iio: trigger: Introduce IIO hrtimer based trigger (ac5006a2) · Commits · 戴 / test

drivers/iio/trigger/Kconfig

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Original line number	Diff line number	Diff line
		@@ -5,6 +5,16 @@

		menu "Triggers - standalone"

		config IIO_HRTIMER_TRIGGER
		tristate "High resolution timer trigger"
		depends on IIO_SW_TRIGGER
		help
		Provides a frequency based IIO trigger using high resolution
		timers as interrupt source.

		To compile this driver as a module, choose M here: the
		module will be called iio-trig-hrtimer.

		config IIO_INTERRUPT_TRIGGER
		tristate "Generic interrupt trigger"
		help

drivers/iio/trigger/Makefile

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		@@ -3,5 +3,7 @@
		#

		# When adding new entries keep the list in alphabetical order

		obj-$(CONFIG_IIO_HRTIMER_TRIGGER) += iio-trig-hrtimer.o
		obj-$(CONFIG_IIO_INTERRUPT_TRIGGER) += iio-trig-interrupt.o
		obj-$(CONFIG_IIO_SYSFS_TRIGGER) += iio-trig-sysfs.o

drivers/iio/trigger/iio-trig-hrtimer.c

0 → 100644

+193 −0

Original line number	Diff line number	Diff line
		/**
		* 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
		*
		* 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 <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 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 = ktime_set(0, 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);
		else
		hrtimer_cancel(&trig_info->timer);

		return 0;
		}

		static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
		.owner = THIS_MODULE,
		.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);
		trig_info->timer.function = iio_hrtimer_trig_handler;

		trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;
		trig_info->period = ktime_set(0, 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");

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