Linux-libre 4.5-gnu

1 files changed, 343 insertions, 0 deletions

diff --git a/drivers/gpio/gpio-104-idi-48.c b/drivers/gpio/gpio-104-idi-48.c
new file mode 100644
index 000000000..52eed328c
--- /dev/null
+++ b/drivers/gpio/gpio-104-idi-48.c
@@ -0,0 +1,343 @@
+/*
+ * 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
+ * @ack_lock:	synchronization lock to prevent IRQ handler 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;
+	spinlock_t ack_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 int idi_48_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct idi_48_gpio *const idi48gpio = gpiochip_get_data(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)
+{
+}
+
+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 = gpiochip_get_data(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 = gpiochip_get_data(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->ack_lock);
+
+	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)) {
+		spin_unlock(&idi48gpio->ack_lock);
+		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));
+		}
+	}
+
+	spin_unlock(&idi48gpio->ack_lock);
+
+	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_data(&idi48gpio->chip, idi48gpio);
+	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");