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         bool state;
  30 };
  31
  32 static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
  33 {
  34         struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
  35         int ret;
  36         if (trig_info->frequency == 0 && state)
  37                 return -EINVAL;
  38         dev_dbg(&trig_info->rtc->dev, "trigger frequency is %d\n",
  39                         trig_info->frequency);
  40         ret = rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
  41         if (ret == 0)
  42                 trig_info->state = state;
  43
  44         return ret;
  45 }
  46
  47 static ssize_t iio_trig_periodic_read_freq(struct device *dev,
  48                                            struct device_attribute *attr,
  49                                            char *buf)
  50 {
  51         struct iio_trigger *trig = to_iio_trigger(dev);
  52         struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
  53         return sprintf(buf, "%u\n", trig_info->frequency);
  54 }
  55
  56 static ssize_t iio_trig_periodic_write_freq(struct device *dev,
  57                                             struct device_attribute *attr,
  58                                             const char *buf,
  59                                             size_t len)
  60 {
  61         struct iio_trigger *trig = to_iio_trigger(dev);
  62         struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
  63         int val;
  64         int ret;
  65
  66         ret = kstrtoint(buf, 10, &val);
  67         if (ret)
  68                 goto error_ret;
  69
  70         if (val > 0) {
  71                 ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
  72                 if (ret == 0 && trig_info->state && trig_info->frequency == 0)
  73                         ret = rtc_irq_set_state(trig_info->rtc, &trig_info->task, 1);
  74         } else if (val == 0) {
  75                 ret = rtc_irq_set_state(trig_info->rtc, &trig_info->task, 0);
  76         } else
  77                 ret = -EINVAL;
  78         if (ret)
  79                 goto error_ret;
  80
  81         trig_info->frequency = val;
  82
  83         return len;
  84
  85 error_ret:
  86         return ret;
  87 }
  88
  89 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
  90             iio_trig_periodic_read_freq,
  91             iio_trig_periodic_write_freq);
  92
  93 static struct attribute *iio_trig_prtc_attrs[] = {
  94         &dev_attr_frequency.attr,
  95         NULL,
  96 };
  97
  98 static const struct attribute_group iio_trig_prtc_attr_group = {
  99         .attrs = iio_trig_prtc_attrs,
 100 };
 101
 102 static const struct attribute_group *iio_trig_prtc_attr_groups[] = {
 103         &iio_trig_prtc_attr_group,
 104         NULL
 105 };
 106
 107 static void iio_prtc_trigger_poll(void *private_data)
 108 {
 109         iio_trigger_poll(private_data);
 110 }
 111
 112 static const struct iio_trigger_ops iio_prtc_trigger_ops = {
 113         .owner = THIS_MODULE,
 114         .set_trigger_state = &iio_trig_periodic_rtc_set_state,
 115 };
 116
 117 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
 118 {
 119         char **pdata = dev->dev.platform_data;
 120         struct iio_prtc_trigger_info *trig_info;
 121         struct iio_trigger *trig, *trig2;
 122
 123         int i, ret;
 124
 125         for (i = 0;; i++) {
 126                 if (pdata[i] == NULL)
 127                         break;
 128                 trig = iio_trigger_alloc("periodic%s", pdata[i]);
 129                 if (!trig) {
 130                         ret = -ENOMEM;
 131                         goto error_free_completed_registrations;
 132                 }
 133                 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
 134
 135                 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
 136                 if (!trig_info) {
 137                         ret = -ENOMEM;
 138                         goto error_put_trigger_and_remove_from_list;
 139                 }
 140                 iio_trigger_set_drvdata(trig, trig_info);
 141                 trig->ops = &iio_prtc_trigger_ops;
 142                 /* RTC access */
 143                 trig_info->rtc = rtc_class_open(pdata[i]);
 144                 if (trig_info->rtc == NULL) {
 145                         ret = -EINVAL;
 146                         goto error_free_trig_info;
 147                 }
 148                 trig_info->task.func = iio_prtc_trigger_poll;
 149                 trig_info->task.private_data = trig;
 150                 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
 151                 if (ret)
 152                         goto error_close_rtc;
 153                 trig->dev.groups = iio_trig_prtc_attr_groups;
 154                 ret = iio_trigger_register(trig);
 155                 if (ret)
 156                         goto error_unregister_rtc_irq;
 157         }
 158         return 0;
 159 error_unregister_rtc_irq:
 160         rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 161 error_close_rtc:
 162         rtc_class_close(trig_info->rtc);
 163 error_free_trig_info:
 164         kfree(trig_info);
 165 error_put_trigger_and_remove_from_list:
 166         list_del(&trig->alloc_list);
 167         iio_trigger_put(trig);
 168 error_free_completed_registrations:
 169         list_for_each_entry_safe(trig,
 170                                  trig2,
 171                                  &iio_prtc_trigger_list,
 172                                  alloc_list) {
 173                 trig_info = iio_trigger_get_drvdata(trig);
 174                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 175                 rtc_class_close(trig_info->rtc);
 176                 kfree(trig_info);
 177                 iio_trigger_unregister(trig);
 178         }
 179         return ret;
 180 }
 181
 182 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
 183 {
 184         struct iio_trigger *trig, *trig2;
 185         struct iio_prtc_trigger_info *trig_info;
 186         mutex_lock(&iio_prtc_trigger_list_lock);
 187         list_for_each_entry_safe(trig,
 188                                  trig2,
 189                                  &iio_prtc_trigger_list,
 190                                  alloc_list) {
 191                 trig_info = iio_trigger_get_drvdata(trig);
 192                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 193                 rtc_class_close(trig_info->rtc);
 194                 kfree(trig_info);
 195                 iio_trigger_unregister(trig);
 196         }
 197         mutex_unlock(&iio_prtc_trigger_list_lock);
 198         return 0;
 199 }
 200
 201 static struct platform_driver iio_trig_periodic_rtc_driver = {
 202         .probe = iio_trig_periodic_rtc_probe,
 203         .remove = iio_trig_periodic_rtc_remove,
 204         .driver = {
 205                 .name = "iio_prtc_trigger",
 206                 .owner = THIS_MODULE,
 207         },
 208 };
 209
 210 module_platform_driver(iio_trig_periodic_rtc_driver);
 211
 212 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 213 MODULE_DESCRIPTION("Periodic realtime clock trigger for the iio subsystem");
 214 MODULE_LICENSE("GPL v2");