linux/drivers/iio/dummy/iio_simple_dummy_events.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2011 Jonathan Cameron
 *
 * Event handling elements of industrial I/O reference driver.
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/events.h>
#include "iio_simple_dummy.h"

/* Evgen 'fakes' interrupt events for this example */
#include "iio_dummy_evgen.h"

/**
 * iio_simple_dummy_read_event_config() - is event enabled?
 * @indio_dev: the device instance data
 * @chan: channel for the event whose state is being queried
 * @type: type of the event whose state is being queried
 * @dir: direction of the vent whose state is being queried
 *
 * This function would normally query the relevant registers or a cache to
 * discover if the event generation is enabled on the device.
 */
int iio_simple_dummy_read_event_config(struct iio_dev *indio_dev,
				       const struct iio_chan_spec *chan,
				       enum iio_event_type type,
				       enum iio_event_direction dir)
{ … }

/**
 * iio_simple_dummy_write_event_config() - set whether event is enabled
 * @indio_dev: the device instance data
 * @chan: channel for the event whose state is being set
 * @type: type of the event whose state is being set
 * @dir: direction of the vent whose state is being set
 * @state: whether to enable or disable the device.
 *
 * This function would normally set the relevant registers on the devices
 * so that it generates the specified event. Here it just sets up a cached
 * value.
 */
int iio_simple_dummy_write_event_config(struct iio_dev *indio_dev,
					const struct iio_chan_spec *chan,
					enum iio_event_type type,
					enum iio_event_direction dir,
					int state)
{ … }

/**
 * iio_simple_dummy_read_event_value() - get value associated with event
 * @indio_dev: device instance specific data
 * @chan: channel for the event whose value is being read
 * @type: type of the event whose value is being read
 * @dir: direction of the vent whose value is being read
 * @info: info type of the event whose value is being read
 * @val: value for the event code.
 * @val2: unused
 *
 * Many devices provide a large set of events of which only a subset may
 * be enabled at a time, with value registers whose meaning changes depending
 * on the event enabled. This often means that the driver must cache the values
 * associated with each possible events so that the right value is in place when
 * the enabled event is changed.
 */
int iio_simple_dummy_read_event_value(struct iio_dev *indio_dev,
				      const struct iio_chan_spec *chan,
				      enum iio_event_type type,
				      enum iio_event_direction dir,
				      enum iio_event_info info,
				      int *val, int *val2)
{ … }

/**
 * iio_simple_dummy_write_event_value() - set value associate with event
 * @indio_dev: device instance specific data
 * @chan: channel for the event whose value is being set
 * @type: type of the event whose value is being set
 * @dir: direction of the vent whose value is being set
 * @info: info type of the event whose value is being set
 * @val: the value to be set.
 * @val2: unused
 */
int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
				       const struct iio_chan_spec *chan,
				       enum iio_event_type type,
				       enum iio_event_direction dir,
				       enum iio_event_info info,
				       int val, int val2)
{ … }

static irqreturn_t iio_simple_dummy_get_timestamp(int irq, void *private)
{ … }

/**
 * iio_simple_dummy_event_handler() - identify and pass on event
 * @irq: irq of event line
 * @private: pointer to device instance state.
 *
 * This handler is responsible for querying the device to find out what
 * event occurred and for then pushing that event towards userspace.
 * Here only one event occurs so we push that directly on with locally
 * grabbed timestamp.
 */
static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
{ … }

/**
 * iio_simple_dummy_events_register() - setup interrupt handling for events
 * @indio_dev: device instance data
 *
 * This function requests the threaded interrupt to handle the events.
 * Normally the irq is a hardware interrupt and the number comes
 * from board configuration files.  Here we get it from a companion
 * module that fakes the interrupt for us. Note that module in
 * no way forms part of this example. Just assume that events magically
 * appear via the provided interrupt.
 */
int iio_simple_dummy_events_register(struct iio_dev *indio_dev)
{ … }

/**
 * iio_simple_dummy_events_unregister() - tidy up interrupt handling on remove
 * @indio_dev: device instance data
 */
void iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
{ … }