iio: Add support for creating IIO devices via configfs
This is similar with support for creating triggers via configfs.
Devices will be hosted under:
* /config/iio/devices
We allow users to register "device types" under:
* /config/iio/devices/<device_types>/
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/industrialio-sw-device.c b/drivers/iio/industrialio-sw-device.c
new file mode 100644
index 0000000..81b49cf
--- /dev/null
+++ b/drivers/iio/industrialio-sw-device.c
@@ -0,0 +1,182 @@
+/*
+ * The Industrial I/O core, software IIO devices functions
+ *
+ * Copyright (c) 2016 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_device.h>
+#include <linux/iio/configfs.h>
+#include <linux/configfs.h>
+
+static struct config_group *iio_devices_group;
+static struct config_item_type iio_device_type_group_type;
+
+static struct config_item_type iio_devices_group_type = {
+ .ct_owner = THIS_MODULE,
+};
+
+static LIST_HEAD(iio_device_types_list);
+static DEFINE_MUTEX(iio_device_types_lock);
+
+static
+struct iio_sw_device_type *__iio_find_sw_device_type(const char *name,
+ unsigned len)
+{
+ struct iio_sw_device_type *d = NULL, *iter;
+
+ list_for_each_entry(iter, &iio_device_types_list, list)
+ if (!strcmp(iter->name, name)) {
+ d = iter;
+ break;
+ }
+
+ return d;
+}
+
+int iio_register_sw_device_type(struct iio_sw_device_type *d)
+{
+ struct iio_sw_device_type *iter;
+ int ret = 0;
+
+ mutex_lock(&iio_device_types_lock);
+ iter = __iio_find_sw_device_type(d->name, strlen(d->name));
+ if (iter)
+ ret = -EBUSY;
+ else
+ list_add_tail(&d->list, &iio_device_types_list);
+ mutex_unlock(&iio_device_types_lock);
+
+ if (ret)
+ return ret;
+
+ d->group = configfs_register_default_group(iio_devices_group, d->name,
+ &iio_device_type_group_type);
+ if (IS_ERR(d->group))
+ ret = PTR_ERR(d->group);
+
+ return ret;
+}
+EXPORT_SYMBOL(iio_register_sw_device_type);
+
+void iio_unregister_sw_device_type(struct iio_sw_device_type *dt)
+{
+ struct iio_sw_device_type *iter;
+
+ mutex_lock(&iio_device_types_lock);
+ iter = __iio_find_sw_device_type(dt->name, strlen(dt->name));
+ if (iter)
+ list_del(&dt->list);
+ mutex_unlock(&iio_device_types_lock);
+
+ configfs_unregister_default_group(dt->group);
+}
+EXPORT_SYMBOL(iio_unregister_sw_device_type);
+
+static
+struct iio_sw_device_type *iio_get_sw_device_type(const char *name)
+{
+ struct iio_sw_device_type *dt;
+
+ mutex_lock(&iio_device_types_lock);
+ dt = __iio_find_sw_device_type(name, strlen(name));
+ if (dt && !try_module_get(dt->owner))
+ dt = NULL;
+ mutex_unlock(&iio_device_types_lock);
+
+ return dt;
+}
+
+struct iio_sw_device *iio_sw_device_create(const char *type, const char *name)
+{
+ struct iio_sw_device *d;
+ struct iio_sw_device_type *dt;
+
+ dt = iio_get_sw_device_type(type);
+ if (!dt) {
+ pr_err("Invalid device type: %s\n", type);
+ return ERR_PTR(-EINVAL);
+ }
+ d = dt->ops->probe(name);
+ if (IS_ERR(d))
+ goto out_module_put;
+
+ d->device_type = dt;
+
+ return d;
+out_module_put:
+ module_put(dt->owner);
+ return d;
+}
+EXPORT_SYMBOL(iio_sw_device_create);
+
+void iio_sw_device_destroy(struct iio_sw_device *d)
+{
+ struct iio_sw_device_type *dt = d->device_type;
+
+ dt->ops->remove(d);
+ module_put(dt->owner);
+}
+EXPORT_SYMBOL(iio_sw_device_destroy);
+
+static struct config_group *device_make_group(struct config_group *group,
+ const char *name)
+{
+ struct iio_sw_device *d;
+
+ d = iio_sw_device_create(group->cg_item.ci_name, name);
+ if (IS_ERR(d))
+ return ERR_CAST(d);
+
+ config_item_set_name(&d->group.cg_item, "%s", name);
+
+ return &d->group;
+}
+
+static void device_drop_group(struct config_group *group,
+ struct config_item *item)
+{
+ struct iio_sw_device *d = to_iio_sw_device(item);
+
+ iio_sw_device_destroy(d);
+ config_item_put(item);
+}
+
+static struct configfs_group_operations device_ops = {
+ .make_group = &device_make_group,
+ .drop_item = &device_drop_group,
+};
+
+static struct config_item_type iio_device_type_group_type = {
+ .ct_group_ops = &device_ops,
+ .ct_owner = THIS_MODULE,
+};
+
+static int __init iio_sw_device_init(void)
+{
+ iio_devices_group =
+ configfs_register_default_group(&iio_configfs_subsys.su_group,
+ "devices",
+ &iio_devices_group_type);
+ return PTR_ERR_OR_ZERO(iio_devices_group);
+}
+module_init(iio_sw_device_init);
+
+static void __exit iio_sw_device_exit(void)
+{
+ configfs_unregister_default_group(iio_devices_group);
+}
+module_exit(iio_sw_device_exit);
+
+MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
+MODULE_DESCRIPTION("Industrial I/O software devices support");
+MODULE_LICENSE("GPL v2");