iio: Support triggered events

Support triggered events.

This is useful for chips that don't have their own interrupt sources.
It allows to use generic/standalone iio triggers for those drivers.

Signed-off-by: Vladimir Barinov <vladimir.barinov@cogentembedded.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/Kconfig

@@ -38,6 +38,12 @@ config IIO_CONSUMERS_PER_TRIGGER
 	This value controls the maximum number of consumers that a
 	given trigger may handle. Default is 2.
 
+config IIO_TRIGGERED_EVENT
+	tristate
+	select IIO_TRIGGER
+	help
+	  Provides helper functions for setting up triggered events.
+
 source "drivers/iio/accel/Kconfig"
 source "drivers/iio/adc/Kconfig"
 source "drivers/iio/amplifiers/Kconfig"

drivers/iio/Makefile

@@ -7,6 +7,8 @@ industrialio-y := industrialio-core.o industrialio-event.o inkern.o
 industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
 industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
 
+obj-$(CONFIG_IIO_TRIGGERED_EVENT) += industrialio-triggered-event.o
+
 obj-y += accel/
 obj-y += adc/
 obj-y += amplifiers/

drivers/iio/industrialio-core.c

@@ -962,7 +962,7 @@ static void iio_device_unregister_sysfs(struct iio_dev *indio_dev)
 static void iio_dev_release(struct device *device)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(device);
-	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
 		iio_device_unregister_trigger_consumer(indio_dev);
 	iio_device_unregister_eventset(indio_dev);
 	iio_device_unregister_sysfs(indio_dev);
@@ -1243,7 +1243,7 @@ int iio_device_register(struct iio_dev *indio_dev)
 			"Failed to register event set\n");
 		goto error_free_sysfs;
 	}
-	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
+	if (indio_dev->modes & (INDIO_BUFFER_TRIGGERED | INDIO_EVENT_TRIGGERED))
 		iio_device_register_trigger_consumer(indio_dev);
 
 	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&

drivers/iio/industrialio-trigger.c

@@ -366,10 +366,18 @@ static ssize_t iio_trigger_write_current(struct device *dev,
 
 	indio_dev->trig = trig;
 
-	if (oldtrig)
+	if (oldtrig) {
+		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
+			iio_trigger_detach_poll_func(oldtrig,
+						     indio_dev->pollfunc_event);
 		iio_trigger_put(oldtrig);
-	if (indio_dev->trig)
+	}
+	if (indio_dev->trig) {
 		iio_trigger_get(indio_dev->trig);
+		if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
+			iio_trigger_attach_poll_func(indio_dev->trig,
+						     indio_dev->pollfunc_event);
+	}
 
 	return len;
 }

drivers/iio/industrialio-triggered-event.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2015 Cogent Embedded, Inc.
+ *
+ * This program is free software; you can redistribute  it and/or modify it
+ * under  the terms of  the GNU General  Public License as published by the
+ * Free Software Foundation;  either version 2 of the  License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/module.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/triggered_event.h>
+#include <linux/iio/trigger_consumer.h>
+
+/**
+ * iio_triggered_event_setup() - Setup pollfunc_event for triggered event
+ * @indio_dev:	IIO device structure
+ * @h:		Function which will be used as pollfunc_event top half
+ * @thread:	Function which will be used as pollfunc_event bottom half
+ *
+ * This function combines some common tasks which will normally be performed
+ * when setting up a triggered event. It will allocate the pollfunc_event and
+ * set mode to use it for triggered event.
+ *
+ * Before calling this function the indio_dev structure should already be
+ * completely initialized, but not yet registered. In practice this means that
+ * this function should be called right before iio_device_register().
+ *
+ * To free the resources allocated by this function call
+ * iio_triggered_event_cleanup().
+ */
+int iio_triggered_event_setup(struct iio_dev *indio_dev,
+			      irqreturn_t (*h)(int irq, void *p),
+			      irqreturn_t (*thread)(int irq, void *p))
+{
+	indio_dev->pollfunc_event = iio_alloc_pollfunc(h,
+						       thread,
+						       IRQF_ONESHOT,
+						       indio_dev,
+						       "%s_consumer%d",
+						       indio_dev->name,
+						       indio_dev->id);
+	if (indio_dev->pollfunc_event == NULL)
+		return -ENOMEM;
+
+	/* Flag that events polling is possible */
+	indio_dev->modes |= INDIO_EVENT_TRIGGERED;
+
+	return 0;
+}
+EXPORT_SYMBOL(iio_triggered_event_setup);
+
+/**
+ * iio_triggered_event_cleanup() - Free resources allocated by iio_triggered_event_setup()
+ * @indio_dev: IIO device structure
+ */
+void iio_triggered_event_cleanup(struct iio_dev *indio_dev)
+{
+	indio_dev->modes &= ~INDIO_EVENT_TRIGGERED;
+	iio_dealloc_pollfunc(indio_dev->pollfunc_event);
+}
+EXPORT_SYMBOL(iio_triggered_event_cleanup);
+
+MODULE_AUTHOR("Vladimir Barinov");
+MODULE_DESCRIPTION("IIO helper functions for setting up triggered events");
+MODULE_LICENSE("GPL");

include/linux/iio/iio.h

@@ -294,6 +294,7 @@ static inline s64 iio_get_time_ns(void)
 #define INDIO_BUFFER_TRIGGERED		0x02
 #define INDIO_BUFFER_SOFTWARE		0x04
 #define INDIO_BUFFER_HARDWARE		0x08
+#define INDIO_EVENT_TRIGGERED		0x10
 
 #define INDIO_ALL_BUFFER_MODES					\
 	(INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE | INDIO_BUFFER_SOFTWARE)
@@ -457,6 +458,7 @@ struct iio_buffer_setup_ops {
  * @scan_index_timestamp:[INTERN] cache of the index to the timestamp
  * @trig:		[INTERN] current device trigger (buffer modes)
  * @pollfunc:		[DRIVER] function run on trigger being received
+ * @pollfunc_event:	[DRIVER] function run on events trigger being received
  * @channels:		[DRIVER] channel specification structure table
  * @num_channels:	[DRIVER] number of channels specified in @channels.
  * @channel_attr_list:	[INTERN] keep track of automatically created channel
@@ -495,6 +497,7 @@ struct iio_dev {
 	unsigned			scan_index_timestamp;
 	struct iio_trigger		*trig;
 	struct iio_poll_func		*pollfunc;
+	struct iio_poll_func		*pollfunc_event;
 
 	struct iio_chan_spec const	*channels;
 	int				num_channels;

include/linux/iio/triggered_event.h

@@ -0,0 +1,11 @@
+#ifndef _LINUX_IIO_TRIGGERED_EVENT_H_
+#define _LINUX_IIO_TRIGGERED_EVENT_H_
+
+#include <linux/interrupt.h>
+
+int iio_triggered_event_setup(struct iio_dev *indio_dev,
+	irqreturn_t (*h)(int irq, void *p),
+	irqreturn_t (*thread)(int irq, void *p));
+void iio_triggered_event_cleanup(struct iio_dev *indio_dev);
+
+#endif