1 /* The industrial I/O periodic RTC trigger driver
3 * Copyright (c) 2008 Jonathan Cameron
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
9 * This is a heavily rewritten version of the periodic timer system in
10 * earlier version of industrialio. It supplies the same functionality
11 * but via a trigger rather than a specific periodic timer system.
14 #include <linux/platform_device.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/rtc.h>
19 #include <linux/iio/iio.h>
20 #include <linux/iio/trigger.h>
22 static LIST_HEAD(iio_prtc_trigger_list);
23 static DEFINE_MUTEX(iio_prtc_trigger_list_lock);
25 struct iio_prtc_trigger_info {
26 struct rtc_device *rtc;
27 unsigned int frequency;
32 static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
34 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
37 if (trig_info->frequency == 0 && state)
39 dev_dbg(&trig_info->rtc->dev, "trigger frequency is %u\n",
40 trig_info->frequency);
41 ret = rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
43 trig_info->state = state;
48 static ssize_t iio_trig_periodic_read_freq(struct device *dev,
49 struct device_attribute *attr,
52 struct iio_trigger *trig = to_iio_trigger(dev);
53 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
55 return sprintf(buf, "%u\n", trig_info->frequency);
58 static ssize_t iio_trig_periodic_write_freq(struct device *dev,
59 struct device_attribute *attr,
63 struct iio_trigger *trig = to_iio_trigger(dev);
64 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
68 ret = kstrtouint(buf, 10, &val);
73 ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
74 if (ret == 0 && trig_info->state && trig_info->frequency == 0)
75 ret = rtc_irq_set_state(trig_info->rtc,
78 ret = rtc_irq_set_state(trig_info->rtc, &trig_info->task, 0);
83 trig_info->frequency = val;
91 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
92 iio_trig_periodic_read_freq,
93 iio_trig_periodic_write_freq);
95 static struct attribute *iio_trig_prtc_attrs[] = {
96 &dev_attr_frequency.attr,
100 static const struct attribute_group iio_trig_prtc_attr_group = {
101 .attrs = iio_trig_prtc_attrs,
104 static const struct attribute_group *iio_trig_prtc_attr_groups[] = {
105 &iio_trig_prtc_attr_group,
109 static void iio_prtc_trigger_poll(void *private_data)
111 iio_trigger_poll(private_data);
114 static const struct iio_trigger_ops iio_prtc_trigger_ops = {
115 .owner = THIS_MODULE,
116 .set_trigger_state = &iio_trig_periodic_rtc_set_state,
119 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
121 char **pdata = dev->dev.platform_data;
122 struct iio_prtc_trigger_info *trig_info;
123 struct iio_trigger *trig, *trig2;
130 trig = iio_trigger_alloc("periodic%s", pdata[i]);
133 goto error_free_completed_registrations;
135 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
137 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
140 goto error_put_trigger_and_remove_from_list;
142 iio_trigger_set_drvdata(trig, trig_info);
143 trig->ops = &iio_prtc_trigger_ops;
145 trig_info->rtc = rtc_class_open(pdata[i]);
146 if (!trig_info->rtc) {
148 goto error_free_trig_info;
150 trig_info->task.func = iio_prtc_trigger_poll;
151 trig_info->task.private_data = trig;
152 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
154 goto error_close_rtc;
155 trig->dev.groups = iio_trig_prtc_attr_groups;
156 ret = iio_trigger_register(trig);
158 goto error_unregister_rtc_irq;
161 error_unregister_rtc_irq:
162 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
164 rtc_class_close(trig_info->rtc);
165 error_free_trig_info:
167 error_put_trigger_and_remove_from_list:
168 list_del(&trig->alloc_list);
169 iio_trigger_put(trig);
170 error_free_completed_registrations:
171 list_for_each_entry_safe(trig,
173 &iio_prtc_trigger_list,
175 trig_info = iio_trigger_get_drvdata(trig);
176 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
177 rtc_class_close(trig_info->rtc);
179 iio_trigger_unregister(trig);
184 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
186 struct iio_trigger *trig, *trig2;
187 struct iio_prtc_trigger_info *trig_info;
189 mutex_lock(&iio_prtc_trigger_list_lock);
190 list_for_each_entry_safe(trig,
192 &iio_prtc_trigger_list,
194 trig_info = iio_trigger_get_drvdata(trig);
195 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
196 rtc_class_close(trig_info->rtc);
198 iio_trigger_unregister(trig);
200 mutex_unlock(&iio_prtc_trigger_list_lock);
204 static struct platform_driver iio_trig_periodic_rtc_driver = {
205 .probe = iio_trig_periodic_rtc_probe,
206 .remove = iio_trig_periodic_rtc_remove,
208 .name = "iio_prtc_trigger",
212 module_platform_driver(iio_trig_periodic_rtc_driver);
214 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
215 MODULE_DESCRIPTION("Periodic realtime clock trigger for the iio subsystem");
216 MODULE_LICENSE("GPL v2");