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, instance: 0, method_id: 1, in: &input, out: &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(objp: 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(objp: obj);
88
89 return return_code;
90}
91
92static int led_on(void)
93{
94 return dell_led_perform_fn(length: 3, /* Length of command */
95 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */
96 DEVICE_ID_PANEL_BACK, /* Device ID */
97 CMD_LED_ON, /* Command */
98 on_time: 0, /* not used */
99 off_time: 0); /* not used */
100}
101
102static int led_off(void)
103{
104 return dell_led_perform_fn(length: 3, /* Length of command */
105 INTERFACE_ERROR, /* Init to INTERFACE_ERROR */
106 DEVICE_ID_PANEL_BACK, /* Device ID */
107 CMD_LED_OFF, /* Command */
108 on_time: 0, /* not used */
109 off_time: 0); /* not used */
110}
111
112static int led_blink(unsigned char on_eighths, unsigned char off_eighths)
113{
114 return dell_led_perform_fn(length: 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_time: on_eighths, /* blink on in eigths of a second */
119 off_time: 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, led_cdev: &dell_led);
176}
177
178static void __exit dell_led_exit(void)
179{
180 led_classdev_unregister(led_cdev: &dell_led);
181
182 led_off();
183}
184
185module_init(dell_led_init);
186module_exit(dell_led_exit);
187

source code of linux/drivers/platform/x86/dell/dell-wmi-led.c