staging:iio:dummy Add event support + fake event generator
The event generator is not very pretty but does the job and
allows this driver to look a lot more like a normal driver
than it otherwise would.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/iio/iio_simple_dummy_events.c b/drivers/staging/iio/iio_simple_dummy_events.c
new file mode 100644
index 0000000..9f00cff
--- /dev/null
+++ b/drivers/staging/iio/iio_simple_dummy_events.c
@@ -0,0 +1,190 @@
+/**
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * 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 "iio.h"
+#include "sysfs.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
+ * @event_code: event code of the event 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,
+ u64 event_code)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+
+ return st->event_en;
+}
+
+/**
+ * iio_simple_dummy_write_event_config() - set whether event is enabled
+ * @indio_dev: the device instance data
+ * @event_code: event code of event being enabled/disabled
+ * @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,
+ u64 event_code,
+ int state)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+
+ /*
+ * Deliberately over the top code splitting to illustrate
+ * how this is done when multiple events exist.
+ */
+ switch (IIO_EVENT_CODE_EXTRACT_CHAN_TYPE(event_code)) {
+ case IIO_VOLTAGE:
+ switch (IIO_EVENT_CODE_EXTRACT_TYPE(event_code)) {
+ case IIO_EV_TYPE_THRESH:
+ if (IIO_EVENT_CODE_EXTRACT_DIR(event_code) ==
+ IIO_EV_DIR_RISING)
+ st->event_en = state;
+ else
+ return -EINVAL;
+ break;
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+/**
+ * iio_simple_dummy_read_event_value() - get value associated with event
+ * @indio_dev: device instance specific data
+ * @event_code: event code for the event whose value is being queried
+ * @val: value for the event code.
+ *
+ * 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,
+ u64 event_code,
+ int *val)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+
+ *val = st->event_val;
+
+ return 0;
+}
+
+/**
+ * iio_simple_dummy_write_event_value() - set value associate with event
+ * @indio_dev: device instance specific data
+ * @event_code: event code for the event whose value is being set
+ * @val: the value to be set.
+ */
+int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
+ u64 event_code,
+ int val)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+
+ st->event_val = val;
+
+ return 0;
+}
+
+/**
+ * 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 occured 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)
+{
+ struct iio_dev *indio_dev = private;
+ iio_push_event(indio_dev,
+ IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
+ IIO_EV_DIR_RISING,
+ IIO_EV_TYPE_THRESH, 0, 0, 0),
+ iio_get_time_ns());
+ return IRQ_HANDLED;
+}
+
+/**
+ * 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)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+ int ret;
+
+ /* Fire up event source - normally not present */
+ st->event_irq = iio_dummy_evgen_get_irq();
+ if (st->event_irq < 0) {
+ ret = st->event_irq;
+ goto error_ret;
+ }
+ ret = request_threaded_irq(st->event_irq,
+ NULL,
+ &iio_simple_dummy_event_handler,
+ IRQF_ONESHOT,
+ "iio_simple_event",
+ indio_dev);
+ if (ret < 0)
+ goto error_free_evgen;
+ return 0;
+
+error_free_evgen:
+ iio_dummy_evgen_release_irq(st->event_irq);
+error_ret:
+ return ret;
+}
+
+/**
+ * iio_simple_dummy_events_unregister() - tidy up interrupt handling on remove
+ * @indio_dev: device instance data
+ */
+int iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
+{
+ struct iio_dummy_state *st = iio_priv(indio_dev);
+
+ free_irq(st->event_irq, indio_dev);
+ /* Not part of normal driver */
+ iio_dummy_evgen_release_irq(st->event_irq);
+
+ return 0;
+}