Re: [PATCH v7 3/5] iio: core: Introduce IIO software triggers

[Vladimir Barinov <vladimir.barinov@cogentembedded.com>]

Hi Daniel,

Minor comments since I need your hrtimer trigger support.

1) The drivers/iio/industrialio-sw-trigger.c should probably
come to drivers/iio/trigger/ folder which is under ifdef condition
in drivers/iio/Kconfig

2) it breaks compilation
enabling IIO_HRTIMER_TRIGGER selects IIO_SW_TRIGGER.
But IIO_SW_TRIGGER fail to compile without IIO_CONFIGFS

3) Probably the IIO_SW_TRIGGER should be tristate like other
standalone triggers

I will report test results when I try hrtimer trigger.

Regards,
Vladimir

On 11.08.2015 01:42, Daniel Baluta wrote:
> 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-configfs.c   |  49 ++++++++++++++
>   drivers/iio/industrialio-sw-trigger.c | 119 ++++++++++++++++++++++++++++++++++
>   include/linux/iio/sw_trigger.h        |  99 ++++++++++++++++++++++++++++
>   5 files changed, 276 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 f2b0d77..117c05a 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -66,6 +66,14 @@ 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 dbf5f9a..31aead3 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-configfs.c b/drivers/iio/industrialio-configfs.c
> index 3edee90..ced7115 100644
> --- a/drivers/iio/industrialio-configfs.c
> +++ b/drivers/iio/industrialio-configfs.c
> @@ -15,6 +15,40 @@
>   #include <linux/slab.h>
>   
>   #include <linux/iio/iio.h>
> +#include <linux/iio/sw_trigger.h>
> +
> +static struct config_group *trigger_make_group(struct config_group *group,
> +					       const char *name)
> +{
> +	struct iio_sw_trigger *t;
> +
> +	t = iio_sw_trigger_create(group->cg_item.ci_name, name);
> +	if (IS_ERR(t))
> +		return ERR_CAST(t);
> +
> +	config_item_set_name(&t->group.cg_item, name);
> +
> +	return &t->group;
> +}
> +
> +static void trigger_drop_group(struct config_group *group,
> +			       struct config_item *item)
> +{
> +	struct iio_sw_trigger *t = to_iio_sw_trigger(item);
> +
> +	iio_sw_trigger_destroy(t);
> +	config_item_put(item);
> +}
> +
> +static struct configfs_group_operations trigger_ops = {
> +	.make_group	= &trigger_make_group,
> +	.drop_item	= &trigger_drop_group,
> +};
> +
> +static struct config_item_type iio_trigger_type_group_type = {
> +	.ct_group_ops = &trigger_ops,
> +	.ct_owner       = THIS_MODULE,
> +};
>   
>   static struct config_item_type iio_triggers_group_type = {
>   	.ct_owner = THIS_MODULE,
> @@ -47,6 +81,21 @@ static struct configfs_subsystem iio_configfs_subsys = {
>   	.su_mutex = __MUTEX_INITIALIZER(iio_configfs_subsys.su_mutex),
>   };
>   
> +int iio_sw_trigger_type_configfs_register(struct iio_sw_trigger_type *tt)
> +{
> +	config_group_init_type_name(&tt->group, tt->name,
> +		&iio_trigger_type_group_type);
> +
> +	return configfs_register_group(&iio_triggers_group, &tt->group);
> +}
> +EXPORT_SYMBOL_GPL(iio_sw_trigger_type_configfs_register);
> +
> +void iio_sw_trigger_type_configfs_unregister(struct iio_sw_trigger_type *tt)
> +{
> +	configfs_unregister_group(&tt->group);
> +}
> +EXPORT_SYMBOL_GPL(iio_sw_trigger_type_configfs_unregister);
> +
>   static int __init iio_configfs_init(void)
>   {
>   	config_group_init(&iio_triggers_group);
> diff --git a/drivers/iio/industrialio-sw-trigger.c b/drivers/iio/industrialio-sw-trigger.c
> new file mode 100644
> index 0000000..761418e
> --- /dev/null
> +++ b/drivers/iio/industrialio-sw-trigger.c
> @@ -0,0 +1,119 @@
> +/*
> + * 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_MUTEX(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;
> +
> +	mutex_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);
> +		iio_sw_trigger_type_configfs_register(t);
> +	}
> +	mutex_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;
> +
> +	mutex_lock(&iio_trigger_types_lock);
> +	iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
> +	if (!iter) {
> +		ret = -EINVAL;
> +	} else {
> +		iio_sw_trigger_type_configfs_unregister(t);
> +		list_del(&t->list);
> +	}
> +	mutex_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;
> +
> +	mutex_lock(&iio_trigger_types_lock);
> +	t = __iio_find_sw_trigger_type(name, strlen(name));
> +	if (t && !try_module_get(t->owner))
> +		t = NULL;
> +	mutex_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..762a3b7
> --- /dev/null
> +++ b/include/linux/iio/sw_trigger.h
> @@ -0,0 +1,99 @@
> +/*
> + * 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>
> +#include <linux/configfs.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 config_group group;
> +};
> +
> +struct iio_sw_trigger {
> +	struct iio_trigger *trigger;
> +	struct iio_sw_trigger_type *trigger_type;
> +	struct config_group group;
> +};
> +
> +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 *);
> +
> +static inline
> +struct iio_sw_trigger *to_iio_sw_trigger(struct config_item *item)
> +{
> +	return container_of(to_config_group(item), struct iio_sw_trigger,
> +			    group);
> +}
> +
> +#ifdef CONFIG_CONFIGFS_FS
> +int iio_sw_trigger_type_configfs_register(struct iio_sw_trigger_type *tt);
> +void iio_sw_trigger_type_configfs_unregister(struct iio_sw_trigger_type *tt);
> +
> +static inline
> +void iio_swt_group_init_type_name(struct iio_sw_trigger *t,
> +				  const char *name,
> +				  struct config_item_type *type)
> +{
> +	config_group_init_type_name(&t->group, name, type);
> +}
> +#else
> +static inline
> +int iio_sw_trigger_type_configfs_register(struct iio_sw_trigger_type *tt)
> +{
> +       return 0;
> +}
> +
> +static inline
> +void iio_sw_trigger_type_configfs_unregister(struct iio_sw_trigger_type *tt)
> +{ }
> +
> +static inline
> +void iio_swt_group_init_type_name(struct iio_sw_trigger *t,
> +				  const char *name,
> +				  struct config_item_type *type)
> +{ }
> +#endif
> +
> +#endif /* __IIO_SW_TRIGGER */