1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Apple Motion Sensor driver (joystick emulation)
4  *
5  * Copyright (C) 2005 Stelian Pop (stelian@popies.net)
6  * Copyright (C) 2006 Michael Hanselmann (linux-kernel@hansmi.ch)
7  */
8 
9 #include <linux/module.h>
10 
11 #include <linux/types.h>
12 #include <linux/errno.h>
13 #include <linux/init.h>
14 #include <linux/delay.h>
15 
16 #include "ams.h"
17 
18 static bool joystick;
19 module_param(joystick, bool, S_IRUGO);
20 MODULE_PARM_DESC(joystick, "Enable the input class device on module load");
21 
22 static bool invert;
23 module_param(invert, bool, S_IWUSR | S_IRUGO);
24 MODULE_PARM_DESC(invert, "Invert input data on X and Y axis");
25 
26 static DEFINE_MUTEX(ams_input_mutex);
27 
28 static void ams_idev_poll(struct input_dev *idev)
29 {
30 	s8 x, y, z;
31 
32 	mutex_lock(&ams_info.lock);
33 
34 	ams_sensors(&x, &y, &z);
35 
36 	x -= ams_info.xcalib;
37 	y -= ams_info.ycalib;
38 	z -= ams_info.zcalib;
39 
40 	input_report_abs(idev, ABS_X, invert ? -x : x);
41 	input_report_abs(idev, ABS_Y, invert ? -y : y);
42 	input_report_abs(idev, ABS_Z, z);
43 
44 	input_sync(idev);
45 
46 	mutex_unlock(&ams_info.lock);
47 }
48 
49 /* Call with ams_info.lock held! */
50 static int ams_input_enable(void)
51 {
52 	struct input_dev *input;
53 	s8 x, y, z;
54 	int error;
55 
56 	ams_sensors(&x, &y, &z);
57 	ams_info.xcalib = x;
58 	ams_info.ycalib = y;
59 	ams_info.zcalib = z;
60 
61 	input = input_allocate_device();
62 	if (!input)
63 		return -ENOMEM;
64 
65 	input->name = "Apple Motion Sensor";
66 	input->id.bustype = ams_info.bustype;
67 	input->id.vendor = 0;
68 	input->dev.parent = &ams_info.of_dev->dev;
69 
70 	input_set_abs_params(input, ABS_X, -50, 50, 3, 0);
71 	input_set_abs_params(input, ABS_Y, -50, 50, 3, 0);
72 	input_set_abs_params(input, ABS_Z, -50, 50, 3, 0);
73 	input_set_capability(input, EV_KEY, BTN_TOUCH);
74 
75 	error = input_setup_polling(input, ams_idev_poll);
76 	if (error)
77 		goto err_free_input;
78 
79 	input_set_poll_interval(input, 25);
80 
81 	error = input_register_device(input);
82 	if (error)
83 		goto err_free_input;
84 
85 	ams_info.idev = input;
86 	joystick = true;
87 
88 	return 0;
89 
90 err_free_input:
91 	input_free_device(input);
92 	return error;
93 }
94 
95 static void ams_input_disable(void)
96 {
97 	if (ams_info.idev) {
98 		input_unregister_device(ams_info.idev);
99 		ams_info.idev = NULL;
100 	}
101 
102 	joystick = false;
103 }
104 
105 static ssize_t ams_input_show_joystick(struct device *dev,
106 	struct device_attribute *attr, char *buf)
107 {
108 	return sprintf(buf, "%d\n", joystick);
109 }
110 
111 static ssize_t ams_input_store_joystick(struct device *dev,
112 	struct device_attribute *attr, const char *buf, size_t count)
113 {
114 	unsigned long enable;
115 	int error = 0;
116 	int ret;
117 
118 	ret = kstrtoul(buf, 0, &enable);
119 	if (ret)
120 		return ret;
121 	if (enable > 1)
122 		return -EINVAL;
123 
124 	mutex_lock(&ams_input_mutex);
125 
126 	if (enable != joystick) {
127 		if (enable)
128 			error = ams_input_enable();
129 		else
130 			ams_input_disable();
131 	}
132 
133 	mutex_unlock(&ams_input_mutex);
134 
135 	return error ? error : count;
136 }
137 
138 static DEVICE_ATTR(joystick, S_IRUGO | S_IWUSR,
139 	ams_input_show_joystick, ams_input_store_joystick);
140 
141 int ams_input_init(void)
142 {
143 	if (joystick)
144 		ams_input_enable();
145 
146 	return device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
147 }
148 
149 void ams_input_exit(void)
150 {
151 	device_remove_file(&ams_info.of_dev->dev, &dev_attr_joystick);
152 
153 	mutex_lock(&ams_input_mutex);
154 	ams_input_disable();
155 	mutex_unlock(&ams_input_mutex);
156 }
157