1/* 2 * dell_led.c - Dell LED Driver 3 * 4 * Copyright (C) 2010 Dell Inc. 5 * Louis Davis <louis_davis@dell.com> 6 * Jim Dailey <jim_dailey@dell.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14#include <linux/acpi.h> 15#include <linux/leds.h> 16#include <linux/slab.h> 17 18MODULE_AUTHOR("Louis Davis/Jim Dailey"); 19MODULE_DESCRIPTION("Dell LED Control Driver"); 20MODULE_LICENSE("GPL"); 21 22#define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396" 23MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID); 24 25/* Error Result Codes: */ 26#define INVALID_DEVICE_ID 250 27#define INVALID_PARAMETER 251 28#define INVALID_BUFFER 252 29#define INTERFACE_ERROR 253 30#define UNSUPPORTED_COMMAND 254 31#define UNSPECIFIED_ERROR 255 32 33/* Device ID */ 34#define DEVICE_ID_PANEL_BACK 1 35 36/* LED Commands */ 37#define CMD_LED_ON 16 38#define CMD_LED_OFF 17 39#define CMD_LED_BLINK 18 40 41struct bios_args { 42 unsigned char length; 43 unsigned char result_code; 44 unsigned char device_id; 45 unsigned char command; 46 unsigned char on_time; 47 unsigned char off_time; 48}; 49 50static int dell_led_perform_fn(u8 length, 51 u8 result_code, 52 u8 device_id, 53 u8 command, 54 u8 on_time, 55 u8 off_time) 56{ 57 struct bios_args *bios_return; 58 u8 return_code; 59 union acpi_object *obj; 60 struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; 61 struct acpi_buffer input; 62 acpi_status status; 63 64 struct bios_args args; 65 args.length = length; 66 args.result_code = result_code; 67 args.device_id = device_id; 68 args.command = command; 69 args.on_time = on_time; 70 args.off_time = off_time; 71 72 input.length = sizeof(struct bios_args); 73 input.pointer = &args; 74 75 status = wmi_evaluate_method(DELL_LED_BIOS_GUID, 76 1, 77 1, 78 &input, 79 &output); 80 81 if (ACPI_FAILURE(status)) 82 return status; 83 84 obj = output.pointer; 85 86 if (!obj) 87 return -EINVAL; 88 else if (obj->type != ACPI_TYPE_BUFFER) { 89 kfree(obj); 90 return -EINVAL; 91 } 92 93 bios_return = ((struct bios_args *)obj->buffer.pointer); 94 return_code = bios_return->result_code; 95 96 kfree(obj); 97 98 return return_code; 99} 100 101static int led_on(void) 102{ 103 return dell_led_perform_fn(3, /* Length of command */ 104 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 105 DEVICE_ID_PANEL_BACK, /* Device ID */ 106 CMD_LED_ON, /* Command */ 107 0, /* not used */ 108 0); /* not used */ 109} 110 111static int led_off(void) 112{ 113 return dell_led_perform_fn(3, /* Length of command */ 114 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 115 DEVICE_ID_PANEL_BACK, /* Device ID */ 116 CMD_LED_OFF, /* Command */ 117 0, /* not used */ 118 0); /* not used */ 119} 120 121static int led_blink(unsigned char on_eighths, 122 unsigned char off_eighths) 123{ 124 return dell_led_perform_fn(5, /* Length of command */ 125 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 126 DEVICE_ID_PANEL_BACK, /* Device ID */ 127 CMD_LED_BLINK, /* Command */ 128 on_eighths, /* blink on in eigths of a second */ 129 off_eighths); /* blink off in eights of a second */ 130} 131 132static void dell_led_set(struct led_classdev *led_cdev, 133 enum led_brightness value) 134{ 135 if (value == LED_OFF) 136 led_off(); 137 else 138 led_on(); 139} 140 141static int dell_led_blink(struct led_classdev *led_cdev, 142 unsigned long *delay_on, 143 unsigned long *delay_off) 144{ 145 unsigned long on_eighths; 146 unsigned long off_eighths; 147 148 /* The Dell LED delay is based on 125ms intervals. 149 Need to round up to next interval. */ 150 151 on_eighths = (*delay_on + 124) / 125; 152 if (0 == on_eighths) 153 on_eighths = 1; 154 if (on_eighths > 255) 155 on_eighths = 255; 156 *delay_on = on_eighths * 125; 157 158 off_eighths = (*delay_off + 124) / 125; 159 if (0 == off_eighths) 160 off_eighths = 1; 161 if (off_eighths > 255) 162 off_eighths = 255; 163 *delay_off = off_eighths * 125; 164 165 led_blink(on_eighths, off_eighths); 166 167 return 0; 168} 169 170static struct led_classdev dell_led = { 171 .name = "dell::lid", 172 .brightness = LED_OFF, 173 .max_brightness = 1, 174 .brightness_set = dell_led_set, 175 .blink_set = dell_led_blink, 176 .flags = LED_CORE_SUSPENDRESUME, 177}; 178 179static int __init dell_led_init(void) 180{ 181 int error = 0; 182 183 if (!wmi_has_guid(DELL_LED_BIOS_GUID)) 184 return -ENODEV; 185 186 error = led_off(); 187 if (error != 0) 188 return -ENODEV; 189 190 return led_classdev_register(NULL, &dell_led); 191} 192 193static void __exit dell_led_exit(void) 194{ 195 led_classdev_unregister(&dell_led); 196 197 led_off(); 198} 199 200module_init(dell_led_init); 201module_exit(dell_led_exit); 202