From 1637db44413e32a0f100dd4bd164644e641842f7 Mon Sep 17 00:00:00 2001 From: Jonathan Cameron Date: Tue, 18 Aug 2009 18:06:26 +0100 Subject: [PATCH] Staging: IIO: Trigger support added to core. Add general registration support for IIO triggers. These are currently only used to initialize a 'poll' of a given device. Examples include the lis3l02dq's data ready signal being used to initialize a read and gpio triggers being used to allow externally synchronized sensor reading. Each trigger can cause any number of 'consumer' devices to be polled with each storing data into a related ring buffer. Two stage triggering is supported with 'fast' and 'slow' paths. The first is used for things like pulling a data hold line high and the second for actual read which may take far longer. Changes since V2: * As with IIO triggers now use a registration approach much closer to that of input leading to cleaner code. Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- drivers/staging/iio/Kconfig | 8 + drivers/staging/iio/Makefile | 1 + drivers/staging/iio/industrialio-trigger.c | 399 +++++++++++++++++++++ drivers/staging/iio/trigger.h | 151 ++++++++ drivers/staging/iio/trigger_consumer.h | 21 +- 5 files changed, 579 insertions(+), 1 deletion(-) create mode 100644 drivers/staging/iio/industrialio-trigger.c create mode 100644 drivers/staging/iio/trigger.h diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig index e554a9e0bf7e..6da4fb96cd28 100644 --- a/drivers/staging/iio/Kconfig +++ b/drivers/staging/iio/Kconfig @@ -17,6 +17,14 @@ config IIO_RING_BUFFER Provide core support for various ring buffer based data acquisition methods. +config IIO_TRIGGER + boolean "Enable triggered sampling support" + help + Provides IIO core support for triggers. Currently these + are used to initialize capture of samples to push into + ring buffers. The triggers are effectively a 'capture + data now' interrupt. + source "drivers/staging/iio/accel/Kconfig" source "drivers/staging/iio/adc/Kconfig" source "drivers/staging/iio/light/Kconfig" diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile index 670b8f33c02e..327151816775 100644 --- a/drivers/staging/iio/Makefile +++ b/drivers/staging/iio/Makefile @@ -5,6 +5,7 @@ obj-$(CONFIG_IIO) += industrialio.o industrialio-y := industrialio-core.o industrialio-$(CONFIG_IIO_RING_BUFFER) += industrialio-ring.o +industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o obj-y += accel/ obj-y += adc/ diff --git a/drivers/staging/iio/industrialio-trigger.c b/drivers/staging/iio/industrialio-trigger.c new file mode 100644 index 000000000000..693ebc48597c --- /dev/null +++ b/drivers/staging/iio/industrialio-trigger.c @@ -0,0 +1,399 @@ +/* The industrial I/O core, trigger handling functions + * + * Copyright (c) 2008 Jonathan Cameron + * + * 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 +#include +#include +#include +#include +#include +#include + +#include "iio.h" +#include "trigger.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_IDR(iio_trigger_idr); +static DEFINE_SPINLOCK(iio_trigger_idr_lock); + +/* Single list of all available triggers */ +static LIST_HEAD(iio_trigger_list); +static DEFINE_MUTEX(iio_trigger_list_lock); + +/** + * iio_trigger_register_sysfs() - create a device for this trigger + * @trig_info: the trigger + * + * Also adds any control attribute registered by the trigger driver + **/ +static int iio_trigger_register_sysfs(struct iio_trigger *trig_info) +{ + int ret = 0; + + if (trig_info->control_attrs) + ret = sysfs_create_group(&trig_info->dev.kobj, + trig_info->control_attrs); + + return ret; +} + +static void iio_trigger_unregister_sysfs(struct iio_trigger *trig_info) +{ + if (trig_info->control_attrs) + sysfs_remove_group(&trig_info->dev.kobj, + trig_info->control_attrs); +} + + +/** + * iio_trigger_register_id() - get a unique id for this trigger + * @trig_info: the trigger + **/ +static int iio_trigger_register_id(struct iio_trigger *trig_info) +{ + int ret = 0; + +idr_again: + if (unlikely(idr_pre_get(&iio_trigger_idr, GFP_KERNEL) == 0)) + return -ENOMEM; + + spin_lock(&iio_trigger_idr_lock); + ret = idr_get_new(&iio_trigger_idr, NULL, &trig_info->id); + spin_unlock(&iio_trigger_idr_lock); + if (unlikely(ret == -EAGAIN)) + goto idr_again; + else if (likely(!ret)) + trig_info->id = trig_info->id & MAX_ID_MASK; + + return ret; +} + +/** + * iio_trigger_unregister_id() - free up unique id for use by another trigger + * @trig_info: the trigger + **/ +static void iio_trigger_unregister_id(struct iio_trigger *trig_info) +{ + spin_lock(&iio_trigger_idr_lock); + idr_remove(&iio_trigger_idr, trig_info->id); + spin_unlock(&iio_trigger_idr_lock); +} + +int iio_trigger_register(struct iio_trigger *trig_info) +{ + int ret; + + ret = iio_trigger_register_id(trig_info); + if (ret) + goto error_ret; + /* Set the name used for the sysfs directory etc */ + dev_set_name(&trig_info->dev, "trigger%ld", + (unsigned long) trig_info->id); + + ret = device_add(&trig_info->dev); + if (ret) + goto error_unregister_id; + + ret = iio_trigger_register_sysfs(trig_info); + if (ret) + goto error_device_del; + + /* Add to list of available triggers held by the IIO core */ + mutex_lock(&iio_trigger_list_lock); + list_add_tail(&trig_info->list, &iio_trigger_list); + mutex_unlock(&iio_trigger_list_lock); + + return 0; + +error_device_del: + device_del(&trig_info->dev); +error_unregister_id: + iio_trigger_unregister_id(trig_info); +error_ret: + return ret; +} +EXPORT_SYMBOL(iio_trigger_register); + +void iio_trigger_unregister(struct iio_trigger *trig_info) +{ + struct iio_trigger *cursor; + + mutex_lock(&iio_trigger_list_lock); + list_for_each_entry(cursor, &iio_trigger_list, list) + if (cursor == trig_info) { + list_del(&cursor->list); + break; + } + mutex_unlock(&iio_trigger_list_lock); + + iio_trigger_unregister_sysfs(trig_info); + iio_trigger_unregister_id(trig_info); + /* Possible issue in here */ + device_unregister(&trig_info->dev); +} +EXPORT_SYMBOL(iio_trigger_unregister); + +struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len) +{ + struct iio_trigger *trig; + bool found = false; + + mutex_lock(&iio_trigger_list_lock); + list_for_each_entry(trig, &iio_trigger_list, list) { + if (strncmp(trig->name, name, len) == 0) { + found = true; + break; + } + } + mutex_unlock(&iio_trigger_list_lock); + + return found ? trig : NULL; +}; +EXPORT_SYMBOL(iio_trigger_find_by_name); + +void iio_trigger_poll(struct iio_trigger *trig) +{ + struct iio_poll_func *pf_cursor; + + list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) { + if (pf_cursor->poll_func_immediate) { + pf_cursor->poll_func_immediate(pf_cursor->private_data); + trig->use_count++; + } + } + list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) { + if (pf_cursor->poll_func_main) { + pf_cursor->poll_func_main(pf_cursor->private_data); + trig->use_count++; + } + } +} +EXPORT_SYMBOL(iio_trigger_poll); + +void iio_trigger_notify_done(struct iio_trigger *trig) +{ + trig->use_count--; + if (trig->use_count == 0 && trig->try_reenable) + if (trig->try_reenable(trig)) { + /* Missed and interrupt so launch new poll now */ + trig->timestamp = 0; + iio_trigger_poll(trig); + } +} +EXPORT_SYMBOL(iio_trigger_notify_done); + +/** + * iio_trigger_read_name() - retrieve useful identifying name + **/ +ssize_t iio_trigger_read_name(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_trigger *trig = dev_get_drvdata(dev); + return sprintf(buf, "%s\n", trig->name); +} +EXPORT_SYMBOL(iio_trigger_read_name); + +/* Trigger Consumer related functions */ + +/* 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) +{ + int ret = 0; + unsigned long flags; + + spin_lock_irqsave(&trig->pollfunc_list_lock, flags); + list_add_tail(&pf->list, &trig->pollfunc_list); + spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags); + + if (trig->set_trigger_state) + ret = trig->set_trigger_state(trig, true); + if (ret) { + printk(KERN_ERR "set trigger state failed\n"); + list_del(&pf->list); + } + return ret; +} +EXPORT_SYMBOL(iio_trigger_attach_poll_func); + +int iio_trigger_dettach_poll_func(struct iio_trigger *trig, + struct iio_poll_func *pf) +{ + struct iio_poll_func *pf_cursor; + unsigned long flags; + int ret = -EINVAL; + + spin_lock_irqsave(&trig->pollfunc_list_lock, flags); + list_for_each_entry(pf_cursor, &trig->pollfunc_list, list) + if (pf_cursor == pf) { + ret = 0; + break; + } + if (!ret) { + if (list_is_singular(&trig->pollfunc_list) + && trig->set_trigger_state) { + spin_unlock_irqrestore(&trig->pollfunc_list_lock, + flags); + /* May sleep hence cannot hold the spin lock */ + ret = trig->set_trigger_state(trig, false); + if (ret) + goto error_ret; + spin_lock_irqsave(&trig->pollfunc_list_lock, flags); + } + /* + * Now we can delete safe in the knowledge that, if this is + * the last pollfunc then we have disabled the trigger anyway + * and so nothing should be able to call the pollfunc. + */ + list_del(&pf_cursor->list); + } + spin_unlock_irqrestore(&trig->pollfunc_list_lock, flags); + +error_ret: + return ret; +} +EXPORT_SYMBOL(iio_trigger_dettach_poll_func); + +/** + * iio_trigger_read_currrent() trigger consumer sysfs query which trigger + * + * For trigger consumers the current_trigger interface allows the trigger + * used by the device to be queried. + **/ +static ssize_t iio_trigger_read_current(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct iio_dev *dev_info = dev_get_drvdata(dev); + int len = 0; + if (dev_info->trig) + len = snprintf(buf, + IIO_TRIGGER_NAME_LENGTH, + "%s\n", + dev_info->trig->name); + return len; +} + +/** + * iio_trigger_write_current() trigger consumer sysfs set current trigger + * + * For trigger consumers the current_trigger interface allows the trigger + * used for this device to be specified at run time based on the triggers + * name. + **/ +static ssize_t iio_trigger_write_current(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + struct iio_dev *dev_info = dev_get_drvdata(dev); + struct iio_trigger *oldtrig = dev_info->trig; + mutex_lock(&dev_info->mlock); + if (dev_info->currentmode == INDIO_RING_TRIGGERED) { + mutex_unlock(&dev_info->mlock); + return -EBUSY; + } + mutex_unlock(&dev_info->mlock); + + len = len < IIO_TRIGGER_NAME_LENGTH ? len : IIO_TRIGGER_NAME_LENGTH; + + dev_info->trig = iio_trigger_find_by_name(buf, len); + if (oldtrig && dev_info->trig != oldtrig) + iio_put_trigger(oldtrig); + if (dev_info->trig) + iio_get_trigger(dev_info->trig); + + return len; +} + +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); + kfree(trig); + iio_put(); +} + +static struct device_type iio_trig_type = { + .release = iio_trig_release, +}; + +struct iio_trigger *iio_allocate_trigger(void) +{ + struct iio_trigger *trig; + trig = kzalloc(sizeof *trig, GFP_KERNEL); + if (trig) { + trig->dev.type = &iio_trig_type; + trig->dev.class = &iio_class; + device_initialize(&trig->dev); + dev_set_drvdata(&trig->dev, (void *)trig); + spin_lock_init(&trig->pollfunc_list_lock); + INIT_LIST_HEAD(&trig->list); + INIT_LIST_HEAD(&trig->pollfunc_list); + iio_get(); + } + return trig; +} +EXPORT_SYMBOL(iio_allocate_trigger); + +void iio_free_trigger(struct iio_trigger *trig) +{ + if (trig) + put_device(&trig->dev); +} +EXPORT_SYMBOL(iio_free_trigger); + +int iio_device_register_trigger_consumer(struct iio_dev *dev_info) +{ + int ret; + ret = sysfs_create_group(&dev_info->dev.kobj, + &iio_trigger_consumer_attr_group); + return ret; +} +EXPORT_SYMBOL(iio_device_register_trigger_consumer); + +int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info) +{ + sysfs_remove_group(&dev_info->dev.kobj, + &iio_trigger_consumer_attr_group); + return 0; +} +EXPORT_SYMBOL(iio_device_unregister_trigger_consumer); + diff --git a/drivers/staging/iio/trigger.h b/drivers/staging/iio/trigger.h new file mode 100644 index 000000000000..8284098c9589 --- /dev/null +++ b/drivers/staging/iio/trigger.h @@ -0,0 +1,151 @@ +/* The industrial I/O core, trigger handling functions + * + * Copyright (c) 2008 Jonathan Cameron + * + * 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_TRIGGER_H_ +#define _IIO_TRIGGER_H_ +#define IIO_TRIGGER_NAME_LENGTH 20 +#define IIO_TRIGGER_ID_PREFIX "iio:trigger" +#define IIO_TRIGGER_ID_FORMAT IIO_TRIGGER_ID_PREFIX "%d" + + +/** + * struct iio_trigger - industrial I/O trigger device + * + * @id: [INTERN] unique id number + * @name: [DRIVER] unique name + * @dev: [DRIVER] associated device (if relevant) + * @sysfs_dev: [INTERN] sysfs relevant device + * @private_data: [DRIVER] device specific data + * @list: [INTERN] used in maintenance of global trigger list + * @alloc_list: [DRIVER] used for driver specific trigger list + * @poll_func_list_lock:[INTERN] protection of the polling function list + * @pollfunc_list: [INTERN] list of functions to run on trigger. + * @control_attrs: [DRIVER] sysfs attributes relevant to trigger type + * @set_trigger_state: [DRIVER] switch on/off the trigger on demand + * @timestamp: [INTERN] timestamp usesd by some trigs (e.g. datardy) + * @owner: [DRIVER] used to monitor usage count of the trigger. + **/ +struct iio_trigger { + int id; + const char *name; + struct device dev; + + void *private_data; + struct list_head list; + struct list_head alloc_list; + spinlock_t pollfunc_list_lock; + struct list_head pollfunc_list; + const struct attribute_group *control_attrs; + s64 timestamp; + struct module *owner; + int use_count; + + int (*set_trigger_state)(struct iio_trigger *trig, bool state); + int (*try_reenable)(struct iio_trigger *trig); +}; + +static inline struct iio_trigger *to_iio_trigger(struct device *d) +{ + return container_of(d, struct iio_trigger, dev); +}; + +static inline void iio_put_trigger(struct iio_trigger *trig) +{ + put_device(&trig->dev); + module_put(trig->owner); +}; + +static inline void iio_get_trigger(struct iio_trigger *trig) +{ + __module_get(trig->owner); + get_device(&trig->dev); +}; + +/** + * iio_trigger_read_name() - sysfs access function to get the trigger name + **/ +ssize_t iio_trigger_read_name(struct device *dev, + struct device_attribute *attr, + char *buf); + +#define IIO_TRIGGER_NAME_ATTR DEVICE_ATTR(name, S_IRUGO, \ + iio_trigger_read_name, \ + NULL); + +/** + * iio_trigger_find_by_name() - search global trigger list + **/ +struct iio_trigger *iio_trigger_find_by_name(const char *name, size_t len); + +/** + * iio_trigger_register() - register a trigger with the IIO core + * @trig_info: trigger to be registered + **/ +int iio_trigger_register(struct iio_trigger *trig_info); + +/** + * iio_trigger_unregister() - unregister a trigger from the core + **/ +void iio_trigger_unregister(struct iio_trigger *trig_info); + +/** + * iio_trigger_attach_poll_func() - add a function pair to be run on trigger + * @trig: trigger to which the function pair are being added + * @pf: poll function pair + **/ +int iio_trigger_attach_poll_func(struct iio_trigger *trig, + struct iio_poll_func *pf); + +/** + * iio_trigger_dettach_poll_func() - remove function pair from those to be + * run on trigger. + * @trig: trigger from which the function is being removed. + * @pf: poll function pair + **/ +int iio_trigger_dettach_poll_func(struct iio_trigger *trig, + struct iio_poll_func *pf); + +/** + * iio_trigger_poll() - called on a trigger occuring + * Typically called in relevant hardware interrupt handler. + **/ +void iio_trigger_poll(struct iio_trigger *); +void iio_trigger_notify_done(struct iio_trigger *); + +/** + * struct iio_poll_func - poll function pair + * + * @list: associate this with a triggers pollfunc_list + * @private_data: data specific to device (passed into poll func) + * @poll_func_immediate: function in here is run first. They should be + * extremely lightweight. Typically used for latch + * control on sensor supporting it. + * @poll_func_main: function in here is run after all immediates. + * Reading from sensor etc typically involves + * scheduling + * from here. + * + * The two stage approach used here only important when multiple sensors are + * being triggered by a single trigger. This really comes into it's own with + * simultaneous sampling devices where a simple latch command can be used to + * make the device store the values on all inputs. + **/ +struct iio_poll_func { + struct list_head list; + void *private_data; + void (*poll_func_immediate)(struct iio_dev *indio_dev); + void (*poll_func_main)(struct iio_dev *private_data); + +}; + +struct iio_trigger *iio_allocate_trigger(void); + +void iio_free_trigger(struct iio_trigger *trig); + + +#endif /* _IIO_TRIGGER_H_ */ diff --git a/drivers/staging/iio/trigger_consumer.h b/drivers/staging/iio/trigger_consumer.h index a6053892893f..4c7f527dc79f 100644 --- a/drivers/staging/iio/trigger_consumer.h +++ b/drivers/staging/iio/trigger_consumer.h @@ -8,6 +8,20 @@ * the Free Software Foundation. */ +#ifdef CONFIG_IIO_TRIGGER +/** + * iio_device_register_trigger_consumer() - set up an iio_dev to use triggers. + * @dev_info: iio_dev associated with the device that will consume the trigger + **/ +int iio_device_register_trigger_consumer(struct iio_dev *dev_info); +/** + * iio_device_unregister_trigger_consumer() - reverse the registration process. + * @dev_info: iio_dev associated with the device that consumed the trigger + **/ +int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info); + +#else + /** * iio_device_register_trigger_consumer() - set up an iio_dev to use triggers. * @dev_info: iio_dev associated with the device that will consume the trigger @@ -18,9 +32,14 @@ int iio_device_register_trigger_consumer(struct iio_dev *dev_info) }; /** * iio_device_unregister_trigger_consumer() - reverse the registration process -. * @dev_info: iio_dev associated with the device that consumed the trigger + * @dev_info: iio_dev associated with the device that consumed the trigger **/ int iio_device_unregister_trigger_consumer(struct iio_dev *dev_info) { return 0; }; + +#endif /* CONFIG_TRIGGER_CONSUMER */ + + + -- 2.20.1