diff options
Diffstat (limited to 'drivers/iio/trigger/iio-trig-sysfs.c')
| -rw-r--r-- | drivers/iio/trigger/iio-trig-sysfs.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/drivers/iio/trigger/iio-trig-sysfs.c b/drivers/iio/trigger/iio-trig-sysfs.c new file mode 100644 index 000000000..9ed5b9405 --- /dev/null +++ b/drivers/iio/trigger/iio-trig-sysfs.c @@ -0,0 +1,231 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2011 Analog Devices Inc. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/list.h> +#include <linux/irq_work.h> + +#include <linux/iio/iio.h> +#include <linux/iio/trigger.h> + +struct iio_sysfs_trig { + struct iio_trigger *trig; + struct irq_work work; + int id; + struct list_head l; +}; + +static LIST_HEAD(iio_sysfs_trig_list); +static DEFINE_MUTEX(iio_sysfs_trig_list_mut); + +static int iio_sysfs_trigger_probe(int id); +static ssize_t iio_sysfs_trig_add(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret; + unsigned long input; + + ret = kstrtoul(buf, 10, &input); + if (ret) + return ret; + ret = iio_sysfs_trigger_probe(input); + if (ret) + return ret; + return len; +} +static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add); + +static int iio_sysfs_trigger_remove(int id); +static ssize_t iio_sysfs_trig_remove(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t len) +{ + int ret; + unsigned long input; + + ret = kstrtoul(buf, 10, &input); + if (ret) + return ret; + ret = iio_sysfs_trigger_remove(input); + if (ret) + return ret; + return len; +} + +static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove); + +static struct attribute *iio_sysfs_trig_attrs[] = { + &dev_attr_add_trigger.attr, + &dev_attr_remove_trigger.attr, + NULL, +}; + +static const struct attribute_group iio_sysfs_trig_group = { + .attrs = iio_sysfs_trig_attrs, +}; + +static const struct attribute_group *iio_sysfs_trig_groups[] = { + &iio_sysfs_trig_group, + NULL +}; + + +/* Nothing to actually do upon release */ +static void iio_trigger_sysfs_release(struct device *dev) +{ +} + +static struct device iio_sysfs_trig_dev = { + .bus = &iio_bus_type, + .groups = iio_sysfs_trig_groups, + .release = &iio_trigger_sysfs_release, +}; + +static void iio_sysfs_trigger_work(struct irq_work *work) +{ + struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig, + work); + + iio_trigger_poll(trig->trig); +} + +static ssize_t iio_sysfs_trigger_poll(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + struct iio_trigger *trig = to_iio_trigger(dev); + struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig); + + irq_work_queue(&sysfs_trig->work); + + return count; +} + +static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll); + +static struct attribute *iio_sysfs_trigger_attrs[] = { + &dev_attr_trigger_now.attr, + NULL, +}; + +static const struct attribute_group iio_sysfs_trigger_attr_group = { + .attrs = iio_sysfs_trigger_attrs, +}; + +static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = { + &iio_sysfs_trigger_attr_group, + NULL +}; + +static const struct iio_trigger_ops iio_sysfs_trigger_ops = { +}; + +static int iio_sysfs_trigger_probe(int id) +{ + struct iio_sysfs_trig *t; + int ret; + bool foundit = false; + + mutex_lock(&iio_sysfs_trig_list_mut); + list_for_each_entry(t, &iio_sysfs_trig_list, l) + if (id == t->id) { + foundit = true; + break; + } + if (foundit) { + ret = -EINVAL; + goto out1; + } + t = kmalloc(sizeof(*t), GFP_KERNEL); + if (t == NULL) { + ret = -ENOMEM; + goto out1; + } + t->id = id; + t->trig = iio_trigger_alloc("sysfstrig%d", id); + if (!t->trig) { + ret = -ENOMEM; + goto free_t; + } + + t->trig->dev.groups = iio_sysfs_trigger_attr_groups; + t->trig->ops = &iio_sysfs_trigger_ops; + t->trig->dev.parent = &iio_sysfs_trig_dev; + iio_trigger_set_drvdata(t->trig, t); + + init_irq_work(&t->work, iio_sysfs_trigger_work); + + ret = iio_trigger_register(t->trig); + if (ret) + goto out2; + list_add(&t->l, &iio_sysfs_trig_list); + __module_get(THIS_MODULE); + mutex_unlock(&iio_sysfs_trig_list_mut); + return 0; + +out2: + iio_trigger_free(t->trig); +free_t: + kfree(t); +out1: + mutex_unlock(&iio_sysfs_trig_list_mut); + return ret; +} + +static int iio_sysfs_trigger_remove(int id) +{ + bool foundit = false; + struct iio_sysfs_trig *t; + + mutex_lock(&iio_sysfs_trig_list_mut); + list_for_each_entry(t, &iio_sysfs_trig_list, l) + if (id == t->id) { + foundit = true; + break; + } + if (!foundit) { + mutex_unlock(&iio_sysfs_trig_list_mut); + return -EINVAL; + } + + iio_trigger_unregister(t->trig); + irq_work_sync(&t->work); + iio_trigger_free(t->trig); + + list_del(&t->l); + kfree(t); + module_put(THIS_MODULE); + mutex_unlock(&iio_sysfs_trig_list_mut); + return 0; +} + + +static int __init iio_sysfs_trig_init(void) +{ + int ret; + device_initialize(&iio_sysfs_trig_dev); + dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger"); + ret = device_add(&iio_sysfs_trig_dev); + if (ret) + put_device(&iio_sysfs_trig_dev); + return ret; +} +module_init(iio_sysfs_trig_init); + +static void __exit iio_sysfs_trig_exit(void) +{ + device_unregister(&iio_sysfs_trig_dev); +} +module_exit(iio_sysfs_trig_exit); + +MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); +MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:iio-trig-sysfs"); |