[PATCH v7 2/5] iio: core: Introduce IIO configfs support

[Daniel Baluta <daniel.baluta@intel.com>]

This creates an IIO configfs subystem named "iio", with a default "triggers"
group. Next patches will add trigger types support, allowing new triggers
creation using configfs.

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
---
 drivers/iio/Kconfig                 |  8 +++++
 drivers/iio/Makefile                |  1 +
 drivers/iio/industrialio-configfs.c | 67 +++++++++++++++++++++++++++++++++++++
 3 files changed, 76 insertions(+)
 create mode 100644 drivers/iio/industrialio-configfs.c

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 4011eff..f2b0d77 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -18,6 +18,14 @@ config IIO_BUFFER
 	  Provide core support for various buffer based data
 	  acquisition methods.
 
+config IIO_CONFIGFS
+	bool "Enable IIO configuration via configfs"
+	select CONFIGFS_FS
+	help
+	  This allows configuring various IIO bits through configfs
+	  (e.g. software triggers). For more info see
+	  Documentation/iio/iio_configfs.txt.
+
 if IIO_BUFFER
 
 config IIO_BUFFER_CB
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index 698afc2..dbf5f9a 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -9,6 +9,7 @@ industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
 industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o
 
 obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
+obj-$(CONFIG_IIO_CONFIGFS) += industrialio-configfs.o
 obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
 
 obj-y += accel/
diff --git a/drivers/iio/industrialio-configfs.c b/drivers/iio/industrialio-configfs.c
new file mode 100644
index 0000000..3edee90
--- /dev/null
+++ b/drivers/iio/industrialio-configfs.c
@@ -0,0 +1,67 @@
+/*
+ * Industrial I/O configfs bits
+ *
+ * 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/configfs.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/slab.h>
+
+#include <linux/iio/iio.h>
+
+static struct config_item_type iio_triggers_group_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+static struct config_group iio_triggers_group = {
+	.cg_item = {
+		.ci_namebuf = "triggers",
+		.ci_type = &iio_triggers_group_type,
+	},
+};
+
+static struct config_group *iio_root_default_groups[] = {
+	&iio_triggers_group,
+	NULL
+};
+
+static struct config_item_type iio_root_group_type = {
+	.ct_owner       = THIS_MODULE,
+};
+
+static struct configfs_subsystem iio_configfs_subsys = {
+	.su_group = {
+		.cg_item = {
+			.ci_namebuf = "iio",
+			.ci_type = &iio_root_group_type,
+		},
+		.default_groups = iio_root_default_groups,
+	},
+	.su_mutex = __MUTEX_INITIALIZER(iio_configfs_subsys.su_mutex),
+};
+
+static int __init iio_configfs_init(void)
+{
+	config_group_init(&iio_triggers_group);
+	config_group_init(&iio_configfs_subsys.su_group);
+
+	return configfs_register_subsystem(&iio_configfs_subsys);
+}
+module_init(iio_configfs_init);
+
+static void __exit iio_configfs_exit(void)
+{
+	configfs_unregister_subsystem(&iio_configfs_subsys);
+}
+module_exit(iio_configfs_exit);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("Industrial I/O configfs support");
+MODULE_LICENSE("GPL v2");
-- 
2.1.4