drivers/iio/buffer/industrialio-triggered-buffer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2  /*
   3  * Copyright (c) 2012 Analog Devices, Inc.
   4  *  Author: Lars-Peter Clausen <lars@metafoo.de>
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/export.h>
   9 #include <linux/module.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/iio/buffer.h>
  12 #include <linux/iio/buffer_impl.h>
  13 #include <linux/iio/kfifo_buf.h>
  14 #include <linux/iio/triggered_buffer.h>
  15 #include <linux/iio/trigger_consumer.h>
  16
  17 /**
  18  * iio_triggered_buffer_setup_ext() - Setup triggered buffer and pollfunc
  19  * @indio_dev:          IIO device structure
  20  * @h:                  Function which will be used as pollfunc top half
  21  * @thread:             Function which will be used as pollfunc bottom half
  22  * @direction:          Direction of the data stream (in/out).
  23  * @setup_ops:          Buffer setup functions to use for this device.
  24  *                      If NULL the default setup functions for triggered
  25  *                      buffers will be used.
  26  * @buffer_attrs:       Extra sysfs buffer attributes for this IIO buffer
  27  *
  28  * This function combines some common tasks which will normally be performed
  29  * when setting up a triggered buffer. It will allocate the buffer and the
  30  * pollfunc.
  31  *
  32  * Before calling this function the indio_dev structure should already be
  33  * completely initialized, but not yet registered. In practice this means that
  34  * this function should be called right before iio_device_register().
  35  *
  36  * To free the resources allocated by this function call
  37  * iio_triggered_buffer_cleanup().
  38  */
  39 int iio_triggered_buffer_setup_ext(struct iio_dev *indio_dev,
  40         irqreturn_t (*h)(int irq, void *p),
  41         irqreturn_t (*thread)(int irq, void *p),
  42         enum iio_buffer_direction direction,
  43         const struct iio_buffer_setup_ops *setup_ops,
  44         const struct iio_dev_attr **buffer_attrs)
  45 {
  46         struct iio_buffer *buffer;
  47         int ret;
  48
  49         /*
  50          * iio_triggered_buffer_cleanup() assumes that the buffer allocated here
  51          * is assigned to indio_dev->buffer but this is only the case if this
  52          * function is the first caller to iio_device_attach_buffer(). If
  53          * indio_dev->buffer is already set then we can't proceed otherwise the
  54          * cleanup function will try to free a buffer that was not allocated here.
  55          */
  56         if (indio_dev->buffer)
  57                 return -EADDRINUSE;
  58
  59         buffer = iio_kfifo_allocate();
  60         if (!buffer) {
  61                 ret = -ENOMEM;
  62                 goto error_ret;
  63         }
  64
  65         indio_dev->pollfunc = iio_alloc_pollfunc(h,
  66                                                  thread,
  67                                                  IRQF_ONESHOT,
  68                                                  indio_dev,
  69                                                  "%s_consumer%d",
  70                                                  indio_dev->name,
  71                                                  iio_device_id(indio_dev));
  72         if (indio_dev->pollfunc == NULL) {
  73                 ret = -ENOMEM;
  74                 goto error_kfifo_free;
  75         }
  76
  77         /* Ring buffer functions - here trigger setup related */
  78         indio_dev->setup_ops = setup_ops;
  79
  80         /* Flag that polled ring buffering is possible */
  81         indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
  82
  83         buffer->direction = direction;
  84         buffer->attrs = buffer_attrs;
  85
  86         ret = iio_device_attach_buffer(indio_dev, buffer);
  87         if (ret < 0)
  88                 goto error_dealloc_pollfunc;
  89
  90         return 0;
  91
  92 error_dealloc_pollfunc:
  93         iio_dealloc_pollfunc(indio_dev->pollfunc);
  94 error_kfifo_free:
  95         iio_kfifo_free(buffer);
  96 error_ret:
  97         return ret;
  98 }
  99 EXPORT_SYMBOL(iio_triggered_buffer_setup_ext);
 100
 101 /**
 102  * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup_ext()
 103  * @indio_dev: IIO device structure
 104  */
 105 void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
 106 {
 107         iio_dealloc_pollfunc(indio_dev->pollfunc);
 108         iio_kfifo_free(indio_dev->buffer);
 109 }
 110 EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
 111
 112 static void devm_iio_triggered_buffer_clean(void *indio_dev)
 113 {
 114         iio_triggered_buffer_cleanup(indio_dev);
 115 }
 116
 117 int devm_iio_triggered_buffer_setup_ext(struct device *dev,
 118                                         struct iio_dev *indio_dev,
 119                                         irqreturn_t (*h)(int irq, void *p),
 120                                         irqreturn_t (*thread)(int irq, void *p),
 121                                         enum iio_buffer_direction direction,
 122                                         const struct iio_buffer_setup_ops *ops,
 123                                         const struct iio_dev_attr **buffer_attrs)
 124 {
 125         int ret;
 126
 127         ret = iio_triggered_buffer_setup_ext(indio_dev, h, thread, direction,
 128                                              ops, buffer_attrs);
 129         if (ret)
 130                 return ret;
 131
 132         return devm_add_action_or_reset(dev, devm_iio_triggered_buffer_clean,
 133                                         indio_dev);
 134 }
 135 EXPORT_SYMBOL_GPL(devm_iio_triggered_buffer_setup_ext);
 136
 137 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 138 MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
 139 MODULE_LICENSE("GPL");