linux/drivers/gpio/gpio-104-idio-16.c
Julia Cartwright 3906e8089a gpio: 104-idio-16: make use of raw_spinlock variants
The 104-idio-16 gpio driver currently implements an irq_chip for handling
interrupts; due to how irq_chip handling is done, it's necessary for the
irq_chip methods to be invoked from hardirq context, even on a a
real-time kernel.  Because the spinlock_t type becomes a "sleeping"
spinlock w/ RT kernels, it is not suitable to be used with irq_chips.

A quick audit of the operations under the lock reveal that they do only
minimal, bounded work, and are therefore safe to do under a raw spinlock.

Signed-off-by: Julia Cartwright <julia@ni.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2017-03-28 11:12:36 +02:00

293 lines
7.8 KiB
C

/*
* GPIO driver for the ACCES 104-IDIO-16 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.
*
* This driver supports the following ACCES devices: 104-IDIO-16,
* 104-IDIO-16E, 104-IDO-16, 104-IDIO-8, 104-IDIO-8E, and 104-IDO-8.
*/
#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/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#define IDIO_16_EXTENT 8
#define MAX_NUM_IDIO_16 max_num_isa_dev(IDIO_16_EXTENT)
static unsigned int base[MAX_NUM_IDIO_16];
static unsigned int num_idio_16;
module_param_array(base, uint, &num_idio_16, 0);
MODULE_PARM_DESC(base, "ACCES 104-IDIO-16 base addresses");
static unsigned int irq[MAX_NUM_IDIO_16];
module_param_array(irq, uint, NULL, 0);
MODULE_PARM_DESC(irq, "ACCES 104-IDIO-16 interrupt line numbers");
/**
* struct idio_16_gpio - GPIO device private data structure
* @chip: instance of the gpio_chip
* @lock: synchronization lock to prevent I/O race conditions
* @irq_mask: I/O bits affected by interrupts
* @base: base port address of the GPIO device
* @out_state: output bits state
*/
struct idio_16_gpio {
struct gpio_chip chip;
raw_spinlock_t lock;
unsigned long irq_mask;
unsigned base;
unsigned out_state;
};
static int idio_16_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
if (offset > 15)
return 1;
return 0;
}
static int idio_16_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
return 0;
}
static int idio_16_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
chip->set(chip, offset, value);
return 0;
}
static int idio_16_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned mask = BIT(offset-16);
if (offset < 16)
return -EINVAL;
if (offset < 24)
return !!(inb(idio16gpio->base + 1) & mask);
return !!(inb(idio16gpio->base + 5) & (mask>>8));
}
static void idio_16_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip);
const unsigned mask = BIT(offset);
unsigned long flags;
if (offset > 15)
return;
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
if (value)
idio16gpio->out_state |= mask;
else
idio16gpio->out_state &= ~mask;
if (offset > 7)
outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
else
outb(idio16gpio->out_state, idio16gpio->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 flags;
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
idio16gpio->out_state &= ~*mask;
idio16gpio->out_state |= *mask & *bits;
if (*mask & 0xFF)
outb(idio16gpio->out_state, idio16gpio->base);
if ((*mask >> 8) & 0xFF)
outb(idio16gpio->out_state >> 8, idio16gpio->base + 4);
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);
outb(0, idio16gpio->base + 2);
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);
inb(idio16gpio->base + 2);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
static int idio_16_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 idio_16_irqchip = {
.name = "104-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;
struct gpio_chip *const chip = &idio16gpio->chip;
int gpio;
for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio));
raw_spin_lock(&idio16gpio->lock);
outb(0, idio16gpio->base + 1);
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_probe(struct device *dev, unsigned int id)
{
struct idio_16_gpio *idio16gpio;
const char *const name = dev_name(dev);
int err;
idio16gpio = devm_kzalloc(dev, sizeof(*idio16gpio), GFP_KERNEL);
if (!idio16gpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], IDIO_16_EXTENT, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + IDIO_16_EXTENT);
return -EBUSY;
}
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.set = idio_16_gpio_set;
idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
idio16gpio->base = base[id];
idio16gpio->out_state = 0xFFFF;
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;
}
/* Disable IRQ by default */
outb(0, base[id] + 2);
outb(0, base[id] + 1);
err = gpiochip_irqchip_add(&idio16gpio->chip, &idio_16_irqchip, 0,
handle_edge_irq, IRQ_TYPE_NONE);
if (err) {
dev_err(dev, "Could not add irqchip (%d)\n", err);
return err;
}
err = devm_request_irq(dev, irq[id], idio_16_irq_handler, 0, name,
idio16gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
return err;
}
return 0;
}
static struct isa_driver idio_16_driver = {
.probe = idio_16_probe,
.driver = {
.name = "104-idio-16"
},
};
module_isa_driver(idio_16_driver, num_idio_16);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("ACCES 104-IDIO-16 GPIO driver");
MODULE_LICENSE("GPL v2");