Commit 0e7d0c86 authored by Gabor Juhos's avatar Gabor Juhos Committed by Dmitry Torokhov
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Input: add input driver for polled GPIO buttons 



The existing gpio-keys driver can be usable only for GPIO lines with
interrupt support. Several devices have buttons connected to a GPIO
line which is not capable to generate interrupts. This patch adds a
new input driver using the generic GPIO layer and the input-polldev
to support such buttons.

[Ben Gardiner <bengardiner@nanometrics.ca: fold code to use more
 of the original gpio_keys infrastructure; cleanups and other
 improvements.]

Signed-off-by: default avatarGabor Juhos <juhosg@openwrt.org>
Signed-off-by: default avatarBen Gardiner <bengardiner@nanometrics.ca>
Tested-by: default avatarBen Gardiner <bengardiner@nanometrics.ca>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 8ed9e0e1

drivers/input/keyboard/Kconfig

+16 −0
Original line number Diff line number Diff line
@@ -179,6 +179,22 @@ config KEYBOARD_GPIO 
	  To compile this driver as a module, choose M here: the

	  module will be called gpio_keys.



config KEYBOARD_GPIO_POLLED

	tristate "Polled GPIO buttons"

	depends on GENERIC_GPIO

	select INPUT_POLLDEV

	help

	  This driver implements support for buttons connected

	  to GPIO pins that are not capable of generating interrupts.



	  Say Y here if your device has buttons connected

	  directly to such GPIO pins.  Your board-specific

	  setup logic must also provide a platform device,

	  with configuration data saying which GPIOs are used.



	  To compile this driver as a module, choose M here: the

	  module will be called gpio_keys_polled.



config KEYBOARD_TCA6416

	tristate "TCA6416 Keypad Support"

	depends on I2C

drivers/input/keyboard/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ obj-$(CONFIG_KEYBOARD_BFIN) += bf54x-keys.o 
obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o

obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o

obj-$(CONFIG_KEYBOARD_GPIO)		+= gpio_keys.o

obj-$(CONFIG_KEYBOARD_GPIO_POLLED)	+= gpio_keys_polled.o

obj-$(CONFIG_KEYBOARD_TCA6416)		+= tca6416-keypad.o

obj-$(CONFIG_KEYBOARD_HIL)		+= hil_kbd.o

obj-$(CONFIG_KEYBOARD_HIL_OLD)		+= hilkbd.o

drivers/input/keyboard/gpio_keys_polled.c

0 → 100644
+261 −0
Original line number Diff line number Diff line 
/*

 *  Driver for buttons on GPIO lines not capable of generating interrupts

 *

 *  Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>

 *  Copyright (C) 2010 Nuno Goncalves <nunojpg@gmail.com>

 *

 *  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/kernel.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/slab.h>

#include <linux/input.h>

#include <linux/input-polldev.h>

#include <linux/ioport.h>

#include <linux/platform_device.h>

#include <linux/gpio.h>

#include <linux/gpio_keys.h>



#define DRV_NAME	"gpio-keys-polled"



struct gpio_keys_button_data {

	int last_state;

	int count;

	int threshold;

	int can_sleep;

};



struct gpio_keys_polled_dev {

	struct input_polled_dev *poll_dev;

	struct device *dev;

	struct gpio_keys_platform_data *pdata;

	struct gpio_keys_button_data data[0];

};



static void gpio_keys_polled_check_state(struct input_dev *input,

					 struct gpio_keys_button *button,

					 struct gpio_keys_button_data *bdata)

{

	int state;



	if (bdata->can_sleep)

		state = !!gpio_get_value_cansleep(button->gpio);

	else

		state = !!gpio_get_value(button->gpio);



	if (state != bdata->last_state) {

		unsigned int type = button->type ?: EV_KEY;



		input_event(input, type, button->code,

			    !!(state ^ button->active_low));

		input_sync(input);

		bdata->count = 0;

		bdata->last_state = state;

	}

}



static void gpio_keys_polled_poll(struct input_polled_dev *dev)

{

	struct gpio_keys_polled_dev *bdev = dev->private;

	struct gpio_keys_platform_data *pdata = bdev->pdata;

	struct input_dev *input = dev->input;

	int i;



	for (i = 0; i < bdev->pdata->nbuttons; i++) {

		struct gpio_keys_button_data *bdata = &bdev->data[i];



		if (bdata->count < bdata->threshold)

			bdata->count++;

		else

			gpio_keys_polled_check_state(input, &pdata->buttons[i],

						     bdata);

	}

}



static void gpio_keys_polled_open(struct input_polled_dev *dev)

{

	struct gpio_keys_polled_dev *bdev = dev->private;

	struct gpio_keys_platform_data *pdata = bdev->pdata;



	if (pdata->enable)

		pdata->enable(bdev->dev);

}



static void gpio_keys_polled_close(struct input_polled_dev *dev)

{

	struct gpio_keys_polled_dev *bdev = dev->private;

	struct gpio_keys_platform_data *pdata = bdev->pdata;



	if (pdata->disable)

		pdata->disable(bdev->dev);

}



static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)

{

	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;

	struct device *dev = &pdev->dev;

	struct gpio_keys_polled_dev *bdev;

	struct input_polled_dev *poll_dev;

	struct input_dev *input;

	int error;

	int i;



	if (!pdata || !pdata->poll_interval)

		return -EINVAL;



	bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +

		       pdata->nbuttons * sizeof(struct gpio_keys_button_data),

		       GFP_KERNEL);

	if (!bdev) {

		dev_err(dev, "no memory for private data\n");

		return -ENOMEM;

	}



	poll_dev = input_allocate_polled_device();

	if (!poll_dev) {

		dev_err(dev, "no memory for polled device\n");

		error = -ENOMEM;

		goto err_free_bdev;

	}



	poll_dev->private = bdev;

	poll_dev->poll = gpio_keys_polled_poll;

	poll_dev->poll_interval = pdata->poll_interval;

	poll_dev->open = gpio_keys_polled_open;

	poll_dev->close = gpio_keys_polled_close;



	input = poll_dev->input;



	input->evbit[0] = BIT(EV_KEY);

	input->name = pdev->name;

	input->phys = DRV_NAME"/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_keys_button *button = &pdata->buttons[i];

		struct gpio_keys_button_data *bdata = &bdev->data[i];

		unsigned int gpio = button->gpio;

		unsigned int type = button->type ?: EV_KEY;



		if (button->wakeup) {

			dev_err(dev, DRV_NAME " does not support wakeup\n");

			error = -EINVAL;

			goto err_free_gpio;

		}



		error = gpio_request(gpio,

				     button->desc ? button->desc : DRV_NAME);

		if (error) {

			dev_err(dev, "unable to claim gpio %u, err=%d\n",

				gpio, error);

			goto err_free_gpio;

		}



		error = gpio_direction_input(gpio);

		if (error) {

			dev_err(dev,

				"unable to set direction on gpio %u, err=%d\n",

				gpio, error);

			goto err_free_gpio;

		}



		bdata->can_sleep = gpio_cansleep(gpio);

		bdata->last_state = -1;

		bdata->threshold = DIV_ROUND_UP(button->debounce_interval,

						pdata->poll_interval);



		input_set_capability(input, type, button->code);

	}



	bdev->poll_dev = poll_dev;

	bdev->dev = dev;

	bdev->pdata = pdata;

	platform_set_drvdata(pdev, bdev);



	error = input_register_polled_device(poll_dev);

	if (error) {

		dev_err(dev, "unable to register polled device, err=%d\n",

			error);

		goto err_free_gpio;

	}



	/* report initial state of the buttons */

	for (i = 0; i < pdata->nbuttons; i++)

		gpio_keys_polled_check_state(input, &pdata->buttons[i],

					 &bdev->data[i]);



	return 0;



err_free_gpio:

	while (--i >= 0)

		gpio_free(pdata->buttons[i].gpio);



	input_free_polled_device(poll_dev);



err_free_bdev:

	kfree(bdev);



	platform_set_drvdata(pdev, NULL);

	return error;

}



static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)

{

	struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);

	struct gpio_keys_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_keys_polled_driver = {

	.probe	= gpio_keys_polled_probe,

	.remove	= __devexit_p(gpio_keys_polled_remove),

	.driver	= {

		.name	= DRV_NAME,

		.owner	= THIS_MODULE,

	},

};



static int __init gpio_keys_polled_init(void)

{

	return platform_driver_register(&gpio_keys_polled_driver);

}



static void __exit gpio_keys_polled_exit(void)

{

	platform_driver_unregister(&gpio_keys_polled_driver);

}



module_init(gpio_keys_polled_init);

module_exit(gpio_keys_polled_exit);



MODULE_LICENSE("GPL v2");

MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");

MODULE_DESCRIPTION("Polled GPIO Buttons driver");

MODULE_ALIAS("platform:" DRV_NAME);

include/linux/gpio_keys.h

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,8 @@ struct gpio_keys_button { 
struct gpio_keys_platform_data {

	struct gpio_keys_button *buttons;

	int nbuttons;

	unsigned int poll_interval;	/* polling interval in msecs -

					   for polling driver only */

	unsigned int rep:1;		/* enable input subsystem auto repeat */

	int (*enable)(struct device *dev);

	void (*disable)(struct device *dev);

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