[kernel] add a polled GPIO buttons input driver

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@10766 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 206 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/files/drivers/input/misc/gpio_buttons.c b/target/linux/generic-2.6/files/drivers/input/misc/gpio_buttons.c
new file mode 100644
index 000000000..0d219ff7c
--- /dev/null
+++ b/target/linux/generic-2.6/files/drivers/input/misc/gpio_buttons.c
@@ -0,0 +1,206 @@
+/*
+ *  Driver for buttons on GPIO lines not capable of generating interrupts
+ *
+ *  Copyright (C) 2007,2008 Gabor Juhos <juhosg at openwrt.org>
+ *
+ *  This file was based on: /drivers/input/misc/cobalt_btns.c
+ *	Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
+ *
+ *  also was based on: /drivers/input/keyboard/gpio_keys.c
+ *	Copyright 2005 Phil Blundell
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 as
+ *  published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/input-polldev.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include <linux/gpio_buttons.h>
+
+#include <asm/gpio.h>
+
+#define DRV_NAME	"gpio-buttons"
+#define DRV_VERSION	"0.1.0"
+#define PFX		DRV_NAME ": "
+
+struct gpio_buttons_dev {
+	struct input_polled_dev *poll_dev;
+	struct gpio_buttons_platform_data *pdata;
+};
+
+static void gpio_buttons_poll(struct input_polled_dev *dev)
+{
+	struct gpio_buttons_dev *bdev = dev->private;
+	struct gpio_buttons_platform_data *pdata = bdev->pdata;
+	struct input_dev *input = dev->input;
+	int i;
+
+	for (i = 0; i < bdev->pdata->nbuttons; i++) {
+		struct gpio_button *button = &pdata->buttons[i];
+		unsigned int type = button->type ?: EV_KEY;
+		int state;
+
+		state = gpio_get_value(button->gpio) ? 1 : 0;
+		state ^= button->active_low;
+
+		if (state) {
+			button->count++;
+		} else {
+			if (button->count >= button->threshold) {
+				input_event(input, type, button->code, 1);
+				input_sync(input);
+			}
+			button->count = 0;
+		}
+
+		if (button->count == button->threshold) {
+			input_event(input, type, button->code, 0);
+			input_sync(input);
+		}
+	}
+}
+
+static int __devinit gpio_buttons_probe(struct platform_device *pdev)
+{
+	struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
+	struct gpio_buttons_dev *bdev;
+	struct input_polled_dev *poll_dev;
+	struct input_dev *input;
+	int error, i;
+
+
+	if (!pdata)
+		return -ENXIO;
+
+	bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
+	if (!bdev) {
+		pr_err(DRV_NAME "no memory for device\n");
+		return -ENOMEM;
+	}
+
+	poll_dev = input_allocate_polled_device();
+	if (!poll_dev) {
+		pr_err(DRV_NAME "no memory for polled device\n");
+		error = -ENOMEM;
+		goto err_free_bdev;
+	}
+
+	poll_dev->private = bdev;
+	poll_dev->poll = gpio_buttons_poll;
+	poll_dev->poll_interval = pdata->poll_interval;
+
+	input = poll_dev->input;
+
+	input->evbit[0] = BIT_MASK(EV_KEY);
+	input->name = pdev->name;
+	input->phys = "gpio-buttons/input0";
+	input->dev.parent = &pdev->dev;
+
+	input->id.bustype = BUS_HOST;
+	input->id.vendor = 0x0001;
+	input->id.product = 0x0001;
+	input->id.version = 0x0100;
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		struct gpio_button *button = &pdata->buttons[i];
+		unsigned int gpio = button->gpio;
+		unsigned int type = button->type ?: EV_KEY;
+
+		error = gpio_request(gpio, button->desc ?
+				button->desc : DRV_NAME);
+		if (error) {
+			pr_err(PFX "unable to claim gpio %u, error %d\n",
+				gpio, error);
+			goto err_free_gpio;
+		}
+
+		error = gpio_direction_input(gpio);
+		if (error) {
+			pr_err(PFX "unable to set direction on gpio %u, "
+				"error %d\n", gpio, error);
+			goto err_free_gpio;
+		}
+
+		input_set_capability(input, type, button->code);
+		button->count = 0;
+	}
+
+	bdev->poll_dev = poll_dev;
+	bdev->pdata = pdata;
+	platform_set_drvdata(pdev, bdev);
+
+	error = input_register_polled_device(poll_dev);
+	if (error) {
+		pr_err(PFX "unable to register polled device, error %d\n",
+			    error);
+		goto err_free_gpio;
+	}
+
+	return 0;
+
+err_free_gpio:
+	for (i = i - 1; i >= 0; i--)
+		gpio_free(pdata->buttons[i].gpio);
+
+	input_free_polled_device(poll_dev);
+
+err_free_bdev:
+	kfree(bdev);
+err:
+	platform_set_drvdata(pdev, NULL);
+	return error;
+}
+
+static int __devexit gpio_buttons_remove(struct platform_device *pdev)
+{
+	struct gpio_buttons_dev *bdev = platform_get_drvdata(pdev);
+	struct gpio_buttons_platform_data *pdata = bdev->pdata;
+	int i;
+
+	input_unregister_polled_device(bdev->poll_dev);
+
+	for (i = 0; i < pdata->nbuttons; i++)
+		gpio_free(pdata->buttons[i].gpio);
+
+	input_free_polled_device(bdev->poll_dev);
+
+	kfree(bdev);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver gpio_buttons_driver = {
+	.probe	= gpio_buttons_probe,
+	.remove	= __devexit_p(gpio_buttons_remove),
+	.driver	= {
+		.name	= DRV_NAME,
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init gpio_buttons_init(void)
+{
+	pr_info(DRV_NAME " driver version " DRV_VERSION "\n");
+	return platform_driver_register(&gpio_buttons_driver);
+}
+
+static void __exit gpio_buttons_exit(void)
+{
+	platform_driver_unregister(&gpio_buttons_driver);
+}
+
+module_init(gpio_buttons_init);
+module_exit(gpio_buttons_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Gabor Juhos <juhosg at openwrt.org>");
+MODULE_VERSION(DRV_VERSION);
+MODULE_DESCRIPTION("Polled buttons driver for CPU GPIOs");
+