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 LIST_HEAD(iio_prtc_trigger_list);
  23 DEFINE_MUTEX(iio_prtc_trigger_list_lock);
  24
  25 struct iio_prtc_trigger_info {
  26         struct rtc_device *rtc;
  27         int frequency;
  28         char *name;
  29         struct rtc_task task;
  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 = trig->private_data;
  35         if (trig_info->frequency == 0)
  36                 return -EINVAL;
  37         printk(KERN_INFO "trigger frequency is %d\n", trig_info->frequency);
  38         return rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
  39 }
  40
  41 static ssize_t iio_trig_periodic_read_freq(struct device *dev,
  42                                            struct device_attribute *attr,
  43                                            char *buf)
  44 {
  45         struct iio_trigger *trig = dev_get_drvdata(dev);
  46         struct iio_prtc_trigger_info *trig_info = trig->private_data;
  47         return sprintf(buf, "%u\n", trig_info->frequency);
  48 }
  49
  50 static ssize_t iio_trig_periodic_write_freq(struct device *dev,
  51                                             struct device_attribute *attr,
  52                                             const char *buf,
  53                                             size_t len)
  54 {
  55         struct iio_trigger *trig = dev_get_drvdata(dev);
  56         struct iio_prtc_trigger_info *trig_info = trig->private_data;
  57         unsigned long val;
  58         int ret;
  59
  60         ret = strict_strtoul(buf, 10, &val);
  61         if (ret)
  62                 goto error_ret;
  63
  64         ret = rtc_irq_set_freq(trig_info->rtc, &trig_info->task, val);
  65         if (ret)
  66                 goto error_ret;
  67
  68         trig_info->frequency = val;
  69
  70         return len;
  71
  72 error_ret:
  73         return ret;
  74 }
  75
  76 static ssize_t iio_trig_periodic_read_name(struct device *dev,
  77                                            struct device_attribute *attr,
  78                                            char *buf)
  79 {
  80         struct iio_trigger *trig = dev_get_drvdata(dev);
  81         struct iio_prtc_trigger_info *trig_info = trig->private_data;
  82         return sprintf(buf, "%s\n", trig_info->name);
  83 }
  84
  85 static DEVICE_ATTR(name, S_IRUGO,
  86             iio_trig_periodic_read_name,
  87             NULL);
  88 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
  89             iio_trig_periodic_read_freq,
  90             iio_trig_periodic_write_freq);
  91
  92 static struct attribute *iio_trig_prtc_attrs[] = {
  93         &dev_attr_frequency.attr,
  94         &dev_attr_name.attr,
  95         NULL,
  96 };
  97 static const struct attribute_group iio_trig_prtc_attr_group = {
  98         .attrs = iio_trig_prtc_attrs,
  99 };
 100
 101 static void iio_prtc_trigger_poll(void *private_data)
 102 {
 103         iio_trigger_poll(private_data);
 104 }
 105
 106 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
 107 {
 108         char **pdata = dev->dev.platform_data;
 109         struct iio_prtc_trigger_info *trig_info;
 110         struct iio_trigger *trig, *trig2;
 111
 112         int i, ret;
 113
 114         for (i = 0;; i++) {
 115                 if (pdata[i] == NULL)
 116                         break;
 117                 trig = iio_allocate_trigger();
 118                 if (!trig) {
 119                         ret = -ENOMEM;
 120                         goto error_free_completed_registrations;
 121                 }
 122                 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
 123
 124                 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
 125                 if (!trig_info) {
 126                         ret = -ENOMEM;
 127                         goto error_put_trigger_and_remove_from_list;
 128                 }
 129                 trig->private_data = trig_info;
 130                 trig->owner = THIS_MODULE;
 131                 trig->set_trigger_state = &iio_trig_periodic_rtc_set_state;
 132                 trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
 133                 if (trig->name == NULL) {
 134                         ret = -ENOMEM;
 135                         goto error_free_trig_info;
 136                 }
 137                 snprintf((char *)trig->name,
 138                          IIO_TRIGGER_NAME_LENGTH,
 139                          "periodic%s",
 140                          pdata[i]);
 141                 trig_info->name = (char *)trig->name;
 142                 /* RTC access */
 143                 trig_info->rtc
 144                         = rtc_class_open(pdata[i]);
 145                 if (trig_info->rtc == NULL) {
 146                         ret = -EINVAL;
 147                         goto error_free_name;
 148                 }
 149                 trig_info->task.func = iio_prtc_trigger_poll;
 150                 trig_info->task.private_data = trig;
 151                 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
 152                 if (ret)
 153                         goto error_close_rtc;
 154                 trig->control_attrs = &iio_trig_prtc_attr_group;
 155                 ret = iio_trigger_register(trig);
 156                 if (ret)
 157                         goto error_unregister_rtc_irq;
 158         }
 159         return 0;
 160 error_unregister_rtc_irq:
 161         rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 162 error_close_rtc:
 163         rtc_class_close(trig_info->rtc);
 164 error_free_name:
 165         kfree(trig->name);
 166 error_free_trig_info:
 167         kfree(trig_info);
 168 error_put_trigger_and_remove_from_list:
 169         list_del(&trig->alloc_list);
 170         iio_put_trigger(trig);
 171 error_free_completed_registrations:
 172         list_for_each_entry_safe(trig,
 173                                  trig2,
 174                                  &iio_prtc_trigger_list,
 175                                  alloc_list) {
 176                 trig_info = trig->private_data;
 177                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 178                 rtc_class_close(trig_info->rtc);
 179                 kfree(trig->name);
 180                 kfree(trig_info);
 181                 iio_trigger_unregister(trig);
 182         }
 183         return ret;
 184 }
 185
 186 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
 187 {
 188         struct iio_trigger *trig, *trig2;
 189         struct iio_prtc_trigger_info *trig_info;
 190         mutex_lock(&iio_prtc_trigger_list_lock);
 191         list_for_each_entry_safe(trig,
 192                                  trig2,
 193                                  &iio_prtc_trigger_list,
 194                                  alloc_list) {
 195                 trig_info = trig->private_data;
 196                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 197                 rtc_class_close(trig_info->rtc);
 198                 kfree(trig->name);
 199                 kfree(trig_info);
 200                 iio_trigger_unregister(trig);
 201         }
 202         mutex_unlock(&iio_prtc_trigger_list_lock);
 203         return 0;
 204 }
 205
 206 static struct platform_driver iio_trig_periodic_rtc_driver = {
 207         .probe = iio_trig_periodic_rtc_probe,
 208         .remove = iio_trig_periodic_rtc_remove,
 209         .driver = {
 210                 .name = "iio_prtc_trigger",
 211                 .owner = THIS_MODULE,
 212         },
 213 };
 214
 215 static int __init iio_trig_periodic_rtc_init(void)
 216 {
 217         return platform_driver_register(&iio_trig_periodic_rtc_driver);
 218 }
 219
 220 static void __exit iio_trig_periodic_rtc_exit(void)
 221 {
 222         return platform_driver_unregister(&iio_trig_periodic_rtc_driver);
 223 }
 224
 225 module_init(iio_trig_periodic_rtc_init);
 226 module_exit(iio_trig_periodic_rtc_exit);
 227 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 228 MODULE_DESCRIPTION("Periodic realtime clock  trigger for the iio subsystem");
 229 MODULE_LICENSE("GPL v2");