1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  Driver for Samsung Q10 and related laptops: controls the backlight
4  *
5  *  Copyright (c) 2011 Frederick van der Wyck <fvanderwyck@gmail.com>
6  */
7 
8 #include <linux/module.h>
9 #include <linux/kernel.h>
10 #include <linux/init.h>
11 #include <linux/platform_device.h>
12 #include <linux/backlight.h>
13 #include <linux/dmi.h>
14 #include <linux/acpi.h>
15 
16 #define SAMSUNGQ10_BL_MAX_INTENSITY 7
17 
18 static acpi_handle ec_handle;
19 
20 static bool force;
21 module_param(force, bool, 0);
22 MODULE_PARM_DESC(force,
23 		"Disable the DMI check and force the driver to be loaded");
24 
25 static int samsungq10_bl_set_intensity(struct backlight_device *bd)
26 {
27 
28 	acpi_status status;
29 	int i;
30 
31 	for (i = 0; i < SAMSUNGQ10_BL_MAX_INTENSITY; i++) {
32 		status = acpi_evaluate_object(ec_handle, "_Q63", NULL, NULL);
33 		if (ACPI_FAILURE(status))
34 			return -EIO;
35 	}
36 	for (i = 0; i < bd->props.brightness; i++) {
37 		status = acpi_evaluate_object(ec_handle, "_Q64", NULL, NULL);
38 		if (ACPI_FAILURE(status))
39 			return -EIO;
40 	}
41 
42 	return 0;
43 }
44 
45 static const struct backlight_ops samsungq10_bl_ops = {
46 	.update_status	= samsungq10_bl_set_intensity,
47 };
48 
49 static int samsungq10_probe(struct platform_device *pdev)
50 {
51 
52 	struct backlight_properties props;
53 	struct backlight_device *bd;
54 
55 	memset(&props, 0, sizeof(struct backlight_properties));
56 	props.type = BACKLIGHT_PLATFORM;
57 	props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
58 	bd = backlight_device_register("samsung", &pdev->dev, NULL,
59 				       &samsungq10_bl_ops, &props);
60 	if (IS_ERR(bd))
61 		return PTR_ERR(bd);
62 
63 	platform_set_drvdata(pdev, bd);
64 
65 	return 0;
66 }
67 
68 static void samsungq10_remove(struct platform_device *pdev)
69 {
70 
71 	struct backlight_device *bd = platform_get_drvdata(pdev);
72 
73 	backlight_device_unregister(bd);
74 }
75 
76 static struct platform_driver samsungq10_driver = {
77 	.driver		= {
78 		.name	= KBUILD_MODNAME,
79 	},
80 	.probe		= samsungq10_probe,
81 	.remove_new	= samsungq10_remove,
82 };
83 
84 static struct platform_device *samsungq10_device;
85 
86 static int __init dmi_check_callback(const struct dmi_system_id *id)
87 {
88 	printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
89 	return 1;
90 }
91 
92 static const struct dmi_system_id samsungq10_dmi_table[] __initconst = {
93 	{
94 		.ident = "Samsung Q10",
95 		.matches = {
96 			DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
97 			DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
98 		},
99 		.callback = dmi_check_callback,
100 	},
101 	{
102 		.ident = "Samsung Q20",
103 		.matches = {
104 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
105 			DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
106 		},
107 		.callback = dmi_check_callback,
108 	},
109 	{
110 		.ident = "Samsung Q25",
111 		.matches = {
112 			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
113 			DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
114 		},
115 		.callback = dmi_check_callback,
116 	},
117 	{
118 		.ident = "Dell Latitude X200",
119 		.matches = {
120 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
121 			DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
122 		},
123 		.callback = dmi_check_callback,
124 	},
125 	{ },
126 };
127 MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
128 
129 static int __init samsungq10_init(void)
130 {
131 	if (!force && !dmi_check_system(samsungq10_dmi_table))
132 		return -ENODEV;
133 
134 	ec_handle = ec_get_handle();
135 
136 	if (!ec_handle)
137 		return -ENODEV;
138 
139 	samsungq10_device = platform_create_bundle(&samsungq10_driver,
140 						   samsungq10_probe,
141 						   NULL, 0, NULL, 0);
142 
143 	return PTR_ERR_OR_ZERO(samsungq10_device);
144 }
145 
146 static void __exit samsungq10_exit(void)
147 {
148 	platform_device_unregister(samsungq10_device);
149 	platform_driver_unregister(&samsungq10_driver);
150 }
151 
152 module_init(samsungq10_init);
153 module_exit(samsungq10_exit);
154 
155 MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
156 MODULE_DESCRIPTION("Samsung Q10 Driver");
157 MODULE_LICENSE("GPL");
158