[PATCH v6 1/4] iio: core: Introduce IIO software triggers

Daniel Baluta
2015-05-08T13:33:42Z

A software trigger associates an IIO device trigger with a software
interrupt source (e.g: timer, sysfs). This patch adds the generic
infrastructure for handling software triggers.

Software interrupts sources are kept in a iio_trigger_types_list and
registered separately when the associated kernel module is loaded.

Software triggers can be created directly from drivers or from user
space via configfs interface.

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
---
drivers/iio/Kconfig | 8 +++
drivers/iio/Makefile | 1 +
drivers/iio/industrialio-sw-trigger.c | 115 ++++++++++++++++++++++++++++++++++
include/linux/iio/sw_trigger.h | 58 +++++++++++++++++
4 files changed, 182 insertions(+)
create mode 100644 drivers/iio/industrialio-sw-trigger.c
create mode 100644 include/linux/iio/sw_trigger.h

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 4011eff..de7f1d9 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -58,6 +58,14 @@ config IIO_CONSUMERS_PER_TRIGGER
This value controls the maximum number of consumers that a
given trigger may handle. Default is 2.

+config IIO_SW_TRIGGER
+ bool "Enable software triggers support"
+ depends on IIO_TRIGGER
+ help
+ Provides IIO core support for software triggers. A software
+ trigger can be created via configfs or directly by a driver
+ using the API provided.
+
source "drivers/iio/accel/Kconfig"
source "drivers/iio/adc/Kconfig"
source "drivers/iio/amplifiers/Kconfig"
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 698afc2..df87975 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_IIO) += industrialio.o
industrialio-y := industrialio-core.o industrialio-event.o inkern.o
industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
+industrialio-$(CONFIG_IIO_SW_TRIGGER) += industrialio-sw-trigger.o
industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o

obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
diff --git a/drivers/iio/industrialio-sw-trigger.c b/drivers/iio/industrialio-sw-trigger.c
new file mode 100644
index 0000000..fa1ec51
--- /dev/null
+++ b/drivers/iio/industrialio-sw-trigger.c
@@ -0,0 +1,115 @@
+/*
+ * The Industrial I/O core, software trigger functions
+ *
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * 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.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <linux/iio/sw_trigger.h>
+
+static LIST_HEAD(iio_trigger_types_list);
+static DEFINE_RWLOCK(iio_trigger_types_lock);
+
+static
+struct iio_sw_trigger_type *__iio_find_sw_trigger_type(const char *name,
+ unsigned len)
+{
+ struct iio_sw_trigger_type *t = NULL, *iter;
+
+ list_for_each_entry(iter, &iio_trigger_types_list, list)
+ if (!strncmp(iter->name, name, len)) {
+ t = iter;
+ break;
+ }
+
+ return t;
+}
+
+int iio_register_sw_trigger_type(struct iio_sw_trigger_type *t)
+{
+ struct iio_sw_trigger_type *iter;
+ int ret = 0;
+
+ write_lock(&iio_trigger_types_lock);
+ iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
+ if (iter)
+ ret = -EBUSY;
+ else
+ list_add_tail(&t->list, &iio_trigger_types_list);
+ write_unlock(&iio_trigger_types_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(iio_register_sw_trigger_type);
+
+int iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t)
+{
+ struct iio_sw_trigger_type *iter;
+ int ret = 0;
+
+ write_lock(&iio_trigger_types_lock);
+ iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
+ if (!iter)
+ ret = -EINVAL;
+ else
+ list_del(&t->list);
+ write_unlock(&iio_trigger_types_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL(iio_unregister_sw_trigger_type);
+
+static
+struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name)
+{
+ struct iio_sw_trigger_type *t;
+
+ read_lock(&iio_trigger_types_lock);
+ t = __iio_find_sw_trigger_type(name, strlen(name));
+ if (t && !try_module_get(t->owner))
+ t = NULL;
+ read_unlock(&iio_trigger_types_lock);
+
+ return t;
+}
+
+struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name)
+{
+ struct iio_sw_trigger *t;
+ struct iio_sw_trigger_type *tt;
+
+ tt = iio_get_sw_trigger_type(type);
+ if (!tt) {
+ pr_err("Invalid trigger type: %s\n", type);
+ return ERR_PTR(-EINVAL);
+ }
+ t = tt->ops->probe(name);
+ if (IS_ERR(t))
+ goto out_module_put;
+
+ t->trigger_type = tt;
+
+ return t;
+out_module_put:
+ module_put(tt->owner);
+ return t;
+}
+EXPORT_SYMBOL(iio_sw_trigger_create);
+
+void iio_sw_trigger_destroy(struct iio_sw_trigger *t)
+{
+ struct iio_sw_trigger_type *tt = t->trigger_type;
+
+ tt->ops->remove(t);
+ module_put(tt->owner);
+}
+EXPORT_SYMBOL(iio_sw_trigger_destroy);
diff --git a/include/linux/iio/sw_trigger.h b/include/linux/iio/sw_trigger.h
new file mode 100644
index 0000000..2771a25
--- /dev/null
+++ b/include/linux/iio/sw_trigger.h
@@ -0,0 +1,58 @@
+/*
+ * Industrial I/O software trigger interface
+ *
+ * Copyright (c) 2015 Intel Corporation
+ *
+ * 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.
+ */
+
+#ifndef __IIO_SW_TRIGGER
+#define __IIO_SW_TRIGGER
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/iio/iio.h>
+
+#define module_iio_sw_trigger_driver(__iio_sw_trigger_type) \
+ module_driver(__iio_sw_trigger_type, iio_register_sw_trigger_type, \
+ iio_unregister_sw_trigger_type)
+
+struct iio_sw_trigger_ops;
+
+struct iio_sw_trigger_type {
+ const char *name;
+ struct module *owner;
+ const struct iio_sw_trigger_ops *ops;
+ struct list_head list;
+};
+
+struct iio_sw_trigger {
+ struct iio_trigger *trigger;
+ struct iio_sw_trigger_type *trigger_type;
+};
+
+struct iio_sw_trigger_ops {
+ struct iio_sw_trigger* (*probe)(const char *);
+ int (*remove)(struct iio_sw_trigger *);
+};
+
+/**
+ * iio_register_sw_trigger_type() - register a software trigger type
+ *
+ * @tt: software trigger type to be registered
+ */
+int iio_register_sw_trigger_type(struct iio_sw_trigger_type *tt);
+
+/**
+ * iio_unregister_sw_trigger_type() - unregister a software trigger type
+ *
+ * @tt: software trigger type to be unregistered
+ */
+int iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *tt);
+
+struct iio_sw_trigger *iio_sw_trigger_create(const char *, const char *);
+void iio_sw_trigger_destroy(struct iio_sw_trigger *);
+
+#endif /* __IIO_SW_TRIGGER */
--
1.9.1