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/i8042.h>
18#include <linux/dmi.h>
19
20#define SAMSUNGQ10_BL_MAX_INTENSITY      255
21#define SAMSUNGQ10_BL_DEFAULT_INTENSITY  185
22
23#define SAMSUNGQ10_BL_8042_CMD           0xbe
24#define SAMSUNGQ10_BL_8042_DATA          { 0x89, 0x91 }
25
26static int samsungq10_bl_brightness;
27
28static bool force;
29module_param(force, bool, 0);
30MODULE_PARM_DESC(force,
31		"Disable the DMI check and force the driver to be loaded");
32
33static int samsungq10_bl_set_intensity(struct backlight_device *bd)
34{
35
36	int brightness = bd->props.brightness;
37	unsigned char c[3] = SAMSUNGQ10_BL_8042_DATA;
38
39	c[2] = (unsigned char)brightness;
40	i8042_lock_chip();
41	i8042_command(c, (0x30 << 8) | SAMSUNGQ10_BL_8042_CMD);
42	i8042_unlock_chip();
43	samsungq10_bl_brightness = brightness;
44
45	return 0;
46}
47
48static int samsungq10_bl_get_intensity(struct backlight_device *bd)
49{
50	return samsungq10_bl_brightness;
51}
52
53static const struct backlight_ops samsungq10_bl_ops = {
54	.get_brightness = samsungq10_bl_get_intensity,
55	.update_status	= samsungq10_bl_set_intensity,
56};
57
58#ifdef CONFIG_PM_SLEEP
59static int samsungq10_suspend(struct device *dev)
60{
61	return 0;
62}
63
64static int samsungq10_resume(struct device *dev)
65{
66
67	struct backlight_device *bd = dev_get_drvdata(dev);
68
69	samsungq10_bl_set_intensity(bd);
70	return 0;
71}
72#else
73#define samsungq10_suspend NULL
74#define samsungq10_resume  NULL
75#endif
76
77static SIMPLE_DEV_PM_OPS(samsungq10_pm_ops,
78			  samsungq10_suspend, samsungq10_resume);
79
80static int __devinit samsungq10_probe(struct platform_device *pdev)
81{
82
83	struct backlight_properties props;
84	struct backlight_device *bd;
85
86	memset(&props, 0, sizeof(struct backlight_properties));
87	props.type = BACKLIGHT_PLATFORM;
88	props.max_brightness = SAMSUNGQ10_BL_MAX_INTENSITY;
89	bd = backlight_device_register("samsung", &pdev->dev, NULL,
90				       &samsungq10_bl_ops, &props);
91	if (IS_ERR(bd))
92		return PTR_ERR(bd);
93
94	platform_set_drvdata(pdev, bd);
95
96	bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
97	samsungq10_bl_set_intensity(bd);
98
99	return 0;
100}
101
102static int __devexit samsungq10_remove(struct platform_device *pdev)
103{
104
105	struct backlight_device *bd = platform_get_drvdata(pdev);
106
107	bd->props.brightness = SAMSUNGQ10_BL_DEFAULT_INTENSITY;
108	samsungq10_bl_set_intensity(bd);
109
110	backlight_device_unregister(bd);
111
112	return 0;
113}
114
115static struct platform_driver samsungq10_driver = {
116	.driver		= {
117		.name	= KBUILD_MODNAME,
118		.owner	= THIS_MODULE,
119		.pm	= &samsungq10_pm_ops,
120	},
121	.probe		= samsungq10_probe,
122	.remove		= __devexit_p(samsungq10_remove),
123};
124
125static struct platform_device *samsungq10_device;
126
127static int __init dmi_check_callback(const struct dmi_system_id *id)
128{
129	printk(KERN_INFO KBUILD_MODNAME ": found model '%s'\n", id->ident);
130	return 1;
131}
132
133static struct dmi_system_id __initdata samsungq10_dmi_table[] = {
134	{
135		.ident = "Samsung Q10",
136		.matches = {
137			DMI_MATCH(DMI_SYS_VENDOR, "Samsung"),
138			DMI_MATCH(DMI_PRODUCT_NAME, "SQ10"),
139		},
140		.callback = dmi_check_callback,
141	},
142	{
143		.ident = "Samsung Q20",
144		.matches = {
145			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
146			DMI_MATCH(DMI_PRODUCT_NAME, "SENS Q20"),
147		},
148		.callback = dmi_check_callback,
149	},
150	{
151		.ident = "Samsung Q25",
152		.matches = {
153			DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG Electronics"),
154			DMI_MATCH(DMI_PRODUCT_NAME, "NQ25"),
155		},
156		.callback = dmi_check_callback,
157	},
158	{
159		.ident = "Dell Latitude X200",
160		.matches = {
161			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
162			DMI_MATCH(DMI_PRODUCT_NAME, "X200"),
163		},
164		.callback = dmi_check_callback,
165	},
166	{ },
167};
168MODULE_DEVICE_TABLE(dmi, samsungq10_dmi_table);
169
170static int __init samsungq10_init(void)
171{
172	if (!force && !dmi_check_system(samsungq10_dmi_table))
173		return -ENODEV;
174
175	samsungq10_device = platform_create_bundle(&samsungq10_driver,
176						   samsungq10_probe,
177						   NULL, 0, NULL, 0);
178
179	if (IS_ERR(samsungq10_device))
180		return PTR_ERR(samsungq10_device);
181
182	return 0;
183}
184
185static void __exit samsungq10_exit(void)
186{
187	platform_device_unregister(samsungq10_device);
188	platform_driver_unregister(&samsungq10_driver);
189}
190
191module_init(samsungq10_init);
192module_exit(samsungq10_exit);
193
194MODULE_AUTHOR("Frederick van der Wyck <fvanderwyck@gmail.com>");
195MODULE_DESCRIPTION("Samsung Q10 Driver");
196MODULE_LICENSE("GPL");
197