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/*
* RDC321x GPIO driver
*
* Copyright (C) 2008, Volker Weiss <dev@tintuc.de>
* Copyright (C) 2007-2010 Florian Fainelli <florian@openwrt.org>
*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/platform_device.h>
#include <linux/pci.h>
#include <linux/gpio.h>
#include <asm/rdc321x_defs.h>
struct rdc321x_gpio {
spinlock_t lock;
u32 data_reg[2];
} rdc321x_gpio_dev;
extern int rdc321x_pci_write(int reg, u32 val);
extern int rdc321x_pci_read(int reg, u32 *val);
/* read GPIO pin */
static int rdc_gpio_get_value(struct gpio_chip *chip, unsigned gpio)
{
u32 value = 0;
int reg;
reg = gpio < 32 ? RDC321X_GPIO_DATA_REG1 : RDC321X_GPIO_DATA_REG2;
spin_lock(&rdc321x_gpio_dev.lock);
rdc321x_pci_write(reg, rdc321x_gpio_dev.data_reg[gpio < 32 ? 0 : 1]);
rdc321x_pci_read(reg, &value);
spin_unlock(&rdc321x_gpio_dev.lock);
return (1 << (gpio & 0x1f)) & value ? 1 : 0;
}
static void rdc_gpio_set_value_impl(struct gpio_chip *chip,
unsigned gpio, int value)
{
int reg = (gpio < 32) ? 0 : 1;
if (value)
rdc321x_gpio_dev.data_reg[reg] |= 1 << (gpio & 0x1f);
else
rdc321x_gpio_dev.data_reg[reg] &= ~(1 << (gpio & 0x1f));
rdc321x_pci_write(reg ? RDC321X_GPIO_DATA_REG2 : RDC321X_GPIO_DATA_REG1,
rdc321x_gpio_dev.data_reg[reg]);
}
/* set GPIO pin to value */
static void rdc_gpio_set_value(struct gpio_chip *chip,
unsigned gpio, int value)
{
spin_lock(&rdc321x_gpio_dev.lock);
rdc_gpio_set_value_impl(chip, gpio, value);
spin_unlock(&rdc321x_gpio_dev.lock);
}
static int rdc_gpio_config(struct gpio_chip *chip,
unsigned gpio, int value)
{
int err;
u32 reg;
spin_lock(&rdc321x_gpio_dev.lock);
err = rdc321x_pci_read(gpio < 32 ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
®);
if (err)
goto unlock;
reg |= 1 << (gpio & 0x1f);
err = rdc321x_pci_write(gpio < 32 ? RDC321X_GPIO_CTRL_REG1 : RDC321X_GPIO_CTRL_REG2,
reg);
if (err)
goto unlock;
rdc_gpio_set_value_impl(chip, gpio, value);
unlock:
spin_unlock(&rdc321x_gpio_dev.lock);
return err;
}
/* configure GPIO pin as input */
static int rdc_gpio_direction_input(struct gpio_chip *chip, unsigned gpio)
{
return rdc_gpio_config(chip, gpio, 1);
}
static struct gpio_chip rdc321x_gpio_chip = {
.label = "rdc321x-gpio",
.direction_input = rdc_gpio_direction_input,
.direction_output = rdc_gpio_config,
.get = rdc_gpio_get_value,
.set = rdc_gpio_set_value,
.base = 0,
.ngpio = RDC321X_MAX_GPIO,
};
/* initially setup the 2 copies of the gpio data registers.
This function is called before the platform setup code. */
static int __devinit rdc321x_gpio_probe(struct platform_device *pdev)
{
int err;
/* this might not be, what others (BIOS, bootloader, etc.)
wrote to these registers before, but it's a good guess. Still
better than just using 0xffffffff. */
err = rdc321x_pci_read(RDC321X_GPIO_DATA_REG1, &rdc321x_gpio_dev.data_reg[0]);
if (err)
return err;
err = rdc321x_pci_read(RDC321X_GPIO_DATA_REG2, &rdc321x_gpio_dev.data_reg[1]);
if (err)
return err;
spin_lock_init(&rdc321x_gpio_dev.lock);
printk(KERN_INFO "rdc321x: registering %d GPIOs\n", rdc321x_gpio_chip.ngpio);
return gpiochip_add(&rdc321x_gpio_chip);
}
static int __devexit rdc321x_gpio_remove(struct platform_device *pdev)
{
gpiochip_remove(&rdc321x_gpio_chip);
return 0;
}
static struct platform_driver rdc321x_gpio_driver = {
.driver.name = "rdc321x-gpio",
.driver.owner = THIS_MODULE,
.probe = rdc321x_gpio_probe,
.remove = __devexit_p(rdc321x_gpio_remove),
};
static int __init rdc321x_gpio_init(void)
{
return platform_driver_register(&rdc321x_gpio_driver);
}
static void __exit rdc321x_gpio_exit(void)
{
platform_driver_unregister(&rdc321x_gpio_driver);
}
module_init(rdc321x_gpio_init);
module_exit(rdc321x_gpio_exit);
MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
MODULE_DESCRIPTION("RDC321x GPIO driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:rdc321x-gpio");
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