1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Driver for simulating a mouse on GPIO lines.
4 *
5 * Copyright (C) 2007 Atmel Corporation
6 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
7 */
8
9#include <linux/module.h>
10#include <linux/platform_device.h>
11#include <linux/input.h>
12#include <linux/gpio/consumer.h>
13#include <linux/property.h>
14#include <linux/of.h>
15
16/**
17 * struct gpio_mouse
18 * @scan_ms: the scan interval in milliseconds.
19 * @up: GPIO line for up value.
20 * @down: GPIO line for down value.
21 * @left: GPIO line for left value.
22 * @right: GPIO line for right value.
23 * @bleft: GPIO line for left button.
24 * @bmiddle: GPIO line for middle button.
25 * @bright: GPIO line for right button.
26 *
27 * This struct must be added to the platform_device in the board code.
28 * It is used by the gpio_mouse driver to setup GPIO lines and to
29 * calculate mouse movement.
30 */
31struct gpio_mouse {
32	u32 scan_ms;
33	struct gpio_desc *up;
34	struct gpio_desc *down;
35	struct gpio_desc *left;
36	struct gpio_desc *right;
37	struct gpio_desc *bleft;
38	struct gpio_desc *bmiddle;
39	struct gpio_desc *bright;
40};
41
42/*
43 * Timer function which is run every scan_ms ms when the device is opened.
44 * The dev input variable is set to the input_dev pointer.
45 */
46static void gpio_mouse_scan(struct input_dev *input)
47{
48	struct gpio_mouse *gpio = input_get_drvdata(input);
49	int x, y;
50
51	if (gpio->bleft)
52		input_report_key(input, BTN_LEFT,
53				 gpiod_get_value(gpio->bleft));
54	if (gpio->bmiddle)
55		input_report_key(input, BTN_MIDDLE,
56				 gpiod_get_value(gpio->bmiddle));
57	if (gpio->bright)
58		input_report_key(input, BTN_RIGHT,
59				 gpiod_get_value(gpio->bright));
60
61	x = gpiod_get_value(gpio->right) - gpiod_get_value(gpio->left);
62	y = gpiod_get_value(gpio->down) - gpiod_get_value(gpio->up);
63
64	input_report_rel(input, REL_X, x);
65	input_report_rel(input, REL_Y, y);
66	input_sync(input);
67}
68
69static int gpio_mouse_probe(struct platform_device *pdev)
70{
71	struct device *dev = &pdev->dev;
72	struct gpio_mouse *gmouse;
73	struct input_dev *input;
74	int error;
75
76	gmouse = devm_kzalloc(dev, sizeof(*gmouse), GFP_KERNEL);
77	if (!gmouse)
78		return -ENOMEM;
79
80	/* Assign some default scanning time */
81	error = device_property_read_u32(dev, "scan-interval-ms",
82					 &gmouse->scan_ms);
83	if (error || gmouse->scan_ms == 0) {
84		dev_warn(dev, "invalid scan time, set to 50 ms\n");
85		gmouse->scan_ms = 50;
86	}
87
88	gmouse->up = devm_gpiod_get(dev, "up", GPIOD_IN);
89	if (IS_ERR(gmouse->up))
90		return PTR_ERR(gmouse->up);
91	gmouse->down = devm_gpiod_get(dev, "down", GPIOD_IN);
92	if (IS_ERR(gmouse->down))
93		return PTR_ERR(gmouse->down);
94	gmouse->left = devm_gpiod_get(dev, "left", GPIOD_IN);
95	if (IS_ERR(gmouse->left))
96		return PTR_ERR(gmouse->left);
97	gmouse->right = devm_gpiod_get(dev, "right", GPIOD_IN);
98	if (IS_ERR(gmouse->right))
99		return PTR_ERR(gmouse->right);
100
101	gmouse->bleft = devm_gpiod_get_optional(dev, "button-left", GPIOD_IN);
102	if (IS_ERR(gmouse->bleft))
103		return PTR_ERR(gmouse->bleft);
104	gmouse->bmiddle = devm_gpiod_get_optional(dev, "button-middle",
105						  GPIOD_IN);
106	if (IS_ERR(gmouse->bmiddle))
107		return PTR_ERR(gmouse->bmiddle);
108	gmouse->bright = devm_gpiod_get_optional(dev, "button-right",
109						 GPIOD_IN);
110	if (IS_ERR(gmouse->bright))
111		return PTR_ERR(gmouse->bright);
112
113	input = devm_input_allocate_device(dev);
114	if (!input)
115		return -ENOMEM;
116
117	input->name = pdev->name;
118	input->id.bustype = BUS_HOST;
119
120	input_set_drvdata(input, gmouse);
121
122	input_set_capability(input, EV_REL, REL_X);
123	input_set_capability(input, EV_REL, REL_Y);
124	if (gmouse->bleft)
125		input_set_capability(input, EV_KEY, BTN_LEFT);
126	if (gmouse->bmiddle)
127		input_set_capability(input, EV_KEY, BTN_MIDDLE);
128	if (gmouse->bright)
129		input_set_capability(input, EV_KEY, BTN_RIGHT);
130
131	error = input_setup_polling(input, gpio_mouse_scan);
132	if (error)
133		return error;
134
135	input_set_poll_interval(input, gmouse->scan_ms);
136
137	error = input_register_device(input);
138	if (error) {
139		dev_err(dev, "could not register input device\n");
140		return error;
141	}
142
143	dev_dbg(dev, "%d ms scan time, buttons: %s%s%s\n",
144		gmouse->scan_ms,
145		gmouse->bleft ? "" : "left ",
146		gmouse->bmiddle ? "" : "middle ",
147		gmouse->bright ? "" : "right");
148
149	return 0;
150}
151
152static const struct of_device_id gpio_mouse_of_match[] = {
153	{ .compatible = "gpio-mouse", },
154	{ },
155};
156MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
157
158static struct platform_driver gpio_mouse_device_driver = {
159	.probe		= gpio_mouse_probe,
160	.driver		= {
161		.name	= "gpio_mouse",
162		.of_match_table = gpio_mouse_of_match,
163	}
164};
165module_platform_driver(gpio_mouse_device_driver);
166
167MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
168MODULE_DESCRIPTION("GPIO mouse driver");
169MODULE_LICENSE("GPL");
170MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */
171