1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * The industrial I/O periodic hrtimer trigger driver
4 *
5 * Copyright (C) Intuitive Aerial AB
6 * Written by Marten Svanfeldt, marten@intuitiveaerial.com
7 * Copyright (C) 2012, Analog Devices Inc.
8 * Author: Lars-Peter Clausen <lars@metafoo.de>
9 * Copyright (C) 2015, Intel Corporation
10 */
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 1000000000000LL
21
22 /* default sampling frequency - 100Hz */
23 #define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100
24
25 struct iio_hrtimer_info {
26 struct iio_sw_trigger swt;
27 struct hrtimer timer;
28 int sampling_frequency[2];
29 ktime_t period;
30 };
31
32 static const struct config_item_type iio_hrtimer_type = {
33 .ct_owner = THIS_MODULE,
34 };
35
36 static
iio_hrtimer_show_sampling_frequency(struct device * dev,struct device_attribute * attr,char * buf)37 ssize_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
49 static
iio_hrtimer_store_sampling_frequency(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)50 ssize_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
80 static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
81 iio_hrtimer_show_sampling_frequency,
82 iio_hrtimer_store_sampling_frequency);
83
84 static struct attribute *iio_hrtimer_attrs[] = {
85 &dev_attr_sampling_frequency.attr,
86 NULL
87 };
88
89 static const struct attribute_group iio_hrtimer_attr_group = {
90 .attrs = iio_hrtimer_attrs,
91 };
92
93 static const struct attribute_group *iio_hrtimer_attr_groups[] = {
94 &iio_hrtimer_attr_group,
95 NULL
96 };
97
iio_hrtimer_trig_handler(struct hrtimer * timer)98 static 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
iio_trig_hrtimer_set_state(struct iio_trigger * trig,bool state)110 static 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 else
120 hrtimer_cancel(&trig_info->timer);
121
122 return 0;
123 }
124
125 static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
126 .set_trigger_state = iio_trig_hrtimer_set_state,
127 };
128
iio_trig_hrtimer_probe(const char * name)129 static 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;
160 err_free_trigger:
161 iio_trigger_free(trig_info->swt.trigger);
162 err_free_trig_info:
163 kfree(trig_info);
164
165 return ERR_PTR(ret);
166 }
167
iio_trig_hrtimer_remove(struct iio_sw_trigger * swt)168 static 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
184 static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {
185 .probe = iio_trig_hrtimer_probe,
186 .remove = iio_trig_hrtimer_remove,
187 };
188
189 static struct iio_sw_trigger_type iio_trig_hrtimer = {
190 .name = "hrtimer",
191 .owner = THIS_MODULE,
192 .ops = &iio_trig_hrtimer_ops,
193 };
194
195 module_iio_sw_trigger_driver(iio_trig_hrtimer);
196
197 MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");
198 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
199 MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
200 MODULE_LICENSE("GPL v2");
201