drivers/iio/magnetometer/st_magn_buffer.c

   1 /*
   2  * STMicroelectronics magnetometers driver
   3  *
   4  * Copyright 2012-2013 STMicroelectronics Inc.
   5  *
   6  * Denis Ciocca <denis.ciocca@st.com>
   7  *
   8  * Licensed under the GPL-2.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/slab.h>
  14 #include <linux/stat.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/i2c.h>
  17 #include <linux/delay.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger_consumer.h>
  21 #include <linux/iio/triggered_buffer.h>
  22
  23 #include <linux/iio/common/st_sensors.h>
  24 #include "st_magn.h"
  25
  26 static int st_magn_buffer_preenable(struct iio_dev *indio_dev)
  27 {
  28         return st_sensors_set_enable(indio_dev, true);
  29 }
  30
  31 static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
  32 {
  33         int err;
  34         struct st_sensor_data *mdata = iio_priv(indio_dev);
  35
  36         mdata->buffer_data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
  37         if (mdata->buffer_data == NULL) {
  38                 err = -ENOMEM;
  39                 goto allocate_memory_error;
  40         }
  41
  42         err = iio_triggered_buffer_postenable(indio_dev);
  43         if (err < 0)
  44                 goto st_magn_buffer_postenable_error;
  45
  46         return err;
  47
  48 st_magn_buffer_postenable_error:
  49         kfree(mdata->buffer_data);
  50 allocate_memory_error:
  51         return err;
  52 }
  53
  54 static int st_magn_buffer_predisable(struct iio_dev *indio_dev)
  55 {
  56         int err;
  57         struct st_sensor_data *mdata = iio_priv(indio_dev);
  58
  59         err = iio_triggered_buffer_predisable(indio_dev);
  60         if (err < 0)
  61                 goto st_magn_buffer_predisable_error;
  62
  63         err = st_sensors_set_enable(indio_dev, false);
  64
  65 st_magn_buffer_predisable_error:
  66         kfree(mdata->buffer_data);
  67         return err;
  68 }
  69
  70 static const struct iio_buffer_setup_ops st_magn_buffer_setup_ops = {
  71         .preenable = &st_magn_buffer_preenable,
  72         .postenable = &st_magn_buffer_postenable,
  73         .predisable = &st_magn_buffer_predisable,
  74 };
  75
  76 int st_magn_allocate_ring(struct iio_dev *indio_dev)
  77 {
  78         return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
  79                 &st_sensors_trigger_handler, &st_magn_buffer_setup_ops);
  80 }
  81
  82 void st_magn_deallocate_ring(struct iio_dev *indio_dev)
  83 {
  84         iio_triggered_buffer_cleanup(indio_dev);
  85 }
  86
  87 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
  88 MODULE_DESCRIPTION("STMicroelectronics magnetometers buffer");
  89 MODULE_LICENSE("GPL v2");