Merge tag 'iio-for-4.5a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

First set of new device support, features and cleanups for IIO in the 4.5 cycle

Usual mixed bag, but the big item perhaps in this series is the DMA buffer
support added by Lars-Peter Clausen. It's been in the works for a long time
and it will be interesting to see what hardware support shows up now that
this is available.

New core features + associate cleanup.
* Add generic DMA buffer infrastructure
* Add a DMAengine framework based buffer
 Also associated minor changes.
   - Set the device buffer watermark based on the minimum watermark for all
     attached buffers rather than just the 'primary' one.
   - iio_buffer_init - only set the watermark default if one hasn't already
     been provided.  This allows simple support for devices with a fixed
     watermark.
   - read only attribute for watermark on fixed watermark devices.
   - add explicit buffer enable/disable callbacks to allow the buffer to
     do more than trivial actions when it is being turned on and off.
* IIO_VAL_INT support in write_raw_get_fmt function.

New device support
* Freescale MMA7455/7456L accelerometers
* Memsic MXC6255XC accelerometer
* ST lis2dh12 accelerometer
* TI ADS8688 ADC
* TI Palamas (twl6035/7) gpadc

New driver features
* mma8452
  - support either of the available interrupt pins to cope with the case
    where board layout has lead to a particular one being connected.

Staging graduation
* Dummy driver
  - this driver acts as both an example and a test device for those with
    out hardware to develop userspace code against.

Cleanups and minor bits and bobs.
* treewide
  - Sort out the ordering of iio_device_register/unregister vs runtime
    pm function calls so that it's all nice and consistent and not race
    prone.
  - Check sscanf return values.  None of the cases will actually happen as
    the strings are supplied internally, but best to be consistent on this.
* ad7780
  - switch over to the gpio descriptor interface and remove the now unused
    platform data which gets rid of a header entirely.
* ad7793
  - drop a pointless else statement.
* at91_adc
  - Swap kmalloc_array in for a kmalloc doing the same job.
* dummy
  - get rid of some commented out lines that snuck in during the move of
    the driver.
* lm3533-als
  - Print an error message on provision of an invalid resistance.
* mcp320x
  - Add compatible strings with vendor prefix and deprecate those with
    no vendor prefix.
* mxs-lradc
  - Use BIT macro in various places rather than shifted ones.
* pa12203001
  - Power off the chip if the registration fails.
* pulsedlight-lidar-lite
  - add runtime PM support.
* xilinx XADC
  - constify an iio_buffer_setup_ops structure.

8 files changed, 1664 insertions, 0 deletions

diff --git a/drivers/iio/dummy/Kconfig b/drivers/iio/dummy/Kconfig
new file mode 100644
index 000000000000..e8676aa97d62
--- /dev/null
+++ b/drivers/iio/dummy/Kconfig
@@ -0,0 +1,35 @@
+#
+# Industrial I/O subsystem Dummy Driver configuration
+#
+menu "IIO dummy driver"
+	depends on IIO
+
+config IIO_DUMMY_EVGEN
+       tristate
+
+config IIO_SIMPLE_DUMMY
+       tristate "An example driver with no hardware requirements"
+       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.
+
+config IIO_SIMPLE_DUMMY_BUFFER
+	bool "Buffered capture support"
+	select IIO_BUFFER
+	select IIO_TRIGGER
+	select IIO_KFIFO_BUF
+	help
+	  Add buffered data capture to the simple dummy driver.
+
+endif # IIO_SIMPLE_DUMMY
+
+endmenu
diff --git a/drivers/iio/dummy/Makefile b/drivers/iio/dummy/Makefile
new file mode 100644
index 000000000000..0765e93d7804
--- /dev/null
+++ b/drivers/iio/dummy/Makefile
@@ -0,0 +1,10 @@
+#
+# 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 000000000000..9e83f348df51
--- /dev/null
+++ b/drivers/iio/dummy/iio_dummy_evgen.c
@@ -0,0 +1,262 @@
+/**
+ * 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.
+ *
+ * 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_work.h>
+
+/* Fiddly bit of faking and irq without hardware */
+#define IIO_EVENTGEN_NO 10
+
+/**
+ * struct iio_dummy_handle_irq - helper struct to simulate interrupt generation
+ * @work: irq_work used to run handlers from hardirq context
+ * @irq: fake irq line number to trigger an interrupt
+ */
+struct iio_dummy_handle_irq {
+	struct irq_work work;
+	int irq;
+};
+
+/**
+ * struct iio_dummy_evgen - evgen state
+ * @chip: irq chip we are faking
+ * @base: base of irq range
+ * @enabled: mask of which irqs are enabled
+ * @inuse: mask of which irqs are connected
+ * @regs: irq regs we are faking
+ * @lock: protect the evgen state
+ * @handler: helper for a 'hardware-like' interrupt simulation
+ */
+struct iio_dummy_eventgen {
+	struct irq_chip chip;
+	int base;
+	bool enabled[IIO_EVENTGEN_NO];
+	bool inuse[IIO_EVENTGEN_NO];
+	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
+	struct mutex lock;
+	struct iio_dummy_handle_irq handler;
+};
+
+/* We can only ever have one instance of this 'device' */
+static struct iio_dummy_eventgen *iio_evgen;
+static const char *iio_evgen_name = "iio_dummy_evgen";
+
+static void iio_dummy_event_irqmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_dummy_eventgen *evgen =
+		container_of(chip, struct iio_dummy_eventgen, chip);
+
+	evgen->enabled[d->irq - evgen->base] = false;
+}
+
+static void iio_dummy_event_irqunmask(struct irq_data *d)
+{
+	struct irq_chip *chip = irq_data_get_irq_chip(d);
+	struct iio_dummy_eventgen *evgen =
+		container_of(chip, struct iio_dummy_eventgen, chip);
+
+	evgen->enabled[d->irq - evgen->base] = true;
+}
+
+static void iio_dummy_work_handler(struct irq_work *work)
+{
+	struct iio_dummy_handle_irq *irq_handler;
+
+	irq_handler = container_of(work, struct iio_dummy_handle_irq, work);
+	handle_simple_irq(irq_to_desc(irq_handler->irq));
+}
+
+static int iio_dummy_evgen_create(void)
+{
+	int ret, i;
+
+	iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
+	if (!iio_evgen)
+		return -ENOMEM;
+
+	iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
+	if (iio_evgen->base < 0) {
+		ret = iio_evgen->base;
+		kfree(iio_evgen);
+		return ret;
+	}
+	iio_evgen->chip.name = iio_evgen_name;
+	iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
+	iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
+	for (i = 0; i < IIO_EVENTGEN_NO; i++) {
+		irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
+		irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
+		irq_modify_status(iio_evgen->base + i,
+				  IRQ_NOREQUEST | IRQ_NOAUTOEN,
+				  IRQ_NOPROBE);
+	}
+	init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler);
+	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 = iio_evgen->base + 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)
+{
+	mutex_lock(&iio_evgen->lock);
+	iio_evgen->inuse[irq - iio_evgen->base] = false;
+	mutex_unlock(&iio_evgen->lock);
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
+
+struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
+{
+	return &iio_evgen->regs[irq - iio_evgen->base];
+}
+EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
+
+static void iio_dummy_evgen_free(void)
+{
+	irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
+	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;
+
+	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;
+
+	iio_evgen->handler.irq = iio_evgen->base + this_attr->address;
+	if (iio_evgen->enabled[this_attr->address])
+		irq_work_queue(&iio_evgen->handler.work);
+
+	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");
+	return device_add(&iio_evgen_dev);
+}
+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 000000000000..d044b946e74a
--- /dev/null
+++ b/drivers/iio/dummy/iio_dummy_evgen.h
@@ -0,0 +1,13 @@
+#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 000000000000..43fe4ba7d0dc
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy.c
@@ -0,0 +1,747 @@
+/**
+ * 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.
+ *
+ * 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/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+#include "iio_simple_dummy.h"
+
+/*
+ * A few elements needed to fake a bus for this driver
+ * Note instances parameter controls how many of these
+ * dummy devices are registered.
+ */
+static unsigned instances = 1;
+module_param(instances, uint, 0);
+
+/* Pointer array used to fake bus elements */
+static struct iio_dev **iio_dummy_devs;
+
+/* Fake a name for the part number, usually obtained from the id table */
+static const char *iio_dummy_part_number = "iio_dummy_part_no";
+
+/**
+ * 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 = {
+	.driver_module = THIS_MODULE,
+	.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
+ * @index: an id number for 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 int iio_dummy_probe(int index)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct iio_dummy_state *st;
+
+	/*
+	 * 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(sizeof(*st));
+	if (!indio_dev) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	st = iio_priv(indio_dev);
+	mutex_init(&st->lock);
+
+	iio_dummy_init_device(indio_dev);
+	/*
+	 * With hardware: Set the parent device.
+	 * indio_dev->dev.parent = &spi->dev;
+	 * indio_dev->dev.parent = &client->dev;
+	 */
+
+	 /*
+	 * Make the iio_dev struct available to remove function.
+	 * Bus equivalents
+	 * i2c_set_clientdata(client, indio_dev);
+	 * spi_set_drvdata(spi, indio_dev);
+	 */
+	iio_dummy_devs[index] = 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 = iio_dummy_part_number;
+
+	/* 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_device;
+
+	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;
+
+	return 0;
+error_unconfigure_buffer:
+	iio_simple_dummy_unconfigure_buffer(indio_dev);
+error_unregister_events:
+	iio_simple_dummy_events_unregister(indio_dev);
+error_free_device:
+	iio_device_free(indio_dev);
+error_ret:
+	return ret;
+}
+
+/**
+ * iio_dummy_remove() - device instance removal function
+ * @index: device index.
+ *
+ * Parameters follow those of iio_dummy_probe for buses.
+ */
+static void iio_dummy_remove(int index)
+{
+	/*
+	 * 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 = iio_dummy_devs[index];
+
+	/* 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 */
+	iio_device_free(indio_dev);
+}
+
+/**
+ * iio_dummy_init() -  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
+ * spi:
+ * Documentation/spi/spi-summary
+ */
+static __init int iio_dummy_init(void)
+{
+	int i, ret;
+
+	if (instances > 10) {
+		instances = 1;
+		return -EINVAL;
+	}
+
+	/* Fake a bus */
+	iio_dummy_devs = kcalloc(instances, sizeof(*iio_dummy_devs),
+				 GFP_KERNEL);
+	/* Here we have no actual device so call probe */
+	for (i = 0; i < instances; i++) {
+		ret = iio_dummy_probe(i);
+		if (ret < 0)
+			goto error_remove_devs;
+	}
+	return 0;
+
+error_remove_devs:
+	while (i--)
+		iio_dummy_remove(i);
+
+	kfree(iio_dummy_devs);
+	return ret;
+}
+module_init(iio_dummy_init);
+
+/**
+ * iio_dummy_exit() - device driver removal
+ *
+ * Varies depending on bus type of the device.
+ * As there is no device here, call remove directly.
+ */
+static __exit void iio_dummy_exit(void)
+{
+	int i;
+
+	for (i = 0; i < instances; i++)
+		iio_dummy_remove(i);
+	kfree(iio_dummy_devs);
+}
+module_exit(iio_dummy_exit);
+
+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 000000000000..b9069a180672
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy.h
@@ -0,0 +1,129 @@
+/**
+ * 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.
+ *
+ * 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 000000000000..cf44a6f79431
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c
@@ -0,0 +1,192 @@
+/**
+ * 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.
+ *
+ * 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/trigger_consumer.h>
+#include <linux/iio/kfifo_buf.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 len = 0;
+	u16 *data;
+
+	data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
+	if (!data)
+		goto done;
+
+	if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) {
+		/*
+		 * 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.
+		 */
+		int i, j;
+
+		for (i = 0, j = 0;
+		     i < bitmap_weight(indio_dev->active_scan_mask,
+				       indio_dev->masklength);
+		     i++, j++) {
+			j = find_next_bit(indio_dev->active_scan_mask,
+					  indio_dev->masklength, j);
+			/* random access read from the 'device' */
+			data[i] = fakedata[j];
+			len += 2;
+		}
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns());
+
+	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 = {
+	/*
+	 * iio_triggered_buffer_postenable:
+	 * Generic function that simply attaches the pollfunc to the trigger.
+	 * Replace this to mess with hardware state before we attach the
+	 * trigger.
+	 */
+	.postenable = &iio_triggered_buffer_postenable,
+	/*
+	 * iio_triggered_buffer_predisable:
+	 * Generic function that simple detaches the pollfunc from the trigger.
+	 * Replace this to put hardware state back again after the trigger is
+	 * detached but before userspace knows we have disabled the ring.
+	 */
+	.predisable = &iio_triggered_buffer_predisable,
+};
+
+int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
+{
+	int ret;
+	struct iio_buffer *buffer;
+
+	/* Allocate a buffer to use - here a kfifo */
+	buffer = iio_kfifo_allocate();
+	if (!buffer) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	iio_device_attach_buffer(indio_dev, buffer);
+
+	/* Enable timestamps by default */
+	buffer->scan_timestamp = true;
+
+	/*
+	 * Tell the core what device type specific functions should
+	 * be run on either side of buffer capture enable / disable.
+	 */
+	indio_dev->setup_ops = &iio_simple_dummy_buffer_setup_ops;
+
+	/*
+	 * Configure a polling function.
+	 * When a trigger event with this polling function connected
+	 * occurs, this function is run. Typically this grabs data
+	 * from the device.
+	 *
+	 * NULL for the bottom half. This is normally implemented only if we
+	 * either want to ping a capture now pin (no sleeping) or grab
+	 * a timestamp as close as possible to a data ready trigger firing.
+	 *
+	 * IRQF_ONESHOT ensures irqs are masked such that only one instance
+	 * of the handler can run at a time.
+	 *
+	 * "iio_simple_dummy_consumer%d" formatting string for the irq 'name'
+	 * as seen under /proc/interrupts. Remaining parameters as per printk.
+	 */
+	indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
+						 &iio_simple_dummy_trigger_h,
+						 IRQF_ONESHOT,
+						 indio_dev,
+						 "iio_simple_dummy_consumer%d",
+						 indio_dev->id);
+
+	if (!indio_dev->pollfunc) {
+		ret = -ENOMEM;
+		goto error_free_buffer;
+	}
+
+	/*
+	 * Notify the core that this device is capable of buffered capture
+	 * driven by a trigger.
+	 */
+	indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
+
+	return 0;
+
+error_free_buffer:
+	iio_kfifo_free(indio_dev->buffer);
+error_ret:
+	return ret;
+}
+
+/**
+ * iio_simple_dummy_unconfigure_buffer() - release buffer resources
+ * @indo_dev: device instance state
+ */
+void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
+{
+	iio_dealloc_pollfunc(indio_dev->pollfunc);
+	iio_kfifo_free(indio_dev->buffer);
+}
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 000000000000..bfbf1c56bd22
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy_events.c
@@ -0,0 +1,276 @@
+/**
+ * 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 <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;
+		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.
+ *
+ * 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.
+ */
+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();
+	return IRQ_HANDLED;
+}
+
+/**
+ * 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);
+}