input/mouse/gpio_mouse.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Driver for simulating a mouse on GPIO lines.
0004  *
0005  * Copyright (C) 2007 Atmel Corporation
0006  * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
0007  */
0008
0009 #include <linux/module.h>
0010 #include <linux/platform_device.h>
0011 #include <linux/input.h>
0012 #include <linux/gpio/consumer.h>
0013 #include <linux/property.h>
0014 #include <linux/of.h>
0015
0016 /**
0017  * struct gpio_mouse
0018  * @scan_ms: the scan interval in milliseconds.
0019  * @up: GPIO line for up value.
0020  * @down: GPIO line for down value.
0021  * @left: GPIO line for left value.
0022  * @right: GPIO line for right value.
0023  * @bleft: GPIO line for left button.
0024  * @bmiddle: GPIO line for middle button.
0025  * @bright: GPIO line for right button.
0026  *
0027  * This struct must be added to the platform_device in the board code.
0028  * It is used by the gpio_mouse driver to setup GPIO lines and to
0029  * calculate mouse movement.
0030  */
0031 struct gpio_mouse {
0032     u32 scan_ms;
0033     struct gpio_desc *up;
0034     struct gpio_desc *down;
0035     struct gpio_desc *left;
0036     struct gpio_desc *right;
0037     struct gpio_desc *bleft;
0038     struct gpio_desc *bmiddle;
0039     struct gpio_desc *bright;
0040 };
0041
0042 /*
0043  * Timer function which is run every scan_ms ms when the device is opened.
0044  * The dev input variable is set to the input_dev pointer.
0045  */
0046 static void gpio_mouse_scan(struct input_dev *input)
0047 {
0048     struct gpio_mouse *gpio = input_get_drvdata(input);
0049     int x, y;
0050
0051     if (gpio->bleft)
0052         input_report_key(input, BTN_LEFT,
0053                  gpiod_get_value(gpio->bleft));
0054     if (gpio->bmiddle)
0055         input_report_key(input, BTN_MIDDLE,
0056                  gpiod_get_value(gpio->bmiddle));
0057     if (gpio->bright)
0058         input_report_key(input, BTN_RIGHT,
0059                  gpiod_get_value(gpio->bright));
0060
0061     x = gpiod_get_value(gpio->right) - gpiod_get_value(gpio->left);
0062     y = gpiod_get_value(gpio->down) - gpiod_get_value(gpio->up);
0063
0064     input_report_rel(input, REL_X, x);
0065     input_report_rel(input, REL_Y, y);
0066     input_sync(input);
0067 }
0068
0069 static int gpio_mouse_probe(struct platform_device *pdev)
0070 {
0071     struct device *dev = &pdev->dev;
0072     struct gpio_mouse *gmouse;
0073     struct input_dev *input;
0074     int error;
0075
0076     gmouse = devm_kzalloc(dev, sizeof(*gmouse), GFP_KERNEL);
0077     if (!gmouse)
0078         return -ENOMEM;
0079
0080     /* Assign some default scanning time */
0081     error = device_property_read_u32(dev, "scan-interval-ms",
0082                      &gmouse->scan_ms);
0083     if (error || gmouse->scan_ms == 0) {
0084         dev_warn(dev, "invalid scan time, set to 50 ms\n");
0085         gmouse->scan_ms = 50;
0086     }
0087
0088     gmouse->up = devm_gpiod_get(dev, "up", GPIOD_IN);
0089     if (IS_ERR(gmouse->up))
0090         return PTR_ERR(gmouse->up);
0091     gmouse->down = devm_gpiod_get(dev, "down", GPIOD_IN);
0092     if (IS_ERR(gmouse->down))
0093         return PTR_ERR(gmouse->down);
0094     gmouse->left = devm_gpiod_get(dev, "left", GPIOD_IN);
0095     if (IS_ERR(gmouse->left))
0096         return PTR_ERR(gmouse->left);
0097     gmouse->right = devm_gpiod_get(dev, "right", GPIOD_IN);
0098     if (IS_ERR(gmouse->right))
0099         return PTR_ERR(gmouse->right);
0100
0101     gmouse->bleft = devm_gpiod_get_optional(dev, "button-left", GPIOD_IN);
0102     if (IS_ERR(gmouse->bleft))
0103         return PTR_ERR(gmouse->bleft);
0104     gmouse->bmiddle = devm_gpiod_get_optional(dev, "button-middle",
0105                           GPIOD_IN);
0106     if (IS_ERR(gmouse->bmiddle))
0107         return PTR_ERR(gmouse->bmiddle);
0108     gmouse->bright = devm_gpiod_get_optional(dev, "button-right",
0109                          GPIOD_IN);
0110     if (IS_ERR(gmouse->bright))
0111         return PTR_ERR(gmouse->bright);
0112
0113     input = devm_input_allocate_device(dev);
0114     if (!input)
0115         return -ENOMEM;
0116
0117     input->name = pdev->name;
0118     input->id.bustype = BUS_HOST;
0119
0120     input_set_drvdata(input, gmouse);
0121
0122     input_set_capability(input, EV_REL, REL_X);
0123     input_set_capability(input, EV_REL, REL_Y);
0124     if (gmouse->bleft)
0125         input_set_capability(input, EV_KEY, BTN_LEFT);
0126     if (gmouse->bmiddle)
0127         input_set_capability(input, EV_KEY, BTN_MIDDLE);
0128     if (gmouse->bright)
0129         input_set_capability(input, EV_KEY, BTN_RIGHT);
0130
0131     error = input_setup_polling(input, gpio_mouse_scan);
0132     if (error)
0133         return error;
0134
0135     input_set_poll_interval(input, gmouse->scan_ms);
0136
0137     error = input_register_device(input);
0138     if (error) {
0139         dev_err(dev, "could not register input device\n");
0140         return error;
0141     }
0142
0143     dev_dbg(dev, "%d ms scan time, buttons: %s%s%s\n",
0144         gmouse->scan_ms,
0145         gmouse->bleft ? "" : "left ",
0146         gmouse->bmiddle ? "" : "middle ",
0147         gmouse->bright ? "" : "right");
0148
0149     return 0;
0150 }
0151
0152 static const struct of_device_id gpio_mouse_of_match[] = {
0153     { .compatible = "gpio-mouse", },
0154     { },
0155 };
0156 MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
0157
0158 static struct platform_driver gpio_mouse_device_driver = {
0159     .probe      = gpio_mouse_probe,
0160     .driver     = {
0161         .name   = "gpio_mouse",
0162         .of_match_table = gpio_mouse_of_match,
0163     }
0164 };
0165 module_platform_driver(gpio_mouse_device_driver);
0166
0167 MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
0168 MODULE_DESCRIPTION("GPIO mouse driver");
0169 MODULE_LICENSE("GPL");
0170 MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */