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 
22 static acpi_handle ec_handle;
23 
24 static bool force;
25 module_param(force, bool, 0);
26 MODULE_PARM_DESC(force,
27 		"Disable the DMI check and force the driver to be loaded");
28 
29 static 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 
49 static const struct backlight_ops samsungq10_bl_ops = {
50 	.update_status	= samsungq10_bl_set_intensity,
51 };
52 
53 static 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 
72 static 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 
82 static struct platform_driver samsungq10_driver = {
83 	.driver		= {
84 		.name	= KBUILD_MODNAME,
85 	},
86 	.probe		= samsungq10_probe,
87 	.remove		= samsungq10_remove,
88 };
89 
90 static struct platform_device *samsungq10_device;
91 
92 static 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 
98 static const struct dmi_system_id samsungq10_dmi_table[] __initconst = {
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 };
133 MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
134 
135 static 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 
152 static void __exit samsungq10_exit(void)
153 {
154 	platform_device_unregister(samsungq10_device);
155 	platform_driver_unregister(&samsungq10_driver);
156 }
157 
158 module_init(samsungq10_init);
159 module_exit(samsungq10_exit);
160 
161 MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
162 MODULE_DESCRIPTION("Samsung Q10 Driver");
163 MODULE_LICENSE("GPL");
164