root/drivers/input/mouse/gpio_mouse.c

DEFINITIONS

1. gpio_mouse_scan
2. gpio_mouse_probe

   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 <linus.walleij@linaro.org>
   7  */
   8 
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/input-polldev.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 the input_dev pointer.
  45  */
  46 static void gpio_mouse_scan(struct input_polled_dev *dev)
  47 {
  48         struct gpio_mouse *gpio = dev->private;
  49         struct input_dev *input = dev->input;
  50         int x, y;
  51 
  52         if (gpio->bleft)
  53                 input_report_key(input, BTN_LEFT,
  54                                  gpiod_get_value(gpio->bleft));
  55         if (gpio->bmiddle)
  56                 input_report_key(input, BTN_MIDDLE,
  57                                  gpiod_get_value(gpio->bmiddle));
  58         if (gpio->bright)
  59                 input_report_key(input, BTN_RIGHT,
  60                                  gpiod_get_value(gpio->bright));
  61 
  62         x = gpiod_get_value(gpio->right) - gpiod_get_value(gpio->left);
  63         y = gpiod_get_value(gpio->down) - gpiod_get_value(gpio->up);
  64 
  65         input_report_rel(input, REL_X, x);
  66         input_report_rel(input, REL_Y, y);
  67         input_sync(input);
  68 }
  69 
  70 static int gpio_mouse_probe(struct platform_device *pdev)
  71 {
  72         struct device *dev = &pdev->dev;
  73         struct gpio_mouse *gmouse;
  74         struct input_polled_dev *input_poll;
  75         struct input_dev *input;
  76         int ret;
  77 
  78         gmouse = devm_kzalloc(dev, sizeof(*gmouse), GFP_KERNEL);
  79         if (!gmouse)
  80                 return -ENOMEM;
  81 
  82         /* Assign some default scanning time */
  83         ret = device_property_read_u32(dev, "scan-interval-ms",
  84                                        &gmouse->scan_ms);
  85         if (ret || gmouse->scan_ms == 0) {
  86                 dev_warn(dev, "invalid scan time, set to 50 ms\n");
  87                 gmouse->scan_ms = 50;
  88         }
  89 
  90         gmouse->up = devm_gpiod_get(dev, "up", GPIOD_IN);
  91         if (IS_ERR(gmouse->up))
  92                 return PTR_ERR(gmouse->up);
  93         gmouse->down = devm_gpiod_get(dev, "down", GPIOD_IN);
  94         if (IS_ERR(gmouse->down))
  95                 return PTR_ERR(gmouse->down);
  96         gmouse->left = devm_gpiod_get(dev, "left", GPIOD_IN);
  97         if (IS_ERR(gmouse->left))
  98                 return PTR_ERR(gmouse->left);
  99         gmouse->right = devm_gpiod_get(dev, "right", GPIOD_IN);
 100         if (IS_ERR(gmouse->right))
 101                 return PTR_ERR(gmouse->right);
 102 
 103         gmouse->bleft = devm_gpiod_get_optional(dev, "button-left", GPIOD_IN);
 104         if (IS_ERR(gmouse->bleft))
 105                 return PTR_ERR(gmouse->bleft);
 106         gmouse->bmiddle = devm_gpiod_get_optional(dev, "button-middle",
 107                                                   GPIOD_IN);
 108         if (IS_ERR(gmouse->bmiddle))
 109                 return PTR_ERR(gmouse->bmiddle);
 110         gmouse->bright = devm_gpiod_get_optional(dev, "button-right",
 111                                                  GPIOD_IN);
 112         if (IS_ERR(gmouse->bright))
 113                 return PTR_ERR(gmouse->bright);
 114 
 115         input_poll = devm_input_allocate_polled_device(dev);
 116         if (!input_poll) {
 117                 dev_err(dev, "not enough memory for input device\n");
 118                 return -ENOMEM;
 119         }
 120 
 121         platform_set_drvdata(pdev, input_poll);
 122 
 123         /* set input-polldev handlers */
 124         input_poll->private = gmouse;
 125         input_poll->poll = gpio_mouse_scan;
 126         input_poll->poll_interval = gmouse->scan_ms;
 127 
 128         input = input_poll->input;
 129         input->name = pdev->name;
 130         input->id.bustype = BUS_HOST;
 131         input->dev.parent = &pdev->dev;
 132 
 133         input_set_capability(input, EV_REL, REL_X);
 134         input_set_capability(input, EV_REL, REL_Y);
 135         if (gmouse->bleft)
 136                 input_set_capability(input, EV_KEY, BTN_LEFT);
 137         if (gmouse->bmiddle)
 138                 input_set_capability(input, EV_KEY, BTN_MIDDLE);
 139         if (gmouse->bright)
 140                 input_set_capability(input, EV_KEY, BTN_RIGHT);
 141 
 142         ret = input_register_polled_device(input_poll);
 143         if (ret) {
 144                 dev_err(dev, "could not register input device\n");
 145                 return ret;
 146         }
 147 
 148         dev_dbg(dev, "%d ms scan time, buttons: %s%s%s\n",
 149                 gmouse->scan_ms,
 150                 gmouse->bleft ? "" : "left ",
 151                 gmouse->bmiddle ? "" : "middle ",
 152                 gmouse->bright ? "" : "right");
 153 
 154         return 0;
 155 }
 156 
 157 static const struct of_device_id gpio_mouse_of_match[] = {
 158         { .compatible = "gpio-mouse", },
 159         { },
 160 };
 161 MODULE_DEVICE_TABLE(of, gpio_mouse_of_match);
 162 
 163 static struct platform_driver gpio_mouse_device_driver = {
 164         .probe          = gpio_mouse_probe,
 165         .driver         = {
 166                 .name   = "gpio_mouse",
 167                 .of_match_table = gpio_mouse_of_match,
 168         }
 169 };
 170 module_platform_driver(gpio_mouse_device_driver);
 171 
 172 MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");
 173 MODULE_DESCRIPTION("GPIO mouse driver");
 174 MODULE_LICENSE("GPL");
 175 MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */