LXR linux/drivers/input/mouse/gpio

   1/*
   2 * Driver for simulating a mouse on GPIO lines.
   3 *
   4 * Copyright (C) 2007 Atmel Corporation
   5 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14#include <linux/input-polldev.h>
  15#include <linux/gpio/consumer.h>
  16#include <linux/property.h>
  17#include <linux/of.h>
  18
  19/**
  20 * struct gpio_mouse
  21 * @scan_ms: the scan interval in milliseconds.
  22 * @up: GPIO line for up value.
  23 * @down: GPIO line for down value.
  24 * @left: GPIO line for left value.
  25 * @right: GPIO line for right value.
  26 * @bleft: GPIO line for left button.
  27 * @bmiddle: GPIO line for middle button.
  28 * @bright: GPIO line for right button.
  29 *
  30 * This struct must be added to the platform_device in the board code.
  31 * It is used by the gpio_mouse driver to setup GPIO lines and to
  32 * calculate mouse movement.
  33 */
  34struct gpio_mouse {
  35        u32 scan_ms;
  36        struct gpio_desc *up;
  37        struct gpio_desc *down;
  38        struct gpio_desc *left;
  39        struct gpio_desc *right;
  40        struct gpio_desc *bleft;
  41        struct gpio_desc *bmiddle;
  42        struct gpio_desc *bright;
  43};
  44
  45/*
  46 * Timer function which is run every scan_ms ms when the device is opened.
  47 * The dev input variable is set to the the input_dev pointer.
  48 */
  49static void gpio_mouse_scan(struct input_polled_dev *dev)
  50{
  51        struct gpio_mouse *gpio = dev->private;
  52        struct input_dev *input = dev->input;
  53        int x, y;
  54
  55        if (gpio->bleft)
  56                input_report_key(input, BTN_LEFT,
  57                                 gpiod_get_value(gpio->bleft));
  58        if (gpio->bmiddle)
  59                input_report_key(input, BTN_MIDDLE,
  60                                 gpiod_get_value(gpio->bmiddle));
  61        if (gpio->bright)
  62                input_report_key(input, BTN_RIGHT,
  63                                 gpiod_get_value(gpio->bright));
  64
  65        x = gpiod_get_value(gpio->right) - gpiod_get_value(gpio->left);
  66        y = gpiod_get_value(gpio->down) - gpiod_get_value(gpio->up);
  67
  68        input_report_rel(input, REL_X, x);
  69        input_report_rel(input, REL_Y, y);
  70        input_sync(input);
  71}
  72
  73static int gpio_mouse_probe(struct platform_device *pdev)
  74{
  75        struct device *dev = &pdev->dev;
  76        struct gpio_mouse *gmouse;
  77        struct input_polled_dev *input_poll;
  78        struct input_dev *input;
  79        int ret;
  80
  81        gmouse = devm_kzalloc(dev, sizeof(*gmouse), GFP_KERNEL);
  82        if (!gmouse)
  83                return -ENOMEM;
  84
  85        /* Assign some default scanning time */
  86        ret = device_property_read_u32(dev, "scan-interval-ms",
  87                                       &gmouse->scan_ms);
  88        if (ret || gmouse->scan_ms == 0) {
  89                dev_warn(dev, "invalid scan time, set to 50 ms\n");
  90                gmouse->scan_ms = 50;
  91        }
  92
  93        gmouse->up = devm_gpiod_get(dev, "up", GPIOD_IN);
  94        if (IS_ERR(gmouse->up))
  95                return PTR_ERR(gmouse->up);
  96        gmouse->down = devm_gpiod_get(dev, "down", GPIOD_IN);
  97        if (IS_ERR(gmouse->down))
  98                return PTR_ERR(gmouse->down);
  99        gmouse->left = devm_gpiod_get(dev, "left", GPIOD_IN);
 100        if (IS_ERR(gmouse->left))
 101                return PTR_ERR(gmouse->left);
 102        gmouse->right = devm_gpiod_get(dev, "right", GPIOD_IN);
 103        if (IS_ERR(gmouse->right))
 104                return PTR_ERR(gmouse->right);
 105
 106        gmouse->bleft = devm_gpiod_get_optional(dev, "button-left", GPIOD_IN);
 107        if (IS_ERR(gmouse->bleft))
 108                return PTR_ERR(gmouse->bleft);
 109        gmouse->bmiddle = devm_gpiod_get_optional(dev, "button-middle",
 110                                                  GPIOD_IN);
 111        if (IS_ERR(gmouse->bmiddle))
 112                return PTR_ERR(gmouse->bmiddle);
 113        gmouse->bright = devm_gpiod_get_optional(dev, "button-right",
 114                                                 GPIOD_IN);
 115        if (IS_ERR(gmouse->bright))
 116                return PTR_ERR(gmouse->bright);
 117
 118        input_poll = devm_input_allocate_polled_device(dev);
 119        if (!input_poll) {
 120                dev_err(dev, "not enough memory for input device\n");
 121                return -ENOMEM;
 122        }
 123
 124        platform_set_drvdata(pdev, input_poll);
 125
 126        /* set input-polldev handlers */
 127        input_poll->private = gmouse;
 128        input_poll->poll = gpio_mouse_scan;
 129        input_poll->poll_interval = gmouse->scan_ms;
 130
 131        input = input_poll->input;
 132        input->name = pdev->name;
 133        input->id.bustype = BUS_HOST;
 134        input->dev.parent = &pdev->dev;
 135
 136        input_set_capability(input, EV_REL, REL_X);
 137        input_set_capability(input, EV_REL, REL_Y);
 138        if (gmouse->bleft)
 139                input_set_capability(input, EV_KEY, BTN_LEFT);
 140        if (gmouse->bmiddle)
 141                input_set_capability(input, EV_KEY, BTN_MIDDLE);
 142        if (gmouse->bright)
 143                input_set_capability(input, EV_KEY, BTN_RIGHT);
 144
 145        ret = input_register_polled_device(input_poll);
 146        if (ret) {
 147                dev_err(dev, "could not register input device\n");
 148                return ret;
 149        }
 150
 151        dev_dbg(dev, "%d ms scan time, buttons: %s%s%s\n",
 152                gmouse->scan_ms,
 153                gmouse->bleft ? "" : "left ",
 154                gmouse->bmiddle ? "" : "middle ",
 155                gmouse->bright ? "" : "right");
 156
 157        return 0;
 158}
 159
 160static const struct of_device_id gpio_mouse_of_match[] = {
 161        { .compatible = "gpio-mouse", },
 162        { },
 163};
 164MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
 165
 166static struct platform_driver gpio_mouse_device_driver = {
 167        .probe          = gpio_mouse_probe,
 168        .driver         = {
 169                .name   = "gpio_mouse",
 170                .of_match_table = gpio_mouse_of_match,
 171        }
 172};
 173module_platform_driver(gpio_mouse_device_driver);
 174
 175MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
 176MODULE_DESCRIPTION("GPIO mouse driver");
 177MODULE_LICENSE("GPL");
 178MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */
 179