LXR linux/drivers/input/misc/gpio-beeper.c

   1/*
   2 * Generic GPIO beeper driver
   3 *
   4 * Copyright (C) 2013 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/of_gpio.h>
  15#include <linux/workqueue.h>
  16#include <linux/platform_device.h>
  17
  18#define BEEPER_MODNAME          "gpio-beeper"
  19
  20struct gpio_beeper {
  21        struct work_struct      work;
  22        int                     gpio;
  23        bool                    active_low;
  24        bool                    beeping;
  25};
  26
  27static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
  28{
  29        gpio_set_value_cansleep(beep->gpio, on ^ beep->active_low);
  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        enum of_gpio_flags flags;
  69        struct input_dev *input;
  70        unsigned long gflags;
  71        int err;
  72
  73        beep = devm_kzalloc(&pdev->dev, sizeof(*beep), GFP_KERNEL);
  74        if (!beep)
  75                return -ENOMEM;
  76
  77        beep->gpio = of_get_gpio_flags(pdev->dev.of_node, 0, &flags);
  78        if (!gpio_is_valid(beep->gpio))
  79                return beep->gpio;
  80
  81        input = devm_input_allocate_device(&pdev->dev);
  82        if (!input)
  83                return -ENOMEM;
  84
  85        INIT_WORK(&beep->work, gpio_beeper_work);
  86
  87        input->name             = pdev->name;
  88        input->id.bustype       = BUS_HOST;
  89        input->id.vendor        = 0x0001;
  90        input->id.product       = 0x0001;
  91        input->id.version       = 0x0100;
  92        input->close            = gpio_beeper_close;
  93        input->event            = gpio_beeper_event;
  94
  95        input_set_capability(input, EV_SND, SND_BELL);
  96
  97        beep->active_low = flags & OF_GPIO_ACTIVE_LOW;
  98        gflags = beep->active_low ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
  99
 100        err = devm_gpio_request_one(&pdev->dev, beep->gpio, gflags, pdev->name);
 101        if (err)
 102                return err;
 103
 104        input_set_drvdata(input, beep);
 105
 106        return input_register_device(input);
 107}
 108
 109static struct of_device_id gpio_beeper_of_match[] = {
 110        { .compatible = BEEPER_MODNAME, },
 111        { }
 112};
 113MODULE_DEVICE_TABLE(of, gpio_beeper_of_match);
 114
 115static struct platform_driver gpio_beeper_platform_driver = {
 116        .driver = {
 117                .name           = BEEPER_MODNAME,
 118                .owner          = THIS_MODULE,
 119                .of_match_table = gpio_beeper_of_match,
 120        },
 121        .probe  = gpio_beeper_probe,
 122};
 123module_platform_driver(gpio_beeper_platform_driver);
 124
 125MODULE_LICENSE("GPL");
 126MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 127MODULE_DESCRIPTION("Generic GPIO beeper driver");
 128