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 
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 
dell_led_perform_fn(u8 length,u8 result_code,u8 device_id,u8 command,u8 on_time,u8 off_time)49 static 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 
led_on(void)92 static 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 
led_off(void)102 static 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 
led_blink(unsigned char on_eighths,unsigned char off_eighths)112 static 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 
dell_led_set(struct led_classdev * led_cdev,enum led_brightness value)122 static 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 
dell_led_blink(struct led_classdev * led_cdev,unsigned long * delay_on,unsigned long * delay_off)131 static 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 
155 static 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 
dell_led_init(void)164 static 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 
dell_led_exit(void)178 static void __exit dell_led_exit(void)
179 {
180 	led_classdev_unregister(&dell_led);
181 
182 	led_off();
183 }
184 
185 module_init(dell_led_init);
186 module_exit(dell_led_exit);
187