lkml.org 
[lkml]   [2010]   [Nov]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v5 1/5] [WIP] input: add input driver for polled GPIO buttons
Date
From: Gabor Juhos <juhosg@openwrt.org>

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.

(WIP: this version has incorporated into it the changes I suggested in review
of the original patch by Gabor Junos. I am posting it as part of the da850-evm
series in the hopes that the final version produced by Gabor can be
substituted in its place when the time is right. I don't mean to imply that
this version of the patch should be integrated in the final series)

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: linux-input@vger.kernel.org
Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca>
---
drivers/input/keyboard/Kconfig | 16 ++
drivers/input/keyboard/Makefile | 2 +
drivers/input/keyboard/gpio_keys_polled.c | 240 +++++++++++++++++++++++++++++
include/linux/gpio_keys_polled.h | 26 +++
4 files changed, 284 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/keyboard/gpio_keys_polled.c
create mode 100644 include/linux/gpio_keys_polled.h

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index b8c51b9..9648ff4 100644
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -485,4 +485,20 @@ config KEYBOARD_W90P910
To compile this driver as a module, choose M here: the
module will be called w90p910_keypad.

+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 of various CPUs (and some other chips).
+
+ 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-buttons.
+
endif
diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index a34452e..e6da817 100644
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -44,3 +44,5 @@ obj-$(CONFIG_KEYBOARD_TNETV107X) += tnetv107x-keypad.o
obj-$(CONFIG_KEYBOARD_TWL4030) += twl4030_keypad.o
obj-$(CONFIG_KEYBOARD_XTKBD) += xtkbd.o
obj-$(CONFIG_KEYBOARD_W90P910) += w90p910_keypad.o
+obj-$(CONFIG_KEYBOARD_GPIO_POLLED) += gpio_keys_polled.o
+
diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
new file mode 100644
index 0000000..390ed93
--- /dev/null
+++ b/drivers/input/keyboard/gpio_keys_polled.c
@@ -0,0 +1,240 @@
+/*
+ * 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_polled.h>
+
+#define DRV_NAME "gpio-keys-polled"
+
+struct gpio_keys_button_data {
+ int last_state;
+ int count;
+ int can_sleep;
+};
+
+struct gpio_keys_polled_dev {
+ struct input_polled_dev *poll_dev;
+ struct gpio_keys_polled_platform_data *pdata;
+ struct gpio_keys_button_data *data;
+};
+
+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_polled_platform_data *pdata = bdev->pdata;
+ struct input_dev *input = dev->input;
+ int i, threshold;
+
+ for (i = 0; i < bdev->pdata->nbuttons; i++) {
+ struct gpio_keys_button *button = &pdata->buttons[i];
+ struct gpio_keys_button_data *bdata = &bdev->data[i];
+
+ threshold = round_up(button->debounce_interval,
+ pdata->poll_interval) /
+ pdata->poll_interval;
+ if (bdata->count < threshold)
+ bdata->count++;
+ else
+ gpio_keys_polled_check_state(input, button, bdata);
+
+ }
+}
+
+static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
+{
+ struct gpio_keys_polled_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)
+ return -ENXIO;
+
+ 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;
+ }
+
+ bdev->data = (struct gpio_keys_button_data *) &bdev[1];
+
+ 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;
+
+ 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];
+ 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");
+ 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;
+ }
+
+ bdev->data[i].can_sleep = gpio_cansleep(gpio);
+ bdev->data[i].last_state = -1;
+
+ input_set_capability(input, type, button->code);
+ }
+
+ bdev->poll_dev = poll_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:
+ for (i = i - 1; i >= 0; i--)
+ 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_polled_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");
diff --git a/include/linux/gpio_keys_polled.h b/include/linux/gpio_keys_polled.h
new file mode 100644
index 0000000..bf7f94a
--- /dev/null
+++ b/include/linux/gpio_keys_polled.h
@@ -0,0 +1,26 @@
+/*
+ * Definitions for the GPIO buttons interface driver
+ *
+ * Copyright (C) 2007-2010 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * This file was based on: /include/linux/gpio_keys.h
+ * The original gpio_keys.h seems not to have a license.
+ *
+ * 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.
+ *
+ */
+
+#ifndef _GPIO_BUTTONS_H_
+#define _GPIO_BUTTONS_H_
+
+#include <linux/gpio_keys.h>
+
+struct gpio_keys_polled_platform_data {
+ struct gpio_keys_button *buttons;
+ int nbuttons; /* number of buttons */
+ int poll_interval; /* polling interval in msecs*/
+};
+
+#endif /* _GPIO_BUTTONS_H_ */
--
1.7.0.4


\
 
 \ /
  Last update: 2010-11-24 23:01    [W:0.147 / U:0.288 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site