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);