1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Generic GPIO beeper driver
4  *
5  * Copyright (C) 2013-2014 Alexander Shiyan <shc_work@mail.ru>
6  */
7 
8 #include <linux/input.h>
9 #include <linux/module.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/of.h>
12 #include <linux/workqueue.h>
13 #include <linux/platform_device.h>
14 
15 #define BEEPER_MODNAME		"gpio-beeper"
16 
17 struct gpio_beeper {
18 	struct work_struct	work;
19 	struct gpio_desc	*desc;
20 	bool			beeping;
21 };
22 
gpio_beeper_toggle(struct gpio_beeper * beep,bool on)23 static void gpio_beeper_toggle(struct gpio_beeper *beep, bool on)
24 {
25 	gpiod_set_value_cansleep(beep->desc, on);
26 }
27 
gpio_beeper_work(struct work_struct * work)28 static void gpio_beeper_work(struct work_struct *work)
29 {
30 	struct gpio_beeper *beep = container_of(work, struct gpio_beeper, work);
31 
32 	gpio_beeper_toggle(beep, beep->beeping);
33 }
34 
gpio_beeper_event(struct input_dev * dev,unsigned int type,unsigned int code,int value)35 static int gpio_beeper_event(struct input_dev *dev, unsigned int type,
36 			     unsigned int code, int value)
37 {
38 	struct gpio_beeper *beep = input_get_drvdata(dev);
39 
40 	if (type != EV_SND || code != SND_BELL)
41 		return -ENOTSUPP;
42 
43 	if (value < 0)
44 		return -EINVAL;
45 
46 	beep->beeping = value;
47 	/* Schedule work to actually turn the beeper on or off */
48 	schedule_work(&beep->work);
49 
50 	return 0;
51 }
52 
gpio_beeper_close(struct input_dev * input)53 static void gpio_beeper_close(struct input_dev *input)
54 {
55 	struct gpio_beeper *beep = input_get_drvdata(input);
56 
57 	cancel_work_sync(&beep->work);
58 	gpio_beeper_toggle(beep, false);
59 }
60 
gpio_beeper_probe(struct platform_device * pdev)61 static int gpio_beeper_probe(struct platform_device *pdev)
62 {
63 	struct gpio_beeper *beep;
64 	struct input_dev *input;
65 
66 	beep = devm_kzalloc(&pdev->dev, sizeof(*beep), GFP_KERNEL);
67 	if (!beep)
68 		return -ENOMEM;
69 
70 	beep->desc = devm_gpiod_get(&pdev->dev, NULL, GPIOD_OUT_LOW);
71 	if (IS_ERR(beep->desc))
72 		return PTR_ERR(beep->desc);
73 
74 	input = devm_input_allocate_device(&pdev->dev);
75 	if (!input)
76 		return -ENOMEM;
77 
78 	INIT_WORK(&beep->work, gpio_beeper_work);
79 
80 	input->name		= pdev->name;
81 	input->id.bustype	= BUS_HOST;
82 	input->id.vendor	= 0x0001;
83 	input->id.product	= 0x0001;
84 	input->id.version	= 0x0100;
85 	input->close		= gpio_beeper_close;
86 	input->event		= gpio_beeper_event;
87 
88 	input_set_capability(input, EV_SND, SND_BELL);
89 
90 	input_set_drvdata(input, beep);
91 
92 	return input_register_device(input);
93 }
94 
95 #ifdef CONFIG_OF
96 static const struct of_device_id gpio_beeper_of_match[] = {
97 	{ .compatible = BEEPER_MODNAME, },
98 	{ }
99 };
100 MODULE_DEVICE_TABLE(of, gpio_beeper_of_match);
101 #endif
102 
103 static struct platform_driver gpio_beeper_platform_driver = {
104 	.driver	= {
105 		.name		= BEEPER_MODNAME,
106 		.of_match_table	= of_match_ptr(gpio_beeper_of_match),
107 	},
108 	.probe	= gpio_beeper_probe,
109 };
110 module_platform_driver(gpio_beeper_platform_driver);
111 
112 MODULE_LICENSE("GPL");
113 MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
114 MODULE_DESCRIPTION("Generic GPIO beeper driver");
115