drivers/iio/trigger/iio-trig-sysfs.c

   1 /*
   2  * Copyright 2011 Analog Devices Inc.
   3  *
   4  * Licensed under the GPL-2.
   5  *
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/slab.h>
  12 #include <linux/list.h>
  13 #include <linux/irq_work.h>
  14
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/trigger.h>
  17
  18 struct iio_sysfs_trig {
  19         struct iio_trigger *trig;
  20         struct irq_work work;
  21         int id;
  22         struct list_head l;
  23 };
  24
  25 static LIST_HEAD(iio_sysfs_trig_list);
  26 static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
  27
  28 static int iio_sysfs_trigger_probe(int id);
  29 static ssize_t iio_sysfs_trig_add(struct device *dev,
  30                                   struct device_attribute *attr,
  31                                   const char *buf,
  32                                   size_t len)
  33 {
  34         int ret;
  35         unsigned long input;
  36
  37         ret = kstrtoul(buf, 10, &input);
  38         if (ret)
  39                 return ret;
  40         ret = iio_sysfs_trigger_probe(input);
  41         if (ret)
  42                 return ret;
  43         return len;
  44 }
  45 static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
  46
  47 static int iio_sysfs_trigger_remove(int id);
  48 static ssize_t iio_sysfs_trig_remove(struct device *dev,
  49                                      struct device_attribute *attr,
  50                                      const char *buf,
  51                                      size_t len)
  52 {
  53         int ret;
  54         unsigned long input;
  55
  56         ret = kstrtoul(buf, 10, &input);
  57         if (ret)
  58                 return ret;
  59         ret = iio_sysfs_trigger_remove(input);
  60         if (ret)
  61                 return ret;
  62         return len;
  63 }
  64
  65 static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
  66
  67 static struct attribute *iio_sysfs_trig_attrs[] = {
  68         &dev_attr_add_trigger.attr,
  69         &dev_attr_remove_trigger.attr,
  70         NULL,
  71 };
  72
  73 static const struct attribute_group iio_sysfs_trig_group = {
  74         .attrs = iio_sysfs_trig_attrs,
  75 };
  76
  77 static const struct attribute_group *iio_sysfs_trig_groups[] = {
  78         &iio_sysfs_trig_group,
  79         NULL
  80 };
  81
  82
  83 /* Nothing to actually do upon release */
  84 static void iio_trigger_sysfs_release(struct device *dev)
  85 {
  86 }
  87
  88 static struct device iio_sysfs_trig_dev = {
  89         .bus = &iio_bus_type,
  90         .groups = iio_sysfs_trig_groups,
  91         .release = &iio_trigger_sysfs_release,
  92 };
  93
  94 static void iio_sysfs_trigger_work(struct irq_work *work)
  95 {
  96         struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
  97                                                         work);
  98
  99         iio_trigger_poll(trig->trig);
 100 }
 101
 102 static ssize_t iio_sysfs_trigger_poll(struct device *dev,
 103                 struct device_attribute *attr, const char *buf, size_t count)
 104 {
 105         struct iio_trigger *trig = to_iio_trigger(dev);
 106         struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
 107
 108         irq_work_queue(&sysfs_trig->work);
 109
 110         return count;
 111 }
 112
 113 static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
 114
 115 static struct attribute *iio_sysfs_trigger_attrs[] = {
 116         &dev_attr_trigger_now.attr,
 117         NULL,
 118 };
 119
 120 static const struct attribute_group iio_sysfs_trigger_attr_group = {
 121         .attrs = iio_sysfs_trigger_attrs,
 122 };
 123
 124 static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
 125         &iio_sysfs_trigger_attr_group,
 126         NULL
 127 };
 128
 129 static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
 130 };
 131
 132 static int iio_sysfs_trigger_probe(int id)
 133 {
 134         struct iio_sysfs_trig *t;
 135         int ret;
 136         bool foundit = false;
 137
 138         mutex_lock(&iio_sysfs_trig_list_mut);
 139         list_for_each_entry(t, &iio_sysfs_trig_list, l)
 140                 if (id == t->id) {
 141                         foundit = true;
 142                         break;
 143                 }
 144         if (foundit) {
 145                 ret = -EINVAL;
 146                 goto out1;
 147         }
 148         t = kmalloc(sizeof(*t), GFP_KERNEL);
 149         if (t == NULL) {
 150                 ret = -ENOMEM;
 151                 goto out1;
 152         }
 153         t->id = id;
 154         t->trig = iio_trigger_alloc("sysfstrig%d", id);
 155         if (!t->trig) {
 156                 ret = -ENOMEM;
 157                 goto free_t;
 158         }
 159
 160         t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
 161         t->trig->ops = &iio_sysfs_trigger_ops;
 162         t->trig->dev.parent = &iio_sysfs_trig_dev;
 163         iio_trigger_set_drvdata(t->trig, t);
 164
 165         init_irq_work(&t->work, iio_sysfs_trigger_work);
 166
 167         ret = iio_trigger_register(t->trig);
 168         if (ret)
 169                 goto out2;
 170         list_add(&t->l, &iio_sysfs_trig_list);
 171         __module_get(THIS_MODULE);
 172         mutex_unlock(&iio_sysfs_trig_list_mut);
 173         return 0;
 174
 175 out2:
 176         iio_trigger_free(t->trig);
 177 free_t:
 178         kfree(t);
 179 out1:
 180         mutex_unlock(&iio_sysfs_trig_list_mut);
 181         return ret;
 182 }
 183
 184 static int iio_sysfs_trigger_remove(int id)
 185 {
 186         bool foundit = false;
 187         struct iio_sysfs_trig *t;
 188
 189         mutex_lock(&iio_sysfs_trig_list_mut);
 190         list_for_each_entry(t, &iio_sysfs_trig_list, l)
 191                 if (id == t->id) {
 192                         foundit = true;
 193                         break;
 194                 }
 195         if (!foundit) {
 196                 mutex_unlock(&iio_sysfs_trig_list_mut);
 197                 return -EINVAL;
 198         }
 199
 200         iio_trigger_unregister(t->trig);
 201         iio_trigger_free(t->trig);
 202
 203         list_del(&t->l);
 204         kfree(t);
 205         module_put(THIS_MODULE);
 206         mutex_unlock(&iio_sysfs_trig_list_mut);
 207         return 0;
 208 }
 209
 210
 211 static int __init iio_sysfs_trig_init(void)
 212 {
 213         device_initialize(&iio_sysfs_trig_dev);
 214         dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
 215         return device_add(&iio_sysfs_trig_dev);
 216 }
 217 module_init(iio_sysfs_trig_init);
 218
 219 static void __exit iio_sysfs_trig_exit(void)
 220 {
 221         device_unregister(&iio_sysfs_trig_dev);
 222 }
 223 module_exit(iio_sysfs_trig_exit);
 224
 225 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 226 MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
 227 MODULE_LICENSE("GPL v2");
 228 MODULE_ALIAS("platform:iio-trig-sysfs");