industrialio-trigger.c
// SPDX-License-Identifier: GPL-2.0-only
/* The industrial I/O core, trigger handling functions
*
* Copyright (c) 2008 Jonathan Cameron
*/
#include <linux/kernel.h>
#include <linux/idr.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/iio/iio.h>
#include <linux/iio/iio-opaque.h>
#include <linux/iio/trigger.h>
#include "iio_core.h"
#include "iio_core_trigger.h"
#include <linux/iio/trigger_consumer.h>
/* RFC - Question of approach
* Make the common case (single sensor single trigger)
* simple by starting trigger capture from when first sensors
* is added.
*
* Complex simultaneous start requires use of 'hold' functionality
* of the trigger. (not implemented)
*
* Any other suggestions?
*/
static DEFINE_IDA(iio_trigger_ida);
/* Single list of all available triggers */
static LIST_HEAD(iio_trigger_list);
static DEFINE_MUTEX(iio_trigger_list_lock);
/**
* iio_trigger_read_name() - retrieve useful identifying name
* @dev: device associated with the iio_trigger
* @attr: pointer to the device_attribute structure that is
* being processed
* @buf: buffer to print the name into
*
* Return: a negative number on failure or the number of written
* characters on success.
*/
static ssize_t iio_trigger_read_name(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
return sysfs_emit(buf, "%s\n", trig->name);
}
static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
static struct attribute *iio_trig_dev_attrs[] = {
&dev_attr_name.attr,
NULL,
};
ATTRIBUTE_GROUPS(iio_trig_dev);
static struct iio_trigger *__iio_trigger_find_by_name(const char *name);
int __iio_trigger_register(struct iio_trigger *trig_info,
struct module *this_mod)
{
int ret;
trig_info->owner = this_mod;
trig_info->id = ida_simple_get(&iio_trigger_ida, 0, 0, GFP_KERNEL);
if (trig_info->id < 0)
return trig_info->id;
/* Set the name used for the sysfs directory etc */
dev_set_name(&trig_info->dev, "trigger%d", trig_info->id);
ret = device_add(&trig_info->dev);
if (ret)
goto error_unregister_id;
/* Add to list of available triggers held by the IIO core */
mutex_lock(&iio_trigger_list_lock);
if (__iio_trigger_find_by_name(trig_info->name)) {
pr_err("Duplicate trigger name '%s'\n", trig_info->name);
ret = -EEXIST;
goto error_device_del;
}
list_add_tail(&trig_info->list, &iio_trigger_list);
mutex_unlock(&iio_trigger_list_lock);
return 0;
error_device_del:
mutex_unlock(&iio_trigger_list_lock);
device_del(&trig_info->dev);
error_unregister_id:
ida_simple_remove(&iio_trigger_ida, trig_info->id);
return ret;
}
EXPORT_SYMBOL(__iio_trigger_register);
void iio_trigger_unregister(struct iio_trigger *trig_info)
{
mutex_lock(&iio_trigger_list_lock);
list_del(&trig_info->list);
mutex_unlock(&iio_trigger_list_lock);
ida_simple_remove(&iio_trigger_ida, trig_info->id);
/* Possible issue in here */
device_del(&trig_info->dev);
}
EXPORT_SYMBOL(iio_trigger_unregister);
int iio_trigger_set_immutable(struct iio_dev *indio_dev, struct iio_trigger *trig)
{
struct iio_dev_opaque *iio_dev_opaque;
if (!indio_dev || !trig)
return -EINVAL;
iio_dev_opaque = to_iio_dev_opaque(indio_dev);
mutex_lock(&indio_dev->mlock);
WARN_ON(iio_dev_opaque->trig_readonly);
indio_dev->trig = iio_trigger_get(trig);
iio_dev_opaque->trig_readonly = true;
mutex_unlock(&indio_dev->mlock);
return 0;
}
EXPORT_SYMBOL(iio_trigger_set_immutable);
/* Search for trigger by name, assuming iio_trigger_list_lock held */
static struct iio_trigger *__iio_trigger_find_by_name(const char *name)
{
struct iio_trigger *iter;
list_for_each_entry(iter, &iio_trigger_list, list)
if (!strcmp(iter->name, name))
return iter;
return NULL;
}
static struct iio_trigger *iio_trigger_acquire_by_name(const char *name)
{
struct iio_trigger *trig = NULL, *iter;
mutex_lock(&iio_trigger_list_lock);
list_for_each_entry(iter, &iio_trigger_list, list)
if (sysfs_streq(iter->name, name)) {
trig = iter;
iio_trigger_get(trig);
break;
}
mutex_unlock(&iio_trigger_list_lock);
return trig;
}
static void iio_reenable_work_fn(struct work_struct *work)
{
struct iio_trigger *trig = container_of(work, struct iio_trigger,
reenable_work);
/*
* This 'might' occur after the trigger state is set to disabled -
* in that case the driver should skip reenabling.
*/
trig->ops->reenable(trig);
}
/*
* In general, reenable callbacks may need to sleep and this path is
* not performance sensitive, so just queue up a work item
* to reneable the trigger for us.
*
* Races that can cause this.
* 1) A handler occurs entirely in interrupt context so the counter
* the final decrement is still in this interrupt.
* 2) The trigger has been removed, but one last interrupt gets through.
*
* For (1) we must call reenable, but not in atomic context.
* For (2) it should be safe to call reenanble, if drivers never blindly
* reenable after state is off.
*/
static void iio_trigger_notify_done_atomic(struct iio_trigger *trig)
{
if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
trig->ops->reenable)
schedule_work(&trig->reenable_work);
}
void iio_trigger_poll(struct iio_trigger *trig)
{
int i;
if (!atomic_read(&trig->use_count)) {
atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
if (trig->subirqs[i].enabled)
generic_handle_irq(trig->subirq_base + i);
else
iio_trigger_notify_done_atomic(trig);
}
}
}
EXPORT_SYMBOL(iio_trigger_poll);
irqreturn_t iio_trigger_generic_data_rdy_poll(int irq, void *private)
{
iio_trigger_poll(private);
return IRQ_HANDLED;
}
EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
void iio_trigger_poll_chained(struct iio_trigger *trig)
{
int i;
if (!atomic_read(&trig->use_count)) {
atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
if (trig->subirqs[i].enabled)
handle_nested_irq(trig->subirq_base + i);
else
iio_trigger_notify_done(trig);
}
}
}
EXPORT_SYMBOL(iio_trigger_poll_chained);
void iio_trigger_notify_done(struct iio_trigger *trig)
{
if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
trig->ops->reenable)
trig->ops->reenable(trig);
}
EXPORT_SYMBOL(iio_trigger_notify_done);
/* Trigger Consumer related functions */
static int iio_trigger_get_irq(struct iio_trigger *trig)
{
int ret;
mutex_lock(&trig->pool_lock);
ret = bitmap_find_free_region(trig->pool,
CONFIG_IIO_CONSUMERS_PER_TRIGGER,
ilog2(1));
mutex_unlock(&trig->pool_lock);
if (ret >= 0)
ret += trig->subirq_base;
return ret;
}
static void iio_trigger_put_irq(struct iio_trigger *trig, int irq)
{
mutex_lock(&trig->pool_lock);
clear_bit(irq - trig->subirq_base, trig->pool);
mutex_unlock(&trig->pool_lock);
}
/* Complexity in here. With certain triggers (datardy) an acknowledgement
* may be needed if the pollfuncs do not include the data read for the
* triggering device.
* This is not currently handled. Alternative of not enabling trigger unless
* the relevant function is in there may be the best option.
*/
/* Worth protecting against double additions? */
int iio_trigger_attach_poll_func(struct iio_trigger *trig,
struct iio_poll_func *pf)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
bool notinuse =
bitmap_empty(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
int ret = 0;
/* Prevent the module from being removed whilst attached to a trigger */
__module_get(iio_dev_opaque->driver_module);
/* Get irq number */
pf->irq = iio_trigger_get_irq(trig);
if (pf->irq < 0) {
pr_err("Could not find an available irq for trigger %s, CONFIG_IIO_CONSUMERS_PER_TRIGGER=%d limit might be exceeded\n",
trig->name, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
goto out_put_module;
}
/* Request irq */
ret = request_threaded_irq(pf->irq, pf->h, pf->thread,
pf->type, pf->name,
pf);
if (ret < 0)
goto out_put_irq;
/* Enable trigger in driver */
if (trig->ops && trig->ops->set_trigger_state && notinuse) {
ret = trig->ops->set_trigger_state(trig, true);
if (ret < 0)
goto out_free_irq;
}
/*
* Check if we just registered to our own trigger: we determine that
* this is the case if the IIO device and the trigger device share the
* same parent device.
*/
if (pf->indio_dev->dev.parent == trig->dev.parent)
trig->attached_own_device = true;
return ret;
out_free_irq:
free_irq(pf->irq, pf);
out_put_irq:
iio_trigger_put_irq(trig, pf->irq);
out_put_module:
module_put(iio_dev_opaque->driver_module);
return ret;
}
int iio_trigger_detach_poll_func(struct iio_trigger *trig,
struct iio_poll_func *pf)
{
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(pf->indio_dev);
bool no_other_users =
bitmap_weight(trig->pool, CONFIG_IIO_CONSUMERS_PER_TRIGGER) == 1;
int ret = 0;
if (trig->ops && trig->ops->set_trigger_state && no_other_users) {
ret = trig->ops->set_trigger_state(trig, false);
if (ret)
return ret;
}
if (pf->indio_dev->dev.parent == trig->dev.parent)
trig->attached_own_device = false;
iio_trigger_put_irq(trig, pf->irq);
free_irq(pf->irq, pf);
module_put(iio_dev_opaque->driver_module);
return ret;
}
irqreturn_t iio_pollfunc_store_time(int irq, void *p)
{
struct iio_poll_func *pf = p;
pf->timestamp = iio_get_time_ns(pf->indio_dev);
return IRQ_WAKE_THREAD;
}
EXPORT_SYMBOL(iio_pollfunc_store_time);
struct iio_poll_func
*iio_alloc_pollfunc(irqreturn_t (*h)(int irq, void *p),
irqreturn_t (*thread)(int irq, void *p),
int type,
struct iio_dev *indio_dev,
const char *fmt,
...)
{
va_list vargs;
struct iio_poll_func *pf;
pf = kmalloc(sizeof *pf, GFP_KERNEL);
if (pf == NULL)
return NULL;
va_start(vargs, fmt);
pf->name = kvasprintf(GFP_KERNEL, fmt, vargs);
va_end(vargs);
if (pf->name == NULL) {
kfree(pf);
return NULL;
}
pf->h = h;
pf->thread = thread;
pf->type = type;
pf->indio_dev = indio_dev;
return pf;
}
EXPORT_SYMBOL_GPL(iio_alloc_pollfunc);
void iio_dealloc_pollfunc(struct iio_poll_func *pf)
{
kfree(pf->name);
kfree(pf);
}
EXPORT_SYMBOL_GPL(iio_dealloc_pollfunc);
/**
* iio_trigger_read_current() - trigger consumer sysfs query current trigger
* @dev: device associated with an industrial I/O device
* @attr: pointer to the device_attribute structure that
* is being processed
* @buf: buffer where the current trigger name will be printed into
*
* For trigger consumers the current_trigger interface allows the trigger
* used by the device to be queried.
*
* Return: a negative number on failure, the number of characters written
* on success or 0 if no trigger is available
*/
static ssize_t iio_trigger_read_current(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
if (indio_dev->trig)
return sysfs_emit(buf, "%s\n", indio_dev->trig->name);
return 0;
}
/**
* iio_trigger_write_current() - trigger consumer sysfs set current trigger
* @dev: device associated with an industrial I/O device
* @attr: device attribute that is being processed
* @buf: string buffer that holds the name of the trigger
* @len: length of the trigger name held by buf
*
* For trigger consumers the current_trigger interface allows the trigger
* used for this device to be specified at run time based on the trigger's
* name.
*
* Return: negative error code on failure or length of the buffer
* on success
*/
static ssize_t iio_trigger_write_current(struct device *dev,
struct device_attribute *attr,
const char *buf,
size_t len)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
struct iio_trigger *oldtrig = indio_dev->trig;
struct iio_trigger *trig;
int ret;
mutex_lock(&indio_dev->mlock);
if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) {
mutex_unlock(&indio_dev->mlock);
return -EBUSY;
}
if (iio_dev_opaque->trig_readonly) {
mutex_unlock(&indio_dev->mlock);
return -EPERM;
}
mutex_unlock(&indio_dev->mlock);
trig = iio_trigger_acquire_by_name(buf);
if (oldtrig == trig) {
ret = len;
goto out_trigger_put;
}
if (trig && indio_dev->info->validate_trigger) {
ret = indio_dev->info->validate_trigger(indio_dev, trig);
if (ret)
goto out_trigger_put;
}
if (trig && trig->ops && trig->ops->validate_device) {
ret = trig->ops->validate_device(trig, indio_dev);
if (ret)
goto out_trigger_put;
}
indio_dev->trig = trig;
if (oldtrig) {
if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
iio_trigger_detach_poll_func(oldtrig,
indio_dev->pollfunc_event);
iio_trigger_put(oldtrig);
}
if (indio_dev->trig) {
if (indio_dev->modes & INDIO_EVENT_TRIGGERED)
iio_trigger_attach_poll_func(indio_dev->trig,
indio_dev->pollfunc_event);
}
return len;
out_trigger_put:
if (trig)
iio_trigger_put(trig);
return ret;
}
static DEVICE_ATTR(current_trigger, S_IRUGO | S_IWUSR,
iio_trigger_read_current,
iio_trigger_write_current);
static struct attribute *iio_trigger_consumer_attrs[] = {
&dev_attr_current_trigger.attr,
NULL,
};
static const struct attribute_group iio_trigger_consumer_attr_group = {
.name = "trigger",
.attrs = iio_trigger_consumer_attrs,
};
static void iio_trig_release(struct device *device)
{
struct iio_trigger *trig = to_iio_trigger(device);
int i;
if (trig->subirq_base) {
for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
irq_modify_status(trig->subirq_base + i,
IRQ_NOAUTOEN,
IRQ_NOREQUEST | IRQ_NOPROBE);
irq_set_chip(trig->subirq_base + i,
NULL);
irq_set_handler(trig->subirq_base + i,
NULL);
}
irq_free_descs(trig->subirq_base,
CONFIG_IIO_CONSUMERS_PER_TRIGGER);
}
kfree(trig->name);
kfree(trig);
}
static const struct device_type iio_trig_type = {
.release = iio_trig_release,
.groups = iio_trig_dev_groups,
};
static void iio_trig_subirqmask(struct irq_data *d)
{
struct irq_chip *chip = irq_data_get_irq_chip(d);
struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
trig->subirqs[d->irq - trig->subirq_base].enabled = false;
}
static void iio_trig_subirqunmask(struct irq_data *d)
{
struct irq_chip *chip = irq_data_get_irq_chip(d);
struct iio_trigger *trig = container_of(chip, struct iio_trigger, subirq_chip);
trig->subirqs[d->irq - trig->subirq_base].enabled = true;
}
static __printf(2, 0)
struct iio_trigger *viio_trigger_alloc(struct device *parent,
const char *fmt,
va_list vargs)
{
struct iio_trigger *trig;
int i;
trig = kzalloc(sizeof *trig, GFP_KERNEL);
if (!trig)
return NULL;
trig->dev.parent = parent;
trig->dev.type = &iio_trig_type;
trig->dev.bus = &iio_bus_type;
device_initialize(&trig->dev);
INIT_WORK(&trig->reenable_work, iio_reenable_work_fn);
mutex_init(&trig->pool_lock);
trig->subirq_base = irq_alloc_descs(-1, 0,
CONFIG_IIO_CONSUMERS_PER_TRIGGER,
0);
if (trig->subirq_base < 0)
goto free_trig;
trig->name = kvasprintf(GFP_KERNEL, fmt, vargs);
if (trig->name == NULL)
goto free_descs;
trig->subirq_chip.name = trig->name;
trig->subirq_chip.irq_mask = &iio_trig_subirqmask;
trig->subirq_chip.irq_unmask = &iio_trig_subirqunmask;
for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
irq_set_chip(trig->subirq_base + i, &trig->subirq_chip);
irq_set_handler(trig->subirq_base + i, &handle_simple_irq);
irq_modify_status(trig->subirq_base + i,
IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
}
return trig;
free_descs:
irq_free_descs(trig->subirq_base, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
free_trig:
kfree(trig);
return NULL;
}
/**
* iio_trigger_alloc - Allocate a trigger
* @parent: Device to allocate iio_trigger for
* @fmt: trigger name format. If it includes format
* specifiers, the additional arguments following
* format are formatted and inserted in the resulting
* string replacing their respective specifiers.
* RETURNS:
* Pointer to allocated iio_trigger on success, NULL on failure.
*/
struct iio_trigger *iio_trigger_alloc(struct device *parent, const char *fmt, ...)
{
struct iio_trigger *trig;
va_list vargs;
va_start(vargs, fmt);
trig = viio_trigger_alloc(parent, fmt, vargs);
va_end(vargs);
return trig;
}
EXPORT_SYMBOL(iio_trigger_alloc);
void iio_trigger_free(struct iio_trigger *trig)
{
if (trig)
put_device(&trig->dev);
}
EXPORT_SYMBOL(iio_trigger_free);
static void devm_iio_trigger_release(struct device *dev, void *res)
{
iio_trigger_free(*(struct iio_trigger **)res);
}
/**
* devm_iio_trigger_alloc - Resource-managed iio_trigger_alloc()
* Managed iio_trigger_alloc. iio_trigger allocated with this function is
* automatically freed on driver detach.
* @parent: Device to allocate iio_trigger for
* @fmt: trigger name format. If it includes format
* specifiers, the additional arguments following
* format are formatted and inserted in the resulting
* string replacing their respective specifiers.
*
*
* RETURNS:
* Pointer to allocated iio_trigger on success, NULL on failure.
*/
struct iio_trigger *devm_iio_trigger_alloc(struct device *parent, const char *fmt, ...)
{
struct iio_trigger **ptr, *trig;
va_list vargs;
ptr = devres_alloc(devm_iio_trigger_release, sizeof(*ptr),
GFP_KERNEL);
if (!ptr)
return NULL;
/* use raw alloc_dr for kmalloc caller tracing */
va_start(vargs, fmt);
trig = viio_trigger_alloc(parent, fmt, vargs);
va_end(vargs);
if (trig) {
*ptr = trig;
devres_add(parent, ptr);
} else {
devres_free(ptr);
}
return trig;
}
EXPORT_SYMBOL_GPL(devm_iio_trigger_alloc);
static void devm_iio_trigger_unreg(void *trigger_info)
{
iio_trigger_unregister(trigger_info);
}
/**
* __devm_iio_trigger_register - Resource-managed iio_trigger_register()
* @dev: device this trigger was allocated for
* @trig_info: trigger to register
* @this_mod: module registering the trigger
*
* Managed iio_trigger_register(). The IIO trigger registered with this
* function is automatically unregistered on driver detach. This function
* calls iio_trigger_register() internally. Refer to that function for more
* information.
*
* RETURNS:
* 0 on success, negative error number on failure.
*/
int __devm_iio_trigger_register(struct device *dev,
struct iio_trigger *trig_info,
struct module *this_mod)
{
int ret;
ret = __iio_trigger_register(trig_info, this_mod);
if (ret)
return ret;
return devm_add_action_or_reset(dev, devm_iio_trigger_unreg, trig_info);
}
EXPORT_SYMBOL_GPL(__devm_iio_trigger_register);
bool iio_trigger_using_own(struct iio_dev *indio_dev)
{
return indio_dev->trig->attached_own_device;
}
EXPORT_SYMBOL(iio_trigger_using_own);
/**
* iio_trigger_validate_own_device - Check if a trigger and IIO device belong to
* the same device
* @trig: The IIO trigger to check
* @indio_dev: the IIO device to check
*
* This function can be used as the validate_device callback for triggers that
* can only be attached to their own device.
*
* Return: 0 if both the trigger and the IIO device belong to the same
* device, -EINVAL otherwise.
*/
int iio_trigger_validate_own_device(struct iio_trigger *trig,
struct iio_dev *indio_dev)
{
if (indio_dev->dev.parent != trig->dev.parent)
return -EINVAL;
return 0;
}
EXPORT_SYMBOL(iio_trigger_validate_own_device);
int iio_device_register_trigger_consumer(struct iio_dev *indio_dev)
{
return iio_device_register_sysfs_group(indio_dev,
&iio_trigger_consumer_attr_group);
}
void iio_device_unregister_trigger_consumer(struct iio_dev *indio_dev)
{
/* Clean up an associated but not attached trigger reference */
if (indio_dev->trig)
iio_trigger_put(indio_dev->trig);
}