linux/drivers/iio/industrialio-triggered-buffer.c
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   1 /*
   2 * Copyright (c) 2012 Analog Devices, Inc.
   3 *  Author: Lars-Peter Clausen <lars@metafoo.de>
   4 *
   5 * This program is free software; you can redistribute it and/or modify it
   6 * under the terms of the GNU General Public License version 2 as published by
   7 * the Free Software Foundation.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/export.h>
  12#include <linux/module.h>
  13#include <linux/iio/iio.h>
  14#include <linux/iio/buffer.h>
  15#include <linux/iio/kfifo_buf.h>
  16#include <linux/iio/triggered_buffer.h>
  17#include <linux/iio/trigger_consumer.h>
  18
  19static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
  20        .preenable = &iio_sw_buffer_preenable,
  21        .postenable = &iio_triggered_buffer_postenable,
  22        .predisable = &iio_triggered_buffer_predisable,
  23};
  24
  25/**
  26 * iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
  27 * @indio_dev:          IIO device structure
  28 * @pollfunc_bh:        Function which will be used as pollfunc bottom half
  29 * @pollfunc_th:        Function which will be used as pollfunc top half
  30 * @setup_ops:          Buffer setup functions to use for this device.
  31 *                      If NULL the default setup functions for triggered
  32 *                      buffers will be used.
  33 *
  34 * This function combines some common tasks which will normally be performed
  35 * when setting up a triggered buffer. It will allocate the buffer and the
  36 * pollfunc, as well as register the buffer with the IIO core.
  37 *
  38 * Before calling this function the indio_dev structure should already be
  39 * completely initialized, but not yet registered. In practice this means that
  40 * this function should be called right before iio_device_register().
  41 *
  42 * To free the resources allocated by this function call
  43 * iio_triggered_buffer_cleanup().
  44 */
  45int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
  46        irqreturn_t (*pollfunc_bh)(int irq, void *p),
  47        irqreturn_t (*pollfunc_th)(int irq, void *p),
  48        const struct iio_buffer_setup_ops *setup_ops)
  49{
  50        int ret;
  51
  52        indio_dev->buffer = iio_kfifo_allocate(indio_dev);
  53        if (!indio_dev->buffer) {
  54                ret = -ENOMEM;
  55                goto error_ret;
  56        }
  57
  58        indio_dev->pollfunc = iio_alloc_pollfunc(pollfunc_bh,
  59                                                 pollfunc_th,
  60                                                 IRQF_ONESHOT,
  61                                                 indio_dev,
  62                                                 "%s_consumer%d",
  63                                                 indio_dev->name,
  64                                                 indio_dev->id);
  65        if (indio_dev->pollfunc == NULL) {
  66                ret = -ENOMEM;
  67                goto error_kfifo_free;
  68        }
  69
  70        /* Ring buffer functions - here trigger setup related */
  71        if (setup_ops)
  72                indio_dev->setup_ops = setup_ops;
  73        else
  74                indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
  75
  76        /* Flag that polled ring buffering is possible */
  77        indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
  78
  79        ret = iio_buffer_register(indio_dev,
  80                                  indio_dev->channels,
  81                                  indio_dev->num_channels);
  82        if (ret)
  83                goto error_dealloc_pollfunc;
  84
  85        return 0;
  86
  87error_dealloc_pollfunc:
  88        iio_dealloc_pollfunc(indio_dev->pollfunc);
  89error_kfifo_free:
  90        iio_kfifo_free(indio_dev->buffer);
  91error_ret:
  92        return ret;
  93}
  94EXPORT_SYMBOL(iio_triggered_buffer_setup);
  95
  96/**
  97 * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
  98 * @indio_dev: IIO device structure
  99 */
 100void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
 101{
 102        iio_buffer_unregister(indio_dev);
 103        iio_dealloc_pollfunc(indio_dev->pollfunc);
 104        iio_kfifo_free(indio_dev->buffer);
 105}
 106EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
 107
 108MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 109MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
 110MODULE_LICENSE("GPL");
 111
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