dell-wmi-led.c (4253B)
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 12#include <linux/acpi.h> 13#include <linux/leds.h> 14#include <linux/slab.h> 15#include <linux/module.h> 16 17MODULE_AUTHOR("Louis Davis/Jim Dailey"); 18MODULE_DESCRIPTION("Dell LED Control Driver"); 19MODULE_LICENSE("GPL"); 20 21#define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396" 22MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID); 23 24/* Error Result Codes: */ 25#define INVALID_DEVICE_ID 250 26#define INVALID_PARAMETER 251 27#define INVALID_BUFFER 252 28#define INTERFACE_ERROR 253 29#define UNSUPPORTED_COMMAND 254 30#define UNSPECIFIED_ERROR 255 31 32/* Device ID */ 33#define DEVICE_ID_PANEL_BACK 1 34 35/* LED Commands */ 36#define CMD_LED_ON 16 37#define CMD_LED_OFF 17 38#define CMD_LED_BLINK 18 39 40struct bios_args { 41 unsigned char length; 42 unsigned char result_code; 43 unsigned char device_id; 44 unsigned char command; 45 unsigned char on_time; 46 unsigned char off_time; 47}; 48 49static int dell_led_perform_fn(u8 length, u8 result_code, u8 device_id, 50 u8 command, u8 on_time, u8 off_time) 51{ 52 struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; 53 struct bios_args *bios_return; 54 struct acpi_buffer input; 55 union acpi_object *obj; 56 acpi_status status; 57 u8 return_code; 58 59 struct bios_args args = { 60 .length = length, 61 .result_code = result_code, 62 .device_id = device_id, 63 .command = command, 64 .on_time = on_time, 65 .off_time = off_time 66 }; 67 68 input.length = sizeof(struct bios_args); 69 input.pointer = &args; 70 71 status = wmi_evaluate_method(DELL_LED_BIOS_GUID, 0, 1, &input, &output); 72 if (ACPI_FAILURE(status)) 73 return status; 74 75 obj = output.pointer; 76 77 if (!obj) 78 return -EINVAL; 79 if (obj->type != ACPI_TYPE_BUFFER) { 80 kfree(obj); 81 return -EINVAL; 82 } 83 84 bios_return = ((struct bios_args *)obj->buffer.pointer); 85 return_code = bios_return->result_code; 86 87 kfree(obj); 88 89 return return_code; 90} 91 92static int led_on(void) 93{ 94 return dell_led_perform_fn(3, /* Length of command */ 95 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 96 DEVICE_ID_PANEL_BACK, /* Device ID */ 97 CMD_LED_ON, /* Command */ 98 0, /* not used */ 99 0); /* not used */ 100} 101 102static int led_off(void) 103{ 104 return dell_led_perform_fn(3, /* Length of command */ 105 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 106 DEVICE_ID_PANEL_BACK, /* Device ID */ 107 CMD_LED_OFF, /* Command */ 108 0, /* not used */ 109 0); /* not used */ 110} 111 112static int led_blink(unsigned char on_eighths, unsigned char off_eighths) 113{ 114 return dell_led_perform_fn(5, /* Length of command */ 115 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */ 116 DEVICE_ID_PANEL_BACK, /* Device ID */ 117 CMD_LED_BLINK, /* Command */ 118 on_eighths, /* blink on in eigths of a second */ 119 off_eighths); /* blink off in eights of a second */ 120} 121 122static void dell_led_set(struct led_classdev *led_cdev, 123 enum led_brightness value) 124{ 125 if (value == LED_OFF) 126 led_off(); 127 else 128 led_on(); 129} 130 131static int dell_led_blink(struct led_classdev *led_cdev, 132 unsigned long *delay_on, unsigned long *delay_off) 133{ 134 unsigned long on_eighths; 135 unsigned long off_eighths; 136 137 /* 138 * The Dell LED delay is based on 125ms intervals. 139 * Need to round up to next interval. 140 */ 141 142 on_eighths = DIV_ROUND_UP(*delay_on, 125); 143 on_eighths = clamp_t(unsigned long, on_eighths, 1, 255); 144 *delay_on = on_eighths * 125; 145 146 off_eighths = DIV_ROUND_UP(*delay_off, 125); 147 off_eighths = clamp_t(unsigned long, off_eighths, 1, 255); 148 *delay_off = off_eighths * 125; 149 150 led_blink(on_eighths, off_eighths); 151 152 return 0; 153} 154 155static struct led_classdev dell_led = { 156 .name = "dell::lid", 157 .brightness = LED_OFF, 158 .max_brightness = 1, 159 .brightness_set = dell_led_set, 160 .blink_set = dell_led_blink, 161 .flags = LED_CORE_SUSPENDRESUME, 162}; 163 164static int __init dell_led_init(void) 165{ 166 int error = 0; 167 168 if (!wmi_has_guid(DELL_LED_BIOS_GUID)) 169 return -ENODEV; 170 171 error = led_off(); 172 if (error != 0) 173 return -ENODEV; 174 175 return led_classdev_register(NULL, &dell_led); 176} 177 178static void __exit dell_led_exit(void) 179{ 180 led_classdev_unregister(&dell_led); 181 182 led_off(); 183} 184 185module_init(dell_led_init); 186module_exit(dell_led_exit);