linux/drivers/gpio/timbgpio.c
Tomas Hallenberg 76d800a5b6 gpio: timbgpio: use a copy of the IER register to avoid it being trashed
Some versions of the hardware can trash the IER register if simultaneous
interrupts occur.  This patch works around it by using a local copy of the
register and restoring it after every interrupt.

Signed-off-by: Tomas Hallenberg <tomas.hallenberg@pelagicore.com>
Acked-by: Richard Röjfors <richard.rojfors@pelagicore.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-10-27 18:03:07 -07:00

380 lines
8.9 KiB
C

/*
* 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/irq.h>
#include <linux/io.h>
#include <linux/timb_gpio.h>
#include <linux/interrupt.h>
#include <linux/slab.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
#define TGPIO_VER 0x20
#define TGPIO_BFLR 0x24
struct timbgpio {
void __iomem *membase;
spinlock_t lock; /* mutual exclusion */
struct gpio_chip gpio;
int irq_base;
unsigned long last_ier;
};
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;
unsigned long flags;
spin_lock_irqsave(&tgpio->lock, flags);
tgpio->last_ier &= ~(1 << offset);
iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
spin_unlock_irqrestore(&tgpio->lock, flags);
}
static void timbgpio_irq_enable(unsigned irq)
{
struct timbgpio *tgpio = get_irq_chip_data(irq);
int offset = irq - tgpio->irq_base;
unsigned long flags;
spin_lock_irqsave(&tgpio->lock, flags);
tgpio->last_ier |= 1 << offset;
iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
spin_unlock_irqrestore(&tgpio->lock, flags);
}
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, bflr = 0;
u32 ver;
int ret = 0;
if (offset < 0 || offset > tgpio->gpio.ngpio)
return -EINVAL;
ver = ioread32(tgpio->membase + TGPIO_VER);
spin_lock_irqsave(&tgpio->lock, flags);
lvr = ioread32(tgpio->membase + TGPIO_LVR);
flr = ioread32(tgpio->membase + TGPIO_FLR);
if (ver > 2)
bflr = ioread32(tgpio->membase + TGPIO_BFLR);
if (trigger & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW)) {
bflr &= ~(1 << offset);
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) {
if (ver < 3) {
ret = -EINVAL;
goto out;
}
else {
flr |= 1 << offset;
bflr |= 1 << offset;
}
} else {
bflr &= ~(1 << offset);
flr |= 1 << offset;
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);
if (ver > 2)
iowrite32(bflr, tgpio->membase + TGPIO_BFLR);
iowrite32(1 << offset, tgpio->membase + TGPIO_ICR);
out:
spin_unlock_irqrestore(&tgpio->lock, flags);
return ret;
}
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);
/*
* Some versions of the hardware trash the IER register if more than
* one interrupt is received simultaneously.
*/
iowrite32(0, tgpio->membase + TGPIO_IER);
for_each_set_bit(offset, &ipr, tgpio->gpio.ngpio)
generic_handle_irq(timbgpio_to_irq(&tgpio->gpio, offset));
iowrite32(tgpio->last_ier, tgpio->membase + TGPIO_IER);
}
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);