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 "../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
  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
  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
  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
  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 int iio_trig_periodic_rtc_probe(struct platform_device *dev)
 100 {
 101         char **pdata = dev->dev.platform_data;
 102         struct iio_prtc_trigger_info *trig_info;
 103         struct iio_trigger *trig, *trig2;
 104
 105         int i, ret;
 106
 107         for (i = 0;; i++) {
 108                 if (pdata[i] == NULL)
 109                         break;
 110                 trig = iio_allocate_trigger("periodic%s", pdata[i]);
 111                 if (!trig) {
 112                         ret = -ENOMEM;
 113                         goto error_free_completed_registrations;
 114                 }
 115                 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
 116
 117                 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
 118                 if (!trig_info) {
 119                         ret = -ENOMEM;
 120                         goto error_put_trigger_and_remove_from_list;
 121                 }
 122                 trig->private_data = trig_info;
 123                 trig->owner = THIS_MODULE;
 124                 trig->set_trigger_state = &iio_trig_periodic_rtc_set_state;
 125                 /* RTC access */
 126                 trig_info->rtc
 127                         = rtc_class_open(pdata[i]);
 128                 if (trig_info->rtc == NULL) {
 129                         ret = -EINVAL;
 130                         goto error_free_trig_info;
 131                 }
 132                 trig_info->task.func = iio_prtc_trigger_poll;
 133                 trig_info->task.private_data = trig;
 134                 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
 135                 if (ret)
 136                         goto error_close_rtc;
 137                 trig->dev.groups = iio_trig_prtc_attr_groups;
 138                 ret = iio_trigger_register(trig);
 139                 if (ret)
 140                         goto error_unregister_rtc_irq;
 141         }
 142         return 0;
 143 error_unregister_rtc_irq:
 144         rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 145 error_close_rtc:
 146         rtc_class_close(trig_info->rtc);
 147 error_free_trig_info:
 148         kfree(trig_info);
 149 error_put_trigger_and_remove_from_list:
 150         list_del(&trig->alloc_list);
 151         iio_put_trigger(trig);
 152 error_free_completed_registrations:
 153         list_for_each_entry_safe(trig,
 154                                  trig2,
 155                                  &iio_prtc_trigger_list,
 156                                  alloc_list) {
 157                 trig_info = trig->private_data;
 158                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 159                 rtc_class_close(trig_info->rtc);
 160                 kfree(trig_info);
 161                 iio_trigger_unregister(trig);
 162         }
 163         return ret;
 164 }
 165
 166 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
 167 {
 168         struct iio_trigger *trig, *trig2;
 169         struct iio_prtc_trigger_info *trig_info;
 170         mutex_lock(&iio_prtc_trigger_list_lock);
 171         list_for_each_entry_safe(trig,
 172                                  trig2,
 173                                  &iio_prtc_trigger_list,
 174                                  alloc_list) {
 175                 trig_info = trig->private_data;
 176                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 177                 rtc_class_close(trig_info->rtc);
 178                 kfree(trig_info);
 179                 iio_trigger_unregister(trig);
 180         }
 181         mutex_unlock(&iio_prtc_trigger_list_lock);
 182         return 0;
 183 }
 184
 185 static struct platform_driver iio_trig_periodic_rtc_driver = {
 186         .probe = iio_trig_periodic_rtc_probe,
 187         .remove = iio_trig_periodic_rtc_remove,
 188         .driver = {
 189                 .name = "iio_prtc_trigger",
 190                 .owner = THIS_MODULE,
 191         },
 192 };
 193
 194 static int __init iio_trig_periodic_rtc_init(void)
 195 {
 196         return platform_driver_register(&iio_trig_periodic_rtc_driver);
 197 }
 198
 199 static void __exit iio_trig_periodic_rtc_exit(void)
 200 {
 201         return platform_driver_unregister(&iio_trig_periodic_rtc_driver);
 202 }
 203
 204 module_init(iio_trig_periodic_rtc_init);
 205 module_exit(iio_trig_periodic_rtc_exit);
 206 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 207 MODULE_DESCRIPTION("Periodic realtime clock  trigger for the iio subsystem");
 208 MODULE_LICENSE("GPL v2");