2 * Copyright (c) 2011 Jonathan Cameron
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 as published by
6 * the Free Software Foundation.
8 * Event handling elements of industrial I/O reference driver.
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/interrupt.h>
13 #include <linux/irq.h>
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17 #include <linux/iio/events.h>
18 #include "iio_simple_dummy.h"
20 /* Evgen 'fakes' interrupt events for this example */
21 #include "iio_dummy_evgen.h"
24 * iio_simple_dummy_read_event_config() - is event enabled?
25 * @indio_dev: the device instance data
26 * @chan: channel for the event whose state is being queried
27 * @type: type of the event whose state is being queried
28 * @dir: direction of the vent whose state is being queried
30 * This function would normally query the relevant registers or a cache to
31 * discover if the event generation is enabled on the device.
33 int iio_simple_dummy_read_event_config(struct iio_dev *indio_dev,
34 const struct iio_chan_spec *chan,
35 enum iio_event_type type,
36 enum iio_event_direction dir)
38 struct iio_dummy_state *st = iio_priv(indio_dev);
44 * iio_simple_dummy_write_event_config() - set whether event is enabled
45 * @indio_dev: the device instance data
46 * @chan: channel for the event whose state is being set
47 * @type: type of the event whose state is being set
48 * @dir: direction of the vent whose state is being set
49 * @state: whether to enable or disable the device.
51 * This function would normally set the relevant registers on the devices
52 * so that it generates the specified event. Here it just sets up a cached
55 int iio_simple_dummy_write_event_config(struct iio_dev *indio_dev,
56 const struct iio_chan_spec *chan,
57 enum iio_event_type type,
58 enum iio_event_direction dir,
61 struct iio_dummy_state *st = iio_priv(indio_dev);
64 * Deliberately over the top code splitting to illustrate
65 * how this is done when multiple events exist.
70 case IIO_EV_TYPE_THRESH:
71 if (dir == IIO_EV_DIR_RISING)
81 case IIO_EV_TYPE_THRESH:
89 case IIO_EV_TYPE_CHANGE:
103 * iio_simple_dummy_read_event_value() - get value associated with event
104 * @indio_dev: device instance specific data
105 * @chan: channel for the event whose value is being read
106 * @type: type of the event whose value is being read
107 * @dir: direction of the vent whose value is being read
108 * @info: info type of the event whose value is being read
109 * @val: value for the event code.
111 * Many devices provide a large set of events of which only a subset may
112 * be enabled at a time, with value registers whose meaning changes depending
113 * on the event enabled. This often means that the driver must cache the values
114 * associated with each possible events so that the right value is in place when
115 * the enabled event is changed.
117 int iio_simple_dummy_read_event_value(struct iio_dev *indio_dev,
118 const struct iio_chan_spec *chan,
119 enum iio_event_type type,
120 enum iio_event_direction dir,
121 enum iio_event_info info,
124 struct iio_dummy_state *st = iio_priv(indio_dev);
126 *val = st->event_val;
132 * iio_simple_dummy_write_event_value() - set value associate with event
133 * @indio_dev: device instance specific data
134 * @chan: channel for the event whose value is being set
135 * @type: type of the event whose value is being set
136 * @dir: direction of the vent whose value is being set
137 * @info: info type of the event whose value is being set
138 * @val: the value to be set.
140 int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
141 const struct iio_chan_spec *chan,
142 enum iio_event_type type,
143 enum iio_event_direction dir,
144 enum iio_event_info info,
147 struct iio_dummy_state *st = iio_priv(indio_dev);
155 * iio_simple_dummy_event_handler() - identify and pass on event
156 * @irq: irq of event line
157 * @private: pointer to device instance state.
159 * This handler is responsible for querying the device to find out what
160 * event occurred and for then pushing that event towards userspace.
161 * Here only one event occurs so we push that directly on with locally
164 static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
166 struct iio_dev *indio_dev = private;
167 struct iio_dummy_state *st = iio_priv(indio_dev);
169 dev_dbg(&indio_dev->dev, "id %x event %x\n",
170 st->regs->reg_id, st->regs->reg_data);
172 switch (st->regs->reg_data) {
174 iio_push_event(indio_dev,
175 IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
177 IIO_EV_TYPE_THRESH, 0, 0, 0),
181 if (st->activity_running > st->event_val)
182 iio_push_event(indio_dev,
183 IIO_EVENT_CODE(IIO_ACTIVITY, 0,
191 if (st->activity_walking < st->event_val)
192 iio_push_event(indio_dev,
193 IIO_EVENT_CODE(IIO_ACTIVITY, 0,
201 iio_push_event(indio_dev,
202 IIO_EVENT_CODE(IIO_STEPS, 0, IIO_NO_MOD,
204 IIO_EV_TYPE_CHANGE, 0, 0, 0),
215 * iio_simple_dummy_events_register() - setup interrupt handling for events
216 * @indio_dev: device instance data
218 * This function requests the threaded interrupt to handle the events.
219 * Normally the irq is a hardware interrupt and the number comes
220 * from board configuration files. Here we get it from a companion
221 * module that fakes the interrupt for us. Note that module in
222 * no way forms part of this example. Just assume that events magically
223 * appear via the provided interrupt.
225 int iio_simple_dummy_events_register(struct iio_dev *indio_dev)
227 struct iio_dummy_state *st = iio_priv(indio_dev);
230 /* Fire up event source - normally not present */
231 st->event_irq = iio_dummy_evgen_get_irq();
232 if (st->event_irq < 0) {
236 st->regs = iio_dummy_evgen_get_regs(st->event_irq);
238 ret = request_threaded_irq(st->event_irq,
240 &iio_simple_dummy_event_handler,
245 goto error_free_evgen;
249 iio_dummy_evgen_release_irq(st->event_irq);
255 * iio_simple_dummy_events_unregister() - tidy up interrupt handling on remove
256 * @indio_dev: device instance data
258 int iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
260 struct iio_dummy_state *st = iio_priv(indio_dev);
262 free_irq(st->event_irq, indio_dev);
263 /* Not part of normal driver */
264 iio_dummy_evgen_release_irq(st->event_irq);