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Linux/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c

  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 <linux/iio/iio.h>
 20 #include <linux/iio/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 
 31 static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
 32 {
 33         struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
 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 
 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 = 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);
 47 }
 48 
 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 = to_iio_trigger(dev);
 55         struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
 56         int val;
 57         int ret;
 58 
 59         ret = kstrtoint(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 
 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 
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_trigger_alloc("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                 iio_trigger_set_drvdata(trig, 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_trigger_put(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 = iio_trigger_get_drvdata(trig);
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 
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 = iio_trigger_get_drvdata(trig);
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@kernel.org>");
201 MODULE_DESCRIPTION("Periodic realtime clock  trigger for the iio subsystem");
202 MODULE_LICENSE("GPL v2");
203 

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