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
33ACPI_MODULE_NAME(MODULE_NAME);
34
35MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
36MODULE_LICENSE("GPL");
37
38static const struct acpi_device_id ebook_device_ids[] = {
39	{ XO15_EBOOK_HID, 0 },
40	{ "", 0 },
41};
42MODULE_DEVICE_TABLE(acpi, ebook_device_ids);
43
44struct ebook_switch {
45	struct input_dev *input;
46	char phys[32];			/* for input device */
47};
48
49static 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
65static 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
80static int ebook_switch_resume(struct device *dev)
81{
82	return ebook_send_state(to_acpi_device(dev));
83}
84#endif
85
86static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);
87
88static 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
152static 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
161static 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};
172module_acpi_driver(xo15_ebook_driver);
173