blob: a26d8be6f7959b5f67ac20aac069c00202a31272 [file] [log] [blame]
* Driver for simulating a mouse on GPIO lines.
* Copyright (C) 2007 Atmel Corporation
* Copyright (C) 2017 Linus Walleij <>
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/input-polldev.h>
#include <linux/gpio/consumer.h>
#include <linux/property.h>
#include <linux/of.h>
* struct gpio_mouse
* @scan_ms: the scan interval in milliseconds.
* @up: GPIO line for up value.
* @down: GPIO line for down value.
* @left: GPIO line for left value.
* @right: GPIO line for right value.
* @bleft: GPIO line for left button.
* @bmiddle: GPIO line for middle button.
* @bright: GPIO line for right button.
* This struct must be added to the platform_device in the board code.
* It is used by the gpio_mouse driver to setup GPIO lines and to
* calculate mouse movement.
struct gpio_mouse {
u32 scan_ms;
struct gpio_desc *up;
struct gpio_desc *down;
struct gpio_desc *left;
struct gpio_desc *right;
struct gpio_desc *bleft;
struct gpio_desc *bmiddle;
struct gpio_desc *bright;
* Timer function which is run every scan_ms ms when the device is opened.
* The dev input variable is set to the the input_dev pointer.
static void gpio_mouse_scan(struct input_polled_dev *dev)
struct gpio_mouse *gpio = dev->private;
struct input_dev *input = dev->input;
int x, y;
if (gpio->bleft)
input_report_key(input, BTN_LEFT,
if (gpio->bmiddle)
input_report_key(input, BTN_MIDDLE,
if (gpio->bright)
input_report_key(input, BTN_RIGHT,
x = gpiod_get_value(gpio->right) - gpiod_get_value(gpio->left);
y = gpiod_get_value(gpio->down) - gpiod_get_value(gpio->up);
input_report_rel(input, REL_X, x);
input_report_rel(input, REL_Y, y);
static int gpio_mouse_probe(struct platform_device *pdev)
struct device *dev = &pdev->dev;
struct gpio_mouse *gmouse;
struct input_polled_dev *input_poll;
struct input_dev *input;
int ret;
gmouse = devm_kzalloc(dev, sizeof(*gmouse), GFP_KERNEL);
if (!gmouse)
return -ENOMEM;
/* Assign some default scanning time */
ret = device_property_read_u32(dev, "scan-interval-ms",
if (ret || gmouse->scan_ms == 0) {
dev_warn(dev, "invalid scan time, set to 50 ms\n");
gmouse->scan_ms = 50;
gmouse->up = devm_gpiod_get(dev, "up", GPIOD_IN);
if (IS_ERR(gmouse->up))
return PTR_ERR(gmouse->up);
gmouse->down = devm_gpiod_get(dev, "down", GPIOD_IN);
if (IS_ERR(gmouse->down))
return PTR_ERR(gmouse->down);
gmouse->left = devm_gpiod_get(dev, "left", GPIOD_IN);
if (IS_ERR(gmouse->left))
return PTR_ERR(gmouse->left);
gmouse->right = devm_gpiod_get(dev, "right", GPIOD_IN);
if (IS_ERR(gmouse->right))
return PTR_ERR(gmouse->right);
gmouse->bleft = devm_gpiod_get_optional(dev, "button-left", GPIOD_IN);
if (IS_ERR(gmouse->bleft))
return PTR_ERR(gmouse->bleft);
gmouse->bmiddle = devm_gpiod_get_optional(dev, "button-middle",
if (IS_ERR(gmouse->bmiddle))
return PTR_ERR(gmouse->bmiddle);
gmouse->bright = devm_gpiod_get_optional(dev, "button-right",
if (IS_ERR(gmouse->bright))
return PTR_ERR(gmouse->bright);
input_poll = devm_input_allocate_polled_device(dev);
if (!input_poll) {
dev_err(dev, "not enough memory for input device\n");
return -ENOMEM;
platform_set_drvdata(pdev, input_poll);
/* set input-polldev handlers */
input_poll->private = gmouse;
input_poll->poll = gpio_mouse_scan;
input_poll->poll_interval = gmouse->scan_ms;
input = input_poll->input;
input->name = pdev->name;
input->id.bustype = BUS_HOST;
input->dev.parent = &pdev->dev;
input_set_capability(input, EV_REL, REL_X);
input_set_capability(input, EV_REL, REL_Y);
if (gmouse->bleft)
input_set_capability(input, EV_KEY, BTN_LEFT);
if (gmouse->bmiddle)
input_set_capability(input, EV_KEY, BTN_MIDDLE);
if (gmouse->bright)
input_set_capability(input, EV_KEY, BTN_RIGHT);
ret = input_register_polled_device(input_poll);
if (ret) {
dev_err(dev, "could not register input device\n");
return ret;
dev_dbg(dev, "%d ms scan time, buttons: %s%s%s\n",
gmouse->bleft ? "" : "left ",
gmouse->bmiddle ? "" : "middle ",
gmouse->bright ? "" : "right");
return 0;
static const struct of_device_id gpio_mouse_of_match[] = {
{ .compatible = "gpio-mouse", },
{ },
MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
static struct platform_driver gpio_mouse_device_driver = {
.probe = gpio_mouse_probe,
.driver = {
.name = "gpio_mouse",
.of_match_table = gpio_mouse_of_match,
MODULE_AUTHOR("Hans-Christian Egtvedt <>");
MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */