1 /* The industrial I/O periodic RTC trigger driver
2 *
3 * Copyright (c) 2008 Jonathan Cameron
4 *
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.
8 *
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.
12 */
13
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 "../iio.h"
20 #include "../trigger.h"
21
22 static LIST_HEAD(iio_prtc_trigger_list);
23 static DEFINE_MUTEX(iio_prtc_trigger_list_lock);
24
25 struct iio_prtc_trigger_info {
26 struct rtc_device *rtc;
27 int frequency;
28 struct rtc_task task;
29 };
30
iio_trig_periodic_rtc_set_state(struct iio_trigger * trig,bool state)31 static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
32 {
33 struct iio_prtc_trigger_info *trig_info = trig->private_data;
34 if (trig_info->frequency == 0)
35 return -EINVAL;
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);
38 }
39
iio_trig_periodic_read_freq(struct device * dev,struct device_attribute * attr,char * buf)40 static ssize_t iio_trig_periodic_read_freq(struct device *dev,
41 struct device_attribute *attr,
42 char *buf)
43 {
44 struct iio_trigger *trig = dev_get_drvdata(dev);
45 struct iio_prtc_trigger_info *trig_info = trig->private_data;
46 return sprintf(buf, "%u\n", trig_info->frequency);
47 }
48
iio_trig_periodic_write_freq(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)49 static ssize_t iio_trig_periodic_write_freq(struct device *dev,
50 struct device_attribute *attr,
51 const char *buf,
52 size_t len)
53 {
54 struct iio_trigger *trig = dev_get_drvdata(dev);
55 struct iio_prtc_trigger_info *trig_info = trig->private_data;
56 unsigned long val;
57 int ret;
58
59 ret = strict_strtoul(buf, 10, &val);
60 if (ret)
61 goto error_ret;
62
63 ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
64 if (ret)
65 goto error_ret;
66
67 trig_info->frequency = val;
68
69 return len;
70
71 error_ret:
72 return ret;
73 }
74
75 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
76 iio_trig_periodic_read_freq,
77 iio_trig_periodic_write_freq);
78
79 static struct attribute *iio_trig_prtc_attrs[] = {
80 &dev_attr_frequency.attr,
81 NULL,
82 };
83
84 static const struct attribute_group iio_trig_prtc_attr_group = {
85 .attrs = iio_trig_prtc_attrs,
86 };
87
88 static const struct attribute_group *iio_trig_prtc_attr_groups[] = {
89 &iio_trig_prtc_attr_group,
90 NULL
91 };
92
iio_prtc_trigger_poll(void * private_data)93 static void iio_prtc_trigger_poll(void *private_data)
94 {
95 /* Timestamp is not provided currently */
96 iio_trigger_poll(private_data, 0);
97 }
98
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,
102 };
103
iio_trig_periodic_rtc_probe(struct platform_device * dev)104 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
105 {
106 char **pdata = dev->dev.platform_data;
107 struct iio_prtc_trigger_info *trig_info;
108 struct iio_trigger *trig, *trig2;
109
110 int i, ret;
111
112 for (i = 0;; i++) {
113 if (pdata[i] == NULL)
114 break;
115 trig = iio_allocate_trigger("periodic%s", pdata[i]);
116 if (!trig) {
117 ret = -ENOMEM;
118 goto error_free_completed_registrations;
119 }
120 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
121
122 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
123 if (!trig_info) {
124 ret = -ENOMEM;
125 goto error_put_trigger_and_remove_from_list;
126 }
127 trig->private_data = trig_info;
128 trig->ops = &iio_prtc_trigger_ops;
129 /* RTC access */
130 trig_info->rtc
131 = rtc_class_open(pdata[i]);
132 if (trig_info->rtc == NULL) {
133 ret = -EINVAL;
134 goto error_free_trig_info;
135 }
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);
139 if (ret)
140 goto error_close_rtc;
141 trig->dev.groups = iio_trig_prtc_attr_groups;
142 ret = iio_trigger_register(trig);
143 if (ret)
144 goto error_unregister_rtc_irq;
145 }
146 return 0;
147 error_unregister_rtc_irq:
148 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
149 error_close_rtc:
150 rtc_class_close(trig_info->rtc);
151 error_free_trig_info:
152 kfree(trig_info);
153 error_put_trigger_and_remove_from_list:
154 list_del(&trig->alloc_list);
155 iio_put_trigger(trig);
156 error_free_completed_registrations:
157 list_for_each_entry_safe(trig,
158 trig2,
159 &iio_prtc_trigger_list,
160 alloc_list) {
161 trig_info = trig->private_data;
162 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
163 rtc_class_close(trig_info->rtc);
164 kfree(trig_info);
165 iio_trigger_unregister(trig);
166 }
167 return ret;
168 }
169
iio_trig_periodic_rtc_remove(struct platform_device * dev)170 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
171 {
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,
176 trig2,
177 &iio_prtc_trigger_list,
178 alloc_list) {
179 trig_info = trig->private_data;
180 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
181 rtc_class_close(trig_info->rtc);
182 kfree(trig_info);
183 iio_trigger_unregister(trig);
184 }
185 mutex_unlock(&iio_prtc_trigger_list_lock);
186 return 0;
187 }
188
189 static struct platform_driver iio_trig_periodic_rtc_driver = {
190 .probe = iio_trig_periodic_rtc_probe,
191 .remove = iio_trig_periodic_rtc_remove,
192 .driver = {
193 .name = "iio_prtc_trigger",
194 .owner = THIS_MODULE,
195 },
196 };
197
198 module_platform_driver(iio_trig_periodic_rtc_driver);
199
200 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
201 MODULE_DESCRIPTION("Periodic realtime clock trigger for the iio subsystem");
202 MODULE_LICENSE("GPL v2");
203