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         .postenable = &iio_triggered_buffer_postenable,
  21         .predisable = &iio_triggered_buffer_predisable,
  22 };
  23
  24 /**
  25  * iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
  26  * @indio_dev:          IIO device structure
  27  * @pollfunc_bh:        Function which will be used as pollfunc bottom half
  28  * @pollfunc_th:        Function which will be used as pollfunc top half
  29  * @setup_ops:          Buffer setup functions to use for this device.
  30  *                      If NULL the default setup functions for triggered
  31  *                      buffers will be used.
  32  *
  33  * This function combines some common tasks which will normally be performed
  34  * when setting up a triggered buffer. It will allocate the buffer and the
  35  * pollfunc.
  36  *
  37  * Before calling this function the indio_dev structure should already be
  38  * completely initialized, but not yet registered. In practice this means that
  39  * this function should be called right before iio_device_register().
  40  *
  41  * To free the resources allocated by this function call
  42  * iio_triggered_buffer_cleanup().
  43  */
  44 int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
  45         irqreturn_t (*pollfunc_bh)(int irq, void *p),
  46         irqreturn_t (*pollfunc_th)(int irq, void *p),
  47         const struct iio_buffer_setup_ops *setup_ops)
  48 {
  49         struct iio_buffer *buffer;
  50         int ret;
  51
  52         buffer = iio_kfifo_allocate();
  53         if (!buffer) {
  54                 ret = -ENOMEM;
  55                 goto error_ret;
  56         }
  57
  58         iio_device_attach_buffer(indio_dev, buffer);
  59
  60         indio_dev->pollfunc = iio_alloc_pollfunc(pollfunc_bh,
  61                                                  pollfunc_th,
  62                                                  IRQF_ONESHOT,
  63                                                  indio_dev,
  64                                                  "%s_consumer%d",
  65                                                  indio_dev->name,
  66                                                  indio_dev->id);
  67         if (indio_dev->pollfunc == NULL) {
  68                 ret = -ENOMEM;
  69                 goto error_kfifo_free;
  70         }
  71
  72         /* Ring buffer functions - here trigger setup related */
  73         if (setup_ops)
  74                 indio_dev->setup_ops = setup_ops;
  75         else
  76                 indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
  77
  78         /* Flag that polled ring buffering is possible */
  79         indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
  80
  81         return 0;
  82
  83 error_kfifo_free:
  84         iio_kfifo_free(indio_dev->buffer);
  85 error_ret:
  86         return ret;
  87 }
  88 EXPORT_SYMBOL(iio_triggered_buffer_setup);
  89
  90 /**
  91  * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
  92  * @indio_dev: IIO device structure
  93  */
  94 void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
  95 {
  96         iio_dealloc_pollfunc(indio_dev->pollfunc);
  97         iio_kfifo_free(indio_dev->buffer);
  98 }
  99 EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
 100
 101 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 102 MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
 103 MODULE_LICENSE("GPL");