drivers/iio/common/st_sensors/st_sensors_buffer.c

   1 /*
   2  * STMicroelectronics sensors buffer library 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/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/trigger.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/iio/buffer.h>
  18 #include <linux/iio/trigger_consumer.h>
  19 #include <linux/iio/triggered_buffer.h>
  20 #include <linux/irqreturn.h>
  21
  22 #include <linux/iio/common/st_sensors.h>
  23
  24
  25 int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
  26 {
  27         int i, len;
  28         int total = 0;
  29         struct st_sensor_data *sdata = iio_priv(indio_dev);
  30         unsigned int num_data_channels = sdata->num_data_channels;
  31
  32         for (i = 0; i < num_data_channels; i++) {
  33                 unsigned int bytes_to_read;
  34
  35                 if (test_bit(i, indio_dev->active_scan_mask)) {
  36                         bytes_to_read = indio_dev->channels[i].scan_type.storagebits >> 3;
  37                         len = sdata->tf->read_multiple_byte(&sdata->tb,
  38                                 sdata->dev, indio_dev->channels[i].address,
  39                                 bytes_to_read,
  40                                 buf + total, sdata->multiread_bit);
  41
  42                         if (len < bytes_to_read)
  43                                 return -EIO;
  44
  45                         /* Advance the buffer pointer */
  46                         total += len;
  47                 }
  48         }
  49
  50         return total;
  51 }
  52 EXPORT_SYMBOL(st_sensors_get_buffer_element);
  53
  54 irqreturn_t st_sensors_trigger_handler(int irq, void *p)
  55 {
  56         int len;
  57         struct iio_poll_func *pf = p;
  58         struct iio_dev *indio_dev = pf->indio_dev;
  59         struct st_sensor_data *sdata = iio_priv(indio_dev);
  60         s64 timestamp;
  61
  62         /* If we do timetamping here, do it before reading the values */
  63         if (sdata->hw_irq_trigger)
  64                 timestamp = sdata->hw_timestamp;
  65         else
  66                 timestamp = iio_get_time_ns();
  67
  68         len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
  69         if (len < 0)
  70                 goto st_sensors_get_buffer_element_error;
  71
  72         iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
  73                                            timestamp);
  74
  75 st_sensors_get_buffer_element_error:
  76         iio_trigger_notify_done(indio_dev->trig);
  77
  78         return IRQ_HANDLED;
  79 }
  80 EXPORT_SYMBOL(st_sensors_trigger_handler);
  81
  82 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
  83 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer");
  84 MODULE_LICENSE("GPL v2");