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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * The industrial I/O periodic hrtimer trigger driver4 *5 * Copyright (C) Intuitive Aerial AB6 * Written by Marten Svanfeldt, marten@intuitiveaerial.com7 * Copyright (C) 2012, Analog Devices Inc.8 * Author: Lars-Peter Clausen <lars@metafoo.de>9 * Copyright (C) 2015, Intel Corporation10 */11#include <linux/kernel.h>12#include <linux/slab.h>13#include <linux/hrtimer.h>14 15#include <linux/iio/iio.h>16#include <linux/iio/trigger.h>17#include <linux/iio/sw_trigger.h>18 19/* Defined locally, not in time64.h yet. */20#define PSEC_PER_SEC 1000000000000LL21 22/* default sampling frequency - 100Hz */23#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 10024 25struct iio_hrtimer_info {26 struct iio_sw_trigger swt;27 struct hrtimer timer;28 int sampling_frequency[2];29 ktime_t period;30};31 32static const struct config_item_type iio_hrtimer_type = {33 .ct_owner = THIS_MODULE,34};35 36static37ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,38 struct device_attribute *attr,39 char *buf)40{41 struct iio_trigger *trig = to_iio_trigger(dev);42 struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);43 44 return iio_format_value(buf, IIO_VAL_INT_PLUS_MICRO,45 ARRAY_SIZE(info->sampling_frequency),46 info->sampling_frequency);47}48 49static50ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,51 struct device_attribute *attr,52 const char *buf, size_t len)53{54 struct iio_trigger *trig = to_iio_trigger(dev);55 struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);56 unsigned long long val;57 u64 period;58 int integer, fract, ret;59 60 ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);61 if (ret)62 return ret;63 if (integer < 0 || fract < 0)64 return -ERANGE;65 66 val = fract + 1000ULL * integer; /* mHz */67 68 if (!val || val > UINT_MAX)69 return -EINVAL;70 71 info->sampling_frequency[0] = integer; /* Hz */72 info->sampling_frequency[1] = fract * 1000; /* uHz */73 period = PSEC_PER_SEC;74 do_div(period, val);75 info->period = period; /* nS */76 77 return len;78}79 80static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,81 iio_hrtimer_show_sampling_frequency,82 iio_hrtimer_store_sampling_frequency);83 84static struct attribute *iio_hrtimer_attrs[] = {85 &dev_attr_sampling_frequency.attr,86 NULL87};88 89static const struct attribute_group iio_hrtimer_attr_group = {90 .attrs = iio_hrtimer_attrs,91};92 93static const struct attribute_group *iio_hrtimer_attr_groups[] = {94 &iio_hrtimer_attr_group,95 NULL96};97 98static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)99{100 struct iio_hrtimer_info *info;101 102 info = container_of(timer, struct iio_hrtimer_info, timer);103 104 hrtimer_forward_now(timer, info->period);105 iio_trigger_poll(info->swt.trigger);106 107 return HRTIMER_RESTART;108}109 110static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)111{112 struct iio_hrtimer_info *trig_info;113 114 trig_info = iio_trigger_get_drvdata(trig);115 116 if (state)117 hrtimer_start(&trig_info->timer, trig_info->period,118 HRTIMER_MODE_REL_HARD);119 else120 hrtimer_cancel(&trig_info->timer);121 122 return 0;123}124 125static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {126 .set_trigger_state = iio_trig_hrtimer_set_state,127};128 129static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name)130{131 struct iio_hrtimer_info *trig_info;132 int ret;133 134 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);135 if (!trig_info)136 return ERR_PTR(-ENOMEM);137 138 trig_info->swt.trigger = iio_trigger_alloc(NULL, "%s", name);139 if (!trig_info->swt.trigger) {140 ret = -ENOMEM;141 goto err_free_trig_info;142 }143 144 iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);145 trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops;146 trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;147 148 hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);149 trig_info->timer.function = iio_hrtimer_trig_handler;150 151 trig_info->sampling_frequency[0] = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;152 trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency[0];153 154 ret = iio_trigger_register(trig_info->swt.trigger);155 if (ret)156 goto err_free_trigger;157 158 iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type);159 return &trig_info->swt;160err_free_trigger:161 iio_trigger_free(trig_info->swt.trigger);162err_free_trig_info:163 kfree(trig_info);164 165 return ERR_PTR(ret);166}167 168static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt)169{170 struct iio_hrtimer_info *trig_info;171 172 trig_info = iio_trigger_get_drvdata(swt->trigger);173 174 iio_trigger_unregister(swt->trigger);175 176 /* cancel the timer after unreg to make sure no one rearms it */177 hrtimer_cancel(&trig_info->timer);178 iio_trigger_free(swt->trigger);179 kfree(trig_info);180 181 return 0;182}183 184static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {185 .probe = iio_trig_hrtimer_probe,186 .remove = iio_trig_hrtimer_remove,187};188 189static struct iio_sw_trigger_type iio_trig_hrtimer = {190 .name = "hrtimer",191 .owner = THIS_MODULE,192 .ops = &iio_trig_hrtimer_ops,193};194 195module_iio_sw_trigger_driver(iio_trig_hrtimer);196 197MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");198MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");199MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");200MODULE_LICENSE("GPL v2");201