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);
187