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: Gabor Juhos <juhosg@openwrt.org>
Signed-off-by: Ben Gardiner <bengardiner@nanometrics.ca>
Tested-by: Ben Gardiner <bengardiner@nanometrics.ca>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

diff --git a/drivers/input/keyboard/Kconfig b/drivers/input/keyboard/Kconfig
index b8c51b9781dbfb5e51c9a9d84071f534bf44e1d1..3a87f3ba5f75ee1f6a94973c2a5414f0653e48a8 100644 (file)
--- a/drivers/input/keyboard/Kconfig
+++ b/drivers/input/keyboard/Kconfig
@@ -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

diff --git a/drivers/input/keyboard/Makefile b/drivers/input/keyboard/Makefile
index a34452e8ebe2a1cb190f82d5c5f9c037860fcf07..622de73a445dbe620db5ae86d5e8ccd2bd90aeb2 100644 (file)
--- a/drivers/input/keyboard/Makefile
+++ b/drivers/input/keyboard/Makefile
@@ -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

diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c
new file mode 100644 (file)
index 0000000..4c17aff
--- /dev/null
+++ b/drivers/input/keyboard/gpio_keys_polled.c
@@ -0,0 +1,261 @@
+/*
+ *  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);

diff --git a/include/linux/gpio_keys.h b/include/linux/gpio_keys.h
index ce73a30113b4d0181ef7a2131c060ca18f1de027..dd1a56fbe9241235f4baa059394d5d36bd050de7 100644 (file)
--- a/include/linux/gpio_keys.h
+++ b/include/linux/gpio_keys.h
@@ -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);