3 files changed, 249 insertions, 0 deletions

diff --git a/drivers/iio/trigger/Kconfig b/drivers/iio/trigger/Kconfig
new file mode 100644
index 000000000000..a4e68db2f23f
--- /dev/null
+++ b/drivers/iio/trigger/Kconfig
@@ -0,0 +1,17 @@
+#
+# Industrial I/O standalone triggers
+#
+menu "Triggers - standalone"
+
+config IIO_SYSFS_TRIGGER
+	tristate "SYSFS trigger"
+	depends on SYSFS
+	select IRQ_WORK
+	help
+	  Provides support for using SYSFS entry as IIO triggers.
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called iio-trig-sysfs.
+
+endmenu
diff --git a/drivers/iio/trigger/Makefile b/drivers/iio/trigger/Makefile
new file mode 100644
index 000000000000..e0b21831072f
--- /dev/null
+++ b/drivers/iio/trigger/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for triggers not associated with iio-devices
+#
+
+obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c
new file mode 100644
index 000000000000..b727bde8b7fe
--- /dev/null
+++ b/drivers/iio/trigger/iio-trig-sysfs.c
@@ -0,0 +1,227 @@
+/*
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/irq_work.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
+
+struct iio_sysfs_trig {
+	struct iio_trigger *trig;
+	struct irq_work work;
+	int id;
+	struct list_head l;
+};
+
+static LIST_HEAD(iio_sysfs_trig_list);
+static DEFINE_MUTEX(iio_syfs_trig_list_mut);
+
+static int iio_sysfs_trigger_probe(int id);
+static ssize_t iio_sysfs_trig_add(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf,
+				  size_t len)
+{
+	int ret;
+	unsigned long input;
+
+	ret = strict_strtoul(buf, 10, &input);
+	if (ret)
+		return ret;
+	ret = iio_sysfs_trigger_probe(input);
+	if (ret)
+		return ret;
+	return len;
+}
+static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
+
+static int iio_sysfs_trigger_remove(int id);
+static ssize_t iio_sysfs_trig_remove(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf,
+				     size_t len)
+{
+	int ret;
+	unsigned long input;
+
+	ret = strict_strtoul(buf, 10, &input);
+	if (ret)
+		return ret;
+	ret = iio_sysfs_trigger_remove(input);
+	if (ret)
+		return ret;
+	return len;
+}
+
+static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
+
+static struct attribute *iio_sysfs_trig_attrs[] = {
+	&dev_attr_add_trigger.attr,
+	&dev_attr_remove_trigger.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_sysfs_trig_group = {
+	.attrs = iio_sysfs_trig_attrs,
+};
+
+static const struct attribute_group *iio_sysfs_trig_groups[] = {
+	&iio_sysfs_trig_group,
+	NULL
+};
+
+
+/* Nothing to actually do upon release */
+static void iio_trigger_sysfs_release(struct device *dev)
+{
+}
+
+static struct device iio_sysfs_trig_dev = {
+	.bus = &iio_bus_type,
+	.groups = iio_sysfs_trig_groups,
+	.release = &iio_trigger_sysfs_release,
+};
+
+static void iio_sysfs_trigger_work(struct irq_work *work)
+{
+	struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
+							work);
+
+	iio_trigger_poll(trig->trig, 0);
+}
+
+static ssize_t iio_sysfs_trigger_poll(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t count)
+{
+	struct iio_trigger *trig = to_iio_trigger(dev);
+	struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
+
+	irq_work_queue(&sysfs_trig->work);
+
+	return count;
+}
+
+static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
+
+static struct attribute *iio_sysfs_trigger_attrs[] = {
+	&dev_attr_trigger_now.attr,
+	NULL,
+};
+
+static const struct attribute_group iio_sysfs_trigger_attr_group = {
+	.attrs = iio_sysfs_trigger_attrs,
+};
+
+static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
+	&iio_sysfs_trigger_attr_group,
+	NULL
+};
+
+static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
+	.owner = THIS_MODULE,
+};
+
+static int iio_sysfs_trigger_probe(int id)
+{
+	struct iio_sysfs_trig *t;
+	int ret;
+	bool foundit = false;
+	mutex_lock(&iio_syfs_trig_list_mut);
+	list_for_each_entry(t, &iio_sysfs_trig_list, l)
+		if (id == t->id) {
+			foundit = true;
+			break;
+		}
+	if (foundit) {
+		ret = -EINVAL;
+		goto out1;
+	}
+	t = kmalloc(sizeof(*t), GFP_KERNEL);
+	if (t == NULL) {
+		ret = -ENOMEM;
+		goto out1;
+	}
+	t->id = id;
+	t->trig = iio_trigger_alloc("sysfstrig%d", id);
+	if (!t->trig) {
+		ret = -ENOMEM;
+		goto free_t;
+	}
+
+	t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
+	t->trig->ops = &iio_sysfs_trigger_ops;
+	t->trig->dev.parent = &iio_sysfs_trig_dev;
+	iio_trigger_set_drvdata(t->trig, t);
+
+	init_irq_work(&t->work, iio_sysfs_trigger_work);
+
+	ret = iio_trigger_register(t->trig);
+	if (ret)
+		goto out2;
+	list_add(&t->l, &iio_sysfs_trig_list);
+	__module_get(THIS_MODULE);
+	mutex_unlock(&iio_syfs_trig_list_mut);
+	return 0;
+
+out2:
+	iio_trigger_put(t->trig);
+free_t:
+	kfree(t);
+out1:
+	mutex_unlock(&iio_syfs_trig_list_mut);
+	return ret;
+}
+
+static int iio_sysfs_trigger_remove(int id)
+{
+	bool foundit = false;
+	struct iio_sysfs_trig *t;
+	mutex_lock(&iio_syfs_trig_list_mut);
+	list_for_each_entry(t, &iio_sysfs_trig_list, l)
+		if (id == t->id) {
+			foundit = true;
+			break;
+		}
+	if (!foundit) {
+		mutex_unlock(&iio_syfs_trig_list_mut);
+		return -EINVAL;
+	}
+
+	iio_trigger_unregister(t->trig);
+	iio_trigger_free(t->trig);
+
+	list_del(&t->l);
+	kfree(t);
+	module_put(THIS_MODULE);
+	mutex_unlock(&iio_syfs_trig_list_mut);
+	return 0;
+}
+
+
+static int __init iio_sysfs_trig_init(void)
+{
+	device_initialize(&iio_sysfs_trig_dev);
+	dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
+	return device_add(&iio_sysfs_trig_dev);
+}
+module_init(iio_sysfs_trig_init);
+
+static void __exit iio_sysfs_trig_exit(void)
+{
+	device_unregister(&iio_sysfs_trig_dev);
+}
+module_exit(iio_sysfs_trig_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:iio-trig-sysfs");