Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

8 files changed, 1523 insertions, 0 deletions

diff --git a/drivers/iio/dummy/Kconfig b/drivers/iio/dummy/Kconfig
new file mode 100644
index 000000000..1f46cb9e5
--- /dev/null
+++ b/drivers/iio/dummy/Kconfig
@@ -0,0 +1,46 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Industrial I/O subsystem Dummy Driver configuration
+#
+menu "IIO dummy driver"
+	depends on IIO
+
+config IIO_DUMMY_EVGEN
+	select IRQ_SIM
+	tristate
+
+config IIO_SIMPLE_DUMMY
+	tristate "An example driver with no hardware requirements"
+	depends on IIO_SW_DEVICE
+	help
+	  Driver intended mainly as documentation for how to write
+	  a driver. May also be useful for testing userspace code
+	  without hardware.
+
+if IIO_SIMPLE_DUMMY
+
+config IIO_SIMPLE_DUMMY_EVENTS
+	bool "Event generation support"
+	select IIO_DUMMY_EVGEN
+	help
+	  Add some dummy events to the simple dummy driver.
+
+	  The purpose of this is to generate 'fake' event interrupts thus
+	  allowing that driver's code to be as close as possible to that
+	  a normal driver talking to hardware.
+
+config IIO_SIMPLE_DUMMY_BUFFER
+	bool "Buffered capture support"
+	select IIO_BUFFER
+	select IIO_TRIGGER
+	select IIO_KFIFO_BUF
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Add buffered data capture to the simple dummy driver.
+
+	  Buffer handling elements of industrial I/O reference driver.
+	  Uses the kfifo buffer.
+
+endif # IIO_SIMPLE_DUMMY
+
+endmenu
diff --git a/drivers/iio/dummy/Makefile b/drivers/iio/dummy/Makefile
new file mode 100644
index 000000000..f14fe20f3
--- /dev/null
+++ b/drivers/iio/dummy/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the IIO Dummy Driver
+#
+
+obj-$(CONFIG_IIO_SIMPLE_DUMMY) += iio_dummy.o
+iio_dummy-y := iio_simple_dummy.o
+iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_EVENTS) += iio_simple_dummy_events.o
+iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
+
+obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
diff --git a/drivers/iio/dummy/iio_dummy_evgen.c b/drivers/iio/dummy/iio_dummy_evgen.c
new file mode 100644
index 000000000..5a0072727
--- /dev/null
+++ b/drivers/iio/dummy/iio_dummy_evgen.c
@@ -0,0 +1,222 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * Companion module to the iio simple dummy example driver.
+ * The purpose of this is to generate 'fake' event interrupts thus
+ * allowing that driver's code to be as close as possible to that of
+ * a normal driver talking to hardware.  The approach used here
+ * is not intended to be general and just happens to work for this
+ * particular use case.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/sysfs.h>
+
+#include "iio_dummy_evgen.h"
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/irq_sim.h>
+
+/* Fiddly bit of faking and irq without hardware */
+#define IIO_EVENTGEN_NO 10
+
+/**
+ * struct iio_dummy_eventgen - event generator specific state
+ * @regs: irq regs we are faking
+ * @lock: protect the evgen state
+ * @inuse: mask of which irqs are connected
+ * @irq_sim: interrupt simulator
+ * @base: base of irq range
+ * @irq_sim_domain: irq simulator domain
+ */
+struct iio_dummy_eventgen {
+	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
+	struct mutex lock;
+	bool inuse[IIO_EVENTGEN_NO];
+	struct irq_domain *irq_sim_domain;
+};
+
+/* We can only ever have one instance of this 'device' */
+static struct iio_dummy_eventgen *iio_evgen;
+
+static int iio_dummy_evgen_create(void)
+{
+	int ret;
+
+	iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
+	if (!iio_evgen)
+		return -ENOMEM;
+
+	iio_evgen->irq_sim_domain = irq_domain_create_sim(NULL,
+							  IIO_EVENTGEN_NO);
+	if (IS_ERR(iio_evgen->irq_sim_domain)) {
+		ret = PTR_ERR(iio_evgen->irq_sim_domain);
+		kfree(iio_evgen);
+		return ret;
+	}
+
+	mutex_init(&iio_evgen->lock);
+
+	return 0;
+}
+
+/**
+ * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
+ *
+ * This function will give a free allocated irq to a client device.
+ * That irq can then be caused to 'fire' by using the associated sysfs file.
+ */
+int iio_dummy_evgen_get_irq(void)
+{
+	int i, ret = 0;
+
+	if (!iio_evgen)
+		return -ENODEV;
+
+	mutex_lock(&iio_evgen->lock);
+	for (i = 0; i < IIO_EVENTGEN_NO; i++) {
+		if (!iio_evgen->inuse[i]) {
+			ret = irq_create_mapping(iio_evgen->irq_sim_domain, i);
+			iio_evgen->inuse[i] = true;
+			break;
+		}
+	}
+	mutex_unlock(&iio_evgen->lock);
+	if (i == IIO_EVENTGEN_NO)
+		return -ENOMEM;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
+
+/**
+ * iio_dummy_evgen_release_irq() - give the irq back.
+ * @irq: irq being returned to the pool
+ *
+ * Used by client driver instances to give the irqs back when they disconnect
+ */
+void iio_dummy_evgen_release_irq(int irq)
+{
+	struct irq_data *irqd = irq_get_irq_data(irq);
+
+	mutex_lock(&iio_evgen->lock);
+	iio_evgen->inuse[irqd_to_hwirq(irqd)] = false;
+	irq_dispose_mapping(irq);
+	mutex_unlock(&iio_evgen->lock);
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
+
+struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
+{
+	struct irq_data *irqd = irq_get_irq_data(irq);
+
+	return &iio_evgen->regs[irqd_to_hwirq(irqd)];
+
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
+
+static void iio_dummy_evgen_free(void)
+{
+	irq_domain_remove_sim(iio_evgen->irq_sim_domain);
+	kfree(iio_evgen);
+}
+
+static void iio_evgen_release(struct device *dev)
+{
+	iio_dummy_evgen_free();
+}
+
+static ssize_t iio_evgen_poke(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf,
+			      size_t len)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	unsigned long event;
+	int ret, irq;
+
+	ret = kstrtoul(buf, 10, &event);
+	if (ret)
+		return ret;
+
+	iio_evgen->regs[this_attr->address].reg_id   = this_attr->address;
+	iio_evgen->regs[this_attr->address].reg_data = event;
+
+	irq = irq_find_mapping(iio_evgen->irq_sim_domain, this_attr->address);
+	ret = irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, true);
+	if (ret)
+		return ret;
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
+static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
+static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
+static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
+static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
+static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
+static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
+static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
+static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
+static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
+
+static struct attribute *iio_evgen_attrs[] = {
+	&iio_dev_attr_poke_ev0.dev_attr.attr,
+	&iio_dev_attr_poke_ev1.dev_attr.attr,
+	&iio_dev_attr_poke_ev2.dev_attr.attr,
+	&iio_dev_attr_poke_ev3.dev_attr.attr,
+	&iio_dev_attr_poke_ev4.dev_attr.attr,
+	&iio_dev_attr_poke_ev5.dev_attr.attr,
+	&iio_dev_attr_poke_ev6.dev_attr.attr,
+	&iio_dev_attr_poke_ev7.dev_attr.attr,
+	&iio_dev_attr_poke_ev8.dev_attr.attr,
+	&iio_dev_attr_poke_ev9.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_evgen_group = {
+	.attrs = iio_evgen_attrs,
+};
+
+static const struct attribute_group *iio_evgen_groups[] = {
+	&iio_evgen_group,
+	NULL
+};
+
+static struct device iio_evgen_dev = {
+	.bus = &iio_bus_type,
+	.groups = iio_evgen_groups,
+	.release = &iio_evgen_release,
+};
+
+static __init int iio_dummy_evgen_init(void)
+{
+	int ret = iio_dummy_evgen_create();
+
+	if (ret < 0)
+		return ret;
+	device_initialize(&iio_evgen_dev);
+	dev_set_name(&iio_evgen_dev, "iio_evgen");
+	ret = device_add(&iio_evgen_dev);
+	if (ret)
+		put_device(&iio_evgen_dev);
+	return ret;
+}
+module_init(iio_dummy_evgen_init);
+
+static __exit void iio_dummy_evgen_exit(void)
+{
+	device_unregister(&iio_evgen_dev);
+}
+module_exit(iio_dummy_evgen_exit);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("IIO dummy driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/dummy/iio_dummy_evgen.h b/drivers/iio/dummy/iio_dummy_evgen.h
new file mode 100644
index 000000000..e0bf64fe9
--- /dev/null
+++ b/drivers/iio/dummy/iio_dummy_evgen.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _IIO_DUMMY_EVGEN_H_
+#define _IIO_DUMMY_EVGEN_H_
+
+struct iio_dummy_regs {
+	u32 reg_id;
+	u32 reg_data;
+};
+
+struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq);
+int iio_dummy_evgen_get_irq(void);
+void iio_dummy_evgen_release_irq(int irq);
+
+#endif /* _IIO_DUMMY_EVGEN_H_ */
diff --git a/drivers/iio/dummy/iio_simple_dummy.c b/drivers/iio/dummy/iio_simple_dummy.c
new file mode 100644
index 000000000..c24f609c2
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy.c
@@ -0,0 +1,722 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * A reference industrial I/O driver to illustrate the functionality available.
+ *
+ * There are numerous real drivers to illustrate the finer points.
+ * The purpose of this driver is to provide a driver with far more comments
+ * and explanatory notes than any 'real' driver would have.
+ * Anyone starting out writing an IIO driver should first make sure they
+ * understand all of this driver except those bits specifically marked
+ * as being present to allow us to 'fake' the presence of hardware.
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/sw_device.h>
+#include "iio_simple_dummy.h"
+
+static const struct config_item_type iio_dummy_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/**
+ * struct iio_dummy_accel_calibscale - realworld to register mapping
+ * @val: first value in read_raw - here integer part.
+ * @val2: second value in read_raw etc - here micro part.
+ * @regval: register value - magic device specific numbers.
+ */
+struct iio_dummy_accel_calibscale {
+	int val;
+	int val2;
+	int regval; /* what would be written to hardware */
+};
+
+static const struct iio_dummy_accel_calibscale dummy_scales[] = {
+	{ 0, 100, 0x8 }, /* 0.000100 */
+	{ 0, 133, 0x7 }, /* 0.000133 */
+	{ 733, 13, 0x9 }, /* 733.000013 */
+};
+
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+
+/*
+ * simple event - triggered when value rises above
+ * a threshold
+ */
+static const struct iio_event_spec iio_dummy_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_RISING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple step detect event - triggered when a step is detected
+ */
+static const struct iio_event_spec step_detect_event = {
+	.type = IIO_EV_TYPE_CHANGE,
+	.dir = IIO_EV_DIR_NONE,
+	.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple transition event - triggered when the reported running confidence
+ * value rises above a threshold value
+ */
+static const struct iio_event_spec iio_running_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_RISING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple transition event - triggered when the reported walking confidence
+ * value falls under a threshold value
+ */
+static const struct iio_event_spec iio_walking_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_FALLING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+#endif
+
+/*
+ * iio_dummy_channels - Description of available channels
+ *
+ * This array of structures tells the IIO core about what the device
+ * actually provides for a given channel.
+ */
+static const struct iio_chan_spec iio_dummy_channels[] = {
+	/* indexed ADC channel in_voltage0_raw etc */
+	{
+		.type = IIO_VOLTAGE,
+		/* Channel has a numeric index of 0 */
+		.indexed = 1,
+		.channel = 0,
+		/* What other information is available? */
+		.info_mask_separate =
+		/*
+		 * in_voltage0_raw
+		 * Raw (unscaled no bias removal etc) measurement
+		 * from the device.
+		 */
+		BIT(IIO_CHAN_INFO_RAW) |
+		/*
+		 * in_voltage0_offset
+		 * Offset for userspace to apply prior to scale
+		 * when converting to standard units (microvolts)
+		 */
+		BIT(IIO_CHAN_INFO_OFFSET) |
+		/*
+		 * in_voltage0_scale
+		 * Multipler for userspace to apply post offset
+		 * when converting to standard units (microvolts)
+		 */
+		BIT(IIO_CHAN_INFO_SCALE),
+		/*
+		 * sampling_frequency
+		 * The frequency in Hz at which the channels are sampled
+		 */
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		/* The ordering of elements in the buffer via an enum */
+		.scan_index = DUMMY_INDEX_VOLTAGE_0,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 'u', /* unsigned */
+			.realbits = 13, /* 13 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_dummy_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	/* Differential ADC channel in_voltage1-voltage2_raw etc*/
+	{
+		.type = IIO_VOLTAGE,
+		.differential = 1,
+		/*
+		 * Indexing for differential channels uses channel
+		 * for the positive part, channel2 for the negative.
+		 */
+		.indexed = 1,
+		.channel = 1,
+		.channel2 = 2,
+		/*
+		 * in_voltage1-voltage2_raw
+		 * Raw (unscaled no bias removal etc) measurement
+		 * from the device.
+		 */
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		/*
+		 * in_voltage-voltage_scale
+		 * Shared version of scale - shared by differential
+		 * input channels of type IIO_VOLTAGE.
+		 */
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		/*
+		 * sampling_frequency
+		 * The frequency in Hz at which the channels are sampled
+		 */
+		.scan_index = DUMMY_INDEX_DIFFVOLTAGE_1M2,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 's', /* signed */
+			.realbits = 12, /* 12 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+	},
+	/* Differential ADC channel in_voltage3-voltage4_raw etc*/
+	{
+		.type = IIO_VOLTAGE,
+		.differential = 1,
+		.indexed = 1,
+		.channel = 3,
+		.channel2 = 4,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = DUMMY_INDEX_DIFFVOLTAGE_3M4,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 11,
+			.storagebits = 16,
+			.shift = 0,
+		},
+	},
+	/*
+	 * 'modified' (i.e. axis specified) acceleration channel
+	 * in_accel_z_raw
+	 */
+	{
+		.type = IIO_ACCEL,
+		.modified = 1,
+		/* Channel 2 is use for modifiers */
+		.channel2 = IIO_MOD_X,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		/*
+		 * Internal bias and gain correction values. Applied
+		 * by the hardware or driver prior to userspace
+		 * seeing the readings. Typically part of hardware
+		 * calibration.
+		 */
+		BIT(IIO_CHAN_INFO_CALIBSCALE) |
+		BIT(IIO_CHAN_INFO_CALIBBIAS),
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = DUMMY_INDEX_ACCELX,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 's', /* signed */
+			.realbits = 16, /* 16 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+	},
+	/*
+	 * Convenience macro for timestamps. 4 is the index in
+	 * the buffer.
+	 */
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+	/* DAC channel out_voltage0_raw */
+	{
+		.type = IIO_VOLTAGE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.scan_index = -1, /* No buffer support */
+		.output = 1,
+		.indexed = 1,
+		.channel = 0,
+	},
+	{
+		.type = IIO_STEPS,
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_ENABLE) |
+			BIT(IIO_CHAN_INFO_CALIBHEIGHT),
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &step_detect_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	{
+		.type = IIO_ACTIVITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_RUNNING,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_running_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	{
+		.type = IIO_ACTIVITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_WALKING,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_walking_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+};
+
+/**
+ * iio_dummy_read_raw() - data read function.
+ * @indio_dev:	the struct iio_dev associated with this device instance
+ * @chan:	the channel whose data is to be read
+ * @val:	first element of returned value (typically INT)
+ * @val2:	second element of returned value (typically MICRO)
+ * @mask:	what we actually want to read as per the info_mask_*
+ *		in iio_chan_spec.
+ */
+static int iio_dummy_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val,
+			      int *val2,
+			      long mask)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+	int ret = -EINVAL;
+
+	mutex_lock(&st->lock);
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: /* magic value - channel value read */
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chan->output) {
+				/* Set integer part to cached value */
+				*val = st->dac_val;
+				ret = IIO_VAL_INT;
+			} else if (chan->differential) {
+				if (chan->channel == 1)
+					*val = st->differential_adc_val[0];
+				else
+					*val = st->differential_adc_val[1];
+				ret = IIO_VAL_INT;
+			} else {
+				*val = st->single_ended_adc_val;
+				ret = IIO_VAL_INT;
+			}
+			break;
+		case IIO_ACCEL:
+			*val = st->accel_val;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->steps;
+			ret = IIO_VAL_INT;
+			break;
+		case IIO_ACTIVITY:
+			switch (chan->channel2) {
+			case IIO_MOD_RUNNING:
+				*val = st->activity_running;
+				ret = IIO_VAL_INT;
+				break;
+			case IIO_MOD_WALKING:
+				*val = st->activity_walking;
+				ret = IIO_VAL_INT;
+				break;
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_OFFSET:
+		/* only single ended adc -> 7 */
+		*val = 7;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			switch (chan->differential) {
+			case 0:
+				/* only single ended adc -> 0.001333 */
+				*val = 0;
+				*val2 = 1333;
+				ret = IIO_VAL_INT_PLUS_MICRO;
+				break;
+			case 1:
+				/* all differential adc -> 0.000001344 */
+				*val = 0;
+				*val2 = 1344;
+				ret = IIO_VAL_INT_PLUS_NANO;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		/* only the acceleration axis - read from cache */
+		*val = st->accel_calibbias;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = st->accel_calibscale->val;
+		*val2 = st->accel_calibscale->val2;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = 3;
+		*val2 = 33;
+		ret = IIO_VAL_INT_PLUS_NANO;
+		break;
+	case IIO_CHAN_INFO_ENABLE:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->steps_enabled;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_CALIBHEIGHT:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->height;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	default:
+		break;
+	}
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+/**
+ * iio_dummy_write_raw() - data write function.
+ * @indio_dev:	the struct iio_dev associated with this device instance
+ * @chan:	the channel whose data is to be written
+ * @val:	first element of value to set (typically INT)
+ * @val2:	second element of value to set (typically MICRO)
+ * @mask:	what we actually want to write as per the info_mask_*
+ *		in iio_chan_spec.
+ *
+ * Note that all raw writes are assumed IIO_VAL_INT and info mask elements
+ * are assumed to be IIO_INT_PLUS_MICRO unless the callback write_raw_get_fmt
+ * in struct iio_info is provided by the driver.
+ */
+static int iio_dummy_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	int i;
+	int ret = 0;
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chan->output == 0)
+				return -EINVAL;
+
+			/* Locking not required as writing single value */
+			mutex_lock(&st->lock);
+			st->dac_val = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_STEPS:
+			mutex_lock(&st->lock);
+			st->steps = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		case IIO_ACTIVITY:
+			if (val < 0)
+				val = 0;
+			if (val > 100)
+				val = 100;
+			switch (chan->channel2) {
+			case IIO_MOD_RUNNING:
+				st->activity_running = val;
+				return 0;
+			case IIO_MOD_WALKING:
+				st->activity_walking = val;
+				return 0;
+			default:
+				return -EINVAL;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_CALIBSCALE:
+		mutex_lock(&st->lock);
+		/* Compare against table - hard matching here */
+		for (i = 0; i < ARRAY_SIZE(dummy_scales); i++)
+			if (val == dummy_scales[i].val &&
+			    val2 == dummy_scales[i].val2)
+				break;
+		if (i == ARRAY_SIZE(dummy_scales))
+			ret = -EINVAL;
+		else
+			st->accel_calibscale = &dummy_scales[i];
+		mutex_unlock(&st->lock);
+		return ret;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		mutex_lock(&st->lock);
+		st->accel_calibbias = val;
+		mutex_unlock(&st->lock);
+		return 0;
+	case IIO_CHAN_INFO_ENABLE:
+		switch (chan->type) {
+		case IIO_STEPS:
+			mutex_lock(&st->lock);
+			st->steps_enabled = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_CALIBHEIGHT:
+		switch (chan->type) {
+		case IIO_STEPS:
+			st->height = val;
+			return 0;
+		default:
+			return -EINVAL;
+		}
+
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Device type specific information.
+ */
+static const struct iio_info iio_dummy_info = {
+	.read_raw = &iio_dummy_read_raw,
+	.write_raw = &iio_dummy_write_raw,
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+	.read_event_config = &iio_simple_dummy_read_event_config,
+	.write_event_config = &iio_simple_dummy_write_event_config,
+	.read_event_value = &iio_simple_dummy_read_event_value,
+	.write_event_value = &iio_simple_dummy_write_event_value,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+};
+
+/**
+ * iio_dummy_init_device() - device instance specific init
+ * @indio_dev: the iio device structure
+ *
+ * Most drivers have one of these to set up default values,
+ * reset the device to known state etc.
+ */
+static int iio_dummy_init_device(struct iio_dev *indio_dev)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	st->dac_val = 0;
+	st->single_ended_adc_val = 73;
+	st->differential_adc_val[0] = 33;
+	st->differential_adc_val[1] = -34;
+	st->accel_val = 34;
+	st->accel_calibbias = -7;
+	st->accel_calibscale = &dummy_scales[0];
+	st->steps = 47;
+	st->activity_running = 98;
+	st->activity_walking = 4;
+
+	return 0;
+}
+
+/**
+ * iio_dummy_probe() - device instance probe
+ * @name: name of this instance.
+ *
+ * Arguments are bus type specific.
+ * I2C: iio_dummy_probe(struct i2c_client *client,
+ *                      const struct i2c_device_id *id)
+ * SPI: iio_dummy_probe(struct spi_device *spi)
+ */
+static struct iio_sw_device *iio_dummy_probe(const char *name)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct iio_dummy_state *st;
+	struct iio_sw_device *swd;
+	struct device *parent = NULL;
+
+	/*
+	 * With hardware: Set the parent device.
+	 * parent = &spi->dev;
+	 * parent = &client->dev;
+	 */
+
+	swd = kzalloc(sizeof(*swd), GFP_KERNEL);
+	if (!swd)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Allocate an IIO device.
+	 *
+	 * This structure contains all generic state
+	 * information about the device instance.
+	 * It also has a region (accessed by iio_priv()
+	 * for chip specific state information.
+	 */
+	indio_dev = iio_device_alloc(parent, sizeof(*st));
+	if (!indio_dev) {
+		ret = -ENOMEM;
+		goto error_free_swd;
+	}
+
+	st = iio_priv(indio_dev);
+	mutex_init(&st->lock);
+
+	iio_dummy_init_device(indio_dev);
+
+	 /*
+	 * Make the iio_dev struct available to remove function.
+	 * Bus equivalents
+	 * i2c_set_clientdata(client, indio_dev);
+	 * spi_set_drvdata(spi, indio_dev);
+	 */
+	swd->device = indio_dev;
+
+	/*
+	 * Set the device name.
+	 *
+	 * This is typically a part number and obtained from the module
+	 * id table.
+	 * e.g. for i2c and spi:
+	 *    indio_dev->name = id->name;
+	 *    indio_dev->name = spi_get_device_id(spi)->name;
+	 */
+	indio_dev->name = kstrdup(name, GFP_KERNEL);
+	if (!indio_dev->name) {
+		ret = -ENOMEM;
+		goto error_free_device;
+	}
+
+	/* Provide description of available channels */
+	indio_dev->channels = iio_dummy_channels;
+	indio_dev->num_channels = ARRAY_SIZE(iio_dummy_channels);
+
+	/*
+	 * Provide device type specific interface functions and
+	 * constant data.
+	 */
+	indio_dev->info = &iio_dummy_info;
+
+	/* Specify that device provides sysfs type interfaces */
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_simple_dummy_events_register(indio_dev);
+	if (ret < 0)
+		goto error_free_name;
+
+	ret = iio_simple_dummy_configure_buffer(indio_dev);
+	if (ret < 0)
+		goto error_unregister_events;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto error_unconfigure_buffer;
+
+	iio_swd_group_init_type_name(swd, name, &iio_dummy_type);
+
+	return swd;
+error_unconfigure_buffer:
+	iio_simple_dummy_unconfigure_buffer(indio_dev);
+error_unregister_events:
+	iio_simple_dummy_events_unregister(indio_dev);
+error_free_name:
+	kfree(indio_dev->name);
+error_free_device:
+	iio_device_free(indio_dev);
+error_free_swd:
+	kfree(swd);
+	return ERR_PTR(ret);
+}
+
+/**
+ * iio_dummy_remove() - device instance removal function
+ * @swd: pointer to software IIO device abstraction
+ *
+ * Parameters follow those of iio_dummy_probe for buses.
+ */
+static int iio_dummy_remove(struct iio_sw_device *swd)
+{
+	/*
+	 * Get a pointer to the device instance iio_dev structure
+	 * from the bus subsystem. E.g.
+	 * struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	 * struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	 */
+	struct iio_dev *indio_dev = swd->device;
+
+	/* Unregister the device */
+	iio_device_unregister(indio_dev);
+
+	/* Device specific code to power down etc */
+
+	/* Buffered capture related cleanup */
+	iio_simple_dummy_unconfigure_buffer(indio_dev);
+
+	iio_simple_dummy_events_unregister(indio_dev);
+
+	/* Free all structures */
+	kfree(indio_dev->name);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+/*
+ * module_iio_sw_device_driver() -  device driver registration
+ *
+ * Varies depending on bus type of the device. As there is no device
+ * here, call probe directly. For information on device registration
+ * i2c:
+ * Documentation/i2c/writing-clients.rst
+ * spi:
+ * Documentation/spi/spi-summary.rst
+ */
+static const struct iio_sw_device_ops iio_dummy_device_ops = {
+	.probe = iio_dummy_probe,
+	.remove = iio_dummy_remove,
+};
+
+static struct iio_sw_device_type iio_dummy_device = {
+	.name = "dummy",
+	.owner = THIS_MODULE,
+	.ops = &iio_dummy_device_ops,
+};
+
+module_iio_sw_device_driver(iio_dummy_device);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("IIO dummy driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/iio/dummy/iio_simple_dummy.h b/drivers/iio/dummy/iio_simple_dummy.h
new file mode 100644
index 000000000..a91622ac5
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy.h
@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/**
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * Join together the various functionality of iio_simple_dummy driver
+ */
+
+#ifndef _IIO_SIMPLE_DUMMY_H_
+#define _IIO_SIMPLE_DUMMY_H_
+#include <linux/kernel.h>
+
+struct iio_dummy_accel_calibscale;
+struct iio_dummy_regs;
+
+/**
+ * struct iio_dummy_state - device instance specific state.
+ * @dac_val:			cache for dac value
+ * @single_ended_adc_val:	cache for single ended adc value
+ * @differential_adc_val:	cache for differential adc value
+ * @accel_val:			cache for acceleration value
+ * @accel_calibbias:		cache for acceleration calibbias
+ * @accel_calibscale:		cache for acceleration calibscale
+ * @lock:			lock to ensure state is consistent
+ * @event_irq:			irq number for event line (faked)
+ * @event_val:			cache for event threshold value
+ * @event_en:			cache of whether event is enabled
+ */
+struct iio_dummy_state {
+	int dac_val;
+	int single_ended_adc_val;
+	int differential_adc_val[2];
+	int accel_val;
+	int accel_calibbias;
+	int activity_running;
+	int activity_walking;
+	const struct iio_dummy_accel_calibscale *accel_calibscale;
+	struct mutex lock;
+	struct iio_dummy_regs *regs;
+	int steps_enabled;
+	int steps;
+	int height;
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+	int event_irq;
+	int event_val;
+	bool event_en;
+	s64 event_timestamp;
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+};
+
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+
+struct iio_dev;
+
+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);
+
+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);
+
+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);
+
+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);
+
+int iio_simple_dummy_events_register(struct iio_dev *indio_dev);
+void iio_simple_dummy_events_unregister(struct iio_dev *indio_dev);
+
+#else /* Stubs for when events are disabled at compile time */
+
+static inline int
+iio_simple_dummy_events_register(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline void
+iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
+{}
+
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS*/
+
+/**
+ * enum iio_simple_dummy_scan_elements - scan index enum
+ * @DUMMY_INDEX_VOLTAGE_0:         the single ended voltage channel
+ * @DUMMY_INDEX_DIFFVOLTAGE_1M2:   first differential channel
+ * @DUMMY_INDEX_DIFFVOLTAGE_3M4:   second differential channel
+ * @DUMMY_INDEX_ACCELX:            acceleration channel
+ *
+ * Enum provides convenient numbering for the scan index.
+ */
+enum iio_simple_dummy_scan_elements {
+	DUMMY_INDEX_VOLTAGE_0,
+	DUMMY_INDEX_DIFFVOLTAGE_1M2,
+	DUMMY_INDEX_DIFFVOLTAGE_3M4,
+	DUMMY_INDEX_ACCELX,
+};
+
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_BUFFER
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev);
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev);
+#else
+static inline int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{}
+
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_BUFFER */
+#endif /* _IIO_SIMPLE_DUMMY_H_ */
diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c
new file mode 100644
index 000000000..9b2f99449
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
@@ -0,0 +1,106 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * Buffer handling elements of industrial I/O reference driver.
+ * Uses the kfifo buffer.
+ *
+ * To test without hardware use the sysfs trigger.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/bitmap.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include "iio_simple_dummy.h"
+
+/* Some fake data */
+
+static const s16 fakedata[] = {
+	[DUMMY_INDEX_VOLTAGE_0] = 7,
+	[DUMMY_INDEX_DIFFVOLTAGE_1M2] = -33,
+	[DUMMY_INDEX_DIFFVOLTAGE_3M4] = -2,
+	[DUMMY_INDEX_ACCELX] = 344,
+};
+
+/**
+ * iio_simple_dummy_trigger_h() - the trigger handler function
+ * @irq: the interrupt number
+ * @p: private data - always a pointer to the poll func.
+ *
+ * This is the guts of buffered capture. On a trigger event occurring,
+ * if the pollfunc is attached then this handler is called as a threaded
+ * interrupt (and hence may sleep). It is responsible for grabbing data
+ * from the device and pushing it into the associated buffer.
+ */
+static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	int i = 0, j;
+	u16 *data;
+
+	data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (!data)
+		goto done;
+
+	/*
+	 * Three common options here:
+	 * hardware scans:
+	 *   certain combinations of channels make up a fast read. The capture
+	 *   will consist of all of them. Hence we just call the grab data
+	 *   function and fill the buffer without processing.
+	 * software scans:
+	 *   can be considered to be random access so efficient reading is just
+	 *   a case of minimal bus transactions.
+	 * software culled hardware scans:
+	 *   occasionally a driver may process the nearest hardware scan to avoid
+	 *   storing elements that are not desired. This is the fiddliest option
+	 *   by far.
+	 * Here let's pretend we have random access. And the values are in the
+	 * constant table fakedata.
+	 */
+	for_each_set_bit(j, indio_dev->active_scan_mask, indio_dev->masklength)
+		data[i++] = fakedata[j];
+
+	iio_push_to_buffers_with_timestamp(indio_dev, data,
+					   iio_get_time_ns(indio_dev));
+
+	kfree(data);
+
+done:
+	/*
+	 * Tell the core we are done with this trigger and ready for the
+	 * next one.
+	 */
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {
+};
+
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+	return iio_triggered_buffer_setup(indio_dev, NULL,
+					  iio_simple_dummy_trigger_h,
+					  &iio_simple_dummy_buffer_setup_ops);
+}
+
+/**
+ * iio_simple_dummy_unconfigure_buffer() - release buffer resources
+ * @indio_dev: device instance state
+ */
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{
+	iio_triggered_buffer_cleanup(indio_dev);
+}
diff --git a/drivers/iio/dummy/iio_simple_dummy_events.c b/drivers/iio/dummy/iio_simple_dummy_events.c
new file mode 100644
index 000000000..63a2b844b
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_events.c
@@ -0,0 +1,276 @@
+// 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)
+{
+	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
+ * @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)
+{
+	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 (chan->type) {
+	case IIO_VOLTAGE:
+		switch (type) {
+		case IIO_EV_TYPE_THRESH:
+			if (dir == IIO_EV_DIR_RISING)
+				st->event_en = state;
+			else
+				return -EINVAL;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_ACTIVITY:
+		switch (type) {
+		case IIO_EV_TYPE_THRESH:
+			st->event_en = state;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_STEPS:
+		switch (type) {
+		case IIO_EV_TYPE_CHANGE:
+			st->event_en = state;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * 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)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	*val = st->event_val;
+
+	return IIO_VAL_INT;
+}
+
+/**
+ * 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)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	st->event_val = val;
+
+	return 0;
+}
+
+static irqreturn_t iio_simple_dummy_get_timestamp(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	st->event_timestamp = iio_get_time_ns(indio_dev);
+	return IRQ_WAKE_THREAD;
+}
+
+/**
+ * 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)
+{
+	struct iio_dev *indio_dev = private;
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	dev_dbg(&indio_dev->dev, "id %x event %x\n",
+		st->regs->reg_id, st->regs->reg_data);
+
+	switch (st->regs->reg_data) {
+	case 0:
+		iio_push_event(indio_dev,
+			       IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
+					      IIO_EV_DIR_RISING,
+					      IIO_EV_TYPE_THRESH, 0, 0, 0),
+			       st->event_timestamp);
+		break;
+	case 1:
+		if (st->activity_running > st->event_val)
+			iio_push_event(indio_dev,
+				       IIO_EVENT_CODE(IIO_ACTIVITY, 0,
+						      IIO_MOD_RUNNING,
+						      IIO_EV_DIR_RISING,
+						      IIO_EV_TYPE_THRESH,
+						      0, 0, 0),
+				       st->event_timestamp);
+		break;
+	case 2:
+		if (st->activity_walking < st->event_val)
+			iio_push_event(indio_dev,
+				       IIO_EVENT_CODE(IIO_ACTIVITY, 0,
+						      IIO_MOD_WALKING,
+						      IIO_EV_DIR_FALLING,
+						      IIO_EV_TYPE_THRESH,
+						      0, 0, 0),
+				       st->event_timestamp);
+		break;
+	case 3:
+		iio_push_event(indio_dev,
+			       IIO_EVENT_CODE(IIO_STEPS, 0, IIO_NO_MOD,
+					      IIO_EV_DIR_NONE,
+					      IIO_EV_TYPE_CHANGE, 0, 0, 0),
+			       st->event_timestamp);
+		break;
+	default:
+		break;
+	}
+
+	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;
+	}
+	st->regs = iio_dummy_evgen_get_regs(st->event_irq);
+
+	ret = request_threaded_irq(st->event_irq,
+				   &iio_simple_dummy_get_timestamp,
+				   &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
+ */
+void 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);
+}