--- /dev/null
+/*
+ * GPIO driver for the Diamond Systems GPIO-MM
+ * 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.
+ *
+ * This driver supports the following Diamond Systems devices: GPIO-MM and
+ * GPIO-MM-12.
+ */
+#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/isa.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/spinlock.h>
+
+#define GPIOMM_EXTENT 8
+#define MAX_NUM_GPIOMM max_num_isa_dev(GPIOMM_EXTENT)
+
+static unsigned int base[MAX_NUM_GPIOMM];
+static unsigned int num_gpiomm;
+module_param_array(base, uint, &num_gpiomm, 0);
+MODULE_PARM_DESC(base, "Diamond Systems GPIO-MM base addresses");
+
+/**
+ * struct gpiomm_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
+ * @control: Control registers state
+ * @lock: synchronization lock to prevent I/O race conditions
+ * @base: base port address of the GPIO device
+ */
+struct gpiomm_gpio {
+ struct gpio_chip chip;
+ unsigned char io_state[6];
+ unsigned char out_state[6];
+ unsigned char control[2];
+ spinlock_t lock;
+ unsigned int base;
+};
+
+static int gpiomm_gpio_get_direction(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ const unsigned int port = offset / 8;
+ const unsigned int mask = BIT(offset % 8);
+
+ return !!(gpiommgpio->io_state[port] & mask);
+}
+
+static int gpiomm_gpio_direction_input(struct gpio_chip *chip,
+ unsigned int offset)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ const unsigned int io_port = offset / 8;
+ const unsigned int control_port = io_port / 3;
+ const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
+ unsigned long flags;
+ unsigned int control;
+
+ spin_lock_irqsave(&gpiommgpio->lock, flags);
+
+ /* Check if configuring Port C */
+ if (io_port == 2 || io_port == 5) {
+ /* Port C can be configured by nibble */
+ if (offset % 8 > 3) {
+ gpiommgpio->io_state[io_port] |= 0xF0;
+ gpiommgpio->control[control_port] |= BIT(3);
+ } else {
+ gpiommgpio->io_state[io_port] |= 0x0F;
+ gpiommgpio->control[control_port] |= BIT(0);
+ }
+ } else {
+ gpiommgpio->io_state[io_port] |= 0xFF;
+ if (io_port == 0 || io_port == 3)
+ gpiommgpio->control[control_port] |= BIT(4);
+ else
+ gpiommgpio->control[control_port] |= BIT(1);
+ }
+
+ control = BIT(7) | gpiommgpio->control[control_port];
+ outb(control, control_addr);
+
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+
+ return 0;
+}
+
+static int gpiomm_gpio_direction_output(struct gpio_chip *chip,
+ unsigned int offset, int value)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ const unsigned int io_port = offset / 8;
+ const unsigned int control_port = io_port / 3;
+ const unsigned int mask = BIT(offset % 8);
+ const unsigned int control_addr = gpiommgpio->base + 3 + control_port*4;
+ const unsigned int out_port = (io_port > 2) ? io_port + 1 : io_port;
+ unsigned long flags;
+ unsigned int control;
+
+ spin_lock_irqsave(&gpiommgpio->lock, flags);
+
+ /* Check if configuring Port C */
+ if (io_port == 2 || io_port == 5) {
+ /* Port C can be configured by nibble */
+ if (offset % 8 > 3) {
+ gpiommgpio->io_state[io_port] &= 0x0F;
+ gpiommgpio->control[control_port] &= ~BIT(3);
+ } else {
+ gpiommgpio->io_state[io_port] &= 0xF0;
+ gpiommgpio->control[control_port] &= ~BIT(0);
+ }
+ } else {
+ gpiommgpio->io_state[io_port] &= 0x00;
+ if (io_port == 0 || io_port == 3)
+ gpiommgpio->control[control_port] &= ~BIT(4);
+ else
+ gpiommgpio->control[control_port] &= ~BIT(1);
+ }
+
+ if (value)
+ gpiommgpio->out_state[io_port] |= mask;
+ else
+ gpiommgpio->out_state[io_port] &= ~mask;
+
+ control = BIT(7) | gpiommgpio->control[control_port];
+ outb(control, control_addr);
+
+ outb(gpiommgpio->out_state[io_port], gpiommgpio->base + out_port);
+
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+
+ return 0;
+}
+
+static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ const unsigned int port = offset / 8;
+ const unsigned int mask = BIT(offset % 8);
+ const unsigned int in_port = (port > 2) ? port + 1 : port;
+ unsigned long flags;
+ unsigned int port_state;
+
+ spin_lock_irqsave(&gpiommgpio->lock, flags);
+
+ /* ensure that GPIO is set for input */
+ if (!(gpiommgpio->io_state[port] & mask)) {
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+ return -EINVAL;
+ }
+
+ port_state = inb(gpiommgpio->base + in_port);
+
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+
+ return !!(port_state & mask);
+}
+
+static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset,
+ int value)
+{
+ struct gpiomm_gpio *const gpiommgpio = gpiochip_get_data(chip);
+ const unsigned int port = offset / 8;
+ const unsigned int mask = BIT(offset % 8);
+ const unsigned int out_port = (port > 2) ? port + 1 : port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&gpiommgpio->lock, flags);
+
+ if (value)
+ gpiommgpio->out_state[port] |= mask;
+ else
+ gpiommgpio->out_state[port] &= ~mask;
+
+ outb(gpiommgpio->out_state[port], gpiommgpio->base + out_port);
+
+ spin_unlock_irqrestore(&gpiommgpio->lock, flags);
+}
+
+static int gpiomm_probe(struct device *dev, unsigned int id)
+{
+ struct gpiomm_gpio *gpiommgpio;
+ const char *const name = dev_name(dev);
+ int err;
+
+ gpiommgpio = devm_kzalloc(dev, sizeof(*gpiommgpio), GFP_KERNEL);
+ if (!gpiommgpio)
+ return -ENOMEM;
+
+ if (!devm_request_region(dev, base[id], GPIOMM_EXTENT, name)) {
+ dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
+ base[id], base[id] + GPIOMM_EXTENT);
+ return -EBUSY;
+ }
+
+ gpiommgpio->chip.label = name;
+ gpiommgpio->chip.parent = dev;
+ gpiommgpio->chip.owner = THIS_MODULE;
+ gpiommgpio->chip.base = -1;
+ gpiommgpio->chip.ngpio = 48;
+ gpiommgpio->chip.get_direction = gpiomm_gpio_get_direction;
+ gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input;
+ gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output;
+ gpiommgpio->chip.get = gpiomm_gpio_get;
+ gpiommgpio->chip.set = gpiomm_gpio_set;
+ gpiommgpio->base = base[id];
+
+ spin_lock_init(&gpiommgpio->lock);
+
+ dev_set_drvdata(dev, gpiommgpio);
+
+ err = gpiochip_add_data(&gpiommgpio->chip, gpiommgpio);
+ if (err) {
+ dev_err(dev, "GPIO registering failed (%d)\n", err);
+ return err;
+ }
+
+ /* initialize all GPIO as output */
+ outb(0x80, base[id] + 3);
+ outb(0x00, base[id]);
+ outb(0x00, base[id] + 1);
+ outb(0x00, base[id] + 2);
+ outb(0x80, base[id] + 7);
+ outb(0x00, base[id] + 4);
+ outb(0x00, base[id] + 5);
+ outb(0x00, base[id] + 6);
+
+ return 0;
+}
+
+static int gpiomm_remove(struct device *dev, unsigned int id)
+{
+ struct gpiomm_gpio *const gpiommgpio = dev_get_drvdata(dev);
+
+ gpiochip_remove(&gpiommgpio->chip);
+
+ return 0;
+}
+
+static struct isa_driver gpiomm_driver = {
+ .probe = gpiomm_probe,
+ .driver = {
+ .name = "gpio-mm"
+ },
+ .remove = gpiomm_remove
+};
+
+module_isa_driver(gpiomm_driver, num_gpiomm);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("Diamond Systems GPIO-MM GPIO driver");
+MODULE_LICENSE("GPL v2");
projects / linux.git / commitdiff