diff options
Diffstat (limited to 'drivers/gpio/gpio-104-idi-48.c')
| -rw-r--r-- | drivers/gpio/gpio-104-idi-48.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c new file mode 100644 index 000000000000..52eed328ce99 --- /dev/null +++ b/drivers/gpio/gpio-104-idi-48.c @@ -0,0 +1,343 @@ +/* + * GPIO driver for the ACCES 104-IDI-48 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/bitops.h> +#include <linux/device.h> +#include <linux/errno.h> +#include <linux/gpio/driver.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/interrupt.h> +#include <linux/irqdesc.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> + +static unsigned idi_48_base; +module_param(idi_48_base, uint, 0); +MODULE_PARM_DESC(idi_48_base, "ACCES 104-IDI-48 base address"); +static unsigned idi_48_irq; +module_param(idi_48_irq, uint, 0); +MODULE_PARM_DESC(idi_48_irq, "ACCES 104-IDI-48 interrupt line number"); + +/** + * struct idi_48_gpio - GPIO device private data structure + * @chip: instance of the gpio_chip + * @lock: synchronization lock to prevent I/O race conditions + * @ack_lock: synchronization lock to prevent IRQ handler race conditions + * @irq_mask: input bits affected by interrupts + * @base: base port address of the GPIO device + * @extent: extent of port address region of the GPIO device + * @irq: Interrupt line number + * @cos_enb: Change-Of-State IRQ enable boundaries mask + */ +struct idi_48_gpio { + struct gpio_chip chip; + spinlock_t lock; + spinlock_t ack_lock; + unsigned char irq_mask[6]; + unsigned base; + unsigned extent; + unsigned irq; + unsigned char cos_enb; +}; + +static int idi_48_gpio_get_direction(struct gpio_chip *chip, unsigned offset) +{ + return 1; +} + +static int idi_48_gpio_direction_input(struct gpio_chip *chip, unsigned offset) +{ + return 0; +} + +static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip); + unsigned i; + const unsigned register_offset[6] = { 0, 1, 2, 4, 5, 6 }; + unsigned base_offset; + unsigned mask; + + for (i = 0; i < 48; i += 8) + if (offset < i + 8) { + base_offset = register_offset[i / 8]; + mask = BIT(offset - i); + + return !!(inb(idi48gpio->base + base_offset) & mask); + } + + /* The following line should never execute since offset < 48 */ + return 0; +} + +static void idi_48_irq_ack(struct irq_data *data) +{ +} + +static void idi_48_irq_mask(struct irq_data *data) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip); + const unsigned offset = irqd_to_hwirq(data); + unsigned i; + unsigned mask; + unsigned boundary; + unsigned long flags; + + for (i = 0; i < 48; i += 8) + if (offset < i + 8) { + mask = BIT(offset - i); + boundary = i / 8; + + idi48gpio->irq_mask[boundary] &= ~mask; + + if (!idi48gpio->irq_mask[boundary]) { + idi48gpio->cos_enb &= ~BIT(boundary); + + spin_lock_irqsave(&idi48gpio->lock, flags); + + outb(idi48gpio->cos_enb, idi48gpio->base + 7); + + spin_unlock_irqrestore(&idi48gpio->lock, flags); + } + + return; + } +} + +static void idi_48_irq_unmask(struct irq_data *data) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct idi_48_gpio *const idi48gpio = gpiochip_get_data(chip); + const unsigned offset = irqd_to_hwirq(data); + unsigned i; + unsigned mask; + unsigned boundary; + unsigned prev_irq_mask; + unsigned long flags; + + for (i = 0; i < 48; i += 8) + if (offset < i + 8) { + mask = BIT(offset - i); + boundary = i / 8; + prev_irq_mask = idi48gpio->irq_mask[boundary]; + + idi48gpio->irq_mask[boundary] |= mask; + + if (!prev_irq_mask) { + idi48gpio->cos_enb |= BIT(boundary); + + spin_lock_irqsave(&idi48gpio->lock, flags); + + outb(idi48gpio->cos_enb, idi48gpio->base + 7); + + spin_unlock_irqrestore(&idi48gpio->lock, flags); + } + + return; + } +} + +static int idi_48_irq_set_type(struct irq_data *data, unsigned flow_type) +{ + /* The only valid irq types are none and both-edges */ + if (flow_type != IRQ_TYPE_NONE && + (flow_type & IRQ_TYPE_EDGE_BOTH) != IRQ_TYPE_EDGE_BOTH) + return -EINVAL; + + return 0; +} + +static struct irq_chip idi_48_irqchip = { + .name = "104-idi-48", + .irq_ack = idi_48_irq_ack, + .irq_mask = idi_48_irq_mask, + .irq_unmask = idi_48_irq_unmask, + .irq_set_type = idi_48_irq_set_type +}; + +static irqreturn_t idi_48_irq_handler(int irq, void *dev_id) +{ + struct idi_48_gpio *const idi48gpio = dev_id; + unsigned long cos_status; + unsigned long boundary; + unsigned long irq_mask; + unsigned long bit_num; + unsigned long gpio; + struct gpio_chip *const chip = &idi48gpio->chip; + + spin_lock(&idi48gpio->ack_lock); + + spin_lock(&idi48gpio->lock); + + cos_status = inb(idi48gpio->base + 7); + + spin_unlock(&idi48gpio->lock); + + /* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */ + if (cos_status & BIT(6)) { + spin_unlock(&idi48gpio->ack_lock); + return IRQ_NONE; + } + + /* Bit 0-5 indicate which Change-Of-State boundary triggered the IRQ */ + cos_status &= 0x3F; + + for_each_set_bit(boundary, &cos_status, 6) { + irq_mask = idi48gpio->irq_mask[boundary]; + + for_each_set_bit(bit_num, &irq_mask, 8) { + gpio = bit_num + boundary * 8; + + generic_handle_irq(irq_find_mapping(chip->irqdomain, + gpio)); + } + } + + spin_unlock(&idi48gpio->ack_lock); + + return IRQ_HANDLED; +} + +static int __init idi_48_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct idi_48_gpio *idi48gpio; + const unsigned base = idi_48_base; + const unsigned extent = 8; + const char *const name = dev_name(dev); + int err; + const unsigned irq = idi_48_irq; + + idi48gpio = devm_kzalloc(dev, sizeof(*idi48gpio), GFP_KERNEL); + if (!idi48gpio) + 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; + } + + idi48gpio->chip.label = name; + idi48gpio->chip.parent = dev; + idi48gpio->chip.owner = THIS_MODULE; + idi48gpio->chip.base = -1; + idi48gpio->chip.ngpio = 48; + idi48gpio->chip.get_direction = idi_48_gpio_get_direction; + idi48gpio->chip.direction_input = idi_48_gpio_direction_input; + idi48gpio->chip.get = idi_48_gpio_get; + idi48gpio->base = base; + idi48gpio->extent = extent; + idi48gpio->irq = irq; + + spin_lock_init(&idi48gpio->lock); + + dev_set_drvdata(dev, idi48gpio); + + err = gpiochip_add_data(&idi48gpio->chip, idi48gpio); + if (err) { + dev_err(dev, "GPIO registering failed (%d)\n", err); + goto err_gpio_register; + } + + /* Disable IRQ by default */ + outb(0, base + 7); + inb(base + 7); + + err = gpiochip_irqchip_add(&idi48gpio->chip, &idi_48_irqchip, 0, + handle_edge_irq, IRQ_TYPE_NONE); + if (err) { + dev_err(dev, "Could not add irqchip (%d)\n", err); + goto err_gpiochip_irqchip_add; + } + + err = request_irq(irq, idi_48_irq_handler, 0, name, idi48gpio); + if (err) { + dev_err(dev, "IRQ handler registering failed (%d)\n", err); + goto err_request_irq; + } + + return 0; + +err_request_irq: +err_gpiochip_irqchip_add: + gpiochip_remove(&idi48gpio->chip); +err_gpio_register: + release_region(base, extent); +err_lock_io_port: + return err; +} + +static int idi_48_remove(struct platform_device *pdev) +{ + struct idi_48_gpio *const idi48gpio = platform_get_drvdata(pdev); + + free_irq(idi48gpio->irq, idi48gpio); + gpiochip_remove(&idi48gpio->chip); + release_region(idi48gpio->base, idi48gpio->extent); + + return 0; +} + +static struct platform_device *idi_48_device; + +static struct platform_driver idi_48_driver = { + .driver = { + .name = "104-idi-48" + }, + .remove = idi_48_remove +}; + +static void __exit idi_48_exit(void) +{ + platform_device_unregister(idi_48_device); + platform_driver_unregister(&idi_48_driver); +} + +static int __init idi_48_init(void) +{ + int err; + + idi_48_device = platform_device_alloc(idi_48_driver.driver.name, -1); + if (!idi_48_device) + return -ENOMEM; + + err = platform_device_add(idi_48_device); + if (err) + goto err_platform_device; + + err = platform_driver_probe(&idi_48_driver, idi_48_probe); + if (err) + goto err_platform_driver; + + return 0; + +err_platform_driver: + platform_device_del(idi_48_device); +err_platform_device: + platform_device_put(idi_48_device); + return err; +} + +module_init(idi_48_init); +module_exit(idi_48_exit); + +MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); +MODULE_DESCRIPTION("ACCES 104-IDI-48 GPIO driver"); +MODULE_LICENSE("GPL"); |