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
  20 struct gpio_beeper {
  21         struct work_struct      work;
  22         int                     gpio;
  23         bool                    active_low;
  24         bool                    beeping;
  25 };
  26
  27 static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
  28 {
  29         gpio_set_value_cansleep(beep->gpio, on ^ beep->active_low);
  30 }
  31
  32 static 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
  39 static 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
  57 static 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
  65 static 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
 109 static struct of_device_id gpio_beeper_of_match[] = {
 110         { .compatible = BEEPER_MODNAME, },
 111         { }
 112 };
 113 MODULE_DEVICE_TABLE(of, gpio_beeper_of_match);
 114
 115 static 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 };
 123 module_platform_driver(gpio_beeper_platform_driver);
 124
 125 MODULE_LICENSE("GPL");
 126 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
 127 MODULE_DESCRIPTION("Generic GPIO beeper driver");