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 <[email protected]>
   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 #include <linux/regmap.h>
  21
  22 #include <linux/iio/common/st_sensors.h>
  23
  24
  25 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
  26 {
  27         struct st_sensor_data *sdata = iio_priv(indio_dev);
  28         unsigned int num_data_channels = sdata->num_data_channels;
  29         int i;
  30
  31         for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
  32                 const struct iio_chan_spec *channel = &indio_dev->channels[i];
  33                 unsigned int bytes_to_read =
  34                         DIV_ROUND_UP(channel->scan_type.realbits +
  35                                      channel->scan_type.shift, 8);
  36                 unsigned int storage_bytes =
  37                         channel->scan_type.storagebits >> 3;
  38
  39                 buf = PTR_ALIGN(buf, storage_bytes);
  40                 if (regmap_bulk_read(sdata->regmap, channel->address,
  41                                      buf, bytes_to_read) < 0)
  42                         return -EIO;
  43
  44                 /* Advance the buffer pointer */
  45                 buf += storage_bytes;
  46         }
  47
  48         return 0;
  49 }
  50
  51 irqreturn_t st_sensors_trigger_handler(int irq, void *p)
  52 {
  53         int len;
  54         struct iio_poll_func *pf = p;
  55         struct iio_dev *indio_dev = pf->indio_dev;
  56         struct st_sensor_data *sdata = iio_priv(indio_dev);
  57         s64 timestamp;
  58
  59         /*
  60          * If we do timetamping here, do it before reading the values, because
  61          * once we've read the values, new interrupts can occur (when using
  62          * the hardware trigger) and the hw_timestamp may get updated.
  63          * By storing it in a local variable first, we are safe.
  64          */
  65         if (iio_trigger_using_own(indio_dev))
  66                 timestamp = sdata->hw_timestamp;
  67         else
  68                 timestamp = iio_get_time_ns(indio_dev);
  69
  70         len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
  71         if (len < 0)
  72                 goto st_sensors_get_buffer_element_error;
  73
  74         iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
  75                                            timestamp);
  76
  77 st_sensors_get_buffer_element_error:
  78         iio_trigger_notify_done(indio_dev->trig);
  79
  80         return IRQ_HANDLED;
  81 }
  82 EXPORT_SYMBOL(st_sensors_trigger_handler);
  83
  84 MODULE_AUTHOR("Denis Ciocca <[email protected]>");
  85 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer");
  86 MODULE_LICENSE("GPL v2");