diff options
Diffstat (limited to 'drivers/gpio/gpio-104-idio-16.c')
| -rw-r--r-- | drivers/gpio/gpio-104-idio-16.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-104-idio-16.c b/drivers/gpio/gpio-104-idio-16.c new file mode 100644 index 000000000000..5400d7d4d8fd --- /dev/null +++ b/drivers/gpio/gpio-104-idio-16.c @@ -0,0 +1,216 @@ +/* + * 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"); |