gpio: add GPIO driver for the Timberdale FPGA

A GPIO driver for the Timberdale FPGA found on the Intel Atom board
Russellville.

The GPIO driver also has an IRQ-chip to support interrupts on the pins.

Signed-off-by: Richard Röjfors <richard.rojfors@mocean-labs.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 342 insertions, 0 deletions

diff --git a/drivers/gpio/timbgpio.c b/drivers/gpio/timbgpio.c
new file mode 100644
index 00000000000..a4d344ba8e5
--- /dev/null
+++ b/drivers/gpio/timbgpio.c
@@ -0,0 +1,342 @@
+/*
+ * timbgpio.c timberdale FPGA GPIO driver
+ * Copyright (c) 2009 Intel Corporation
+ *
+ * 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.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+/* Supports:
+ * Timberdale FPGA GPIO
+ */
+
+#include <linux/module.h>
+#include <linux/gpio.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/timb_gpio.h>
+#include <linux/interrupt.h>
+
+#define DRIVER_NAME "timb-gpio"
+
+#define TGPIOVAL	0x00
+#define TGPIODIR	0x04
+#define TGPIO_IER	0x08
+#define TGPIO_ISR	0x0c
+#define TGPIO_IPR	0x10
+#define TGPIO_ICR	0x14
+#define TGPIO_FLR	0x18
+#define TGPIO_LVR	0x1c
+
+struct timbgpio {
+	void __iomem		*membase;
+	spinlock_t		lock; /* mutual exclusion */
+	struct gpio_chip	gpio;
+	int			irq_base;
+};
+
+static int timbgpio_update_bit(struct gpio_chip *gpio, unsigned index,
+	unsigned offset, bool enabled)
+{
+	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
+	u32 reg;
+
+	spin_lock(&tgpio->lock);
+	reg = ioread32(tgpio->membase + offset);
+
+	if (enabled)
+		reg |= (1 << index);
+	else
+		reg &= ~(1 << index);
+
+	iowrite32(reg, tgpio->membase + offset);
+	spin_unlock(&tgpio->lock);
+
+	return 0;
+}
+
+static int timbgpio_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
+{
+	return timbgpio_update_bit(gpio, nr, TGPIODIR, true);
+}
+
+static int timbgpio_gpio_get(struct gpio_chip *gpio, unsigned nr)
+{
+	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
+	u32 value;
+
+	value = ioread32(tgpio->membase + TGPIOVAL);
+	return (value & (1 << nr)) ? 1 : 0;
+}
+
+static int timbgpio_gpio_direction_output(struct gpio_chip *gpio,
+						unsigned nr, int val)
+{
+	return timbgpio_update_bit(gpio, nr, TGPIODIR, false);
+}
+
+static void timbgpio_gpio_set(struct gpio_chip *gpio,
+				unsigned nr, int val)
+{
+	timbgpio_update_bit(gpio, nr, TGPIOVAL, val != 0);
+}
+
+static int timbgpio_to_irq(struct gpio_chip *gpio, unsigned offset)
+{
+	struct timbgpio *tgpio = container_of(gpio, struct timbgpio, gpio);
+
+	if (tgpio->irq_base <= 0)
+		return -EINVAL;
+
+	return tgpio->irq_base + offset;
+}
+
+/*
+ * GPIO IRQ
+ */
+static void timbgpio_irq_disable(unsigned irq)
+{
+	struct timbgpio *tgpio = get_irq_chip_data(irq);
+	int offset = irq - tgpio->irq_base;
+
+	timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 0);
+}
+
+static void timbgpio_irq_enable(unsigned irq)
+{
+	struct timbgpio *tgpio = get_irq_chip_data(irq);
+	int offset = irq - tgpio->irq_base;
+
+	timbgpio_update_bit(&tgpio->gpio, offset, TGPIO_IER, 1);
+}
+
+static int timbgpio_irq_type(unsigned irq, unsigned trigger)
+{
+	struct timbgpio *tgpio = get_irq_chip_data(irq);
+	int offset = irq - tgpio->irq_base;
+	unsigned long flags;
+	u32 lvr, flr;
+
+	if (offset < 0 || offset > tgpio->gpio.ngpio)
+		return -EINVAL;
+
+	spin_lock_irqsave(&tgpio->lock, flags);
+
+	lvr = ioread32(tgpio->membase + TGPIO_LVR);
+	flr = ioread32(tgpio->membase + TGPIO_FLR);
+
+	if (trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
+		flr &= ~(1 << offset);
+		if (trigger & IRQ_TYPE_LEVEL_HIGH)
+			lvr |= 1 << offset;
+		else
+			lvr &= ~(1 << offset);
+	}
+
+	if ((trigger & IRQ_TYPE_EDGE_BOTH) == IRQ_TYPE_EDGE_BOTH)
+		return -EINVAL;
+	else {
+		flr |= 1 << offset;
+		/* opposite compared to the datasheet, but it mirrors the
+		 * reality
+		 */
+		if (trigger & IRQ_TYPE_EDGE_FALLING)
+			lvr |= 1 << offset;
+		else
+			lvr &= ~(1 << offset);
+	}
+
+	iowrite32(lvr, tgpio->membase + TGPIO_LVR);
+	iowrite32(flr, tgpio->membase + TGPIO_FLR);
+	iowrite32(1 << offset, tgpio->membase + TGPIO_ICR);
+	spin_unlock_irqrestore(&tgpio->lock, flags);
+
+	return 0;
+}
+
+static void timbgpio_irq(unsigned int irq, struct irq_desc *desc)
+{
+	struct timbgpio *tgpio = get_irq_data(irq);
+	unsigned long ipr;
+	int offset;
+
+	desc->chip->ack(irq);
+	ipr = ioread32(tgpio->membase + TGPIO_IPR);
+	iowrite32(ipr, tgpio->membase + TGPIO_ICR);
+
+	for_each_bit(offset, &ipr, tgpio->gpio.ngpio)
+		generic_handle_irq(timbgpio_to_irq(&tgpio->gpio, offset));
+}
+
+static struct irq_chip timbgpio_irqchip = {
+	.name		= "GPIO",
+	.enable		= timbgpio_irq_enable,
+	.disable	= timbgpio_irq_disable,
+	.set_type	= timbgpio_irq_type,
+};
+
+static int __devinit timbgpio_probe(struct platform_device *pdev)
+{
+	int err, i;
+	struct gpio_chip *gc;
+	struct timbgpio *tgpio;
+	struct resource *iomem;
+	struct timbgpio_platform_data *pdata = pdev->dev.platform_data;
+	int irq = platform_get_irq(pdev, 0);
+
+	if (!pdata || pdata->nr_pins > 32) {
+		err = -EINVAL;
+		goto err_mem;
+	}
+
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!iomem) {
+		err = -EINVAL;
+		goto err_mem;
+	}
+
+	tgpio = kzalloc(sizeof(*tgpio), GFP_KERNEL);
+	if (!tgpio) {
+		err = -EINVAL;
+		goto err_mem;
+	}
+	tgpio->irq_base = pdata->irq_base;
+
+	spin_lock_init(&tgpio->lock);
+
+	if (!request_mem_region(iomem->start, resource_size(iomem),
+		DRIVER_NAME)) {
+		err = -EBUSY;
+		goto err_request;
+	}
+
+	tgpio->membase = ioremap(iomem->start, resource_size(iomem));
+	if (!tgpio->membase) {
+		err = -ENOMEM;
+		goto err_ioremap;
+	}
+
+	gc = &tgpio->gpio;
+
+	gc->label = dev_name(&pdev->dev);
+	gc->owner = THIS_MODULE;
+	gc->dev = &pdev->dev;
+	gc->direction_input = timbgpio_gpio_direction_input;
+	gc->get = timbgpio_gpio_get;
+	gc->direction_output = timbgpio_gpio_direction_output;
+	gc->set = timbgpio_gpio_set;
+	gc->to_irq = (irq >= 0 && tgpio->irq_base > 0) ? timbgpio_to_irq : NULL;
+	gc->dbg_show = NULL;
+	gc->base = pdata->gpio_base;
+	gc->ngpio = pdata->nr_pins;
+	gc->can_sleep = 0;
+
+	err = gpiochip_add(gc);
+	if (err)
+		goto err_chipadd;
+
+	platform_set_drvdata(pdev, tgpio);
+
+	/* make sure to disable interrupts */
+	iowrite32(0x0, tgpio->membase + TGPIO_IER);
+
+	if (irq < 0 || tgpio->irq_base <= 0)
+		return 0;
+
+	for (i = 0; i < pdata->nr_pins; i++) {
+		set_irq_chip_and_handler_name(tgpio->irq_base + i,
+			&timbgpio_irqchip, handle_simple_irq, "mux");
+		set_irq_chip_data(tgpio->irq_base + i, tgpio);
+#ifdef CONFIG_ARM
+		set_irq_flags(tgpio->irq_base + i, IRQF_VALID | IRQF_PROBE);
+#endif
+	}
+
+	set_irq_data(irq, tgpio);
+	set_irq_chained_handler(irq, timbgpio_irq);
+
+	return 0;
+
+err_chipadd:
+	iounmap(tgpio->membase);
+err_ioremap:
+	release_mem_region(iomem->start, resource_size(iomem));
+err_request:
+	kfree(tgpio);
+err_mem:
+	printk(KERN_ERR DRIVER_NAME": Failed to register GPIOs: %d\n", err);
+
+	return err;
+}
+
+static int __devexit timbgpio_remove(struct platform_device *pdev)
+{
+	int err;
+	struct timbgpio_platform_data *pdata = pdev->dev.platform_data;
+	struct timbgpio *tgpio = platform_get_drvdata(pdev);
+	struct resource *iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	int irq = platform_get_irq(pdev, 0);
+
+	if (irq >= 0 && tgpio->irq_base > 0) {
+		int i;
+		for (i = 0; i < pdata->nr_pins; i++) {
+			set_irq_chip(tgpio->irq_base + i, NULL);
+			set_irq_chip_data(tgpio->irq_base + i, NULL);
+		}
+
+		set_irq_handler(irq, NULL);
+		set_irq_data(irq, NULL);
+	}
+
+	err = gpiochip_remove(&tgpio->gpio);
+	if (err)
+		printk(KERN_ERR DRIVER_NAME": failed to remove gpio_chip\n");
+
+	iounmap(tgpio->membase);
+	release_mem_region(iomem->start, resource_size(iomem));
+	kfree(tgpio);
+
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver timbgpio_platform_driver = {
+	.driver = {
+		.name	= DRIVER_NAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= timbgpio_probe,
+	.remove		= timbgpio_remove,
+};
+
+/*--------------------------------------------------------------------------*/
+
+static int __init timbgpio_init(void)
+{
+	return platform_driver_register(&timbgpio_platform_driver);
+}
+
+static void __exit timbgpio_exit(void)
+{
+	platform_driver_unregister(&timbgpio_platform_driver);
+}
+
+module_init(timbgpio_init);
+module_exit(timbgpio_exit);
+
+MODULE_DESCRIPTION("Timberdale GPIO driver");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Mocean Laboratories");
+MODULE_ALIAS("platform:"DRIVER_NAME);
+