--- /dev/null
+/*
+ * 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");
Code Review / kvmfornfv.git / blobdiff