https://github.com/torvalds/linux
Tip revision: 2dcd0af568b0cf583645c8a317dd12e344b1c72a authored by Linus Torvalds on 15 May 2016, 22:43:13 UTC
Linux 4.6
Linux 4.6
Tip revision: 2dcd0af
gpio-104-idi-48.c
/*
* 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
* @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 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 (!devm_request_region(dev, base, extent, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base, base + extent);
return -EBUSY;
}
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->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);
return err;
}
/* 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_remove;
}
err = request_irq(irq, idi_48_irq_handler, IRQF_SHARED, name,
idi48gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
goto err_gpiochip_remove;
}
return 0;
err_gpiochip_remove:
gpiochip_remove(&idi48gpio->chip);
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);
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 v2");