drivers/iio/industrialio-triggered-buffer.c

   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
  19 static 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  */
  45 int 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
  87 error_dealloc_pollfunc:
  88         iio_dealloc_pollfunc(indio_dev->pollfunc);
  89 error_kfifo_free:
  90         iio_kfifo_free(indio_dev->buffer);
  91 error_ret:
  92         return ret;
  93 }
  94 EXPORT_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  */
 100 void 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 }
 106 EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
 107
 108 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 109 MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
 110 MODULE_LICENSE("GPL");