/*
* Copyright 2010 Analog Devices Inc.
* Copyright (C) 2008 Jonathan Cameron
*
* Licensed under the GPL-2 or later.
*
* ad7476_ring.c
*/
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/spi/spi.h>
#include "../iio.h"
#include "../ring_generic.h"
#include "../ring_sw.h"
#include "../trigger.h"
#include "../sysfs.h"
#include "ad7476.h"
static IIO_SCAN_EL_C(in0, 0, 0, NULL);
static IIO_SCAN_EL_TIMESTAMP(1);
static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
static ssize_t ad7476_show_type(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *indio_dev = ring->indio_dev;
struct ad7476_state *st = indio_dev->dev_data;
return sprintf(buf, "%c%d/%d>>%d\n", st->chip_info->sign,
st->chip_info->bits, st->chip_info->storagebits,
st->chip_info->res_shift);
}
static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7476_show_type, NULL, 0);
static struct attribute *ad7476_scan_el_attrs[] = {
&iio_scan_el_in0.dev_attr.attr,
&iio_const_attr_in0_index.dev_attr.attr,
&iio_const_attr_timestamp_index.dev_attr.attr,
&iio_scan_el_timestamp.dev_attr.attr,
&iio_const_attr_timestamp_type.dev_attr.attr,
&iio_dev_attr_in_type.dev_attr.attr,
NULL,
};
static struct attribute_group ad7476_scan_el_group = {
.name = "scan_elements",
.attrs = ad7476_scan_el_attrs,
};
int ad7476_scan_from_ring(struct ad7476_state *st)
{
struct iio_ring_buffer *ring = st->indio_dev->ring;
int ret;
u8 *ring_data;
ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
if (ring_data == NULL) {
ret = -ENOMEM;
goto error_ret;
}
ret = ring->access.read_last(ring, ring_data);
if (ret)
goto error_free_ring_data;
ret = (ring_data[0] << 8) | ring_data[1];
error_free_ring_data:
kfree(ring_data);
error_ret:
return ret;
}
/**
* ad7476_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 ad7476_ring_preenable(struct iio_dev *indio_dev)
{
struct ad7476_state *st = indio_dev->dev_data;
struct iio_ring_buffer *ring = indio_dev->ring;
st->d_size = ring->scan_count * st->chip_info->storagebits / 8;
if (ring->scan_timestamp) {
st->d_size += sizeof(s64);
if (st->d_size % sizeof(s64))
st->d_size += sizeof(s64) - (st->d_size % sizeof(s64));
}
if (indio_dev->ring->access.set_bytes_per_datum)
indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
st->d_size);
return 0;
}
/**
* ad7476_poll_func_th() th of trigger launched polling to ring buffer
*
* As sampling only occurs on i2c comms occurring, leave timestamping until
* then. Some triggers will generate their own time stamp. Currently
* there is no way of notifying them when no one cares.
**/
static void ad7476_poll_func_th(struct iio_dev *indio_dev, s64 time)
{
struct ad7476_state *st = indio_dev->dev_data;
schedule_work(&st->poll_work);
return;
}
/**
* ad7476_poll_bh_to_ring() bh of trigger launched polling to ring buffer
* @work_s: the work struct through which this was scheduled
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
* I think the one copy of this at a time was to avoid problems if the
* trigger was set far too high and the reads then locked up the computer.
**/
static void ad7476_poll_bh_to_ring(struct work_struct *work_s)
{
struct ad7476_state *st = container_of(work_s, struct ad7476_state,
poll_work);
struct iio_dev *indio_dev = st->indio_dev;
struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
s64 time_ns;
__u8 *rxbuf;
int b_sent;
/* Ensure only one copy of this function running at a time */
if (atomic_inc_return(&st->protect_ring) > 1)
return;
rxbuf = kzalloc(st->d_size, GFP_KERNEL);
if (rxbuf == NULL)
return;
b_sent = spi_read(st->spi, rxbuf, st->chip_info->storagebits / 8);
if (b_sent < 0)
goto done;
time_ns = iio_get_time_ns();
if (indio_dev->ring->scan_timestamp)
memcpy(rxbuf + st->d_size - sizeof(s64),
&time_ns, sizeof(time_ns));
indio_dev->ring->access.store_to(&sw_ring->buf, rxbuf, time_ns);
done:
kfree(rxbuf);
atomic_dec(&st->protect_ring);
}
int ad7476_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
struct ad7476_state *st = indio_dev->dev_data;
int ret = 0;
indio_dev->ring = iio_sw_rb_allocate(indio_dev);
if (!indio_dev->ring) {
ret = -ENOMEM;
goto error_ret;
}
/* Effectively select the ring buffer implementation */
iio_ring_sw_register_funcs(&indio_dev->ring->access);
ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7476_poll_func_th);
if (ret)
goto error_deallocate_sw_rb;
/* Ring buffer functions - here trigger setup related */
indio_dev->ring->preenable = &ad7476_ring_preenable;
indio_dev->ring->postenable = &iio_triggered_ring_postenable;
indio_dev->ring->predisable = &iio_triggered_ring_predisable;
indio_dev->ring->scan_el_attrs = &ad7476_scan_el_group;
indio_dev->ring->scan_timestamp = true;
INIT_WORK(&st->poll_work, &ad7476_poll_bh_to_ring);
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_RING_TRIGGERED;
return 0;
error_deallocate_sw_rb:
iio_sw_rb_free(indio_dev->ring);
error_ret:
return ret;
}
void ad7476_ring_cleanup(struct iio_dev *indio_dev)
{
/* ensure that the trigger has been detached */
if (indio_dev->trig) {
iio_put_trigger(indio_dev->trig);
iio_trigger_dettach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
kfree(indio_dev->pollfunc);
iio_sw_rb_free(indio_dev->ring);
}
