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15#include <linux/kernel.h>
16#include <linux/slab.h>
17#include <linux/hrtimer.h>
18
19#include <linux/iio/iio.h>
20#include <linux/iio/trigger.h>
21#include <linux/iio/sw_trigger.h>
22
23
24#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100
25
26struct iio_hrtimer_info {
27 struct iio_sw_trigger swt;
28 struct hrtimer timer;
29 unsigned long sampling_frequency;
30 ktime_t period;
31};
32
33static const struct config_item_type iio_hrtimer_type = {
34 .ct_owner = THIS_MODULE,
35};
36
37static
38ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,
39 struct device_attribute *attr,
40 char *buf)
41{
42 struct iio_trigger *trig = to_iio_trigger(dev);
43 struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
44
45 return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency);
46}
47
48static
49ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
50 struct device_attribute *attr,
51 const char *buf, size_t len)
52{
53 struct iio_trigger *trig = to_iio_trigger(dev);
54 struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
55 unsigned long val;
56 int ret;
57
58 ret = kstrtoul(buf, 10, &val);
59 if (ret)
60 return ret;
61
62 if (!val || val > NSEC_PER_SEC)
63 return -EINVAL;
64
65 info->sampling_frequency = val;
66 info->period = NSEC_PER_SEC / val;
67
68 return len;
69}
70
71static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
72 iio_hrtimer_show_sampling_frequency,
73 iio_hrtimer_store_sampling_frequency);
74
75static struct attribute *iio_hrtimer_attrs[] = {
76 &dev_attr_sampling_frequency.attr,
77 NULL
78};
79
80static const struct attribute_group iio_hrtimer_attr_group = {
81 .attrs = iio_hrtimer_attrs,
82};
83
84static const struct attribute_group *iio_hrtimer_attr_groups[] = {
85 &iio_hrtimer_attr_group,
86 NULL
87};
88
89static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)
90{
91 struct iio_hrtimer_info *info;
92
93 info = container_of(timer, struct iio_hrtimer_info, timer);
94
95 hrtimer_forward_now(timer, info->period);
96 iio_trigger_poll(info->swt.trigger);
97
98 return HRTIMER_RESTART;
99}
100
101static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
102{
103 struct iio_hrtimer_info *trig_info;
104
105 trig_info = iio_trigger_get_drvdata(trig);
106
107 if (state)
108 hrtimer_start(&trig_info->timer, trig_info->period,
109 HRTIMER_MODE_REL);
110 else
111 hrtimer_cancel(&trig_info->timer);
112
113 return 0;
114}
115
116static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
117 .set_trigger_state = iio_trig_hrtimer_set_state,
118};
119
120static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name)
121{
122 struct iio_hrtimer_info *trig_info;
123 int ret;
124
125 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
126 if (!trig_info)
127 return ERR_PTR(-ENOMEM);
128
129 trig_info->swt.trigger = iio_trigger_alloc("%s", name);
130 if (!trig_info->swt.trigger) {
131 ret = -ENOMEM;
132 goto err_free_trig_info;
133 }
134
135 iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);
136 trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops;
137 trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;
138
139 hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
140 trig_info->timer.function = iio_hrtimer_trig_handler;
141
142 trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;
143 trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency;
144
145 ret = iio_trigger_register(trig_info->swt.trigger);
146 if (ret)
147 goto err_free_trigger;
148
149 iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type);
150 return &trig_info->swt;
151err_free_trigger:
152 iio_trigger_free(trig_info->swt.trigger);
153err_free_trig_info:
154 kfree(trig_info);
155
156 return ERR_PTR(ret);
157}
158
159static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt)
160{
161 struct iio_hrtimer_info *trig_info;
162
163 trig_info = iio_trigger_get_drvdata(swt->trigger);
164
165 iio_trigger_unregister(swt->trigger);
166
167
168 hrtimer_cancel(&trig_info->timer);
169 iio_trigger_free(swt->trigger);
170 kfree(trig_info);
171
172 return 0;
173}
174
175static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {
176 .probe = iio_trig_hrtimer_probe,
177 .remove = iio_trig_hrtimer_remove,
178};
179
180static struct iio_sw_trigger_type iio_trig_hrtimer = {
181 .name = "hrtimer",
182 .owner = THIS_MODULE,
183 .ops = &iio_trig_hrtimer_ops,
184};
185
186module_iio_sw_trigger_driver(iio_trig_hrtimer);
187
188MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");
189MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
190MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
191MODULE_LICENSE("GPL v2");
192
