2 * Driver for buttons on GPIO lines not capable of generating interrupts
4 * Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
5 * Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>
7 * This file was based on: /drivers/input/misc/cobalt_btns.c
8 * Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
10 * also was based on: /drivers/input/keyboard/gpio_keys.c
11 * Copyright 2005 Phil Blundell
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/init.h>
23 #include <linux/input.h>
24 #include <linux/input-polldev.h>
25 #include <linux/ioport.h>
26 #include <linux/platform_device.h>
28 #include <linux/gpio_buttons.h>
32 #define DRV_NAME "gpio-buttons"
33 #define DRV_VERSION "0.1.2"
34 #define PFX DRV_NAME ": "
36 struct gpio_button_data {
41 struct gpio_buttons_dev {
42 struct input_polled_dev *poll_dev;
43 struct gpio_buttons_platform_data *pdata;
44 struct gpio_button_data *data;
47 static void gpio_buttons_poll(struct input_polled_dev *dev)
49 struct gpio_buttons_dev *bdev = dev->private;
50 struct gpio_buttons_platform_data *pdata = bdev->pdata;
51 struct input_dev *input = dev->input;
54 for (i = 0; i < bdev->pdata->nbuttons; i++) {
55 struct gpio_button *button = &pdata->buttons[i];
56 unsigned int type = button->type ?: EV_KEY;
59 if (bdev->data[i].count < button->threshold) {
60 bdev->data[i].count++;
64 state = gpio_get_value(button->gpio) ? 1 : 0;
65 if (state != bdev->data[i].last_state) {
66 input_event(input, type, button->code,
67 !!(state ^ button->active_low));
69 bdev->data[i].count = 0;
70 bdev->data[i].last_state = state;
75 static int __devinit gpio_buttons_probe(struct platform_device *pdev)
77 struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
78 struct gpio_buttons_dev *bdev;
79 struct input_polled_dev *poll_dev;
80 struct input_dev *input;
86 bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
87 sizeof(struct gpio_button_data) * pdata->nbuttons,
90 printk(KERN_ERR DRV_NAME "no memory for device\n");
94 bdev->data = (struct gpio_button_data *) &bdev[1];
96 poll_dev = input_allocate_polled_device();
98 printk(KERN_ERR DRV_NAME "no memory for polled device\n");
103 poll_dev->private = bdev;
104 poll_dev->poll = gpio_buttons_poll;
105 poll_dev->poll_interval = pdata->poll_interval;
107 input = poll_dev->input;
109 input->evbit[0] = BIT(EV_KEY);
110 input->name = pdev->name;
111 input->phys = "gpio-buttons/input0";
112 input->dev.parent = &pdev->dev;
114 input->id.bustype = BUS_HOST;
115 input->id.vendor = 0x0001;
116 input->id.product = 0x0001;
117 input->id.version = 0x0100;
119 for (i = 0; i < pdata->nbuttons; i++) {
120 struct gpio_button *button = &pdata->buttons[i];
121 unsigned int gpio = button->gpio;
122 unsigned int type = button->type ?: EV_KEY;
124 error = gpio_request(gpio, button->desc ?
125 button->desc : DRV_NAME);
127 printk(KERN_ERR PFX "unable to claim gpio %u, "
128 "error %d\n", gpio, error);
132 error = gpio_direction_input(gpio);
134 printk(KERN_ERR PFX "unable to set direction on "
135 "gpio %u, error %d\n", gpio, error);
139 input_set_capability(input, type, button->code);
140 bdev->data[i].last_state = gpio_get_value(button->gpio) ? 1 : 0;
143 bdev->poll_dev = poll_dev;
145 platform_set_drvdata(pdev, bdev);
147 error = input_register_polled_device(poll_dev);
149 printk(KERN_ERR PFX "unable to register polled device, "
150 "error %d\n", error);
157 for (i = i - 1; i >= 0; i--)
158 gpio_free(pdata->buttons[i].gpio);
160 input_free_polled_device(poll_dev);
165 platform_set_drvdata(pdev, NULL);
169 static int __devexit gpio_buttons_remove(struct platform_device *pdev)
171 struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
172 struct gpio_buttons_platform_data *pdata = bdev->pdata;
175 input_unregister_polled_device(bdev->poll_dev);
177 for (i = 0; i < pdata->nbuttons; i++)
178 gpio_free(pdata->buttons[i].gpio);
180 input_free_polled_device(bdev->poll_dev);
183 platform_set_drvdata(pdev, NULL);
188 static struct platform_driver gpio_buttons_driver = {
189 .probe = gpio_buttons_probe,
190 .remove = __devexit_p(gpio_buttons_remove),
193 .owner = THIS_MODULE,
197 static int __init gpio_buttons_init(void)
199 printk(KERN_INFO DRV_NAME " driver version " DRV_VERSION "\n");
200 return platform_driver_register(&gpio_buttons_driver);
203 static void __exit gpio_buttons_exit(void)
205 platform_driver_unregister(&gpio_buttons_driver);
208 module_init(gpio_buttons_init);
209 module_exit(gpio_buttons_exit);
211 MODULE_LICENSE("GPL");
212 MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
213 MODULE_VERSION(DRV_VERSION);
214 MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");