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/*
* AD7298 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include "../iio.h"
#include "../ring_generic.h"
#include "../ring_sw.h"
#include "../trigger.h"
#include "../sysfs.h"
#include "ad7298.h"
static IIO_SCAN_EL_C(in0, 0, 0, NULL);
static IIO_SCAN_EL_C(in1, 1, 0, NULL);
static IIO_SCAN_EL_C(in2, 2, 0, NULL);
static IIO_SCAN_EL_C(in3, 3, 0, NULL);
static IIO_SCAN_EL_C(in4, 4, 0, NULL);
static IIO_SCAN_EL_C(in5, 5, 0, NULL);
static IIO_SCAN_EL_C(in6, 6, 0, NULL);
static IIO_SCAN_EL_C(in7, 7, 0, NULL);
static IIO_SCAN_EL_TIMESTAMP(8);
static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
static IIO_CONST_ATTR(in_type, "u12/16") ;
static struct attribute *ad7298_scan_el_attrs[] = {
&iio_scan_el_in0.dev_attr.attr,
&iio_const_attr_in0_index.dev_attr.attr,
&iio_scan_el_in1.dev_attr.attr,
&iio_const_attr_in1_index.dev_attr.attr,
&iio_scan_el_in2.dev_attr.attr,
&iio_const_attr_in2_index.dev_attr.attr,
&iio_scan_el_in3.dev_attr.attr,
&iio_const_attr_in3_index.dev_attr.attr,
&iio_scan_el_in4.dev_attr.attr,
&iio_const_attr_in4_index.dev_attr.attr,
&iio_scan_el_in5.dev_attr.attr,
&iio_const_attr_in5_index.dev_attr.attr,
&iio_scan_el_in6.dev_attr.attr,
&iio_const_attr_in6_index.dev_attr.attr,
&iio_scan_el_in7.dev_attr.attr,
&iio_const_attr_in7_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_const_attr_in_type.dev_attr.attr,
NULL,
};
static struct attribute_group ad7298_scan_el_group = {
.name = "scan_elements",
.attrs = ad7298_scan_el_attrs,
};
int ad7298_scan_from_ring(struct ad7298_state *st, long ch)
{
struct iio_ring_buffer *ring = st->indio_dev->ring;
int ret;
u16 *ring_data;
if (!(ring->scan_mask & (1 << ch))) {
ret = -EBUSY;
goto error_ret;
}
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, (u8 *) ring_data);
if (ret)
goto error_free_ring_data;
ret = be16_to_cpu(ring_data[ch]);
error_free_ring_data:
kfree(ring_data);
error_ret:
return ret;
}
/**
* 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 = indio_dev->dev_data;
struct iio_ring_buffer *ring = indio_dev->ring;
size_t d_size;
int i, m;
unsigned short command;
d_size = ring->scan_count * (AD7298_STORAGE_BITS / 8);
if (ring->scan_timestamp) {
d_size += sizeof(s64);
if (d_size % sizeof(s64))
d_size += sizeof(s64) - (d_size % sizeof(s64));
}
if (ring->access.set_bytes_per_datum)
ring->access.set_bytes_per_datum(ring, d_size);
st->d_size = d_size;
command = AD7298_WRITE | st->ext_ref;
for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
if (ring->scan_mask & (1 << i))
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 < ring->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_poll_func_th() th of trigger launched polling to ring buffer
*
* As sampling only occurs on spi comms occuring, 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 ad7298_poll_func_th(struct iio_dev *indio_dev, s64 time)
{
struct ad7298_state *st = indio_dev->dev_data;
schedule_work(&st->poll_work);
return;
}
/**
* ad7298_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 ad7298_poll_bh_to_ring(struct work_struct *work_s)
{
struct ad7298_state *st = container_of(work_s, struct ad7298_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);
struct iio_ring_buffer *ring = indio_dev->ring;
s64 time_ns;
__u16 buf[16];
int b_sent, i;
/* Ensure only one copy of this function running at a time */
if (atomic_inc_return(&st->protect_ring) > 1)
return;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
goto done;
if (ring->scan_timestamp) {
time_ns = iio_get_time_ns();
memcpy((u8 *)buf + st->d_size - sizeof(s64),
&time_ns, sizeof(time_ns));
}
for (i = 0; i < ring->scan_count; i++)
buf[i] = be16_to_cpu(st->rx_buf[i]);
indio_dev->ring->access.store_to(&sw_ring->buf, (u8 *)buf, time_ns);
done:
atomic_dec(&st->protect_ring);
}
int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
struct ad7298_state *st = indio_dev->dev_data;
int ret;
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, &ad7298_poll_func_th);
if (ret)
goto error_deallocate_sw_rb;
/* Ring buffer functions - here trigger setup related */
indio_dev->ring->preenable = &ad7298_ring_preenable;
indio_dev->ring->postenable = &iio_triggered_ring_postenable;
indio_dev->ring->predisable = &iio_triggered_ring_predisable;
indio_dev->ring->scan_el_attrs = &ad7298_scan_el_group;
indio_dev->ring->scan_timestamp = true;
INIT_WORK(&st->poll_work, &ad7298_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 ad7298_ring_cleanup(struct iio_dev *indio_dev)
{
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);
}
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