gpio: Add GPIO support for the ACCES 104-DIO-48E
The ACCES 104-DIO-48E device provides 48 lines digital I/O via two
Programmable Peripheral Interface (PPI) chips of type 82C55. Bit C3 at
each 24-bit Group can be used as an external interrupt, triggered by a
rising edge.
This driver provides GPIO and IRQ support for these 48 channels of
digital I/O. The base port address for the device may be configured via
the dio_48e_base module parameter. The interrupt line number for the
device may be configured via the dio_48e_irq module parameter.
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
new file mode 100644
index 0000000..279de39
--- /dev/null
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -0,0 +1,439 @@
+/*
+ * GPIO driver for the ACCES 104-DIO-48E
+ * 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/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+static unsigned dio_48e_base;
+module_param(dio_48e_base, uint, 0);
+MODULE_PARM_DESC(dio_48e_base, "ACCES 104-DIO-48E base address");
+static unsigned dio_48e_irq;
+module_param(dio_48e_irq, uint, 0);
+MODULE_PARM_DESC(dio_48e_irq, "ACCES 104-DIO-48E interrupt line number");
+
+/**
+ * struct dio48e_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
+ * @extent: extent of port address region of the GPIO device
+ * @irq: Interrupt line number
+ * @irq_mask: I/O bits affected by interrupts
+ */
+struct dio48e_gpio {
+ struct gpio_chip chip;
+ unsigned char io_state[6];
+ unsigned char out_state[6];
+ unsigned char control[2];
+ spinlock_t lock;
+ unsigned base;
+ unsigned extent;
+ unsigned irq;
+ unsigned char irq_mask;
+};
+
+static int dio48e_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned port = offset / 8;
+ const unsigned mask = BIT(offset % 8);
+
+ return !!(dio48egpio->io_state[port] & mask);
+}
+
+static int dio48e_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned io_port = offset / 8;
+ const unsigned control_port = io_port / 2;
+ const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
+ unsigned long flags;
+ unsigned control;
+
+ spin_lock_irqsave(&dio48egpio->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) {
+ dio48egpio->io_state[io_port] |= 0xF0;
+ dio48egpio->control[control_port] |= BIT(3);
+ } else {
+ dio48egpio->io_state[io_port] |= 0x0F;
+ dio48egpio->control[control_port] |= BIT(0);
+ }
+ } else {
+ dio48egpio->io_state[io_port] |= 0xFF;
+ if (io_port == 0 || io_port == 3)
+ dio48egpio->control[control_port] |= BIT(4);
+ else
+ dio48egpio->control[control_port] |= BIT(1);
+ }
+
+ control = BIT(7) | dio48egpio->control[control_port];
+ outb(control, control_addr);
+ control &= ~BIT(7);
+ outb(control, control_addr);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+
+ return 0;
+}
+
+static int dio48e_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
+ int value)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned io_port = offset / 8;
+ const unsigned control_port = io_port / 2;
+ const unsigned mask = BIT(offset % 8);
+ const unsigned control_addr = dio48egpio->base + 3 + control_port*4;
+ const unsigned out_port = (io_port > 2) ? io_port + 1 : io_port;
+ unsigned long flags;
+ unsigned control;
+
+ spin_lock_irqsave(&dio48egpio->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) {
+ dio48egpio->io_state[io_port] &= 0x0F;
+ dio48egpio->control[control_port] &= ~BIT(3);
+ } else {
+ dio48egpio->io_state[io_port] &= 0xF0;
+ dio48egpio->control[control_port] &= ~BIT(0);
+ }
+ } else {
+ dio48egpio->io_state[io_port] &= 0x00;
+ if (io_port == 0 || io_port == 3)
+ dio48egpio->control[control_port] &= ~BIT(4);
+ else
+ dio48egpio->control[control_port] &= ~BIT(1);
+ }
+
+ if (value)
+ dio48egpio->out_state[io_port] |= mask;
+ else
+ dio48egpio->out_state[io_port] &= ~mask;
+
+ control = BIT(7) | dio48egpio->control[control_port];
+ outb(control, control_addr);
+
+ outb(dio48egpio->out_state[io_port], dio48egpio->base + out_port);
+
+ control &= ~BIT(7);
+ outb(control, control_addr);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+
+ return 0;
+}
+
+static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned port = offset / 8;
+ const unsigned mask = BIT(offset % 8);
+ const unsigned in_port = (port > 2) ? port + 1 : port;
+ unsigned long flags;
+ unsigned port_state;
+
+ spin_lock_irqsave(&dio48egpio->lock, flags);
+
+ /* ensure that GPIO is set for input */
+ if (!(dio48egpio->io_state[port] & mask)) {
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+ return -EINVAL;
+ }
+
+ port_state = inb(dio48egpio->base + in_port);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+
+ return !!(port_state & mask);
+}
+
+static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned port = offset / 8;
+ const unsigned mask = BIT(offset % 8);
+ const unsigned out_port = (port > 2) ? port + 1 : port;
+ unsigned long flags;
+
+ spin_lock_irqsave(&dio48egpio->lock, flags);
+
+ if (value)
+ dio48egpio->out_state[port] |= mask;
+ else
+ dio48egpio->out_state[port] &= ~mask;
+
+ outb(dio48egpio->out_state[port], dio48egpio->base + out_port);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+}
+
+static void dio48e_irq_ack(struct irq_data *data)
+{
+}
+
+static void dio48e_irq_mask(struct irq_data *data)
+{
+ struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned long offset = irqd_to_hwirq(data);
+ unsigned long flags;
+
+ /* only bit 3 on each respective Port C supports interrupts */
+ if (offset != 19 && offset != 43)
+ return;
+
+ spin_lock_irqsave(&dio48egpio->lock, flags);
+
+ if (offset == 19)
+ dio48egpio->irq_mask &= ~BIT(0);
+ else
+ dio48egpio->irq_mask &= ~BIT(1);
+
+ if (!dio48egpio->irq_mask)
+ /* disable interrupts */
+ inb(dio48egpio->base + 0xB);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+}
+
+static void dio48e_irq_unmask(struct irq_data *data)
+{
+ struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
+ struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
+ const unsigned long offset = irqd_to_hwirq(data);
+ unsigned long flags;
+
+ /* only bit 3 on each respective Port C supports interrupts */
+ if (offset != 19 && offset != 43)
+ return;
+
+ spin_lock_irqsave(&dio48egpio->lock, flags);
+
+ if (!dio48egpio->irq_mask) {
+ /* enable interrupts */
+ outb(0x00, dio48egpio->base + 0xF);
+ outb(0x00, dio48egpio->base + 0xB);
+ }
+
+ if (offset == 19)
+ dio48egpio->irq_mask |= BIT(0);
+ else
+ dio48egpio->irq_mask |= BIT(1);
+
+ spin_unlock_irqrestore(&dio48egpio->lock, flags);
+}
+
+static int dio48e_irq_set_type(struct irq_data *data, unsigned flow_type)
+{
+ const unsigned long offset = irqd_to_hwirq(data);
+
+ /* only bit 3 on each respective Port C supports interrupts */
+ if (offset != 19 && offset != 43)
+ return -EINVAL;
+
+ if (flow_type != IRQ_TYPE_NONE && flow_type != IRQ_TYPE_EDGE_RISING)
+ return -EINVAL;
+
+ return 0;
+}
+
+static struct irq_chip dio48e_irqchip = {
+ .name = "104-dio-48e",
+ .irq_ack = dio48e_irq_ack,
+ .irq_mask = dio48e_irq_mask,
+ .irq_unmask = dio48e_irq_unmask,
+ .irq_set_type = dio48e_irq_set_type
+};
+
+static irqreturn_t dio48e_irq_handler(int irq, void *dev_id)
+{
+ struct dio48e_gpio *const dio48egpio = dev_id;
+ struct gpio_chip *const chip = &dio48egpio->chip;
+ const unsigned long irq_mask = dio48egpio->irq_mask;
+ unsigned long gpio;
+
+ for_each_set_bit(gpio, &irq_mask, 2)
+ generic_handle_irq(irq_find_mapping(chip->irqdomain,
+ 19 + gpio*24));
+
+ spin_lock(&dio48egpio->lock);
+
+ outb(0x00, dio48egpio->base + 0xF);
+
+ spin_unlock(&dio48egpio->lock);
+
+ return IRQ_HANDLED;
+}
+
+static int __init dio48e_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct dio48e_gpio *dio48egpio;
+ const unsigned base = dio_48e_base;
+ const unsigned extent = 16;
+ const char *const name = dev_name(dev);
+ int err;
+ const unsigned irq = dio_48e_irq;
+
+ dio48egpio = devm_kzalloc(dev, sizeof(*dio48egpio), GFP_KERNEL);
+ if (!dio48egpio)
+ 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;
+ }
+
+ dio48egpio->chip.label = name;
+ dio48egpio->chip.parent = dev;
+ dio48egpio->chip.owner = THIS_MODULE;
+ dio48egpio->chip.base = -1;
+ dio48egpio->chip.ngpio = 48;
+ dio48egpio->chip.get_direction = dio48e_gpio_get_direction;
+ dio48egpio->chip.direction_input = dio48e_gpio_direction_input;
+ dio48egpio->chip.direction_output = dio48e_gpio_direction_output;
+ dio48egpio->chip.get = dio48e_gpio_get;
+ dio48egpio->chip.set = dio48e_gpio_set;
+ dio48egpio->base = base;
+ dio48egpio->extent = extent;
+ dio48egpio->irq = irq;
+
+ spin_lock_init(&dio48egpio->lock);
+
+ dev_set_drvdata(dev, dio48egpio);
+
+ err = gpiochip_add_data(&dio48egpio->chip, dio48egpio);
+ if (err) {
+ dev_err(dev, "GPIO registering failed (%d)\n", err);
+ goto err_gpio_register;
+ }
+
+ /* initialize all GPIO as output */
+ outb(0x80, base + 3);
+ outb(0x00, base);
+ outb(0x00, base + 1);
+ outb(0x00, base + 2);
+ outb(0x00, base + 3);
+ outb(0x80, base + 7);
+ outb(0x00, base + 4);
+ outb(0x00, base + 5);
+ outb(0x00, base + 6);
+ outb(0x00, base + 7);
+
+ /* disable IRQ by default */
+ inb(base + 0xB);
+
+ err = gpiochip_irqchip_add(&dio48egpio->chip, &dio48e_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, dio48e_irq_handler, 0, name, dio48egpio);
+ 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(&dio48egpio->chip);
+err_gpio_register:
+ release_region(base, extent);
+err_lock_io_port:
+ return err;
+}
+
+static int dio48e_remove(struct platform_device *pdev)
+{
+ struct dio48e_gpio *const dio48egpio = platform_get_drvdata(pdev);
+
+ free_irq(dio48egpio->irq, dio48egpio);
+ gpiochip_remove(&dio48egpio->chip);
+ release_region(dio48egpio->base, dio48egpio->extent);
+
+ return 0;
+}
+
+static struct platform_device *dio48e_device;
+
+static struct platform_driver dio48e_driver = {
+ .driver = {
+ .name = "104-dio-48e"
+ },
+ .remove = dio48e_remove
+};
+
+static void __exit dio48e_exit(void)
+{
+ platform_device_unregister(dio48e_device);
+ platform_driver_unregister(&dio48e_driver);
+}
+
+static int __init dio48e_init(void)
+{
+ int err;
+
+ dio48e_device = platform_device_alloc(dio48e_driver.driver.name, -1);
+ if (!dio48e_device)
+ return -ENOMEM;
+
+ err = platform_device_add(dio48e_device);
+ if (err)
+ goto err_platform_device;
+
+ err = platform_driver_probe(&dio48e_driver, dio48e_probe);
+ if (err)
+ goto err_platform_driver;
+
+ return 0;
+
+err_platform_driver:
+ platform_device_del(dio48e_device);
+err_platform_device:
+ platform_device_put(dio48e_device);
+ return err;
+}
+
+module_init(dio48e_init);
+module_exit(dio48e_exit);
+
+MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
+MODULE_DESCRIPTION("ACCES 104-DIO-48E GPIO driver");
+MODULE_LICENSE("GPL");