diff options
Diffstat (limited to 'drivers/iio/industrialio-trigger.c')
| -rw-r--r-- | drivers/iio/industrialio-trigger.c | 750 |
1 files changed, 750 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c new file mode 100644 index 000000000..6885a186f --- /dev/null +++ b/drivers/iio/industrialio-trigger.c @@ -0,0 +1,750 @@ +// 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); + +/** + * 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(&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) + 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(&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_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_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); +} |