| // SPDX-License-Identifier: GPL-2.0-only |
| /** |
| * The industrial I/O periodic hrtimer trigger driver |
| * |
| * Copyright (C) Intuitive Aerial AB |
| * Written by Marten Svanfeldt, marten@intuitiveaerial.com |
| * Copyright (C) 2012, Analog Device Inc. |
| * Author: Lars-Peter Clausen <lars@metafoo.de> |
| * Copyright (C) 2015, Intel Corporation |
| */ |
| #include <linux/kernel.h> |
| #include <linux/slab.h> |
| #include <linux/hrtimer.h> |
| |
| #include <linux/iio/iio.h> |
| #include <linux/iio/trigger.h> |
| #include <linux/iio/sw_trigger.h> |
| |
| /* default sampling frequency - 100Hz */ |
| #define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100 |
| |
| struct iio_hrtimer_info { |
| struct iio_sw_trigger swt; |
| struct hrtimer timer; |
| unsigned long sampling_frequency; |
| ktime_t period; |
| }; |
| |
| static const struct config_item_type iio_hrtimer_type = { |
| .ct_owner = THIS_MODULE, |
| }; |
| |
| static |
| ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev, |
| struct device_attribute *attr, |
| char *buf) |
| { |
| struct iio_trigger *trig = to_iio_trigger(dev); |
| struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); |
| |
| return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency); |
| } |
| |
| static |
| ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t len) |
| { |
| struct iio_trigger *trig = to_iio_trigger(dev); |
| struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig); |
| unsigned long val; |
| int ret; |
| |
| ret = kstrtoul(buf, 10, &val); |
| if (ret) |
| return ret; |
| |
| if (!val || val > NSEC_PER_SEC) |
| return -EINVAL; |
| |
| info->sampling_frequency = val; |
| info->period = NSEC_PER_SEC / val; |
| |
| return len; |
| } |
| |
| static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR, |
| iio_hrtimer_show_sampling_frequency, |
| iio_hrtimer_store_sampling_frequency); |
| |
| static struct attribute *iio_hrtimer_attrs[] = { |
| &dev_attr_sampling_frequency.attr, |
| NULL |
| }; |
| |
| static const struct attribute_group iio_hrtimer_attr_group = { |
| .attrs = iio_hrtimer_attrs, |
| }; |
| |
| static const struct attribute_group *iio_hrtimer_attr_groups[] = { |
| &iio_hrtimer_attr_group, |
| NULL |
| }; |
| |
| static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer) |
| { |
| struct iio_hrtimer_info *info; |
| |
| info = container_of(timer, struct iio_hrtimer_info, timer); |
| |
| hrtimer_forward_now(timer, info->period); |
| iio_trigger_poll(info->swt.trigger); |
| |
| return HRTIMER_RESTART; |
| } |
| |
| static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state) |
| { |
| struct iio_hrtimer_info *trig_info; |
| |
| trig_info = iio_trigger_get_drvdata(trig); |
| |
| if (state) |
| hrtimer_start(&trig_info->timer, trig_info->period, |
| HRTIMER_MODE_REL_HARD); |
| else |
| hrtimer_cancel(&trig_info->timer); |
| |
| return 0; |
| } |
| |
| static const struct iio_trigger_ops iio_hrtimer_trigger_ops = { |
| .set_trigger_state = iio_trig_hrtimer_set_state, |
| }; |
| |
| static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name) |
| { |
| struct iio_hrtimer_info *trig_info; |
| int ret; |
| |
| trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL); |
| if (!trig_info) |
| return ERR_PTR(-ENOMEM); |
| |
| trig_info->swt.trigger = iio_trigger_alloc("%s", name); |
| if (!trig_info->swt.trigger) { |
| ret = -ENOMEM; |
| goto err_free_trig_info; |
| } |
| |
| iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info); |
| trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops; |
| trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups; |
| |
| hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
| trig_info->timer.function = iio_hrtimer_trig_handler; |
| |
| trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY; |
| trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency; |
| |
| ret = iio_trigger_register(trig_info->swt.trigger); |
| if (ret) |
| goto err_free_trigger; |
| |
| iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type); |
| return &trig_info->swt; |
| err_free_trigger: |
| iio_trigger_free(trig_info->swt.trigger); |
| err_free_trig_info: |
| kfree(trig_info); |
| |
| return ERR_PTR(ret); |
| } |
| |
| static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt) |
| { |
| struct iio_hrtimer_info *trig_info; |
| |
| trig_info = iio_trigger_get_drvdata(swt->trigger); |
| |
| iio_trigger_unregister(swt->trigger); |
| |
| /* cancel the timer after unreg to make sure no one rearms it */ |
| hrtimer_cancel(&trig_info->timer); |
| iio_trigger_free(swt->trigger); |
| kfree(trig_info); |
| |
| return 0; |
| } |
| |
| static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = { |
| .probe = iio_trig_hrtimer_probe, |
| .remove = iio_trig_hrtimer_remove, |
| }; |
| |
| static struct iio_sw_trigger_type iio_trig_hrtimer = { |
| .name = "hrtimer", |
| .owner = THIS_MODULE, |
| .ops = &iio_trig_hrtimer_ops, |
| }; |
| |
| module_iio_sw_trigger_driver(iio_trig_hrtimer); |
| |
| MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>"); |
| MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); |
| MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem"); |
| MODULE_LICENSE("GPL v2"); |