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.
Signed-off-by: Gabor Juhos <juhosg@xxxxxxxxxxx>
Cc: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
Cc: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: linux-input@xxxxxxxxxxxxxxx
---
Changes since RFC: ---
drivers/input/misc/Kconfig | 16 +++
drivers/input/misc/Makefile | 1 +
drivers/input/misc/gpio_buttons.c | 232 +++++++++++++++++++++++++++++++++++++
include/linux/gpio_buttons.h | 33 +++++
4 files changed, 282 insertions(+), 0 deletions(-)
create mode 100644 drivers/input/misc/gpio_buttons.c
create mode 100644 include/linux/gpio_buttons.h
diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index b99b8cb..3439b79 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -448,4 +448,20 @@ config INPUT_ADXL34X_SPI
To compile this driver as a module, choose M here: the
module will be called adxl34x-spi.
+config INPUT_GPIO_BUTTONS
+ tristate "Polled GPIO buttons interface"
+ 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/misc/Makefile b/drivers/input/misc/Makefile
index 1fe1f6c..3791050 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -42,4 +42,5 @@ obj-$(CONFIG_INPUT_WINBOND_CIR) += winbond-cir.o
obj-$(CONFIG_INPUT_WISTRON_BTNS) += wistron_btns.o
obj-$(CONFIG_INPUT_WM831X_ON) += wm831x-on.o
obj-$(CONFIG_INPUT_YEALINK) += yealink.o
+obj-$(CONFIG_INPUT_GPIO_BUTTONS) += gpio_buttons.o
diff --git a/drivers/input/misc/gpio_buttons.c b/drivers/input/misc/gpio_buttons.c
new file mode 100644
index 0000000..51288a3
--- /dev/null
+++ b/drivers/input/misc/gpio_buttons.c
@@ -0,0 +1,232 @@
+/*
+ * Driver for buttons on GPIO lines not capable of generating interrupts
+ *
+ * Copyright (C) 2007-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ * Copyright (C) 2010 Nuno Goncalves <nunojpg@xxxxxxxxx>
+ *
+ * This file was based on: /drivers/input/misc/cobalt_btns.c
+ * Copyright (C) 2007 Yoichi Yuasa <yoichi_yuasa@xxxxxxxxxxxxxx>
+ *
+ * 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_buttons.h>
+
+#define DRV_NAME "gpio-buttons"
+
+struct gpio_button_data {
+ int last_state;
+ int count;
+ int can_sleep;
+};
+
+struct gpio_buttons_dev {
+ struct input_polled_dev *poll_dev;
+ struct gpio_buttons_platform_data *pdata;
+ struct gpio_button_data *data;
+};
+
+static void gpio_buttons_check_state(struct input_dev *input,
+ struct gpio_button *button,
+ struct gpio_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_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];
+ struct gpio_button_data *bdata = &bdev->data[i];
+
+ if (bdata->count < button->threshold)
+ bdata->count++;
+ else
+ gpio_buttons_check_state(input, button, bdata);
+
+ }
+}
+
+static int __devinit gpio_buttons_probe(struct platform_device *pdev)
+{
+ struct gpio_buttons_platform_data *pdata = pdev->dev.platform_data;
+ struct device *dev = &pdev->dev;
+ struct gpio_buttons_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_buttons_dev) +
+ pdata->nbuttons * sizeof(struct gpio_button_data),
+ GFP_KERNEL);
+ if (!bdev) {
+ dev_err(dev, "no memory for private data\n");
+ return -ENOMEM;
+ }
+
+ bdev->data = (struct gpio_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_buttons_poll;
+ poll_dev->poll_interval = pdata->poll_interval;
+
+ input = poll_dev->input;
+
+ input->evbit[0] = BIT(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) {
+ 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_buttons_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_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)
+{
+ 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 v2");
+MODULE_AUTHOR("Gabor Juhos <juhosg@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Polled GPIO Buttons driver");
diff --git a/include/linux/gpio_buttons.h b/include/linux/gpio_buttons.h
new file mode 100644
index 0000000..f85b993
--- /dev/null
+++ b/include/linux/gpio_buttons.h
@@ -0,0 +1,33 @@
+/*
+ * Definitions for the GPIO buttons interface driver
+ *
+ * Copyright (C) 2007-2010 Gabor Juhos <juhosg@xxxxxxxxxxx>
+ *
+ * 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_
+
+struct gpio_button {
+ int gpio; /* GPIO line number */
+ int active_low;
+ char *desc; /* button description */
+ int type; /* input event type (EV_KEY, EV_SW) */
+ int code; /* input event code (KEY_*, SW_*) */
+ int threshold; /* count threshold */
+};
+
+struct gpio_buttons_platform_data {
+ struct gpio_button *buttons;
+ int nbuttons; /* number of buttons */
+ int poll_interval; /* polling interval */
+};
+
+#endif /* _GPIO_BUTTONS_H_ */
--
1.7.2.1
