217 lines
5.3 KiB
C
217 lines
5.3 KiB
C
![]() |
/*
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* GPIO driver for the ACCES 104-IDIO-16 family
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* Copyright (C) 2015 William Breathitt Gray
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/device.h>
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#include <linux/errno.h>
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#include <linux/gpio/driver.h>
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#include <linux/io.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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static unsigned idio_16_base;
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module_param(idio_16_base, uint, 0);
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MODULE_PARM_DESC(idio_16_base, "ACCES 104-IDIO-16 base address");
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/**
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* struct idio_16_gpio - GPIO device private data structure
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* @chip: instance of the gpio_chip
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* @lock: synchronization lock to prevent gpio_set race conditions
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* @base: base port address of the GPIO device
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* @extent: extent of port address region of the GPIO device
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* @out_state: output bits state
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*/
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struct idio_16_gpio {
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struct gpio_chip chip;
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spinlock_t lock;
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unsigned base;
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unsigned extent;
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unsigned out_state;
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};
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static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
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{
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if (offset > 15)
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return 1;
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return 0;
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}
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static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
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{
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return 0;
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}
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static int idio_16_gpio_direction_output(struct gpio_chip *chip,
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unsigned offset, int value)
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{
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chip->set(chip, offset, value);
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return 0;
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}
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static struct idio_16_gpio *to_idio16gpio(struct gpio_chip *gc)
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{
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return container_of(gc, struct idio_16_gpio, chip);
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}
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static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
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{
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struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip);
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const unsigned BIT_MASK = 1U << (offset-16);
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if (offset < 16)
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return -EINVAL;
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if (offset < 24)
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return !!(inb(idio16gpio->base + 1) & BIT_MASK);
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return !!(inb(idio16gpio->base + 5) & (BIT_MASK>>8));
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}
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static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
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{
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struct idio_16_gpio *const idio16gpio = to_idio16gpio(chip);
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const unsigned BIT_MASK = 1U << offset;
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unsigned long flags;
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if (offset > 15)
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return;
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spin_lock_irqsave(&idio16gpio->lock, flags);
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if (value)
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idio16gpio->out_state |= BIT_MASK;
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else
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idio16gpio->out_state &= ~BIT_MASK;
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if (offset > 7)
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outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
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else
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outb(idio16gpio->out_state, idio16gpio->base);
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spin_unlock_irqrestore(&idio16gpio->lock, flags);
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}
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static int __init idio_16_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct idio_16_gpio *idio16gpio;
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int err;
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const unsigned BASE = idio_16_base;
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const unsigned EXTENT = 8;
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const char *const NAME = dev_name(dev);
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idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
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if (!idio16gpio)
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return -ENOMEM;
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if (!request_region(BASE, EXTENT, NAME)) {
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dev_err(dev, "Unable to lock %s port addresses (0x%X-0x%X)\n",
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NAME, BASE, BASE + EXTENT);
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err = -EBUSY;
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goto err_lock_io_port;
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}
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idio16gpio->chip.label = NAME;
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idio16gpio->chip.dev = dev;
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idio16gpio->chip.owner = THIS_MODULE;
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idio16gpio->chip.base = -1;
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idio16gpio->chip.ngpio = 32;
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idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
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idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
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idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
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idio16gpio->chip.get = idio_16_gpio_get;
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idio16gpio->chip.set = idio_16_gpio_set;
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idio16gpio->base = BASE;
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idio16gpio->extent = EXTENT;
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idio16gpio->out_state = 0xFFFF;
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spin_lock_init(&idio16gpio->lock);
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dev_set_drvdata(dev, idio16gpio);
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err = gpiochip_add(&idio16gpio->chip);
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if (err) {
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dev_err(dev, "GPIO registering failed (%d)\n", err);
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goto err_gpio_register;
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}
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return 0;
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err_gpio_register:
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release_region(BASE, EXTENT);
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err_lock_io_port:
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return err;
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}
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static int idio_16_remove(struct platform_device *pdev)
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{
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struct idio_16_gpio *const idio16gpio = platform_get_drvdata(pdev);
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gpiochip_remove(&idio16gpio->chip);
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release_region(idio16gpio->base, idio16gpio->extent);
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return 0;
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}
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static struct platform_device *idio_16_device;
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static struct platform_driver idio_16_driver = {
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.driver = {
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.name = "104-idio-16"
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},
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.remove = idio_16_remove
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};
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static void __exit idio_16_exit(void)
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{
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platform_device_unregister(idio_16_device);
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platform_driver_unregister(&idio_16_driver);
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}
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static int __init idio_16_init(void)
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{
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int err;
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idio_16_device = platform_device_alloc(idio_16_driver.driver.name, -1);
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if (!idio_16_device)
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return -ENOMEM;
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err = platform_device_add(idio_16_device);
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if (err)
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goto err_platform_device;
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err = platform_driver_probe(&idio_16_driver, idio_16_probe);
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if (err)
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goto err_platform_driver;
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return 0;
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err_platform_driver:
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platform_device_del(idio_16_device);
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err_platform_device:
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platform_device_put(idio_16_device);
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return err;
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}
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module_init(idio_16_init);
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module_exit(idio_16_exit);
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MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
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MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver");
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MODULE_LICENSE("GPL");
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