(indio_dev->buffer, buf, time_ns);
done:
kfree(buf);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_buffer_setup_ops ad7887_ring_setup_ops = {
.preenable = &ad7887_ring_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
.postdisable = &ad7887_ring_postdisable,
};
int ad7887_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(&iio_pollfunc_store_time,
&ad7887_trigger_handler,
IRQF_ONESHOT,
indio_dev,
"ad7887_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 = &ad7887_ring_setup_ops;
/* 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 ad7887_ring_cleanup(struct iio_dev *indio_dev)
{
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_kfifo_free(indio_dev->buffer);
}
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