drivers/input/mouse/gpio_mouse.c

   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 <[email protected]>
   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  */
  31 struct 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  */
  46 static 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
  69 static 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
 152 static const struct of_device_id gpio_mouse_of_match[] = {
 153         { .compatible = "gpio-mouse", },
 154         { },
 155 };
 156 MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
 157
 158 static 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 };
 165 module_platform_driver(gpio_mouse_device_driver);
 166
 167 MODULE_AUTHOR("Hans-Christian Egtvedt <[email protected]>");
 168 MODULE_DESCRIPTION("GPIO mouse driver");
 169 MODULE_LICENSE("GPL");
 170 MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */