ec_sys.c 3.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * ec_sys.c
  4. *
  5. * Copyright (C) 2010 SUSE Products GmbH/Novell
  6. * Author:
  7. * Thomas Renninger <trenn@suse.de>
  8. */
  9. #include <linux/kernel.h>
  10. #include <linux/acpi.h>
  11. #include <linux/debugfs.h>
  12. #include <linux/module.h>
  13. #include <linux/uaccess.h>
  14. #include "internal.h"
  15. MODULE_AUTHOR("Thomas Renninger <trenn@suse.de>");
  16. MODULE_DESCRIPTION("ACPI EC sysfs access driver");
  17. MODULE_LICENSE("GPL");
  18. static bool write_support;
  19. module_param(write_support, bool, 0644);
  20. MODULE_PARM_DESC(write_support, "Dangerous, reboot and removal of battery may "
  21. "be needed.");
  22. #define EC_SPACE_SIZE 256
  23. static struct dentry *acpi_ec_debugfs_dir;
  24. static ssize_t acpi_ec_read_io(struct file *f, char __user *buf,
  25. size_t count, loff_t *off)
  26. {
  27. /* Use this if support reading/writing multiple ECs exists in ec.c:
  28. * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  29. */
  30. unsigned int size = EC_SPACE_SIZE;
  31. loff_t init_off = *off;
  32. int err = 0;
  33. if (*off >= size)
  34. return 0;
  35. if (*off + count >= size) {
  36. size -= *off;
  37. count = size;
  38. } else
  39. size = count;
  40. while (size) {
  41. u8 byte_read;
  42. err = ec_read(*off, &byte_read);
  43. if (err)
  44. return err;
  45. if (put_user(byte_read, buf + *off - init_off)) {
  46. if (*off - init_off)
  47. return *off - init_off; /* partial read */
  48. return -EFAULT;
  49. }
  50. *off += 1;
  51. size--;
  52. }
  53. return count;
  54. }
  55. static ssize_t acpi_ec_write_io(struct file *f, const char __user *buf,
  56. size_t count, loff_t *off)
  57. {
  58. /* Use this if support reading/writing multiple ECs exists in ec.c:
  59. * struct acpi_ec *ec = ((struct seq_file *)f->private_data)->private;
  60. */
  61. unsigned int size = count;
  62. loff_t init_off = *off;
  63. int err = 0;
  64. if (!write_support)
  65. return -EINVAL;
  66. if (*off >= EC_SPACE_SIZE)
  67. return 0;
  68. if (*off + count >= EC_SPACE_SIZE) {
  69. size = EC_SPACE_SIZE - *off;
  70. count = size;
  71. }
  72. while (size) {
  73. u8 byte_write;
  74. if (get_user(byte_write, buf + *off - init_off)) {
  75. if (*off - init_off)
  76. return *off - init_off; /* partial write */
  77. return -EFAULT;
  78. }
  79. err = ec_write(*off, byte_write);
  80. if (err)
  81. return err;
  82. *off += 1;
  83. size--;
  84. }
  85. return count;
  86. }
  87. static const struct file_operations acpi_ec_io_ops = {
  88. .owner = THIS_MODULE,
  89. .open = simple_open,
  90. .read = acpi_ec_read_io,
  91. .write = acpi_ec_write_io,
  92. .llseek = default_llseek,
  93. };
  94. static void acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count)
  95. {
  96. struct dentry *dev_dir;
  97. char name[64];
  98. umode_t mode = 0400;
  99. if (ec_device_count == 0)
  100. acpi_ec_debugfs_dir = debugfs_create_dir("ec", NULL);
  101. sprintf(name, "ec%u", ec_device_count);
  102. dev_dir = debugfs_create_dir(name, acpi_ec_debugfs_dir);
  103. debugfs_create_x32("gpe", 0444, dev_dir, &first_ec->gpe);
  104. debugfs_create_bool("use_global_lock", 0444, dev_dir,
  105. &first_ec->global_lock);
  106. if (write_support)
  107. mode = 0600;
  108. debugfs_create_file("io", mode, dev_dir, ec, &acpi_ec_io_ops);
  109. }
  110. static int __init acpi_ec_sys_init(void)
  111. {
  112. if (first_ec)
  113. acpi_ec_add_debugfs(first_ec, 0);
  114. return 0;
  115. }
  116. static void __exit acpi_ec_sys_exit(void)
  117. {
  118. debugfs_remove_recursive(acpi_ec_debugfs_dir);
  119. }
  120. module_init(acpi_ec_sys_init);
  121. module_exit(acpi_ec_sys_exit);