/* * 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/isa.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/spinlock.h> #define WS16C48_EXTENT 16 #define MAX_NUM_WS16C48 max_num_isa_dev(WS16C48_EXTENT) static unsigned int base[MAX_NUM_WS16C48]; static unsigned int num_ws16c48; module_param_array(base, uint, &num_ws16c48, 0); MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses"); static unsigned int irq[MAX_NUM_WS16C48]; module_param_array(irq, uint, NULL, 0); MODULE_PARM_DESC(irq, "WinSystems WS16C48 interrupt line numbers"); /** * 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 ws16c48_probe(struct device *dev, unsigned int id) { struct ws16c48_gpio *ws16c48gpio; const char *const name = dev_name(dev); int err; ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL); if (!ws16c48gpio) return -ENOMEM; if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) { dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n", base[id], base[id] + WS16C48_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[id]; ws16c48gpio->irq = irq[id]; 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[id] + 7); outb(0, base[id] + 8); outb(0, base[id] + 9); outb(0, base[id] + 10); outb(0xC0, base[id] + 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[id], 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 device *dev, unsigned int id) { struct ws16c48_gpio *const ws16c48gpio = dev_get_drvdata(dev); free_irq(ws16c48gpio->irq, ws16c48gpio); gpiochip_remove(&ws16c48gpio->chip); return 0; } static struct isa_driver ws16c48_driver = { .probe = ws16c48_probe, .driver = { .name = "ws16c48" }, .remove = ws16c48_remove }; module_isa_driver(ws16c48_driver, num_ws16c48); MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>"); MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver"); MODULE_LICENSE("GPL v2");