// SPDX-License-Identifier: GPL-2.0-only /* The industrial I/O core, trigger handling functions * * Copyright (c) 2008 Jonathan Cameron */ #include #include #include #include #include #include #include #include #include #include #include "iio_core.h" #include "iio_core_trigger.h" #include /* 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); /** * name_show() - 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 name_show(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_RO(name); 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) { int ret; trig_info->id = ida_alloc(&iio_trigger_ida, 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_free(&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_free(&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(&iio_dev_opaque->mlock); WARN_ON(iio_dev_opaque->trig_readonly); indio_dev->trig = iio_trigger_get(trig); iio_dev_opaque->trig_readonly = true; mutex_unlock(&iio_dev_opaque->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); } /** * iio_trigger_poll() - Call the IRQ trigger handler of the consumers * @trig: trigger which occurred * * This function should only be called from a hard IRQ context. */ 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); /** * iio_trigger_poll_nested() - Call the threaded trigger handler of the * consumers * @trig: trigger which occurred * * This function should only be called from a kernel thread context. */ void iio_trigger_poll_nested(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_nested); 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) 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 (iio_validate_own_trigger(pf->indio_dev, trig)) 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) 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); /** * current_trigger_show() - 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 current_trigger_show(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; } /** * current_trigger_store() - 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 current_trigger_store(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(&iio_dev_opaque->mlock); if (iio_dev_opaque->currentmode == INDIO_BUFFER_TRIGGERED) { mutex_unlock(&iio_dev_opaque->mlock); return -EBUSY; } if (iio_dev_opaque->trig_readonly) { mutex_unlock(&iio_dev_opaque->mlock); return -EPERM; } mutex_unlock(&iio_dev_opaque->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_RW(current_trigger); 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(3, 0) struct iio_trigger *viio_trigger_alloc(struct device *parent, struct module *this_mod, 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; INIT_LIST_HEAD(&trig->list); trig->owner = this_mod; 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 * @this_mod: module allocating the trigger * @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, struct module *this_mod, const char *fmt, ...) { struct iio_trigger *trig; va_list vargs; va_start(vargs, fmt); trig = viio_trigger_alloc(parent, this_mod, 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 * @this_mod: module allocating the trigger * @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, struct module *this_mod, 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, this_mod, 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 * * 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) { int ret; ret = iio_trigger_register(trig_info); 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_validate_own_trigger - Check if a trigger and IIO device belong to * the same device * @idev: the IIO device to check * @trig: the IIO trigger to check * * This function can be used as the validate_trigger 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_validate_own_trigger(struct iio_dev *idev, struct iio_trigger *trig) { if (idev->dev.parent != trig->dev.parent) return -EINVAL; return 0; } EXPORT_SYMBOL_GPL(iio_validate_own_trigger); /** * 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); }