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_polled_dev *dev)
29 {
30 	struct input_dev *idev = dev->input;
31 	s8 x, y, z;
32 
33 	mutex_lock(&ams_info.lock);
34 
35 	ams_sensors(&x, &y, &z);
36 
37 	x -= ams_info.xcalib;
38 	y -= ams_info.ycalib;
39 	z -= ams_info.zcalib;
40 
41 	input_report_abs(idev, ABS_X, invert ? -x : x);
42 	input_report_abs(idev, ABS_Y, invert ? -y : y);
43 	input_report_abs(idev, ABS_Z, z);
44 
45 	input_sync(idev);
46 
47 	mutex_unlock(&ams_info.lock);
48 }
49 
50 /* Call with ams_info.lock held! */
51 static int ams_input_enable(void)
52 {
53 	struct input_dev *input;
54 	s8 x, y, z;
55 	int error;
56 
57 	ams_sensors(&x, &y, &z);
58 	ams_info.xcalib = x;
59 	ams_info.ycalib = y;
60 	ams_info.zcalib = z;
61 
62 	ams_info.idev = input_allocate_polled_device();
63 	if (!ams_info.idev)
64 		return -ENOMEM;
65 
66 	ams_info.idev->poll = ams_idev_poll;
67 	ams_info.idev->poll_interval = 25;
68 
69 	input = ams_info.idev->input;
70 	input->name = "Apple Motion Sensor";
71 	input->id.bustype = ams_info.bustype;
72 	input->id.vendor = 0;
73 	input->dev.parent = &ams_info.of_dev->dev;
74 
75 	input_set_abs_params(input, ABS_X, -50, 50, 3, 0);
76 	input_set_abs_params(input, ABS_Y, -50, 50, 3, 0);
77 	input_set_abs_params(input, ABS_Z, -50, 50, 3, 0);
78 
79 	set_bit(EV_ABS, input->evbit);
80 	set_bit(EV_KEY, input->evbit);
81 	set_bit(BTN_TOUCH, input->keybit);
82 
83 	error = input_register_polled_device(ams_info.idev);
84 	if (error) {
85 		input_free_polled_device(ams_info.idev);
86 		ams_info.idev = NULL;
87 		return error;
88 	}
89 
90 	joystick = true;
91 
92 	return 0;
93 }
94 
95 static void ams_input_disable(void)
96 {
97 	if (ams_info.idev) {
98 		input_unregister_polled_device(ams_info.idev);
99 		input_free_polled_device(ams_info.idev);
100 		ams_info.idev = NULL;
101 	}
102 
103 	joystick = false;
104 }
105 
106 static ssize_t ams_input_show_joystick(struct device *dev,
107 	struct device_attribute *attr, char *buf)
108 {
109 	return sprintf(buf, "%d\n", joystick);
110 }
111 
112 static ssize_t ams_input_store_joystick(struct device *dev,
113 	struct device_attribute *attr, const char *buf, size_t count)
114 {
115 	unsigned long enable;
116 	int error = 0;
117 	int ret;
118 
119 	ret = kstrtoul(buf, 0, &enable);
120 	if (ret)
121 		return ret;
122 	if (enable > 1)
123 		return -EINVAL;
124 
125 	mutex_lock(&ams_input_mutex);
126 
127 	if (enable != joystick) {
128 		if (enable)
129 			error = ams_input_enable();
130 		else
131 			ams_input_disable();
132 	}
133 
134 	mutex_unlock(&ams_input_mutex);
135 
136 	return error ? error : count;
137 }
138 
139 static DEVICE_ATTR(joystick, S_IRUGO | S_IWUSR,
140 	ams_input_show_joystick, ams_input_store_joystick);
141 
142 int ams_input_init(void)
143 {
144 	if (joystick)
145 		ams_input_enable();
146 
147 	return device_create_file(&ams_info.of_dev->dev, &dev_attr_joystick);
148 }
149 
150 void ams_input_exit(void)
151 {
152 	device_remove_file(&ams_info.of_dev->dev, &dev_attr_joystick);
153 
154 	mutex_lock(&ams_input_mutex);
155 	ams_input_disable();
156 	mutex_unlock(&ams_input_mutex);
157 }
158