iio-trig-sysfs.c 4.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright 2011 Analog Devices Inc.
  4. */
  5. #include <linux/kernel.h>
  6. #include <linux/module.h>
  7. #include <linux/platform_device.h>
  8. #include <linux/slab.h>
  9. #include <linux/list.h>
  10. #include <linux/irq_work.h>
  11. #include <linux/iio/iio.h>
  12. #include <linux/iio/trigger.h>
  13. struct iio_sysfs_trig {
  14. struct iio_trigger *trig;
  15. struct irq_work work;
  16. int id;
  17. struct list_head l;
  18. };
  19. static LIST_HEAD(iio_sysfs_trig_list);
  20. static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
  21. static int iio_sysfs_trigger_probe(int id);
  22. static ssize_t iio_sysfs_trig_add(struct device *dev,
  23. struct device_attribute *attr,
  24. const char *buf,
  25. size_t len)
  26. {
  27. int ret;
  28. unsigned long input;
  29. ret = kstrtoul(buf, 10, &input);
  30. if (ret)
  31. return ret;
  32. ret = iio_sysfs_trigger_probe(input);
  33. if (ret)
  34. return ret;
  35. return len;
  36. }
  37. static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
  38. static int iio_sysfs_trigger_remove(int id);
  39. static ssize_t iio_sysfs_trig_remove(struct device *dev,
  40. struct device_attribute *attr,
  41. const char *buf,
  42. size_t len)
  43. {
  44. int ret;
  45. unsigned long input;
  46. ret = kstrtoul(buf, 10, &input);
  47. if (ret)
  48. return ret;
  49. ret = iio_sysfs_trigger_remove(input);
  50. if (ret)
  51. return ret;
  52. return len;
  53. }
  54. static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
  55. static struct attribute *iio_sysfs_trig_attrs[] = {
  56. &dev_attr_add_trigger.attr,
  57. &dev_attr_remove_trigger.attr,
  58. NULL,
  59. };
  60. static const struct attribute_group iio_sysfs_trig_group = {
  61. .attrs = iio_sysfs_trig_attrs,
  62. };
  63. static const struct attribute_group *iio_sysfs_trig_groups[] = {
  64. &iio_sysfs_trig_group,
  65. NULL
  66. };
  67. /* Nothing to actually do upon release */
  68. static void iio_trigger_sysfs_release(struct device *dev)
  69. {
  70. }
  71. static struct device iio_sysfs_trig_dev = {
  72. .bus = &iio_bus_type,
  73. .groups = iio_sysfs_trig_groups,
  74. .release = &iio_trigger_sysfs_release,
  75. };
  76. static void iio_sysfs_trigger_work(struct irq_work *work)
  77. {
  78. struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
  79. work);
  80. iio_trigger_poll(trig->trig);
  81. }
  82. static ssize_t iio_sysfs_trigger_poll(struct device *dev,
  83. struct device_attribute *attr, const char *buf, size_t count)
  84. {
  85. struct iio_trigger *trig = to_iio_trigger(dev);
  86. struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
  87. irq_work_queue(&sysfs_trig->work);
  88. return count;
  89. }
  90. static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
  91. static struct attribute *iio_sysfs_trigger_attrs[] = {
  92. &dev_attr_trigger_now.attr,
  93. NULL,
  94. };
  95. static const struct attribute_group iio_sysfs_trigger_attr_group = {
  96. .attrs = iio_sysfs_trigger_attrs,
  97. };
  98. static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
  99. &iio_sysfs_trigger_attr_group,
  100. NULL
  101. };
  102. static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
  103. };
  104. static int iio_sysfs_trigger_probe(int id)
  105. {
  106. struct iio_sysfs_trig *t;
  107. int ret;
  108. bool foundit = false;
  109. mutex_lock(&iio_sysfs_trig_list_mut);
  110. list_for_each_entry(t, &iio_sysfs_trig_list, l)
  111. if (id == t->id) {
  112. foundit = true;
  113. break;
  114. }
  115. if (foundit) {
  116. ret = -EINVAL;
  117. goto out1;
  118. }
  119. t = kmalloc(sizeof(*t), GFP_KERNEL);
  120. if (t == NULL) {
  121. ret = -ENOMEM;
  122. goto out1;
  123. }
  124. t->id = id;
  125. t->trig = iio_trigger_alloc("sysfstrig%d", id);
  126. if (!t->trig) {
  127. ret = -ENOMEM;
  128. goto free_t;
  129. }
  130. t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
  131. t->trig->ops = &iio_sysfs_trigger_ops;
  132. t->trig->dev.parent = &iio_sysfs_trig_dev;
  133. iio_trigger_set_drvdata(t->trig, t);
  134. init_irq_work(&t->work, iio_sysfs_trigger_work);
  135. ret = iio_trigger_register(t->trig);
  136. if (ret)
  137. goto out2;
  138. list_add(&t->l, &iio_sysfs_trig_list);
  139. __module_get(THIS_MODULE);
  140. mutex_unlock(&iio_sysfs_trig_list_mut);
  141. return 0;
  142. out2:
  143. iio_trigger_free(t->trig);
  144. free_t:
  145. kfree(t);
  146. out1:
  147. mutex_unlock(&iio_sysfs_trig_list_mut);
  148. return ret;
  149. }
  150. static int iio_sysfs_trigger_remove(int id)
  151. {
  152. bool foundit = false;
  153. struct iio_sysfs_trig *t;
  154. mutex_lock(&iio_sysfs_trig_list_mut);
  155. list_for_each_entry(t, &iio_sysfs_trig_list, l)
  156. if (id == t->id) {
  157. foundit = true;
  158. break;
  159. }
  160. if (!foundit) {
  161. mutex_unlock(&iio_sysfs_trig_list_mut);
  162. return -EINVAL;
  163. }
  164. iio_trigger_unregister(t->trig);
  165. iio_trigger_free(t->trig);
  166. list_del(&t->l);
  167. kfree(t);
  168. module_put(THIS_MODULE);
  169. mutex_unlock(&iio_sysfs_trig_list_mut);
  170. return 0;
  171. }
  172. static int __init iio_sysfs_trig_init(void)
  173. {
  174. device_initialize(&iio_sysfs_trig_dev);
  175. dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
  176. return device_add(&iio_sysfs_trig_dev);
  177. }
  178. module_init(iio_sysfs_trig_init);
  179. static void __exit iio_sysfs_trig_exit(void)
  180. {
  181. device_unregister(&iio_sysfs_trig_dev);
  182. }
  183. module_exit(iio_sysfs_trig_exit);
  184. MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
  185. MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
  186. MODULE_LICENSE("GPL v2");
  187. MODULE_ALIAS("platform:iio-trig-sysfs");