dell-wmi-led.c 4.2 KB

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  1. /*
  2. * Copyright (C) 2010 Dell Inc.
  3. * Louis Davis <louis_davis@dell.com>
  4. * Jim Dailey <jim_dailey@dell.com>
  5. *
  6. * This program is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License as
  8. * published by the Free Software Foundation.
  9. *
  10. */
  11. #include <linux/acpi.h>
  12. #include <linux/leds.h>
  13. #include <linux/slab.h>
  14. #include <linux/module.h>
  15. MODULE_AUTHOR("Louis Davis/Jim Dailey");
  16. MODULE_DESCRIPTION("Dell LED Control Driver");
  17. MODULE_LICENSE("GPL");
  18. #define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396"
  19. MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID);
  20. /* Error Result Codes: */
  21. #define INVALID_DEVICE_ID 250
  22. #define INVALID_PARAMETER 251
  23. #define INVALID_BUFFER 252
  24. #define INTERFACE_ERROR 253
  25. #define UNSUPPORTED_COMMAND 254
  26. #define UNSPECIFIED_ERROR 255
  27. /* Device ID */
  28. #define DEVICE_ID_PANEL_BACK 1
  29. /* LED Commands */
  30. #define CMD_LED_ON 16
  31. #define CMD_LED_OFF 17
  32. #define CMD_LED_BLINK 18
  33. struct bios_args {
  34. unsigned char length;
  35. unsigned char result_code;
  36. unsigned char device_id;
  37. unsigned char command;
  38. unsigned char on_time;
  39. unsigned char off_time;
  40. };
  41. static int dell_led_perform_fn(u8 length, u8 result_code, u8 device_id,
  42. u8 command, u8 on_time, u8 off_time)
  43. {
  44. struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  45. struct bios_args *bios_return;
  46. struct acpi_buffer input;
  47. union acpi_object *obj;
  48. acpi_status status;
  49. u8 return_code;
  50. struct bios_args args = {
  51. .length = length,
  52. .result_code = result_code,
  53. .device_id = device_id,
  54. .command = command,
  55. .on_time = on_time,
  56. .off_time = off_time
  57. };
  58. input.length = sizeof(struct bios_args);
  59. input.pointer = &args;
  60. status = wmi_evaluate_method(DELL_LED_BIOS_GUID, 0, 1, &input, &output);
  61. if (ACPI_FAILURE(status))
  62. return status;
  63. obj = output.pointer;
  64. if (!obj)
  65. return -EINVAL;
  66. if (obj->type != ACPI_TYPE_BUFFER) {
  67. kfree(obj);
  68. return -EINVAL;
  69. }
  70. bios_return = ((struct bios_args *)obj->buffer.pointer);
  71. return_code = bios_return->result_code;
  72. kfree(obj);
  73. return return_code;
  74. }
  75. static int led_on(void)
  76. {
  77. return dell_led_perform_fn(3, /* Length of command */
  78. INTERFACE_ERROR, /* Init to INTERFACE_ERROR */
  79. DEVICE_ID_PANEL_BACK, /* Device ID */
  80. CMD_LED_ON, /* Command */
  81. 0, /* not used */
  82. 0); /* not used */
  83. }
  84. static int led_off(void)
  85. {
  86. return dell_led_perform_fn(3, /* Length of command */
  87. INTERFACE_ERROR, /* Init to INTERFACE_ERROR */
  88. DEVICE_ID_PANEL_BACK, /* Device ID */
  89. CMD_LED_OFF, /* Command */
  90. 0, /* not used */
  91. 0); /* not used */
  92. }
  93. static int led_blink(unsigned char on_eighths, unsigned char off_eighths)
  94. {
  95. return dell_led_perform_fn(5, /* Length of command */
  96. INTERFACE_ERROR, /* Init to INTERFACE_ERROR */
  97. DEVICE_ID_PANEL_BACK, /* Device ID */
  98. CMD_LED_BLINK, /* Command */
  99. on_eighths, /* blink on in eigths of a second */
  100. off_eighths); /* blink off in eights of a second */
  101. }
  102. static void dell_led_set(struct led_classdev *led_cdev,
  103. enum led_brightness value)
  104. {
  105. if (value == LED_OFF)
  106. led_off();
  107. else
  108. led_on();
  109. }
  110. static int dell_led_blink(struct led_classdev *led_cdev,
  111. unsigned long *delay_on, unsigned long *delay_off)
  112. {
  113. unsigned long on_eighths;
  114. unsigned long off_eighths;
  115. /*
  116. * The Dell LED delay is based on 125ms intervals.
  117. * Need to round up to next interval.
  118. */
  119. on_eighths = DIV_ROUND_UP(*delay_on, 125);
  120. on_eighths = clamp_t(unsigned long, on_eighths, 1, 255);
  121. *delay_on = on_eighths * 125;
  122. off_eighths = DIV_ROUND_UP(*delay_off, 125);
  123. off_eighths = clamp_t(unsigned long, off_eighths, 1, 255);
  124. *delay_off = off_eighths * 125;
  125. led_blink(on_eighths, off_eighths);
  126. return 0;
  127. }
  128. static struct led_classdev dell_led = {
  129. .name = "dell::lid",
  130. .brightness = LED_OFF,
  131. .max_brightness = 1,
  132. .brightness_set = dell_led_set,
  133. .blink_set = dell_led_blink,
  134. .flags = LED_CORE_SUSPENDRESUME,
  135. };
  136. static int __init dell_led_init(void)
  137. {
  138. int error = 0;
  139. if (!wmi_has_guid(DELL_LED_BIOS_GUID))
  140. return -ENODEV;
  141. error = led_off();
  142. if (error != 0)
  143. return -ENODEV;
  144. return led_classdev_register(NULL, &dell_led);
  145. }
  146. static void __exit dell_led_exit(void)
  147. {
  148. led_classdev_unregister(&dell_led);
  149. led_off();
  150. }
  151. module_init(dell_led_init);
  152. module_exit(dell_led_exit);