242 lines
6.5 KiB
C
242 lines
6.5 KiB
C
/*
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* Copyright (C) 2008 Jonathan Cameron
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* max1363_ring.c
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*/
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#include <linux/interrupt.h>
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#include <linux/gpio.h>
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#include <linux/workqueue.h>
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/sysfs.h>
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#include <linux/list.h>
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#include <linux/i2c.h>
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#include "../iio.h"
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#include "../ring_generic.h"
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#include "../ring_sw.h"
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#include "../trigger.h"
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#include "../sysfs.h"
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#include "max1363.h"
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ssize_t max1363_scan_from_ring(struct device *dev,
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struct device_attribute *attr,
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char *buf)
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{
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struct iio_dev *dev_info = dev_get_drvdata(dev);
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struct max1363_state *info = dev_info->dev_data;
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int i, ret, len = 0;
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char *ring_data;
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ring_data = kmalloc(info->current_mode->numvals*2, GFP_KERNEL);
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if (ring_data == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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ret = dev_info->ring->access.read_last(dev_info->ring, ring_data);
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if (ret)
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goto error_free_ring_data;
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len += sprintf(buf+len, "ring ");
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for (i = 0; i < info->current_mode->numvals; i++)
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len += sprintf(buf + len, "%d ",
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((int)(ring_data[i*2 + 0] & 0x0F) << 8)
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+ ((int)(ring_data[i*2 + 1])));
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len += sprintf(buf + len, "\n");
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kfree(ring_data);
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return len;
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error_free_ring_data:
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kfree(ring_data);
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error_ret:
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return ret;
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}
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/**
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* max1363_ring_preenable() setup the parameters of the ring before enabling
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*
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* The complex nature of the setting of the nuber of bytes per datum is due
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* to this driver currently ensuring that the timestamp is stored at an 8
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* byte boundary.
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**/
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static int max1363_ring_preenable(struct iio_dev *indio_dev)
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{
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struct max1363_state *st = indio_dev->dev_data;
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size_t d_size;
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if (indio_dev->ring->access.set_bpd) {
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d_size = st->current_mode->numvals*2 + sizeof(s64);
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if (d_size % 8)
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d_size += 8 - (d_size % 8);
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indio_dev->ring->access.set_bpd(indio_dev->ring, d_size);
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}
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return 0;
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}
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/**
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* max1363_ring_postenable() typical ring post enable
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*
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* Only not moved into the core for the hardware ring buffer cases
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* that are more sophisticated.
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**/
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static int max1363_ring_postenable(struct iio_dev *indio_dev)
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{
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if (indio_dev->trig == NULL)
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return 0;
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return iio_trigger_attach_poll_func(indio_dev->trig,
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indio_dev->pollfunc);
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}
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/**
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* max1363_ring_predisable() runs just prior to ring buffer being disabled
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*
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* Typical predisable function which ensures that no trigger events can
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* occur before we disable the ring buffer (and hence would have no idea
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* what to do with them)
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**/
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static int max1363_ring_predisable(struct iio_dev *indio_dev)
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{
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if (indio_dev->trig)
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return iio_trigger_dettach_poll_func(indio_dev->trig,
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indio_dev->pollfunc);
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else
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return 0;
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}
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/**
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* max1363_poll_func_th() th of trigger launched polling to ring buffer
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*
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* As sampling only occurs on i2c comms occuring, leave timestamping until
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* then. Some triggers will generate their own time stamp. Currently
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* there is no way of notifying them when no one cares.
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**/
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void max1363_poll_func_th(struct iio_dev *indio_dev)
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{
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struct max1363_state *st = indio_dev->dev_data;
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schedule_work(&st->poll_work);
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return;
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}
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/**
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* max1363_poll_bh_to_ring() bh of trigger launched polling to ring buffer
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* @work_s: the work struct through which this was scheduled
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*
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* Currently there is no option in this driver to disable the saving of
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* timestamps within the ring.
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* I think the one copy of this at a time was to avoid problems if the
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* trigger was set far too high and the reads then locked up the computer.
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**/
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static void max1363_poll_bh_to_ring(struct work_struct *work_s)
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{
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struct max1363_state *st = container_of(work_s, struct max1363_state,
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poll_work);
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struct iio_dev *indio_dev = st->indio_dev;
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struct iio_sw_ring_buffer *ring = iio_to_sw_ring(indio_dev->ring);
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s64 time_ns;
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__u8 *rxbuf;
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int b_sent;
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size_t d_size;
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/* Ensure the timestamp is 8 byte aligned */
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d_size = st->current_mode->numvals*2 + sizeof(s64);
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if (d_size % sizeof(s64))
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d_size += sizeof(s64) - (d_size % sizeof(s64));
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/* Ensure only one copy of this function running at a time */
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if (atomic_inc_return(&st->protect_ring) > 1)
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return;
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/* Monitor mode prevents reading. Whilst not currently implemented
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* might as well have this test in here in the meantime as it does
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* no harm.
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*/
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if (st->current_mode->numvals == 0)
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return;
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rxbuf = kmalloc(d_size, GFP_KERNEL);
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if (rxbuf == NULL)
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return;
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b_sent = i2c_master_recv(st->client,
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rxbuf,
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st->current_mode->numvals*2);
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if (b_sent < 0)
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goto done;
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time_ns = iio_get_time_ns();
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memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
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indio_dev->ring->access.store_to(&ring->buf, rxbuf, time_ns);
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done:
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kfree(rxbuf);
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atomic_dec(&st->protect_ring);
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}
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int max1363_register_ring_funcs_and_init(struct iio_dev *indio_dev)
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{
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struct max1363_state *st = indio_dev->dev_data;
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int ret = 0;
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indio_dev->ring = iio_sw_rb_allocate(indio_dev);
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if (!indio_dev->ring) {
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ret = -ENOMEM;
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goto error_ret;
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}
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/* Effectively select the ring buffer implementation */
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iio_ring_sw_register_funcs(&st->indio_dev->ring->access);
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indio_dev->pollfunc = kzalloc(sizeof(*indio_dev->pollfunc), GFP_KERNEL);
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if (indio_dev->pollfunc == NULL) {
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ret = -ENOMEM;
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goto error_deallocate_sw_rb;
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}
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/* Configure the polling function called on trigger interrupts */
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indio_dev->pollfunc->poll_func_main = &max1363_poll_func_th;
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indio_dev->pollfunc->private_data = indio_dev;
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/* Ring buffer functions - here trigger setup related */
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indio_dev->ring->postenable = &max1363_ring_postenable;
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indio_dev->ring->preenable = &max1363_ring_preenable;
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indio_dev->ring->predisable = &max1363_ring_predisable;
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INIT_WORK(&st->poll_work, &max1363_poll_bh_to_ring);
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/* Flag that polled ring buffering is possible */
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indio_dev->modes |= INDIO_RING_TRIGGERED;
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return 0;
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error_deallocate_sw_rb:
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iio_sw_rb_free(indio_dev->ring);
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error_ret:
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return ret;
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}
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void max1363_ring_cleanup(struct iio_dev *indio_dev)
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{
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/* ensure that the trigger has been detached */
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if (indio_dev->trig) {
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iio_put_trigger(indio_dev->trig);
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iio_trigger_dettach_poll_func(indio_dev->trig,
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indio_dev->pollfunc);
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}
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kfree(indio_dev->pollfunc);
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iio_sw_rb_free(indio_dev->ring);
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}
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void max1363_uninitialize_ring(struct iio_ring_buffer *ring)
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{
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iio_ring_buffer_unregister(ring);
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};
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int max1363_initialize_ring(struct iio_ring_buffer *ring)
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{
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return iio_ring_buffer_register(ring);
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};
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