/* * Driver for simulating a mouse on GPIO lines. * * Copyright (C) 2007 Atmel Corporation * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org> * * 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, gpiod_get_value(gpio->bleft)); if (gpio->bmiddle) input_report_key(input, BTN_MIDDLE, gpiod_get_value(gpio->bmiddle)); if (gpio->bright) input_report_key(input, BTN_RIGHT, gpiod_get_value(gpio->bright)); 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); input_sync(input); } 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", &gmouse->scan_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", GPIOD_IN); if (IS_ERR(gmouse->bmiddle)) return PTR_ERR(gmouse->bmiddle); gmouse->bright = devm_gpiod_get_optional(dev, "button-right", GPIOD_IN); 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->scan_ms, 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_platform_driver(gpio_mouse_device_driver); MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>"); MODULE_DESCRIPTION("GPIO mouse driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */