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 IIO_TRIGGER_NAME_ATTR;
  76 static DEVICE_ATTR(frequency, S_IRUGO | S_IWUSR,
  77             iio_trig_periodic_read_freq,
  78             iio_trig_periodic_write_freq);
  79
  80 static struct attribute *iio_trig_prtc_attrs[] = {
  81         &dev_attr_frequency.attr,
  82         &dev_attr_name.attr,
  83         NULL,
  84 };
  85 static const struct attribute_group iio_trig_prtc_attr_group = {
  86         .attrs = iio_trig_prtc_attrs,
  87 };
  88
  89 static void iio_prtc_trigger_poll(void *private_data)
  90 {
  91         /* Timestamp is not provided currently */
  92         iio_trigger_poll(private_data, 0);
  93 }
  94
  95 static int iio_trig_periodic_rtc_probe(struct platform_device *dev)
  96 {
  97         char **pdata = dev->dev.platform_data;
  98         struct iio_prtc_trigger_info *trig_info;
  99         struct iio_trigger *trig, *trig2;
 100
 101         int i, ret;
 102
 103         for (i = 0;; i++) {
 104                 if (pdata[i] == NULL)
 105                         break;
 106                 trig = iio_allocate_trigger();
 107                 if (!trig) {
 108                         ret = -ENOMEM;
 109                         goto error_free_completed_registrations;
 110                 }
 111                 list_add(&trig->alloc_list, &iio_prtc_trigger_list);
 112
 113                 trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
 114                 if (!trig_info) {
 115                         ret = -ENOMEM;
 116                         goto error_put_trigger_and_remove_from_list;
 117                 }
 118                 trig->private_data = trig_info;
 119                 trig->owner = THIS_MODULE;
 120                 trig->set_trigger_state = &iio_trig_periodic_rtc_set_state;
 121                 trig->name = kasprintf(GFP_KERNEL, "periodic%s", pdata[i]);
 122                 if (trig->name == NULL) {
 123                         ret = -ENOMEM;
 124                         goto error_free_trig_info;
 125                 }
 126
 127                 /* RTC access */
 128                 trig_info->rtc
 129                         = rtc_class_open(pdata[i]);
 130                 if (trig_info->rtc == NULL) {
 131                         ret = -EINVAL;
 132                         goto error_free_name;
 133                 }
 134                 trig_info->task.func = iio_prtc_trigger_poll;
 135                 trig_info->task.private_data = trig;
 136                 ret = rtc_irq_register(trig_info->rtc, &trig_info->task);
 137                 if (ret)
 138                         goto error_close_rtc;
 139                 trig->control_attrs = &iio_trig_prtc_attr_group;
 140                 ret = iio_trigger_register(trig);
 141                 if (ret)
 142                         goto error_unregister_rtc_irq;
 143         }
 144         return 0;
 145 error_unregister_rtc_irq:
 146         rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 147 error_close_rtc:
 148         rtc_class_close(trig_info->rtc);
 149 error_free_name:
 150         kfree(trig->name);
 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->name);
 165                 kfree(trig_info);
 166                 iio_trigger_unregister(trig);
 167         }
 168         return ret;
 169 }
 170
 171 static int iio_trig_periodic_rtc_remove(struct platform_device *dev)
 172 {
 173         struct iio_trigger *trig, *trig2;
 174         struct iio_prtc_trigger_info *trig_info;
 175         mutex_lock(&iio_prtc_trigger_list_lock);
 176         list_for_each_entry_safe(trig,
 177                                  trig2,
 178                                  &iio_prtc_trigger_list,
 179                                  alloc_list) {
 180                 trig_info = trig->private_data;
 181                 rtc_irq_unregister(trig_info->rtc, &trig_info->task);
 182                 rtc_class_close(trig_info->rtc);
 183                 kfree(trig->name);
 184                 kfree(trig_info);
 185                 iio_trigger_unregister(trig);
 186         }
 187         mutex_unlock(&iio_prtc_trigger_list_lock);
 188         return 0;
 189 }
 190
 191 static struct platform_driver iio_trig_periodic_rtc_driver = {
 192         .probe = iio_trig_periodic_rtc_probe,
 193         .remove = iio_trig_periodic_rtc_remove,
 194         .driver = {
 195                 .name = "iio_prtc_trigger",
 196                 .owner = THIS_MODULE,
 197         },
 198 };
 199
 200 static int __init iio_trig_periodic_rtc_init(void)
 201 {
 202         return platform_driver_register(&iio_trig_periodic_rtc_driver);
 203 }
 204
 205 static void __exit iio_trig_periodic_rtc_exit(void)
 206 {
 207         return platform_driver_unregister(&iio_trig_periodic_rtc_driver);
 208 }
 209
 210 module_init(iio_trig_periodic_rtc_init);
 211 module_exit(iio_trig_periodic_rtc_exit);
 212 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 213 MODULE_DESCRIPTION("Periodic realtime clock  trigger for the iio subsystem");
 214 MODULE_LICENSE("GPL v2");