linux/drivers/input/mouse/gpio_mouse.c
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   1/*
   2 * Driver for simulating a mouse on GPIO lines.
   3 *
   4 * Copyright (C) 2007 Atmel Corporation
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License version 2 as
   8 * published by the Free Software Foundation.
   9 */
  10
  11#include <linux/init.h>
  12#include <linux/module.h>
  13#include <linux/platform_device.h>
  14#include <linux/input-polldev.h>
  15#include <linux/gpio_mouse.h>
  16
  17#include <asm/gpio.h>
  18
  19/*
  20 * Timer function which is run every scan_ms ms when the device is opened.
  21 * The dev input variable is set to the the input_dev pointer.
  22 */
  23static void gpio_mouse_scan(struct input_polled_dev *dev)
  24{
  25        struct gpio_mouse_platform_data *gpio = dev->private;
  26        struct input_dev *input = dev->input;
  27        int x, y;
  28
  29        if (gpio->bleft >= 0)
  30                input_report_key(input, BTN_LEFT,
  31                                gpio_get_value(gpio->bleft) ^ gpio->polarity);
  32        if (gpio->bmiddle >= 0)
  33                input_report_key(input, BTN_MIDDLE,
  34                                gpio_get_value(gpio->bmiddle) ^ gpio->polarity);
  35        if (gpio->bright >= 0)
  36                input_report_key(input, BTN_RIGHT,
  37                                gpio_get_value(gpio->bright) ^ gpio->polarity);
  38
  39        x = (gpio_get_value(gpio->right) ^ gpio->polarity)
  40                - (gpio_get_value(gpio->left) ^ gpio->polarity);
  41        y = (gpio_get_value(gpio->down) ^ gpio->polarity)
  42                - (gpio_get_value(gpio->up) ^ gpio->polarity);
  43
  44        input_report_rel(input, REL_X, x);
  45        input_report_rel(input, REL_Y, y);
  46        input_sync(input);
  47}
  48
  49static int __devinit gpio_mouse_probe(struct platform_device *pdev)
  50{
  51        struct gpio_mouse_platform_data *pdata = pdev->dev.platform_data;
  52        struct input_polled_dev *input_poll;
  53        struct input_dev *input;
  54        int pin, i;
  55        int error;
  56
  57        if (!pdata) {
  58                dev_err(&pdev->dev, "no platform data\n");
  59                error = -ENXIO;
  60                goto out;
  61        }
  62
  63        if (pdata->scan_ms < 0) {
  64                dev_err(&pdev->dev, "invalid scan time\n");
  65                error = -EINVAL;
  66                goto out;
  67        }
  68
  69        for (i = 0; i < GPIO_MOUSE_PIN_MAX; i++) {
  70                pin = pdata->pins[i];
  71
  72                if (pin < 0) {
  73
  74                        if (i <= GPIO_MOUSE_PIN_RIGHT) {
  75                                /* Mouse direction is required. */
  76                                dev_err(&pdev->dev,
  77                                        "missing GPIO for directions\n");
  78                                error = -EINVAL;
  79                                goto out_free_gpios;
  80                        }
  81
  82                        if (i == GPIO_MOUSE_PIN_BLEFT)
  83                                dev_dbg(&pdev->dev, "no left button defined\n");
  84
  85                } else {
  86                        error = gpio_request(pin, "gpio_mouse");
  87                        if (error) {
  88                                dev_err(&pdev->dev, "fail %d pin (%d idx)\n",
  89                                        pin, i);
  90                                goto out_free_gpios;
  91                        }
  92
  93                        gpio_direction_input(pin);
  94                }
  95        }
  96
  97        input_poll = input_allocate_polled_device();
  98        if (!input_poll) {
  99                dev_err(&pdev->dev, "not enough memory for input device\n");
 100                error = -ENOMEM;
 101                goto out_free_gpios;
 102        }
 103
 104        platform_set_drvdata(pdev, input_poll);
 105
 106        /* set input-polldev handlers */
 107        input_poll->private = pdata;
 108        input_poll->poll = gpio_mouse_scan;
 109        input_poll->poll_interval = pdata->scan_ms;
 110
 111        input = input_poll->input;
 112        input->name = pdev->name;
 113        input->id.bustype = BUS_HOST;
 114        input->dev.parent = &pdev->dev;
 115
 116        input_set_capability(input, EV_REL, REL_X);
 117        input_set_capability(input, EV_REL, REL_Y);
 118        if (pdata->bleft >= 0)
 119                input_set_capability(input, EV_KEY, BTN_LEFT);
 120        if (pdata->bmiddle >= 0)
 121                input_set_capability(input, EV_KEY, BTN_MIDDLE);
 122        if (pdata->bright >= 0)
 123                input_set_capability(input, EV_KEY, BTN_RIGHT);
 124
 125        error = input_register_polled_device(input_poll);
 126        if (error) {
 127                dev_err(&pdev->dev, "could not register input device\n");
 128                goto out_free_polldev;
 129        }
 130
 131        dev_dbg(&pdev->dev, "%d ms scan time, buttons: %s%s%s\n",
 132                        pdata->scan_ms,
 133                        pdata->bleft < 0 ? "" : "left ",
 134                        pdata->bmiddle < 0 ? "" : "middle ",
 135                        pdata->bright < 0 ? "" : "right");
 136
 137        return 0;
 138
 139 out_free_polldev:
 140        input_free_polled_device(input_poll);
 141        platform_set_drvdata(pdev, NULL);
 142
 143 out_free_gpios:
 144        while (--i >= 0) {
 145                pin = pdata->pins[i];
 146                if (pin)
 147                        gpio_free(pin);
 148        }
 149 out:
 150        return error;
 151}
 152
 153static int __devexit gpio_mouse_remove(struct platform_device *pdev)
 154{
 155        struct input_polled_dev *input = platform_get_drvdata(pdev);
 156        struct gpio_mouse_platform_data *pdata = input->private;
 157        int pin, i;
 158
 159        input_unregister_polled_device(input);
 160        input_free_polled_device(input);
 161
 162        for (i = 0; i < GPIO_MOUSE_PIN_MAX; i++) {
 163                pin = pdata->pins[i];
 164                if (pin >= 0)
 165                        gpio_free(pin);
 166        }
 167
 168        platform_set_drvdata(pdev, NULL);
 169
 170        return 0;
 171}
 172
 173static struct platform_driver gpio_mouse_device_driver = {
 174        .probe          = gpio_mouse_probe,
 175        .remove         = __devexit_p(gpio_mouse_remove),
 176        .driver         = {
 177                .name   = "gpio_mouse",
 178                .owner  = THIS_MODULE,
 179        }
 180};
 181
 182static int __init gpio_mouse_init(void)
 183{
 184        return platform_driver_register(&gpio_mouse_device_driver);
 185}
 186module_init(gpio_mouse_init);
 187
 188static void __exit gpio_mouse_exit(void)
 189{
 190        platform_driver_unregister(&gpio_mouse_device_driver);
 191}
 192module_exit(gpio_mouse_exit);
 193
 194MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
 195MODULE_DESCRIPTION("GPIO mouse driver");
 196MODULE_LICENSE("GPL");
 197MODULE_ALIAS("platform:gpio_mouse"); /* work with hotplug and coldplug */
 198
 199