diff options
Diffstat (limited to 'drivers/gpio/gpio-ws16c48.c')
| -rw-r--r-- | drivers/gpio/gpio-ws16c48.c | 427 |
1 files changed, 427 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c new file mode 100644 index 000000000000..51f41e8fd21e --- /dev/null +++ b/drivers/gpio/gpio-ws16c48.c @@ -0,0 +1,427 @@ +/* + * GPIO driver for the WinSystems WS16C48 + * Copyright (C) 2016 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 ws16c48_base; +module_param(ws16c48_base, uint, 0); +MODULE_PARM_DESC(ws16c48_base, "WinSystems WS16C48 base address"); +static unsigned ws16c48_irq; +module_param(ws16c48_irq, uint, 0); +MODULE_PARM_DESC(ws16c48_irq, "WinSystems WS16C48 interrupt line number"); + +/** + * struct ws16c48_gpio - GPIO device private data structure + * @chip: instance of the gpio_chip + * @io_state: bit I/O state (whether bit is set to input or output) + * @out_state: output bits state + * @lock: synchronization lock to prevent I/O race conditions + * @irq_mask: I/O bits affected by interrupts + * @flow_mask: IRQ flow type mask for the respective I/O bits + * @base: base port address of the GPIO device + * @irq: Interrupt line number + */ +struct ws16c48_gpio { + struct gpio_chip chip; + unsigned char io_state[6]; + unsigned char out_state[6]; + spinlock_t lock; + unsigned long irq_mask; + unsigned long flow_mask; + unsigned base; + unsigned irq; +}; + +static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset) +{ + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + + return !!(ws16c48gpio->io_state[port] & mask); +} + +static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset) +{ + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + unsigned long flags; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + ws16c48gpio->io_state[port] |= mask; + ws16c48gpio->out_state[port] &= ~mask; + outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + + return 0; +} + +static int ws16c48_gpio_direction_output(struct gpio_chip *chip, + unsigned offset, int value) +{ + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + unsigned long flags; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + ws16c48gpio->io_state[port] &= ~mask; + if (value) + ws16c48gpio->out_state[port] |= mask; + else + ws16c48gpio->out_state[port] &= ~mask; + outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + + return 0; +} + +static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset) +{ + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + unsigned long flags; + unsigned port_state; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + /* ensure that GPIO is set for input */ + if (!(ws16c48gpio->io_state[port] & mask)) { + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + return -EINVAL; + } + + port_state = inb(ws16c48gpio->base + port); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + + return !!(port_state & mask); +} + +static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value) +{ + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + unsigned long flags; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + /* ensure that GPIO is set for output */ + if (ws16c48gpio->io_state[port] & mask) { + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + return; + } + + if (value) + ws16c48gpio->out_state[port] |= mask; + else + ws16c48gpio->out_state[port] &= ~mask; + outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); +} + +static void ws16c48_irq_ack(struct irq_data *data) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned long offset = irqd_to_hwirq(data); + const unsigned port = offset / 8; + const unsigned mask = BIT(offset % 8); + unsigned long flags; + unsigned port_state; + + /* only the first 3 ports support interrupts */ + if (port > 2) + return; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + port_state = ws16c48gpio->irq_mask >> (8*port); + + outb(0x80, ws16c48gpio->base + 7); + outb(port_state & ~mask, ws16c48gpio->base + 8 + port); + outb(port_state | mask, ws16c48gpio->base + 8 + port); + outb(0xC0, ws16c48gpio->base + 7); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); +} + +static void ws16c48_irq_mask(struct irq_data *data) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned long offset = irqd_to_hwirq(data); + const unsigned long mask = BIT(offset); + const unsigned port = offset / 8; + unsigned long flags; + + /* only the first 3 ports support interrupts */ + if (port > 2) + return; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + ws16c48gpio->irq_mask &= ~mask; + + outb(0x80, ws16c48gpio->base + 7); + outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port); + outb(0xC0, ws16c48gpio->base + 7); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); +} + +static void ws16c48_irq_unmask(struct irq_data *data) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned long offset = irqd_to_hwirq(data); + const unsigned long mask = BIT(offset); + const unsigned port = offset / 8; + unsigned long flags; + + /* only the first 3 ports support interrupts */ + if (port > 2) + return; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + ws16c48gpio->irq_mask |= mask; + + outb(0x80, ws16c48gpio->base + 7); + outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port); + outb(0xC0, ws16c48gpio->base + 7); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); +} + +static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type) +{ + struct gpio_chip *chip = irq_data_get_irq_chip_data(data); + struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip); + const unsigned long offset = irqd_to_hwirq(data); + const unsigned long mask = BIT(offset); + const unsigned port = offset / 8; + unsigned long flags; + + /* only the first 3 ports support interrupts */ + if (port > 2) + return -EINVAL; + + spin_lock_irqsave(&ws16c48gpio->lock, flags); + + switch (flow_type) { + case IRQ_TYPE_NONE: + break; + case IRQ_TYPE_EDGE_RISING: + ws16c48gpio->flow_mask |= mask; + break; + case IRQ_TYPE_EDGE_FALLING: + ws16c48gpio->flow_mask &= ~mask; + break; + default: + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + return -EINVAL; + } + + outb(0x40, ws16c48gpio->base + 7); + outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port); + outb(0xC0, ws16c48gpio->base + 7); + + spin_unlock_irqrestore(&ws16c48gpio->lock, flags); + + return 0; +} + +static struct irq_chip ws16c48_irqchip = { + .name = "ws16c48", + .irq_ack = ws16c48_irq_ack, + .irq_mask = ws16c48_irq_mask, + .irq_unmask = ws16c48_irq_unmask, + .irq_set_type = ws16c48_irq_set_type +}; + +static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id) +{ + struct ws16c48_gpio *const ws16c48gpio = dev_id; + struct gpio_chip *const chip = &ws16c48gpio->chip; + unsigned long int_pending; + unsigned long port; + unsigned long int_id; + unsigned long gpio; + + int_pending = inb(ws16c48gpio->base + 6) & 0x7; + if (!int_pending) + return IRQ_NONE; + + /* loop until all pending interrupts are handled */ + do { + for_each_set_bit(port, &int_pending, 3) { + int_id = inb(ws16c48gpio->base + 8 + port); + for_each_set_bit(gpio, &int_id, 8) + generic_handle_irq(irq_find_mapping( + chip->irqdomain, gpio + 8*port)); + } + + int_pending = inb(ws16c48gpio->base + 6) & 0x7; + } while (int_pending); + + return IRQ_HANDLED; +} + +static int __init ws16c48_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct ws16c48_gpio *ws16c48gpio; + const unsigned base = ws16c48_base; + const unsigned extent = 16; + const char *const name = dev_name(dev); + int err; + const unsigned irq = ws16c48_irq; + + ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL); + if (!ws16c48gpio) + return -ENOMEM; + + if (!devm_request_region(dev, base, extent, name)) { + dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", + base, base + extent); + return -EBUSY; + } + + ws16c48gpio->chip.label = name; + ws16c48gpio->chip.parent = dev; + ws16c48gpio->chip.owner = THIS_MODULE; + ws16c48gpio->chip.base = -1; + ws16c48gpio->chip.ngpio = 48; + ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction; + ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input; + ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output; + ws16c48gpio->chip.get = ws16c48_gpio_get; + ws16c48gpio->chip.set = ws16c48_gpio_set; + ws16c48gpio->base = base; + ws16c48gpio->irq = irq; + + spin_lock_init(&ws16c48gpio->lock); + + dev_set_drvdata(dev, ws16c48gpio); + + err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio); + if (err) { + dev_err(dev, "GPIO registering failed (%d)\n", err); + return err; + } + + /* Disable IRQ by default */ + outb(0x80, base + 7); + outb(0, base + 8); + outb(0, base + 9); + outb(0, base + 10); + outb(0xC0, base + 7); + + err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_irqchip, 0, + handle_edge_irq, IRQ_TYPE_NONE); + if (err) { + dev_err(dev, "Could not add irqchip (%d)\n", err); + goto err_gpiochip_remove; + } + + err = request_irq(irq, ws16c48_irq_handler, IRQF_SHARED, name, + ws16c48gpio); + if (err) { + dev_err(dev, "IRQ handler registering failed (%d)\n", err); + goto err_gpiochip_remove; + } + + return 0; + +err_gpiochip_remove: + gpiochip_remove(&ws16c48gpio->chip); + return err; +} + +static int ws16c48_remove(struct platform_device *pdev) +{ + struct ws16c48_gpio *const ws16c48gpio = platform_get_drvdata(pdev); + + free_irq(ws16c48gpio->irq, ws16c48gpio); + gpiochip_remove(&ws16c48gpio->chip); + + return 0; +} + +static struct platform_device *ws16c48_device; + +static struct platform_driver ws16c48_driver = { + .driver = { + .name = "ws16c48" + }, + .remove = ws16c48_remove +}; + +static void __exit ws16c48_exit(void) +{ + platform_device_unregister(ws16c48_device); + platform_driver_unregister(&ws16c48_driver); +} + +static int __init ws16c48_init(void) +{ + int err; + + ws16c48_device = platform_device_alloc(ws16c48_driver.driver.name, -1); + if (!ws16c48_device) + return -ENOMEM; + + err = platform_device_add(ws16c48_device); + if (err) + goto err_platform_device; + + err = platform_driver_probe(&ws16c48_driver, ws16c48_probe); + if (err) + goto err_platform_driver; + + return 0; + +err_platform_driver: + platform_device_del(ws16c48_device); +err_platform_device: + platform_device_put(ws16c48_device); + return err; +} + +module_init(ws16c48_init); +module_exit(ws16c48_exit); + +MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); +MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver"); +MODULE_LICENSE("GPL v2"); |
