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/*
* GPIO driver for the ACCES 104-IDIO-16 family
* Copyright (C) 2015 William Breathitt Gray
*
* 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.
*/
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
static unsigned idio_16_base;
module_param(idio_16_base, uint, 0);
MODULE_PARM_DESC(idio_16_base, "ACCES 104-IDIO-16 base address");
/**
* struct idio_16_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent gpio_set race conditions
* @base: base port address of the GPIO device
* @extent: extent of port address region of the GPIO device
* @out_state: output bits state
*/
struct idio_16_gpio {
struct gpio_chip chip;
spinlock_t lock;
unsigned base;
unsigned extent;
unsigned out_state;
};
static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
if (offset > 15)
return 1;
return 0;
}
static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
return 0;
}
static int idio_16_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
chip->set(chip, offset, value);
return 0;
}
static struct idio_16_gpio *to_idio16gpio(struct gpio_chip *gc)
{
return container_of(gc, struct idio_16_gpio, chip);
}
static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip);
const unsigned BIT_MASK = 1U << (offset-16);
if (offset < 16)
return -EINVAL;
if (offset < 24)
return !!(inb(idio16gpio->base + 1) & BIT_MASK);
return !!(inb(idio16gpio->base + 5) & (BIT_MASK>>8));
}
static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip);
const unsigned BIT_MASK = 1U << offset;
unsigned long flags;
if (offset > 15)
return;
spin_lock_irqsave(&idio16gpio->lock, flags);
if (value)
idio16gpio->out_state |= BIT_MASK;
else
idio16gpio->out_state &= ~BIT_MASK;
if (offset > 7)
outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
else
outb(idio16gpio->out_state, idio16gpio->base);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static int __init idio_16_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct idio_16_gpio *idio16gpio;
int err;
const unsigned BASE = idio_16_base;
const unsigned EXTENT = 8;
const char *const NAME = dev_name(dev);
idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
if (!idio16gpio)
return -ENOMEM;
if (!request_region(BASE, EXTENT, NAME)) {
dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
NAME, BASE, BASE + EXTENT);
err = -EBUSY;
goto err_lock_io_port;
}
idio16gpio->chip.label = NAME;
idio16gpio->chip.dev = dev;
idio16gpio->chip.owner = THIS_MODULE;
idio16gpio->chip.base = -1;
idio16gpio->chip.ngpio = 32;
idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
idio16gpio->chip.get = idio_16_gpio_get;
idio16gpio->chip.set = idio_16_gpio_set;
idio16gpio->base = BASE;
idio16gpio->extent = EXTENT;
idio16gpio->out_state = 0xFFFF;
spin_lock_init(&idio16gpio->lock);
dev_set_drvdata(dev, idio16gpio);
err = gpiochip_add(&idio16gpio->chip);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
goto err_gpio_register;
}
return 0;
err_gpio_register:
release_region(BASE, EXTENT);
err_lock_io_port:
return err;
}
static int idio_16_remove(struct platform_device *pdev)
{
struct idio_16_gpio *const idio16gpio = platform_get_drvdata(pdev);
gpiochip_remove(&idio16gpio->chip);
release_region(idio16gpio->base, idio16gpio->extent);
return 0;
}
static struct platform_device *idio_16_device;
static struct platform_driver idio_16_driver = {
.driver = {
.name = "104-idio-16"
},
.remove = idio_16_remove
};
static void __exit idio_16_exit(void)
{
platform_device_unregister(idio_16_device);
platform_driver_unregister(&idio_16_driver);
}
static int __init idio_16_init(void)
{
int err;
idio_16_device = platform_device_alloc(idio_16_driver.driver.name, -1);
if (!idio_16_device)
return -ENOMEM;
err = platform_device_add(idio_16_device);
if (err)
goto err_platform_device;
err = platform_driver_probe(&idio_16_driver, idio_16_probe);
if (err)
goto err_platform_driver;
return 0;
err_platform_driver:
platform_device_del(idio_16_device);
err_platform_device:
platform_device_put(idio_16_device);
return err;
}
module_init(idio_16_init);
module_exit(idio_16_exit);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver");
MODULE_LICENSE("GPL");
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