1/*
2 *  Driver for Samsung Q10 and related laptops: controls the backlight
3 *
4 *  Copyright (c) 2011 Frederick van der Wyck <fvanderwyck@gmail.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 version 2 as
8 *  published by the Free Software Foundation.
9 *
10 */
11
12#include <linux/module.h>
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/platform_device.h>
16#include <linux/backlight.h>
17#include <linux/dmi.h>
18#include <linux/acpi.h>
19
20#define SAMSUNGQ10_BL_MAX_INTENSITY 7
21
22static acpi_handle ec_handle;
23
24static bool force;
25module_param(force, bool, 0);
26MODULE_PARM_DESC(force,
27		"Disable the DMI check and force the driver to be loaded");
28
29static int samsungq10_bl_set_intensity(struct backlight_device *bd)
30{
31
32	acpi_status status;
33	int i;
34
35	for (i = 0; i < SAMSUNGQ10_BL_MAX_INTENSITY; i++) {
36		status = acpi_evaluate_object(ec_handle, "_Q63", NULL, NULL);
37		if (ACPI_FAILURE(status))
38			return -EIO;
39	}
40	for (i = 0; i < bd->props.brightness; i++) {
41		status = acpi_evaluate_object(ec_handle, "_Q64", NULL, NULL);
42		if (ACPI_FAILURE(status))
43			return -EIO;
44	}
45
46	return 0;
47}
48
49static const struct backlight_ops samsungq10_bl_ops = {
50	.update_status	= samsungq10_bl_set_intensity,
51};
52
53static int samsungq10_probe(struct platform_device *pdev)
54{
55
56	struct backlight_properties props;
57	struct backlight_device *bd;
58
59	memset(&props, 0, sizeof(struct backlight_properties));
60	props.type = BACKLIGHT_PLATFORM;
61	props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
62	bd = backlight_device_register("samsung", &pdev->dev, NULL,
63				       &samsungq10_bl_ops, &props);
64	if (IS_ERR(bd))
65		return PTR_ERR(bd);
66
67	platform_set_drvdata(pdev, bd);
68
69	return 0;
70}
71
72static int samsungq10_remove(struct platform_device *pdev)
73{
74
75	struct backlight_device *bd = platform_get_drvdata(pdev);
76
77	backlight_device_unregister(bd);
78
79	return 0;
80}
81
82static struct platform_driver samsungq10_driver = {
83	.driver		= {
84		.name	= KBUILD_MODNAME,
85	},
86	.probe		= samsungq10_probe,
87	.remove		= samsungq10_remove,
88};
89
90static struct platform_device *samsungq10_device;
91
92static int __init dmi_check_callback(const struct dmi_system_id *id)
93{
94	printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
95	return 1;
96}
97
98static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
99	{
100		.ident = "Samsung Q10",
101		.matches = {
102			DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
103			DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
104		},
105		.callback = dmi_check_callback,
106	},
107	{
108		.ident = "Samsung Q20",
109		.matches = {
110			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
111			DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
112		},
113		.callback = dmi_check_callback,
114	},
115	{
116		.ident = "Samsung Q25",
117		.matches = {
118			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
119			DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
120		},
121		.callback = dmi_check_callback,
122	},
123	{
124		.ident = "Dell Latitude X200",
125		.matches = {
126			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
127			DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
128		},
129		.callback = dmi_check_callback,
130	},
131	{ },
132};
133MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
134
135static int __init samsungq10_init(void)
136{
137	if (!force && !dmi_check_system(samsungq10_dmi_table))
138		return -ENODEV;
139
140	ec_handle = ec_get_handle();
141
142	if (!ec_handle)
143		return -ENODEV;
144
145	samsungq10_device = platform_create_bundle(&samsungq10_driver,
146						   samsungq10_probe,
147						   NULL, 0, NULL, 0);
148
149	return PTR_ERR_OR_ZERO(samsungq10_device);
150}
151
152static void __exit samsungq10_exit(void)
153{
154	platform_device_unregister(samsungq10_device);
155	platform_driver_unregister(&samsungq10_driver);
156}
157
158module_init(samsungq10_init);
159module_exit(samsungq10_exit);
160
161MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
162MODULE_DESCRIPTION("Samsung Q10 Driver");
163MODULE_LICENSE("GPL");
164