/* * dell_led.c - Dell LED Driver * * Copyright (C) 2010 Dell Inc. * Louis Davis <louis_davis@dell.com> * Jim Dailey <jim_dailey@dell.com> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as * published by the Free Software Foundation. * */ #include <linux/acpi.h> #include <linux/leds.h> #include <linux/slab.h> MODULE_AUTHOR("Louis Davis/Jim Dailey"); MODULE_DESCRIPTION("Dell LED Control Driver"); MODULE_LICENSE("GPL"); #define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396" MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID); /* Error Result Codes: */ #define INVALID_DEVICE_ID 250 #define INVALID_PARAMETER 251 #define INVALID_BUFFER 252 #define INTERFACE_ERROR 253 #define UNSUPPORTED_COMMAND 254 #define UNSPECIFIED_ERROR 255 /* Device ID */ #define DEVICE_ID_PANEL_BACK 1 /* LED Commands */ #define CMD_LED_ON 16 #define CMD_LED_OFF 17 #define CMD_LED_BLINK 18 struct bios_args { unsigned char length; unsigned char result_code; unsigned char device_id; unsigned char command; unsigned char on_time; unsigned char off_time; }; static int dell_led_perform_fn(u8 length, u8 result_code, u8 device_id, u8 command, u8 on_time, u8 off_time) { struct bios_args *bios_return; u8 return_code; union acpi_object *obj; struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; struct acpi_buffer input; acpi_status status; struct bios_args args; args.length = length; args.result_code = result_code; args.device_id = device_id; args.command = command; args.on_time = on_time; args.off_time = off_time; input.length = sizeof(struct bios_args); input.pointer = &args; status = wmi_evaluate_method(DELL_LED_BIOS_GUID, 1, 1, &input, &output); if (ACPI_FAILURE(status)) return status; obj = output.pointer; if (!obj) return -EINVAL; else if (obj->type != ACPI_TYPE_BUFFER) { kfree(obj); return -EINVAL; } bios_return = ((struct bios_args *)obj->buffer.pointer); return_code = bios_return->result_code; kfree(obj); return return_code; } static int led_on(void) { return dell_led_perform_fn(3, /* Length of command */ INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ DEVICE_ID_PANEL_BACK, /* Device ID */ CMD_LED_ON, /* Command */ 0, /* not used */ 0); /* not used */ } static int led_off(void) { return dell_led_perform_fn(3, /* Length of command */ INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ DEVICE_ID_PANEL_BACK, /* Device ID */ CMD_LED_OFF, /* Command */ 0, /* not used */ 0); /* not used */ } static int led_blink(unsigned char on_eighths, unsigned char off_eighths) { return dell_led_perform_fn(5, /* Length of command */ INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ DEVICE_ID_PANEL_BACK, /* Device ID */ CMD_LED_BLINK, /* Command */ on_eighths, /* blink on in eigths of a second */ off_eighths); /* blink off in eights of a second */ } static void dell_led_set(struct led_classdev *led_cdev, enum led_brightness value) { if (value == LED_OFF) led_off(); else led_on(); } static int dell_led_blink(struct led_classdev *led_cdev, unsigned long *delay_on, unsigned long *delay_off) { unsigned long on_eighths; unsigned long off_eighths; /* The Dell LED delay is based on 125ms intervals. Need to round up to next interval. */ on_eighths = (*delay_on + 124) / 125; if (0 == on_eighths) on_eighths = 1; if (on_eighths > 255) on_eighths = 255; *delay_on = on_eighths * 125; off_eighths = (*delay_off + 124) / 125; if (0 == off_eighths) off_eighths = 1; if (off_eighths > 255) off_eighths = 255; *delay_off = off_eighths * 125; led_blink(on_eighths, off_eighths); return 0; } static struct led_classdev dell_led = { .name = "dell::lid", .brightness = LED_OFF, .max_brightness = 1, .brightness_set = dell_led_set, .blink_set = dell_led_blink, .flags = LED_CORE_SUSPENDRESUME, }; static int __init dell_led_init(void) { int error = 0; if (!wmi_has_guid(DELL_LED_BIOS_GUID)) return -ENODEV; error = led_off(); if (error != 0) return -ENODEV; return led_classdev_register(NULL, &dell_led); } static void __exit dell_led_exit(void) { led_classdev_unregister(&dell_led); led_off(); } module_init(dell_led_init); module_exit(dell_led_exit);