1 files changed, 480 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
new file mode 100644
index 000000000..c7028eb0b
--- /dev/null
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -0,0 +1,480 @@
+/*
+ * 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/bitmap.h>
+#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_hw_array(base, uint, ioport, &num_ws16c48, 0);
+MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");
+
+static unsigned int irq[MAX_NUM_WS16C48];
+module_param_hw_array(irq, uint, irq, 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
+ */
+struct ws16c48_gpio {
+	struct gpio_chip chip;
+	unsigned char io_state[6];
+	unsigned char out_state[6];
+	raw_spinlock_t lock;
+	unsigned long irq_mask;
+	unsigned long flow_mask;
+	unsigned base;
+};
+
+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;
+
+	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
+
+	ws16c48gpio->io_state[port] |= mask;
+	ws16c48gpio->out_state[port] &= ~mask;
+	outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
+
+	raw_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;
+
+	raw_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);
+
+	raw_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;
+
+	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
+
+	/* ensure that GPIO is set for input */
+	if (!(ws16c48gpio->io_state[port] & mask)) {
+		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+		return -EINVAL;
+	}
+
+	port_state = inb(ws16c48gpio->base + port);
+
+	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+
+	return !!(port_state & mask);
+}
+
+static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
+	const unsigned int gpio_reg_size = 8;
+	size_t i;
+	const size_t num_ports = chip->ngpio / gpio_reg_size;
+	unsigned int bits_offset;
+	size_t word_index;
+	unsigned int word_offset;
+	unsigned long word_mask;
+	const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
+	unsigned long port_state;
+
+	/* clear bits array to a clean slate */
+	bitmap_zero(bits, chip->ngpio);
+
+	/* get bits are evaluated a gpio port register at a time */
+	for (i = 0; i < num_ports; i++) {
+		/* gpio offset in bits array */
+		bits_offset = i * gpio_reg_size;
+
+		/* word index for bits array */
+		word_index = BIT_WORD(bits_offset);
+
+		/* gpio offset within current word of bits array */
+		word_offset = bits_offset % BITS_PER_LONG;
+
+		/* mask of get bits for current gpio within current word */
+		word_mask = mask[word_index] & (port_mask << word_offset);
+		if (!word_mask) {
+			/* no get bits in this port so skip to next one */
+			continue;
+		}
+
+		/* read bits from current gpio port */
+		port_state = inb(ws16c48gpio->base + i);
+
+		/* store acquired bits at respective bits array offset */
+		bits[word_index] |= port_state << word_offset;
+	}
+
+	return 0;
+}
+
+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;
+
+	raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
+
+	/* ensure that GPIO is set for output */
+	if (ws16c48gpio->io_state[port] & mask) {
+		raw_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);
+
+	raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+}
+
+static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
+	unsigned long *mask, unsigned long *bits)
+{
+	struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
+	unsigned int i;
+	const unsigned int gpio_reg_size = 8;
+	unsigned int port;
+	unsigned int iomask;
+	unsigned int bitmask;
+	unsigned long flags;
+
+	/* set bits are evaluated a gpio register size at a time */
+	for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+		/* no more set bits in this mask word; skip to the next word */
+		if (!mask[BIT_WORD(i)]) {
+			i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
+			continue;
+		}
+
+		port = i / gpio_reg_size;
+
+		/* mask out GPIO configured for input */
+		iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
+		bitmask = iomask & bits[BIT_WORD(i)];
+
+		raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
+
+		/* update output state data and set device gpio register */
+		ws16c48gpio->out_state[port] &= ~iomask;
+		ws16c48gpio->out_state[port] |= bitmask;
+		outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
+
+		raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+
+		/* prepare for next gpio register set */
+		mask[BIT_WORD(i)] >>= gpio_reg_size;
+		bits[BIT_WORD(i)] >>= gpio_reg_size;
+	}
+}
+
+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;
+
+	raw_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);
+
+	raw_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;
+
+	raw_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);
+
+	raw_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;
+
+	raw_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);
+
+	raw_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;
+
+	raw_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:
+		raw_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);
+
+	raw_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->irq.domain, gpio + 8*port));
+		}
+
+		int_pending = inb(ws16c48gpio->base + 6) & 0x7;
+	} while (int_pending);
+
+	return IRQ_HANDLED;
+}
+
+#define WS16C48_NGPIO 48
+static const char *ws16c48_names[WS16C48_NGPIO] = {
+	"Port 0 Bit 0", "Port 0 Bit 1", "Port 0 Bit 2", "Port 0 Bit 3",
+	"Port 0 Bit 4", "Port 0 Bit 5", "Port 0 Bit 6", "Port 0 Bit 7",
+	"Port 1 Bit 0", "Port 1 Bit 1", "Port 1 Bit 2", "Port 1 Bit 3",
+	"Port 1 Bit 4", "Port 1 Bit 5", "Port 1 Bit 6", "Port 1 Bit 7",
+	"Port 2 Bit 0", "Port 2 Bit 1", "Port 2 Bit 2", "Port 2 Bit 3",
+	"Port 2 Bit 4", "Port 2 Bit 5", "Port 2 Bit 6", "Port 2 Bit 7",
+	"Port 3 Bit 0", "Port 3 Bit 1", "Port 3 Bit 2", "Port 3 Bit 3",
+	"Port 3 Bit 4", "Port 3 Bit 5", "Port 3 Bit 6", "Port 3 Bit 7",
+	"Port 4 Bit 0", "Port 4 Bit 1", "Port 4 Bit 2", "Port 4 Bit 3",
+	"Port 4 Bit 4", "Port 4 Bit 5", "Port 4 Bit 6", "Port 4 Bit 7",
+	"Port 5 Bit 0", "Port 5 Bit 1", "Port 5 Bit 2", "Port 5 Bit 3",
+	"Port 5 Bit 4", "Port 5 Bit 5", "Port 5 Bit 6", "Port 5 Bit 7"
+};
+
+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 = WS16C48_NGPIO;
+	ws16c48gpio->chip.names = ws16c48_names;
+	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.get_multiple = ws16c48_gpio_get_multiple;
+	ws16c48gpio->chip.set = ws16c48_gpio_set;
+	ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
+	ws16c48gpio->base = base[id];
+
+	raw_spin_lock_init(&ws16c48gpio->lock);
+
+	err = devm_gpiochip_add_data(dev, &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);
+		return err;
+	}
+
+	err = devm_request_irq(dev, irq[id], ws16c48_irq_handler, IRQF_SHARED,
+		name, ws16c48gpio);
+	if (err) {
+		dev_err(dev, "IRQ handler registering failed (%d)\n", err);
+		return err;
+	}
+
+	return 0;
+}
+
+static struct isa_driver ws16c48_driver = {
+	.probe = ws16c48_probe,
+	.driver = {
+		.name = "ws16c48"
+	},
+};
+
+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");