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