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;
31 static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
33 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
34 if (trig_info->frequency == 0)
36 printk(KERN_INFO "trigger frequency is %d\n", trig_info->frequency);
37 return rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
40 static ssize_t iio_trig_periodic_read_freq(struct device *dev,
41 struct device_attribute *attr,
44 struct iio_trigger *trig = to_iio_trigger(dev);
45 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
46 return sprintf(buf, "%u\n", trig_info->frequency);
49 static ssize_t iio_trig_periodic_write_freq(struct device *dev,
50 struct device_attribute *attr,
54 struct iio_trigger *trig = to_iio_trigger(dev);
55 struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
59 ret = kstrtoint(buf, 10, &val);
63 ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
67 trig_info->frequency = val;
75 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
76 iio_trig_periodic_read_freq,
77 iio_trig_periodic_write_freq);
79 static struct attribute *iio_trig_prtc_attrs[] = {
80 &dev_attr_frequency.attr,
84 static const struct attribute_group iio_trig_prtc_attr_group = {
85 .attrs = iio_trig_prtc_attrs,
88 static const struct attribute_group *iio_trig_prtc_attr_groups[] = {
89 &iio_trig_prtc_attr_group,
93 static void iio_prtc_trigger_poll(void *private_data)
95 /* Timestamp is not provided currently */
96 iio_trigger_poll(private_data, 0);
99 static const struct iio_trigger_ops iio_prtc_trigger_ops = {
100 .owner = THIS_MODULE,
101 .set_trigger_state = &iio_trig_periodic_rtc_set_state,
104 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
106 char **pdata = dev->dev.platform_data;
107 struct iio_prtc_trigger_info *trig_info;
108 struct iio_trigger *trig, *trig2;
113 if (pdata[i] == NULL)
115 trig = iio_trigger_alloc("periodic%s", pdata[i]);
118 goto error_free_completed_registrations;
120 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
122 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
125 goto error_put_trigger_and_remove_from_list;
127 iio_trigger_set_drvdata(trig, trig_info);
128 trig->ops = &iio_prtc_trigger_ops;
131 = rtc_class_open(pdata[i]);
132 if (trig_info->rtc == NULL) {
134 goto error_free_trig_info;
136 trig_info->task.func = iio_prtc_trigger_poll;
137 trig_info->task.private_data = trig;
138 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
140 goto error_close_rtc;
141 trig->dev.groups = iio_trig_prtc_attr_groups;
142 ret = iio_trigger_register(trig);
144 goto error_unregister_rtc_irq;
147 error_unregister_rtc_irq:
148 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
150 rtc_class_close(trig_info->rtc);
151 error_free_trig_info:
153 error_put_trigger_and_remove_from_list:
154 list_del(&trig->alloc_list);
155 iio_trigger_put(trig);
156 error_free_completed_registrations:
157 list_for_each_entry_safe(trig,
159 &iio_prtc_trigger_list,
161 trig_info = iio_trigger_get_drvdata(trig);
162 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
163 rtc_class_close(trig_info->rtc);
165 iio_trigger_unregister(trig);
170 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
172 struct iio_trigger *trig, *trig2;
173 struct iio_prtc_trigger_info *trig_info;
174 mutex_lock(&iio_prtc_trigger_list_lock);
175 list_for_each_entry_safe(trig,
177 &iio_prtc_trigger_list,
179 trig_info = iio_trigger_get_drvdata(trig);
180 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
181 rtc_class_close(trig_info->rtc);
183 iio_trigger_unregister(trig);
185 mutex_unlock(&iio_prtc_trigger_list_lock);
189 static struct platform_driver iio_trig_periodic_rtc_driver = {
190 .probe = iio_trig_periodic_rtc_probe,
191 .remove = iio_trig_periodic_rtc_remove,
193 .name = "iio_prtc_trigger",
194 .owner = THIS_MODULE,
198 module_platform_driver(iio_trig_periodic_rtc_driver);
200 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
201 MODULE_DESCRIPTION("Periodic realtime clock trigger for the iio subsystem");
202 MODULE_LICENSE("GPL v2");