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/*
* Copyright (C) 2010 Michael Hennerich, Analog Devices Inc.
* Copyright (C) 2008-2010 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* ad799x_ring.c
*/
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/i2c.h>
#include <linux/bitops.h>
#include "../iio.h"
#include "../ring_generic.h"
#include "../ring_sw.h"
#include "../trigger.h"
#include "../sysfs.h"
#include "ad799x.h"
int ad799x_single_channel_from_ring(struct ad799x_state *st, long mask)
{
struct iio_ring_buffer *ring = st->indio_dev->ring;
int count = 0, ret;
u16 *ring_data;
if (!(ring->scan_mask & mask)) {
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;
/* Need a count of channels prior to this one */
mask >>= 1;
while (mask) {
if (mask & ring->scan_mask)
count++;
mask >>= 1;
}
ret = be16_to_cpu(ring_data[count]);
error_free_ring_data:
kfree(ring_data);
error_ret:
return ret;
}
/**
* ad799x_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 ad799x_ring_preenable(struct iio_dev *indio_dev)
{
struct iio_ring_buffer *ring = indio_dev->ring;
struct ad799x_state *st = indio_dev->dev_data;
/*
* Need to figure out the current mode based upon the requested
* scan mask in iio_dev
*/
if (st->id == ad7997 || st->id == ad7998)
ad799x_set_scan_mode(st, ring->scan_mask);
st->d_size = ring->scan_count * 2;
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;
}
/**
* ad799x_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 ad799x_poll_func_th(struct iio_dev *indio_dev, s64 time)
{
struct ad799x_state *st = indio_dev->dev_data;
schedule_work(&st->poll_work);
return;
}
/**
* ad799x_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 ad799x_poll_bh_to_ring(struct work_struct *work_s)
{
struct ad799x_state *st = container_of(work_s, struct ad799x_state,
poll_work);
struct iio_dev *indio_dev = st->indio_dev;
struct iio_ring_buffer *ring = indio_dev->ring;
struct iio_sw_ring_buffer *ring_sw = iio_to_sw_ring(indio_dev->ring);
s64 time_ns;
__u8 *rxbuf;
int b_sent;
u8 cmd;
/* Ensure only one copy of this function running at a time */
if (atomic_inc_return(&st->protect_ring) > 1)
return;
rxbuf = kmalloc(st->d_size, GFP_KERNEL);
if (rxbuf == NULL)
return;
switch (st->id) {
case ad7991:
case ad7995:
case ad7999:
cmd = st->config | (ring->scan_mask << AD799X_CHANNEL_SHIFT);
break;
case ad7992:
case ad7993:
case ad7994:
cmd = (ring->scan_mask << AD799X_CHANNEL_SHIFT) |
AD7998_CONV_RES_REG;
break;
case ad7997:
case ad7998:
cmd = AD7997_8_READ_SEQUENCE | AD7998_CONV_RES_REG;
break;
default:
cmd = 0;
}
b_sent = i2c_smbus_read_i2c_block_data(st->client,
cmd, ring->scan_count * 2, rxbuf);
if (b_sent < 0)
goto done;
time_ns = iio_get_time_ns();
if (ring->scan_timestamp)
memcpy(rxbuf + st->d_size - sizeof(s64),
&time_ns, sizeof(time_ns));
ring->access.store_to(&ring_sw->buf, rxbuf, time_ns);
done:
kfree(rxbuf);
atomic_dec(&st->protect_ring);
}
int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
struct ad799x_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(&st->indio_dev->ring->access);
ret = iio_alloc_pollfunc(indio_dev, NULL, &ad799x_poll_func_th);
if (ret)
goto error_deallocate_sw_rb;
/* Ring buffer functions - here trigger setup related */
indio_dev->ring->preenable = &ad799x_ring_preenable;
indio_dev->ring->postenable = &iio_triggered_ring_postenable;
indio_dev->ring->predisable = &iio_triggered_ring_predisable;
indio_dev->ring->scan_timestamp = true;
INIT_WORK(&st->poll_work, &ad799x_poll_bh_to_ring);
indio_dev->ring->scan_el_attrs = st->chip_info->scan_attrs;
/* 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 ad799x_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);
}
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