gpio-pci-idio-16.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* GPIO driver for the ACCES PCI-IDIO-16
* Copyright (C) 2017 William Breathitt Gray
*/
#include <linux/bitmap.h>
#include <linux/bitops.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/irqdesc.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/spinlock.h>
#include <linux/types.h>
/**
* struct idio_16_gpio_reg - GPIO device registers structure
* @out0_7: Read: FET Drive Outputs 0-7
* Write: FET Drive Outputs 0-7
* @in0_7: Read: Isolated Inputs 0-7
* Write: Clear Interrupt
* @irq_ctl: Read: Enable IRQ
* Write: Disable IRQ
* @filter_ctl: Read: Activate Input Filters 0-15
* Write: Deactivate Input Filters 0-15
* @out8_15: Read: FET Drive Outputs 8-15
* Write: FET Drive Outputs 8-15
* @in8_15: Read: Isolated Inputs 8-15
* Write: Unused
* @irq_status: Read: Interrupt status
* Write: Unused
*/
struct idio_16_gpio_reg {
u8 out0_7;
u8 in0_7;
u8 irq_ctl;
u8 filter_ctl;
u8 out8_15;
u8 in8_15;
u8 irq_status;
};
/**
* struct idio_16_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent I/O race conditions
* @reg: I/O address offset for the GPIO device registers
* @irq_mask: I/O bits affected by interrupts
*/
struct idio_16_gpio {
struct gpio_chip chip;
raw_spinlock_t lock;
struct idio_16_gpio_reg __iomem *reg;
unsigned long irq_mask;
};
static int idio_16_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
if (offset > 15)
return GPIO_LINE_DIRECTION_IN;
return GPIO_LINE_DIRECTION_OUT;
}
static int idio_16_gpio_direction_input(struct gpio_chip *chip,
unsigned int offset)
{
return 0;
}
static int idio_16_gpio_direction_output(struct gpio_chip *chip,
unsigned int offset, int value)
{
chip->set(chip, offset, value);
return 0;
}
static int idio_16_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
unsigned long mask = BIT(offset);
if (offset < 8)
return !!(ioread8(&idio16gpio->reg->out0_7) & mask);
if (offset < 16)
return !!(ioread8(&idio16gpio->reg->out8_15) & (mask >> 8));
if (offset < 24)
return !!(ioread8(&idio16gpio->reg->in0_7) & (mask >> 16));
return !!(ioread8(&idio16gpio->reg->in8_15) & (mask >> 24));
}
static int idio_16_gpio_get_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
unsigned long offset;
unsigned long gpio_mask;
void __iomem *ports[] = {
&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
&idio16gpio->reg->in0_7, &idio16gpio->reg->in8_15,
};
void __iomem *port_addr;
unsigned long port_state;
/* clear bits array to a clean slate */
bitmap_zero(bits, chip->ngpio);
for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
port_addr = ports[offset / 8];
port_state = ioread8(port_addr) & gpio_mask;
bitmap_set_value8(bits, port_state, offset);
}
return 0;
}
static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
int value)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
unsigned int mask = BIT(offset);
void __iomem *base;
unsigned long flags;
unsigned int out_state;
if (offset > 15)
return;
if (offset > 7) {
mask >>= 8;
base = &idio16gpio->reg->out8_15;
} else
base = &idio16gpio->reg->out0_7;
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
if (value)
out_state = ioread8(base) | mask;
else
out_state = ioread8(base) & ~mask;
iowrite8(out_state, base);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
unsigned long offset;
unsigned long gpio_mask;
void __iomem *ports[] = {
&idio16gpio->reg->out0_7, &idio16gpio->reg->out8_15,
};
size_t index;
void __iomem *port_addr;
unsigned long bitmask;
unsigned long flags;
unsigned long out_state;
for_each_set_clump8(offset, gpio_mask, mask, ARRAY_SIZE(ports) * 8) {
index = offset / 8;
port_addr = ports[index];
bitmask = bitmap_get_value8(bits, offset) & gpio_mask;
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
out_state = ioread8(port_addr) & ~gpio_mask;
out_state |= bitmask;
iowrite8(out_state, port_addr);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static void idio_16_irq_ack(struct irq_data *data)
{
}
static void idio_16_irq_mask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned long mask = BIT(irqd_to_hwirq(data));
unsigned long flags;
idio16gpio->irq_mask &= ~mask;
if (!idio16gpio->irq_mask) {
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
iowrite8(0, &idio16gpio->reg->irq_ctl);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static void idio_16_irq_unmask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned long mask = BIT(irqd_to_hwirq(data));
const unsigned long prev_irq_mask = idio16gpio->irq_mask;
unsigned long flags;
idio16gpio->irq_mask |= mask;
if (!prev_irq_mask) {
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
ioread8(&idio16gpio->reg->irq_ctl);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static int idio_16_irq_set_type(struct irq_data *data, unsigned int 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 idio_16_irqchip = {
.name = "pci-idio-16",
.irq_ack = idio_16_irq_ack,
.irq_mask = idio_16_irq_mask,
.irq_unmask = idio_16_irq_unmask,
.irq_set_type = idio_16_irq_set_type
};
static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
{
struct idio_16_gpio *const idio16gpio = dev_id;
unsigned int irq_status;
struct gpio_chip *const chip = &idio16gpio->chip;
int gpio;
raw_spin_lock(&idio16gpio->lock);
irq_status = ioread8(&idio16gpio->reg->irq_status);
raw_spin_unlock(&idio16gpio->lock);
/* Make sure our device generated IRQ */
if (!(irq_status & 0x3) || !(irq_status & 0x4))
return IRQ_NONE;
for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
generic_handle_domain_irq(chip->irq.domain, gpio);
raw_spin_lock(&idio16gpio->lock);
/* Clear interrupt */
iowrite8(0, &idio16gpio->reg->in0_7);
raw_spin_unlock(&idio16gpio->lock);
return IRQ_HANDLED;
}
#define IDIO_16_NGPIO 32
static const char *idio_16_names[IDIO_16_NGPIO] = {
"OUT0", "OUT1", "OUT2", "OUT3", "OUT4", "OUT5", "OUT6", "OUT7",
"OUT8", "OUT9", "OUT10", "OUT11", "OUT12", "OUT13", "OUT14", "OUT15",
"IIN0", "IIN1", "IIN2", "IIN3", "IIN4", "IIN5", "IIN6", "IIN7",
"IIN8", "IIN9", "IIN10", "IIN11", "IIN12", "IIN13", "IIN14", "IIN15"
};
static int idio_16_irq_init_hw(struct gpio_chip *gc)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(gc);
/* Disable IRQ by default and clear any pending interrupt */
iowrite8(0, &idio16gpio->reg->irq_ctl);
iowrite8(0, &idio16gpio->reg->in0_7);
return 0;
}
static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct device *const dev = &pdev->dev;
struct idio_16_gpio *idio16gpio;
int err;
const size_t pci_bar_index = 2;
const char *const name = pci_name(pdev);
struct gpio_irq_chip *girq;
idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
if (!idio16gpio)
return -ENOMEM;
err = pcim_enable_device(pdev);
if (err) {
dev_err(dev, "Failed to enable PCI device (%d)\n", err);
return err;
}
err = pcim_iomap_regions(pdev, BIT(pci_bar_index), name);
if (err) {
dev_err(dev, "Unable to map PCI I/O addresses (%d)\n", err);
return err;
}
idio16gpio->reg = pcim_iomap_table(pdev)[pci_bar_index];
/* Deactivate input filters */
iowrite8(0, &idio16gpio->reg->filter_ctl);
idio16gpio->chip.label = name;
idio16gpio->chip.parent = dev;
idio16gpio->chip.owner = THIS_MODULE;
idio16gpio->chip.base = -1;
idio16gpio->chip.ngpio = IDIO_16_NGPIO;
idio16gpio->chip.names = idio_16_names;
idio16gpio->chip.get_direction = idio_16_gpio_get_direction;
idio16gpio->chip.direction_input = idio_16_gpio_direction_input;
idio16gpio->chip.direction_output = idio_16_gpio_direction_output;
idio16gpio->chip.get = idio_16_gpio_get;
idio16gpio->chip.get_multiple = idio_16_gpio_get_multiple;
idio16gpio->chip.set = idio_16_gpio_set;
idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
girq = &idio16gpio->chip.irq;
girq->chip = &idio_16_irqchip;
/* This will let us handle the parent IRQ in the driver */
girq->parent_handler = NULL;
girq->num_parents = 0;
girq->parents = NULL;
girq->default_type = IRQ_TYPE_NONE;
girq->handler = handle_edge_irq;
girq->init_hw = idio_16_irq_init_hw;
raw_spin_lock_init(&idio16gpio->lock);
err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
err = devm_request_irq(dev, pdev->irq, idio_16_irq_handler, IRQF_SHARED,
name, idio16gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
return err;
}
return 0;
}
static const struct pci_device_id idio_16_pci_dev_id[] = {
{ PCI_DEVICE(0x494F, 0x0DC8) }, { 0 }
};
MODULE_DEVICE_TABLE(pci, idio_16_pci_dev_id);
static struct pci_driver idio_16_driver = {
.name = "pci-idio-16",
.id_table = idio_16_pci_dev_id,
.probe = idio_16_probe
};
module_pci_driver(idio_16_driver);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES PCI-IDIO-16 GPIO driver");
MODULE_LICENSE("GPL v2");