--- /dev/null
+/*
+ * 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
+ * @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;
+ 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 struct idi_48_gpio *to_idi48gpio(struct gpio_chip *gc)
+{
+ return container_of(gc, struct idi_48_gpio, chip);
+}
+
+static int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct idi_48_gpio *const idi48gpio = to_idi48gpio(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)
+{
+ struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+ struct idi_48_gpio *const idi48gpio = to_idi48gpio(chip);
+ unsigned long flags;
+
+ spin_lock_irqsave(&idi48gpio->lock, flags);
+
+ inb(idi48gpio->base + 7);
+
+ spin_unlock_irqrestore(&idi48gpio->lock, flags);
+}
+
+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 = to_idi48gpio(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 = to_idi48gpio(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->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))
+ 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));
+ }
+ }
+
+ 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(&idi48gpio->chip);
+ 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");
projects / karo-tx-linux.git / commitdiff