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
  17 MODULE_AUTHOR("Louis Davis/Jim Dailey");
  18 MODULE_DESCRIPTION("Dell LED Control Driver");
  19 MODULE_LICENSE("GPL");
  20
  21 #define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396"
  22 MODULE_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
  40 struct 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
  49 static int dell_led_perform_fn(u8 length,
  50                 u8 result_code,
  51                 u8 device_id,
  52                 u8 command,
  53                 u8 on_time,
  54                 u8 off_time)
  55 {
  56         struct bios_args *bios_return;
  57         u8 return_code;
  58         union acpi_object *obj;
  59         struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  60         struct acpi_buffer input;
  61         acpi_status status;
  62
  63         struct bios_args args;
  64         args.length = length;
  65         args.result_code = result_code;
  66         args.device_id = device_id;
  67         args.command = command;
  68         args.on_time = on_time;
  69         args.off_time = off_time;
  70
  71         input.length = sizeof(struct bios_args);
  72         input.pointer = &args;
  73
  74         status = wmi_evaluate_method(DELL_LED_BIOS_GUID,
  75                 1,
  76                 1,
  77                 &input,
  78                 &output);
  79
  80         if (ACPI_FAILURE(status))
  81                 return status;
  82
  83         obj = output.pointer;
  84
  85         if (!obj)
  86                 return -EINVAL;
  87         else if (obj->type != ACPI_TYPE_BUFFER) {
  88                 kfree(obj);
  89                 return -EINVAL;
  90         }
  91
  92         bios_return = ((struct bios_args *)obj->buffer.pointer);
  93         return_code = bios_return->result_code;
  94
  95         kfree(obj);
  96
  97         return return_code;
  98 }
  99
 100 static int led_on(void)
 101 {
 102         return dell_led_perform_fn(3,   /* Length of command */
 103                 INTERFACE_ERROR,        /* Init to  INTERFACE_ERROR */
 104                 DEVICE_ID_PANEL_BACK,   /* Device ID */
 105                 CMD_LED_ON,             /* Command */
 106                 0,                      /* not used */
 107                 0);                     /* not used */
 108 }
 109
 110 static int led_off(void)
 111 {
 112         return dell_led_perform_fn(3,   /* Length of command */
 113                 INTERFACE_ERROR,        /* Init to  INTERFACE_ERROR */
 114                 DEVICE_ID_PANEL_BACK,   /* Device ID */
 115                 CMD_LED_OFF,            /* Command */
 116                 0,                      /* not used */
 117                 0);                     /* not used */
 118 }
 119
 120 static int led_blink(unsigned char on_eighths,
 121                 unsigned char off_eighths)
 122 {
 123         return dell_led_perform_fn(5,   /* Length of command */
 124                 INTERFACE_ERROR,        /* Init to  INTERFACE_ERROR */
 125                 DEVICE_ID_PANEL_BACK,   /* Device ID */
 126                 CMD_LED_BLINK,          /* Command */
 127                 on_eighths,             /* blink on in eigths of a second */
 128                 off_eighths);           /* blink off in eights of a second */
 129 }
 130
 131 static void dell_led_set(struct led_classdev *led_cdev,
 132                 enum led_brightness value)
 133 {
 134         if (value == LED_OFF)
 135                 led_off();
 136         else
 137                 led_on();
 138 }
 139
 140 static int dell_led_blink(struct led_classdev *led_cdev,
 141                 unsigned long *delay_on,
 142                 unsigned long *delay_off)
 143 {
 144         unsigned long on_eighths;
 145         unsigned long off_eighths;
 146
 147         /* The Dell LED delay is based on 125ms intervals.
 148            Need to round up to next interval. */
 149
 150         on_eighths = (*delay_on + 124) / 125;
 151         if (0 == on_eighths)
 152                 on_eighths = 1;
 153         if (on_eighths > 255)
 154                 on_eighths = 255;
 155         *delay_on = on_eighths * 125;
 156
 157         off_eighths = (*delay_off + 124) / 125;
 158         if (0 == off_eighths)
 159                 off_eighths = 1;
 160         if (off_eighths > 255)
 161                 off_eighths = 255;
 162         *delay_off = off_eighths * 125;
 163
 164         led_blink(on_eighths, off_eighths);
 165
 166         return 0;
 167 }
 168
 169 static struct led_classdev dell_led = {
 170         .name           = "dell::lid",
 171         .brightness     = LED_OFF,
 172         .max_brightness = 1,
 173         .brightness_set = dell_led_set,
 174         .blink_set      = dell_led_blink,
 175         .flags          = LED_CORE_SUSPENDRESUME,
 176 };
 177
 178 static int __init dell_led_init(void)
 179 {
 180         int error = 0;
 181
 182         if (!wmi_has_guid(DELL_LED_BIOS_GUID))
 183                 return -ENODEV;
 184
 185         error = led_off();
 186         if (error != 0)
 187                 return -ENODEV;
 188
 189         return led_classdev_register(NULL, &dell_led);
 190 }
 191
 192 static void __exit dell_led_exit(void)
 193 {
 194         led_classdev_unregister(&dell_led);
 195
 196         led_off();
 197 }
 198
 199 module_init(dell_led_init);
 200 module_exit(dell_led_exit);