1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  OLPC XO-1.5 ebook switch driver
4  *  (based on generic ACPI button driver)
5  *
6  *  Copyright (C) 2009 Paul Fox <pgf@laptop.org>
7  *  Copyright (C) 2010 One Laptop per Child
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11 
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/input.h>
17 #include <linux/acpi.h>
18 
19 #define MODULE_NAME "xo15-ebook"
20 
21 #define XO15_EBOOK_CLASS		MODULE_NAME
22 #define XO15_EBOOK_TYPE_UNKNOWN	0x00
23 #define XO15_EBOOK_NOTIFY_STATUS	0x80
24 
25 #define XO15_EBOOK_SUBCLASS		"ebook"
26 #define XO15_EBOOK_HID			"XO15EBK"
27 #define XO15_EBOOK_DEVICE_NAME		"EBook Switch"
28 
29 MODULE_DESCRIPTION("OLPC XO-1.5 ebook switch driver");
30 MODULE_LICENSE("GPL");
31 
32 static const struct acpi_device_id ebook_device_ids[] = {
33 	{ XO15_EBOOK_HID, 0 },
34 	{ "", 0 },
35 };
36 MODULE_DEVICE_TABLE(acpi, ebook_device_ids);
37 
38 struct ebook_switch {
39 	struct input_dev *input;
40 	char phys[32];			/* for input device */
41 };
42 
ebook_send_state(struct acpi_device * device)43 static int ebook_send_state(struct acpi_device *device)
44 {
45 	struct ebook_switch *button = acpi_driver_data(device);
46 	unsigned long long state;
47 	acpi_status status;
48 
49 	status = acpi_evaluate_integer(device->handle, "EBK", NULL, &state);
50 	if (ACPI_FAILURE(status))
51 		return -EIO;
52 
53 	/* input layer checks if event is redundant */
54 	input_report_switch(button->input, SW_TABLET_MODE, !state);
55 	input_sync(button->input);
56 	return 0;
57 }
58 
ebook_switch_notify(struct acpi_device * device,u32 event)59 static void ebook_switch_notify(struct acpi_device *device, u32 event)
60 {
61 	switch (event) {
62 	case ACPI_FIXED_HARDWARE_EVENT:
63 	case XO15_EBOOK_NOTIFY_STATUS:
64 		ebook_send_state(device);
65 		break;
66 	default:
67 		acpi_handle_debug(device->handle,
68 				  "Unsupported event [0x%x]\n", event);
69 		break;
70 	}
71 }
72 
73 #ifdef CONFIG_PM_SLEEP
ebook_switch_resume(struct device * dev)74 static int ebook_switch_resume(struct device *dev)
75 {
76 	return ebook_send_state(to_acpi_device(dev));
77 }
78 #endif
79 
80 static SIMPLE_DEV_PM_OPS(ebook_switch_pm, NULL, ebook_switch_resume);
81 
ebook_switch_add(struct acpi_device * device)82 static int ebook_switch_add(struct acpi_device *device)
83 {
84 	struct ebook_switch *button;
85 	struct input_dev *input;
86 	const char *hid = acpi_device_hid(device);
87 	char *name, *class;
88 	int error;
89 
90 	button = kzalloc(sizeof(struct ebook_switch), GFP_KERNEL);
91 	if (!button)
92 		return -ENOMEM;
93 
94 	device->driver_data = button;
95 
96 	button->input = input = input_allocate_device();
97 	if (!input) {
98 		error = -ENOMEM;
99 		goto err_free_button;
100 	}
101 
102 	name = acpi_device_name(device);
103 	class = acpi_device_class(device);
104 
105 	if (strcmp(hid, XO15_EBOOK_HID)) {
106 		pr_err("Unsupported hid [%s]\n", hid);
107 		error = -ENODEV;
108 		goto err_free_input;
109 	}
110 
111 	strcpy(name, XO15_EBOOK_DEVICE_NAME);
112 	sprintf(class, "%s/%s", XO15_EBOOK_CLASS, XO15_EBOOK_SUBCLASS);
113 
114 	snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
115 
116 	input->name = name;
117 	input->phys = button->phys;
118 	input->id.bustype = BUS_HOST;
119 	input->dev.parent = &device->dev;
120 
121 	input->evbit[0] = BIT_MASK(EV_SW);
122 	set_bit(SW_TABLET_MODE, input->swbit);
123 
124 	error = input_register_device(input);
125 	if (error)
126 		goto err_free_input;
127 
128 	ebook_send_state(device);
129 
130 	if (device->wakeup.flags.valid) {
131 		/* Button's GPE is run-wake GPE */
132 		acpi_enable_gpe(device->wakeup.gpe_device,
133 				device->wakeup.gpe_number);
134 		device_set_wakeup_enable(&device->dev, true);
135 	}
136 
137 	return 0;
138 
139  err_free_input:
140 	input_free_device(input);
141  err_free_button:
142 	kfree(button);
143 	return error;
144 }
145 
ebook_switch_remove(struct acpi_device * device)146 static void ebook_switch_remove(struct acpi_device *device)
147 {
148 	struct ebook_switch *button = acpi_driver_data(device);
149 
150 	input_unregister_device(button->input);
151 	kfree(button);
152 }
153 
154 static struct acpi_driver xo15_ebook_driver = {
155 	.name = MODULE_NAME,
156 	.class = XO15_EBOOK_CLASS,
157 	.ids = ebook_device_ids,
158 	.ops = {
159 		.add = ebook_switch_add,
160 		.remove = ebook_switch_remove,
161 		.notify = ebook_switch_notify,
162 	},
163 	.drv.pm = &ebook_switch_pm,
164 };
165 module_acpi_driver(xo15_ebook_driver);
166