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 int samsungq10_bl_get_intensity(struct backlight_device *bd)
50 {
51 	return bd->props.brightness;
52 }
53 
54 static const struct backlight_ops samsungq10_bl_ops = {
55 	.get_brightness = samsungq10_bl_get_intensity,
56 	.update_status	= samsungq10_bl_set_intensity,
57 };
58 
59 static int samsungq10_probe(struct platform_device *pdev)
60 {
61 
62 	struct backlight_properties props;
63 	struct backlight_device *bd;
64 
65 	memset(&props, 0, sizeof(struct backlight_properties));
66 	props.type = BACKLIGHT_PLATFORM;
67 	props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
68 	bd = backlight_device_register("samsung", &pdev->dev, NULL,
69 				       &samsungq10_bl_ops, &props);
70 	if (IS_ERR(bd))
71 		return PTR_ERR(bd);
72 
73 	platform_set_drvdata(pdev, bd);
74 
75 	return 0;
76 }
77 
78 static int samsungq10_remove(struct platform_device *pdev)
79 {
80 
81 	struct backlight_device *bd = platform_get_drvdata(pdev);
82 
83 	backlight_device_unregister(bd);
84 
85 	return 0;
86 }
87 
88 static struct platform_driver samsungq10_driver = {
89 	.driver		= {
90 		.name	= KBUILD_MODNAME,
91 		.owner	= THIS_MODULE,
92 	},
93 	.probe		= samsungq10_probe,
94 	.remove		= samsungq10_remove,
95 };
96 
97 static struct platform_device *samsungq10_device;
98 
99 static int __init dmi_check_callback(const struct dmi_system_id *id)
100 {
101 	printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
102 	return 1;
103 }
104 
105 static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
106 	{
107 		.ident = "Samsung Q10",
108 		.matches = {
109 			DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
110 			DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
111 		},
112 		.callback = dmi_check_callback,
113 	},
114 	{
115 		.ident = "Samsung Q20",
116 		.matches = {
117 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
118 			DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
119 		},
120 		.callback = dmi_check_callback,
121 	},
122 	{
123 		.ident = "Samsung Q25",
124 		.matches = {
125 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
126 			DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
127 		},
128 		.callback = dmi_check_callback,
129 	},
130 	{
131 		.ident = "Dell Latitude X200",
132 		.matches = {
133 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
134 			DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
135 		},
136 		.callback = dmi_check_callback,
137 	},
138 	{ },
139 };
140 MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
141 
142 static int __init samsungq10_init(void)
143 {
144 	if (!force && !dmi_check_system(samsungq10_dmi_table))
145 		return -ENODEV;
146 
147 	ec_handle = ec_get_handle();
148 
149 	if (!ec_handle)
150 		return -ENODEV;
151 
152 	samsungq10_device = platform_create_bundle(&samsungq10_driver,
153 						   samsungq10_probe,
154 						   NULL, 0, NULL, 0);
155 
156 	return PTR_ERR_OR_ZERO(samsungq10_device);
157 }
158 
159 static void __exit samsungq10_exit(void)
160 {
161 	platform_device_unregister(samsungq10_device);
162 	platform_driver_unregister(&samsungq10_driver);
163 }
164 
165 module_init(samsungq10_init);
166 module_exit(samsungq10_exit);
167 
168 MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
169 MODULE_DESCRIPTION("Samsung Q10 Driver");
170 MODULE_LICENSE("GPL");
171