Input: gpio-keys - keyboard driver for GPIO buttons

This is an interrupt-driven keyboard driver for simple buttons
connected directly to CPU GPIO lines of embedded ARM systems.
It supports pxa architectures and is used by a number of PDAs
and PocketPC phones in the handhelds.org kernel. Support for
other architectures, such as sa11xx and sc2410, will be added
once generic GPIO API is available.
Signed-off-by: Paul Sokolovsky <pmiscml@gmail.com>
Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

drivers/input/keyboard/Kconfig

@@ -214,4 +214,17 @@ config KEYBOARD_AAED2000
 	  To compile this driver as a module, choose M here: the
 	  module will be called aaed2000_kbd.
 
+config KEYBOARD_GPIO
+        tristate "Buttons on CPU GPIOs (PXA)"
+        depends on ARCH_PXA
+	help
+	  This driver implements support for buttons connected
+	  directly to GPIO pins of PXA CPUs.
+
+	  Say Y here if your device has buttons connected
+	  directly to GPIO pins of the CPU.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called gpio-keys.
+
 endif

drivers/input/keyboard/Makefile

@@ -18,4 +18,5 @@ obj-$(CONFIG_KEYBOARD_HIL)		+= hil_kbd.o
 obj-$(CONFIG_KEYBOARD_HIL_OLD)		+= hilkbd.o
 obj-$(CONFIG_KEYBOARD_OMAP)		+= omap-keypad.o
 obj-$(CONFIG_KEYBOARD_AAED2000)		+= aaed2000_kbd.o
+obj-$(CONFIG_KEYBOARD_GPIO)		+= gpio_keys.o
 

drivers/input/keyboard/gpio_keys.c

+/*
+ * Driver for keys on GPIO lines capable of generating interrupts.
+ *
+ * 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/module.h>
+#include <linux/version.h>
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/sched.h>
+#include <linux/pm.h>
+#include <linux/sysctl.h>
+#include <linux/proc_fs.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/irq.h>
+
+#include <asm/arch/pxa-regs.h>
+#include <asm/arch/hardware.h>
+
+#include <asm/hardware/gpio_keys.h>
+
+static irqreturn_t gpio_keys_isr(int irq, void *dev_id)
+{
+	int i;
+	struct platform_device *pdev = dev_id;
+	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+	struct input_dev *input = platform_get_drvdata(pdev);
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		int gpio = pdata->buttons[i].gpio;
+		if (irq == IRQ_GPIO(gpio)) {
+			int state = ((GPLR(gpio) & GPIO_bit(gpio)) ? 1 : 0) ^ (pdata->buttons[i].active_low);
+
+			input_report_key(input, pdata->buttons[i].keycode, state);
+			input_sync(input);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int __devinit gpio_keys_probe(struct platform_device *pdev)
+{
+	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+	struct input_dev *input;
+	int i, error;
+
+	input = input_allocate_device();
+	if (!input)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, input);
+
+	input->evbit[0] = BIT(EV_KEY);
+
+	input->name = pdev->name;
+	input->phys = "gpio-keys/input0";
+	input->cdev.dev = &pdev->dev;
+	input->private = pdata;
+
+	input->id.bustype = BUS_HOST;
+	input->id.vendor = 0x0001;
+	input->id.product = 0x0001;
+	input->id.version = 0x0100;
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		int code = pdata->buttons[i].keycode;
+		int irq = IRQ_GPIO(pdata->buttons[i].gpio);
+
+		set_irq_type(irq, IRQ_TYPE_EDGE_BOTH);
+		error = request_irq(irq, gpio_keys_isr, SA_SAMPLE_RANDOM,
+				     pdata->buttons[i].desc ? pdata->buttons[i].desc : "gpio_keys",
+				     pdev);
+		if (error) {
+			printk(KERN_ERR "gpio-keys: unable to claim irq %d; error %d\n", irq, ret);
+			goto fail;
+		}
+		set_bit(code, input->keybit);
+	}
+
+	error = input_register_device(input);
+	if (error) {
+		printk(KERN_ERR "Unable to register gpio-keys input device\n");
+		goto fail;
+	}
+
+	return 0;
+
+ fail:
+	for (i = i - 1; i >= 0; i--)
+		free_irq(IRQ_GPIO(pdata->buttons[i].gpio), pdev);
+
+	input_free_device(input);
+
+	return error;
+}
+
+static int __devexit gpio_keys_remove(struct platform_device *pdev)
+{
+	struct gpio_keys_platform_data *pdata = pdev->dev.platform_data;
+	struct input_dev *input = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < pdata->nbuttons; i++) {
+		int irq = IRQ_GPIO(pdata->buttons[i].gpio);
+		free_irq(irq, pdev);
+	}
+
+	input_unregister_device(input);
+
+	return 0;
+}
+
+struct platform_driver gpio_keys_device_driver = {
+	.probe		= gpio_keys_probe,
+	.remove		= __devexit_p(gpio_keys_remove),
+	.driver		= {
+		.name	= "gpio-keys",
+	}
+};
+
+static int __init gpio_keys_init(void)
+{
+	return platform_driver_register(&gpio_keys_device_driver);
+}
+
+static void __exit gpio_keys_exit(void)
+{
+	platform_driver_unregister(&gpio_keys_device_driver);
+}
+
+module_init(gpio_keys_init);
+module_exit(gpio_keys_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Phil Blundell <pb@handhelds.org>");
+MODULE_DESCRIPTION("Keyboard driver for CPU GPIOs");

include/asm-arm/hardware/gpio_keys.h

+#ifndef _GPIO_KEYS_H
+#define _GPIO_KEYS_H
+
+struct gpio_keys_button {
+	/* Configuration parameters */
+	int keycode;
+	int gpio;
+	int active_low;
+	char *desc;
+};
+
+struct gpio_keys_platform_data {
+	struct gpio_keys_button *buttons;
+	int nbuttons;
+};
+
+#endif