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/iio/iio.h>
  13 #include <linux/iio/trigger.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/iio/buffer.h>
  16 #include <linux/iio/trigger_consumer.h>
  17 #include <linux/irqreturn.h>
  18 #include <linux/regmap.h>
  19
  20 #include <linux/iio/common/st_sensors.h>
  21
  22
  23 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
  24 {
  25         struct st_sensor_data *sdata = iio_priv(indio_dev);
  26         unsigned int num_data_channels = sdata->num_data_channels;
  27         int i;
  28
  29         for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
  30                 const struct iio_chan_spec *channel = &indio_dev->channels[i];
  31                 unsigned int bytes_to_read =
  32                         DIV_ROUND_UP(channel->scan_type.realbits +
  33                                      channel->scan_type.shift, 8);
  34                 unsigned int storage_bytes =
  35                         channel->scan_type.storagebits >> 3;
  36
  37                 buf = PTR_ALIGN(buf, storage_bytes);
  38                 if (regmap_bulk_read(sdata->regmap, channel->address,
  39                                      buf, bytes_to_read) < 0)
  40                         return -EIO;
  41
  42                 /* Advance the buffer pointer */
  43                 buf += storage_bytes;
  44         }
  45
  46         return 0;
  47 }
  48
  49 irqreturn_t st_sensors_trigger_handler(int irq, void *p)
  50 {
  51         int len;
  52         struct iio_poll_func *pf = p;
  53         struct iio_dev *indio_dev = pf->indio_dev;
  54         struct st_sensor_data *sdata = iio_priv(indio_dev);
  55         s64 timestamp;
  56
  57         /*
  58          * If we do timestamping here, do it before reading the values, because
  59          * once we've read the values, new interrupts can occur (when using
  60          * the hardware trigger) and the hw_timestamp may get updated.
  61          * By storing it in a local variable first, we are safe.
  62          */
  63         if (iio_trigger_using_own(indio_dev))
  64                 timestamp = sdata->hw_timestamp;
  65         else
  66                 timestamp = iio_get_time_ns(indio_dev);
  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");