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 000000000000..a4d344ba8e5c
--- /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);
+