--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/devices/ccat/gpio.c	Tue Feb 16 15:18:34 2016 +0100
@@ -0,0 +1,164 @@
+/**
+    Network Driver for Beckhoff CCAT communication controller
+    Copyright (C) 2014  Beckhoff Automation GmbH
+    Author: Patrick Bruenn <p.bruenn@beckhoff.com>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/version.h>
+#include "module.h"
+
+/**
+ * struct ccat_gpio - CCAT GPIO function
+ * @ioaddr: PCI base address of the CCAT Update function
+ * @info: holds a copy of the CCAT Update function information block (read from PCI config space)
+ */
+struct ccat_gpio {
+	struct gpio_chip chip;
+	void __iomem *ioaddr;
+	struct mutex lock;
+};
+
+/** TODO implement in LED driver
+	#define TC_RED 0x01
+	#define TC_GREEN 0x02
+	#define TC_BLUE 0x04
+	#define FB1_RED 0x08
+	#define FB1_GREEN 0x10
+	#define FB1_BLUE 0x20
+	#define FB2_RED 0x40
+	#define FB2_GREEN 0x80
+	#define FB2_BLUE 0x100
+ */
+
+static int set_bit_in_register(struct mutex *lock, void __iomem * ioaddr,
+			       unsigned nr, int val)
+{
+	volatile unsigned long old;
+
+	mutex_lock(lock);
+	old = ioread32(ioaddr);
+	val ? set_bit(nr, &old) : clear_bit(nr, &old);
+	if (val)
+		set_bit(nr, &old);
+	else
+		clear_bit(nr, &old);
+	iowrite32(old, ioaddr);
+	mutex_unlock(lock);
+	return 0;
+}
+
+static int ccat_gpio_get_direction(struct gpio_chip *chip, unsigned nr)
+{
+	struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip);
+	const size_t byte_offset = 4 * (nr / 32) + 0x8;
+	const u32 mask = 1 << (nr % 32);
+
+	return !(mask & ioread32(gdev->ioaddr + byte_offset));
+}
+
+static int ccat_gpio_direction_input(struct gpio_chip *chip, unsigned nr)
+{
+	struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip);
+
+	return set_bit_in_register(&gdev->lock, gdev->ioaddr + 0x8, nr, 0);
+}
+
+static int ccat_gpio_direction_output(struct gpio_chip *chip, unsigned nr,
+				      int val)
+{
+	struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip);
+
+	return set_bit_in_register(&gdev->lock, gdev->ioaddr + 0x8, nr, 1);
+}
+
+static int ccat_gpio_get(struct gpio_chip *chip, unsigned nr)
+{
+	struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip);
+	const size_t byte_off = 4 * (nr / 32);
+	const int mask = 1 << (nr % 32);
+	int dir_off;
+	int value;
+
+	/** omit direction changes before value was read */
+	mutex_lock(&gdev->lock);
+	dir_off = 0x10 * ccat_gpio_get_direction(chip, nr);
+	value = !(mask & ioread32(gdev->ioaddr + byte_off + dir_off));
+	mutex_unlock(&gdev->lock);
+	return value;
+}
+
+static void ccat_gpio_set(struct gpio_chip *chip, unsigned nr, int val)
+{
+	struct ccat_gpio *gdev = container_of(chip, struct ccat_gpio, chip);
+
+	set_bit_in_register(&gdev->lock, gdev->ioaddr, nr, val);
+}
+
+static const struct gpio_chip ccat_gpio_chip = {
+	.label = KBUILD_MODNAME,
+	.owner = THIS_MODULE,
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,12,0))
+	.get_direction = ccat_gpio_get_direction,
+#endif
+	.direction_input = ccat_gpio_direction_input,
+	.get = ccat_gpio_get,
+	.direction_output = ccat_gpio_direction_output,
+	.set = ccat_gpio_set,
+	.dbg_show = NULL,
+	.base = -1,
+	.can_sleep = false
+};
+
+static int ccat_gpio_probe(struct ccat_function *func)
+{
+	struct ccat_gpio *const gpio = kzalloc(sizeof(*gpio), GFP_KERNEL);
+	int ret;
+
+	if (!gpio)
+		return -ENOMEM;
+
+	gpio->ioaddr = func->ccat->bar_0 + func->info.addr;
+	memcpy(&gpio->chip, &ccat_gpio_chip, sizeof(gpio->chip));
+	gpio->chip.ngpio = func->info.num_gpios;
+	mutex_init(&gpio->lock);
+
+	ret = gpiochip_add(&gpio->chip);
+	if (ret) {
+		kfree(gpio);
+		return ret;
+	}
+	pr_info("registered %s as gpiochip%d with #%d GPIOs.\n",
+		gpio->chip.label, gpio->chip.base, gpio->chip.ngpio);
+	func->private_data = gpio;
+	return 0;
+}
+
+static void ccat_gpio_remove(struct ccat_function *func)
+{
+	struct ccat_gpio *const gpio = func->private_data;
+
+	gpiochip_remove(&gpio->chip);
+};
+
+const struct ccat_driver gpio_driver = {
+	.type = CCATINFO_GPIO,
+	.probe = ccat_gpio_probe,
+	.remove = ccat_gpio_remove,
+};