1 /*
2  *  OLPC XO-1.5 ebook switch driver
3  *  (based on generic ACPI button driver)
4  *
5  *  Copyright (C) 2009 Paul Fox <pgf@laptop.org>
6  *  Copyright (C) 2010 One Laptop per Child
7  *
8  *  This program is free software; you can redistribute it and/or modify
9  *  it under the terms of the GNU General Public License as published by
10  *  the Free Software Foundation; either version 2 of the License, or (at
11  *  your option) any later version.
12  */
13 
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15 
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/init.h>
19 #include <linux/types.h>
20 #include <linux/input.h>
21 #include <linux/acpi.h>
22 
23 #define MODULE_NAME "xo15-ebook"
24 
25 #define XO15_EBOOK_CLASS		MODULE_NAME
26 #define XO15_EBOOK_TYPE_UNKNOWN	0x00
27 #define XO15_EBOOK_NOTIFY_STATUS	0x80
28 
29 #define XO15_EBOOK_SUBCLASS		"ebook"
30 #define XO15_EBOOK_HID			"XO15EBK"
31 #define XO15_EBOOK_DEVICE_NAME		"EBook Switch"
32 
33 ACPI_MODULE_NAME(MODULE_NAME);
34 
35 MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
36 MODULE_LICENSE("GPL");
37 
38 static const struct acpi_device_id ebook_device_ids[] = {
39 	{ XO15_EBOOK_HID, 0 },
40 	{ "", 0 },
41 };
42 MODULE_DEVICE_TABLE(acpi, ebook_device_ids);
43 
44 struct ebook_switch {
45 	struct input_dev *input;
46 	char phys[32];			/* for input device */
47 };
48 
49 static int ebook_send_state(struct acpi_device *device)
50 {
51 	struct ebook_switch *button = acpi_driver_data(device);
52 	unsigned long long state;
53 	acpi_status status;
54 
55 	status = acpi_evaluate_integer(device->handle, "EBK", NULL, &state);
56 	if (ACPI_FAILURE(status))
57 		return -EIO;
58 
59 	/* input layer checks if event is redundant */
60 	input_report_switch(button->input, SW_TABLET_MODE, !state);
61 	input_sync(button->input);
62 	return 0;
63 }
64 
65 static void ebook_switch_notify(struct acpi_device *device, u32 event)
66 {
67 	switch (event) {
68 	case ACPI_FIXED_HARDWARE_EVENT:
69 	case XO15_EBOOK_NOTIFY_STATUS:
70 		ebook_send_state(device);
71 		break;
72 	default:
73 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
74 				  "Unsupported event [0x%x]\n", event));
75 		break;
76 	}
77 }
78 
79 #ifdef CONFIG_PM_SLEEP
80 static int ebook_switch_resume(struct device *dev)
81 {
82 	return ebook_send_state(to_acpi_device(dev));
83 }
84 #endif
85 
86 static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);
87 
88 static int ebook_switch_add(struct acpi_device *device)
89 {
90 	struct ebook_switch *button;
91 	struct input_dev *input;
92 	const char *hid = acpi_device_hid(device);
93 	char *name, *class;
94 	int error;
95 
96 	button = kzalloc(sizeof(struct ebook_switch), GFP_KERNEL);
97 	if (!button)
98 		return -ENOMEM;
99 
100 	device->driver_data = button;
101 
102 	button->input = input = input_allocate_device();
103 	if (!input) {
104 		error = -ENOMEM;
105 		goto err_free_button;
106 	}
107 
108 	name = acpi_device_name(device);
109 	class = acpi_device_class(device);
110 
111 	if (strcmp(hid, XO15_EBOOK_HID)) {
112 		pr_err("Unsupported hid [%s]\n", hid);
113 		error = -ENODEV;
114 		goto err_free_input;
115 	}
116 
117 	strcpy(name, XO15_EBOOK_DEVICE_NAME);
118 	sprintf(class, "%s/%s", XO15_EBOOK_CLASS, XO15_EBOOK_SUBCLASS);
119 
120 	snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
121 
122 	input->name = name;
123 	input->phys = button->phys;
124 	input->id.bustype = BUS_HOST;
125 	input->dev.parent = &device->dev;
126 
127 	input->evbit[0] = BIT_MASK(EV_SW);
128 	set_bit(SW_TABLET_MODE, input->swbit);
129 
130 	error = input_register_device(input);
131 	if (error)
132 		goto err_free_input;
133 
134 	ebook_send_state(device);
135 
136 	if (device->wakeup.flags.valid) {
137 		/* Button's GPE is run-wake GPE */
138 		acpi_enable_gpe(device->wakeup.gpe_device,
139 				device->wakeup.gpe_number);
140 		device_set_wakeup_enable(&device->dev, true);
141 	}
142 
143 	return 0;
144 
145  err_free_input:
146 	input_free_device(input);
147  err_free_button:
148 	kfree(button);
149 	return error;
150 }
151 
152 static int ebook_switch_remove(struct acpi_device *device)
153 {
154 	struct ebook_switch *button = acpi_driver_data(device);
155 
156 	input_unregister_device(button->input);
157 	kfree(button);
158 	return 0;
159 }
160 
161 static struct acpi_driver xo15_ebook_driver = {
162 	.name = MODULE_NAME,
163 	.class = XO15_EBOOK_CLASS,
164 	.ids = ebook_device_ids,
165 	.ops = {
166 		.add = ebook_switch_add,
167 		.remove = ebook_switch_remove,
168 		.notify = ebook_switch_notify,
169 	},
170 	.drv.pm = &ebook_switch_pm,
171 };
172 module_acpi_driver(xo15_ebook_driver);
173