aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/leds/dell-led.c
blob: 52590296af33e4a3f3af3b5de975741c3ffb1fc4 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
/*
 * dell_led.c - Dell LED Driver
 *
 * Copyright (C) 2010 Dell Inc.
 * Louis Davis <louis_davis@dell.com>
 * Jim Dailey <jim_dailey@dell.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 */

#include <linux/acpi.h>
#include <linux/leds.h>
#include <linux/slab.h>

MODULE_AUTHOR("Louis Davis/Jim Dailey");
MODULE_DESCRIPTION("Dell LED Control Driver");
MODULE_LICENSE("GPL");

#define DELL_LED_BIOS_GUID "F6E4FE6E-909D-47cb-8BAB-C9F6F2F8D396"
MODULE_ALIAS("wmi:" DELL_LED_BIOS_GUID);

/* Error Result Codes: */
#define INVALID_DEVICE_ID	250
#define INVALID_PARAMETER	251
#define INVALID_BUFFER		252
#define INTERFACE_ERROR		253
#define UNSUPPORTED_COMMAND	254
#define UNSPECIFIED_ERROR	255

/* Device ID */
#define DEVICE_ID_PANEL_BACK	1

/* LED Commands */
#define CMD_LED_ON	16
#define CMD_LED_OFF	17
#define CMD_LED_BLINK	18

struct bios_args {
	unsigned char length;
	unsigned char result_code;
	unsigned char device_id;
	unsigned char command;
	unsigned char on_time;
	unsigned char off_time;
};

static int dell_led_perform_fn(u8 length,
		u8 result_code,
		u8 device_id,
		u8 command,
		u8 on_time,
		u8 off_time)
{
	struct bios_args *bios_return;
	u8 return_code;
	union acpi_object *obj;
	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
	struct acpi_buffer input;
	acpi_status status;

	struct bios_args args;
	args.length = length;
	args.result_code = result_code;
	args.device_id = device_id;
	args.command = command;
	args.on_time = on_time;
	args.off_time = off_time;

	input.length = sizeof(struct bios_args);
	input.pointer = &args;

	status = wmi_evaluate_method(DELL_LED_BIOS_GUID,
		1,
		1,
		&input,
		&output);

	if (ACPI_FAILURE(status))
		return status;

	obj = output.pointer;

	if (!obj)
		return -EINVAL;
	else if (obj->type != ACPI_TYPE_BUFFER) {
		kfree(obj);
		return -EINVAL;
	}

	bios_return = ((struct bios_args *)obj->buffer.pointer);
	return_code = bios_return->result_code;

	kfree(obj);

	return return_code;
}

static int led_on(void)
{
	return dell_led_perform_fn(3,	/* Length of command */
		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
		DEVICE_ID_PANEL_BACK,	/* Device ID */
		CMD_LED_ON,		/* Command */
		0,			/* not used */
		0);			/* not used */
}

static int led_off(void)
{
	return dell_led_perform_fn(3,	/* Length of command */
		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
		DEVICE_ID_PANEL_BACK,	/* Device ID */
		CMD_LED_OFF,		/* Command */
		0,			/* not used */
		0);			/* not used */
}

static int led_blink(unsigned char on_eighths,
		unsigned char off_eighths)
{
	return dell_led_perform_fn(5,	/* Length of command */
		INTERFACE_ERROR,	/* Init to  INTERFACE_ERROR */
		DEVICE_ID_PANEL_BACK,	/* Device ID */
		CMD_LED_BLINK,		/* Command */
		on_eighths,		/* blink on in eigths of a second */
		off_eighths);		/* blink off in eights of a second */
}

static void dell_led_set(struct led_classdev *led_cdev,
		enum led_brightness value)
{
	if (value == LED_OFF)
		led_off();
	else
		led_on();
}

static int dell_led_blink(struct led_classdev *led_cdev,
		unsigned long *delay_on,
		unsigned long *delay_off)
{
	unsigned long on_eighths;
	unsigned long off_eighths;

	/* The Dell LED delay is based on 125ms intervals.
	   Need to round up to next interval. */

	on_eighths = (*delay_on + 124) / 125;
	if (0 == on_eighths)
		on_eighths = 1;
	if (on_eighths > 255)
		on_eighths = 255;
	*delay_on = on_eighths * 125;

	off_eighths = (*delay_off + 124) / 125;
	if (0 == off_eighths)
		off_eighths = 1;
	if (off_eighths > 255)
		off_eighths = 255;
	*delay_off = off_eighths * 125;

	led_blink(on_eighths, off_eighths);

	return 0;
}

static struct led_classdev dell_led = {
	.name		= "dell::lid",
	.brightness	= LED_OFF,
	.max_brightness = 1,
	.brightness_set = dell_led_set,
	.blink_set	= dell_led_blink,
	.flags		= LED_CORE_SUSPENDRESUME,
};

static int __init dell_led_init(void)
{
	int error = 0;

	if (!wmi_has_guid(DELL_LED_BIOS_GUID))
		return -ENODEV;

	error = led_off();
	if (error != 0)
		return -ENODEV;

	return led_classdev_register(NULL, &dell_led);
}

static void __exit dell_led_exit(void)
{
	led_classdev_unregister(&dell_led);

	led_off();
}

module_init(dell_led_init);
module_exit(dell_led_exit);