drivers/iio/common/st_sensors/st_sensors_buffer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics sensors buffer library driver
   4  *
   5  * Copyright 2012-2013 STMicroelectronics Inc.
   6  *
   7  * Denis Ciocca <denis.ciocca@st.com>
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/iio/trigger.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/iio/buffer.h>
  17 #include <linux/iio/trigger_consumer.h>
  18 #include <linux/iio/triggered_buffer.h>
  19 #include <linux/irqreturn.h>
  20
  21 #include <linux/iio/common/st_sensors.h>
  22
  23
  24 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
  25 {
  26         int i;
  27         struct st_sensor_data *sdata = iio_priv(indio_dev);
  28         unsigned int num_data_channels = sdata->num_data_channels;
  29
  30         for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
  31                 const struct iio_chan_spec *channel = &indio_dev->channels[i];
  32                 unsigned int bytes_to_read =
  33                         DIV_ROUND_UP(channel->scan_type.realbits +
  34                                      channel->scan_type.shift, 8);
  35                 unsigned int storage_bytes =
  36                         channel->scan_type.storagebits >> 3;
  37
  38                 buf = PTR_ALIGN(buf, storage_bytes);
  39                 if (sdata->tf->read_multiple_byte(&sdata->tb, sdata->dev,
  40                                                   channel->address,
  41                                                   bytes_to_read, buf,
  42                                                   sdata->multiread_bit) <
  43                     bytes_to_read)
  44                         return -EIO;
  45
  46                 /* Advance the buffer pointer */
  47                 buf += storage_bytes;
  48         }
  49
  50         return 0;
  51 }
  52
  53 irqreturn_t st_sensors_trigger_handler(int irq, void *p)
  54 {
  55         int len;
  56         struct iio_poll_func *pf = p;
  57         struct iio_dev *indio_dev = pf->indio_dev;
  58         struct st_sensor_data *sdata = iio_priv(indio_dev);
  59         s64 timestamp;
  60
  61         /*
  62          * If we do timetamping here, do it before reading the values, because
  63          * once we've read the values, new interrupts can occur (when using
  64          * the hardware trigger) and the hw_timestamp may get updated.
  65          * By storing it in a local variable first, we are safe.
  66          */
  67         if (iio_trigger_using_own(indio_dev))
  68                 timestamp = sdata->hw_timestamp;
  69         else
  70                 timestamp = iio_get_time_ns(indio_dev);
  71
  72         len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
  73         if (len < 0)
  74                 goto st_sensors_get_buffer_element_error;
  75
  76         iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
  77                                            timestamp);
  78
  79 st_sensors_get_buffer_element_error:
  80         iio_trigger_notify_done(indio_dev->trig);
  81
  82         return IRQ_HANDLED;
  83 }
  84 EXPORT_SYMBOL(st_sensors_trigger_handler);
  85
  86 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
  87 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer");
  88 MODULE_LICENSE("GPL v2");