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>
22 #include <linux/slab.h>
23 #include <linux/input.h>
24 #include <linux/input-polldev.h>
25 #include <linux/ioport.h>
26 #include <linux/platform_device.h>
27 #include <linux/gpio.h>
28 #include <linux/gpio_buttons.h>
30 #define DRV_NAME "gpio-buttons"
32 struct gpio_button_data {
38 struct gpio_buttons_dev {
39 struct input_polled_dev *poll_dev;
40 struct gpio_buttons_platform_data *pdata;
41 struct gpio_button_data *data;
44 static void gpio_buttons_check_state(struct input_dev *input,
45 struct gpio_button *button,
46 struct gpio_button_data *bdata)
51 state = !!gpio_get_value_cansleep(button->gpio);
53 state = !!gpio_get_value(button->gpio);
55 if (state != bdata->last_state) {
56 unsigned int type = button->type ?: EV_KEY;
58 input_event(input, type, button->code,
59 !!(state ^ button->active_low));
62 bdata->last_state = state;
66 static void gpio_buttons_poll(struct input_polled_dev *dev)
68 struct gpio_buttons_dev *bdev = dev->private;
69 struct gpio_buttons_platform_data *pdata = bdev->pdata;
70 struct input_dev *input = dev->input;
73 for (i = 0; i < bdev->pdata->nbuttons; i++) {
74 struct gpio_button *button = &pdata->buttons[i];
75 struct gpio_button_data *bdata = &bdev->data[i];
77 if (bdata->count < button->threshold)
80 gpio_buttons_check_state(input, button, bdata);
85 static int gpio_buttons_probe(struct platform_device *pdev)
87 struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
88 struct device *dev = &pdev->dev;
89 struct gpio_buttons_dev *bdev;
90 struct input_polled_dev *poll_dev;
91 struct input_dev *input;
98 bdev = kzalloc(sizeof(struct gpio_buttons_dev) +
99 pdata->nbuttons * sizeof(struct gpio_button_data),
102 dev_err(dev, "no memory for private data\n");
106 bdev->data = (struct gpio_button_data *) &bdev[1];
108 poll_dev = input_allocate_polled_device();
110 dev_err(dev, "no memory for polled device\n");
115 poll_dev->private = bdev;
116 poll_dev->poll = gpio_buttons_poll;
117 poll_dev->poll_interval = pdata->poll_interval;
119 input = poll_dev->input;
121 input->evbit[0] = BIT(EV_KEY);
122 input->name = pdev->name;
123 input->phys = "gpio-buttons/input0";
124 input->dev.parent = &pdev->dev;
126 input->id.bustype = BUS_HOST;
127 input->id.vendor = 0x0001;
128 input->id.product = 0x0001;
129 input->id.version = 0x0100;
131 for (i = 0; i < pdata->nbuttons; i++) {
132 struct gpio_button *button = &pdata->buttons[i];
133 unsigned int gpio = button->gpio;
134 unsigned int type = button->type ?: EV_KEY;
136 error = gpio_request(gpio,
137 button->desc ? button->desc : DRV_NAME);
139 dev_err(dev, "unable to claim gpio %u, err=%d\n",
144 error = gpio_direction_input(gpio);
147 "unable to set direction on gpio %u, err=%d\n",
152 bdev->data[i].can_sleep = gpio_cansleep(gpio);
153 bdev->data[i].last_state = -1;
155 input_set_capability(input, type, button->code);
158 bdev->poll_dev = poll_dev;
160 platform_set_drvdata(pdev, bdev);
162 error = input_register_polled_device(poll_dev);
164 dev_err(dev, "unable to register polled device, err=%d\n",
169 /* report initial state of the buttons */
170 for (i = 0; i < pdata->nbuttons; i++)
171 gpio_buttons_check_state(input, &pdata->buttons[i],
177 for (i = i - 1; i >= 0; i--)
178 gpio_free(pdata->buttons[i].gpio);
180 input_free_polled_device(poll_dev);
185 platform_set_drvdata(pdev, NULL);
189 static int gpio_buttons_remove(struct platform_device *pdev)
191 struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
192 struct gpio_buttons_platform_data *pdata = bdev->pdata;
195 input_unregister_polled_device(bdev->poll_dev);
197 for (i = 0; i < pdata->nbuttons; i++)
198 gpio_free(pdata->buttons[i].gpio);
200 input_free_polled_device(bdev->poll_dev);
203 platform_set_drvdata(pdev, NULL);
208 static struct platform_driver gpio_buttons_driver = {
209 .probe = gpio_buttons_probe,
210 .remove = gpio_buttons_remove,
213 .owner = THIS_MODULE,
217 static int __init gpio_buttons_init(void)
219 return platform_driver_register(&gpio_buttons_driver);
222 static void __exit gpio_buttons_exit(void)
224 platform_driver_unregister(&gpio_buttons_driver);
227 module_init(gpio_buttons_init);
228 module_exit(gpio_buttons_exit);
230 MODULE_LICENSE("GPL v2");
231 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
232 MODULE_DESCRIPTION("Polled GPIO Buttons driver");