drivers/leds/dell-led.c

   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
  18 MODULE_AUTHOR("Louis Davis/Jim Dailey");
  19 MODULE_DESCRIPTION("Dell LED Control Driver");
  20 MODULE_LICENSE("GPL");
  21
  22 #define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396"
  23 MODULE_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
  41 struct 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
  50 static 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
 101 static 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
 111 static 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
 121 static 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
 132 static 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
 141 static 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
 170 static 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
 179 static 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
 193 static void __exit dell_led_exit(void)
 194 {
 195         led_classdev_unregister(&dell_led);
 196
 197         led_off();
 198 }
 199
 200 module_init(dell_led_init);
 201 module_exit(dell_led_exit);