1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2021 Oleh Kravchenko <oleg@kaa.org.ua>
4  *
5  * SparkFun Qwiic Joystick
6  * Product page:https://www.sparkfun.com/products/15168
7  * Firmware and hardware sources:https://github.com/sparkfun/Qwiic_Joystick
8  */
9 
10 #include <linux/bits.h>
11 #include <linux/i2c.h>
12 #include <linux/input.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 
16 #define DRV_NAME "qwiic-joystick"
17 
18 #define QWIIC_JSK_REG_VERS	1
19 #define QWIIC_JSK_REG_DATA	3
20 
21 #define QWIIC_JSK_MAX_AXIS	GENMASK(9, 0)
22 #define QWIIC_JSK_FUZZ		2
23 #define QWIIC_JSK_FLAT		2
24 #define QWIIC_JSK_POLL_INTERVAL	16
25 #define QWIIC_JSK_POLL_MIN	8
26 #define QWIIC_JSK_POLL_MAX	32
27 
28 struct qwiic_jsk {
29 	char phys[32];
30 	struct input_dev *dev;
31 	struct i2c_client *client;
32 };
33 
34 struct qwiic_ver {
35 	u8 major;
36 	u8 minor;
37 };
38 
39 struct qwiic_data {
40 	__be16 x;
41 	__be16 y;
42 	u8 thumb;
43 };
44 
qwiic_poll(struct input_dev * input)45 static void qwiic_poll(struct input_dev *input)
46 {
47 	struct qwiic_jsk *priv = input_get_drvdata(input);
48 	struct qwiic_data data;
49 	int err;
50 
51 	err = i2c_smbus_read_i2c_block_data(priv->client, QWIIC_JSK_REG_DATA,
52 					    sizeof(data), (u8 *)&data);
53 	if (err != sizeof(data))
54 		return;
55 
56 	input_report_abs(input, ABS_X, be16_to_cpu(data.x) >> 6);
57 	input_report_abs(input, ABS_Y, be16_to_cpu(data.y) >> 6);
58 	input_report_key(input, BTN_THUMBL, !data.thumb);
59 	input_sync(input);
60 }
61 
qwiic_probe(struct i2c_client * client)62 static int qwiic_probe(struct i2c_client *client)
63 {
64 	struct qwiic_jsk *priv;
65 	struct qwiic_ver vers;
66 	int err;
67 
68 	err = i2c_smbus_read_i2c_block_data(client, QWIIC_JSK_REG_VERS,
69 					    sizeof(vers), (u8 *)&vers);
70 	if (err < 0)
71 		return err;
72 	if (err != sizeof(vers))
73 		return -EIO;
74 
75 	dev_dbg(&client->dev, "SparkFun Qwiic Joystick, FW: %u.%u\n",
76 		vers.major, vers.minor);
77 
78 	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
79 	if (!priv)
80 		return -ENOMEM;
81 
82 	priv->client = client;
83 	snprintf(priv->phys, sizeof(priv->phys),
84 		 "i2c/%s", dev_name(&client->dev));
85 	i2c_set_clientdata(client, priv);
86 
87 	priv->dev = devm_input_allocate_device(&client->dev);
88 	if (!priv->dev)
89 		return -ENOMEM;
90 
91 	priv->dev->id.bustype = BUS_I2C;
92 	priv->dev->name = "SparkFun Qwiic Joystick";
93 	priv->dev->phys = priv->phys;
94 	input_set_drvdata(priv->dev, priv);
95 
96 	input_set_abs_params(priv->dev, ABS_X, 0, QWIIC_JSK_MAX_AXIS,
97 			     QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
98 	input_set_abs_params(priv->dev, ABS_Y, 0, QWIIC_JSK_MAX_AXIS,
99 			     QWIIC_JSK_FUZZ, QWIIC_JSK_FLAT);
100 	input_set_capability(priv->dev, EV_KEY, BTN_THUMBL);
101 
102 	err = input_setup_polling(priv->dev, qwiic_poll);
103 	if (err) {
104 		dev_err(&client->dev, "failed to set up polling: %d\n", err);
105 		return err;
106 	}
107 	input_set_poll_interval(priv->dev, QWIIC_JSK_POLL_INTERVAL);
108 	input_set_min_poll_interval(priv->dev, QWIIC_JSK_POLL_MIN);
109 	input_set_max_poll_interval(priv->dev, QWIIC_JSK_POLL_MAX);
110 
111 	err = input_register_device(priv->dev);
112 	if (err) {
113 		dev_err(&client->dev, "failed to register joystick: %d\n", err);
114 		return err;
115 	}
116 
117 	return 0;
118 }
119 
120 #ifdef CONFIG_OF
121 static const struct of_device_id of_qwiic_match[] = {
122 	{ .compatible = "sparkfun,qwiic-joystick", },
123 	{ },
124 };
125 MODULE_DEVICE_TABLE(of, of_qwiic_match);
126 #endif /* CONFIG_OF */
127 
128 static const struct i2c_device_id qwiic_id_table[] = {
129 	{ KBUILD_MODNAME, 0 },
130 	{ },
131 };
132 MODULE_DEVICE_TABLE(i2c, qwiic_id_table);
133 
134 static struct i2c_driver qwiic_driver = {
135 	.driver = {
136 		.name		= DRV_NAME,
137 		.of_match_table	= of_match_ptr(of_qwiic_match),
138 	},
139 	.id_table	= qwiic_id_table,
140 	.probe		= qwiic_probe,
141 };
142 module_i2c_driver(qwiic_driver);
143 
144 MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
145 MODULE_DESCRIPTION("SparkFun Qwiic Joystick driver");
146 MODULE_LICENSE("GPL v2");
147