linux/drivers/input/misc/gpio-beeper.c
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   1/*
   2 * Generic GPIO beeper driver
   3 *
   4 * Copyright (C) 2013-2014 Alexander Shiyan <shc_work@mail.ru>
   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 as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 */
  11
  12#include <linux/input.h>
  13#include <linux/module.h>
  14#include <linux/gpio/consumer.h>
  15#include <linux/of.h>
  16#include <linux/workqueue.h>
  17#include <linux/platform_device.h>
  18
  19#define BEEPER_MODNAME          "gpio-beeper"
  20
  21struct gpio_beeper {
  22        struct work_struct      work;
  23        struct gpio_desc        *desc;
  24        bool                    beeping;
  25};
  26
  27static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
  28{
  29        gpiod_set_value_cansleep(beep->desc, on);
  30}
  31
  32static void gpio_beeper_work(struct work_struct *work)
  33{
  34        struct gpio_beeper *beep = container_of(work, struct gpio_beeper, work);
  35
  36        gpio_beeper_toggle(beep, beep->beeping);
  37}
  38
  39static int gpio_beeper_event(struct input_dev *dev, unsigned int type,
  40                             unsigned int code, int value)
  41{
  42        struct gpio_beeper *beep = input_get_drvdata(dev);
  43
  44        if (type != EV_SND || code != SND_BELL)
  45                return -ENOTSUPP;
  46
  47        if (value < 0)
  48                return -EINVAL;
  49
  50        beep->beeping = value;
  51        /* Schedule work to actually turn the beeper on or off */
  52        schedule_work(&beep->work);
  53
  54        return 0;
  55}
  56
  57static void gpio_beeper_close(struct input_dev *input)
  58{
  59        struct gpio_beeper *beep = input_get_drvdata(input);
  60
  61        cancel_work_sync(&beep->work);
  62        gpio_beeper_toggle(beep, false);
  63}
  64
  65static int gpio_beeper_probe(struct platform_device *pdev)
  66{
  67        struct gpio_beeper *beep;
  68        struct input_dev *input;
  69        int err;
  70
  71        beep = devm_kzalloc(&pdev->dev, sizeof(*beep), GFP_KERNEL);
  72        if (!beep)
  73                return -ENOMEM;
  74
  75        beep->desc = devm_gpiod_get(&pdev->dev, NULL);
  76        if (IS_ERR(beep->desc))
  77                return PTR_ERR(beep->desc);
  78
  79        input = devm_input_allocate_device(&pdev->dev);
  80        if (!input)
  81                return -ENOMEM;
  82
  83        INIT_WORK(&beep->work, gpio_beeper_work);
  84
  85        input->name             = pdev->name;
  86        input->id.bustype       = BUS_HOST;
  87        input->id.vendor        = 0x0001;
  88        input->id.product       = 0x0001;
  89        input->id.version       = 0x0100;
  90        input->close            = gpio_beeper_close;
  91        input->event            = gpio_beeper_event;
  92
  93        input_set_capability(input, EV_SND, SND_BELL);
  94
  95        err = gpiod_direction_output(beep->desc, 0);
  96        if (err)
  97                return err;
  98
  99        input_set_drvdata(input, beep);
 100
 101        return input_register_device(input);
 102}
 103
 104#ifdef CONFIG_OF
 105static const struct of_device_id gpio_beeper_of_match[] = {
 106        { .compatible = BEEPER_MODNAME, },
 107        { }
 108};
 109MODULE_DEVICE_TABLE(of, gpio_beeper_of_match);
 110#endif
 111
 112static struct platform_driver gpio_beeper_platform_driver = {
 113        .driver = {
 114                .name           = BEEPER_MODNAME,
 115                .of_match_table = of_match_ptr(gpio_beeper_of_match),
 116        },
 117        .probe  = gpio_beeper_probe,
 118};
 119module_platform_driver(gpio_beeper_platform_driver);
 120
 121MODULE_LICENSE("GPL");
 122MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 123MODULE_DESCRIPTION("Generic GPIO beeper driver");
 124
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