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linux/drivers/gpio/gpio-ws16c48.c
William Breathitt Gray cc736607c8 gpio: ws16c48: Utilize the ISA bus driver 
The WinSystems WS16C48 communicates via the ISA bus. As such, it is more
appropriate to use the ISA bus driver over the platform driver to
control the WinSystems WS16C48 GPIO driver.

This patch also adds support for multiple devices via the base and irq
module array parameters. Each element of the base array corresponds to a
discrete device; each element of the irq array corresponds to the
respective device addressed in the respective base array element.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-02 09:32:04 -07:00

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/*
* GPIO driver for the WinSystems WS16C48
* 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/isa.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/spinlock.h>
#define WS16C48_EXTENT 16
#define MAX_NUM_WS16C48 max_num_isa_dev(WS16C48_EXTENT)
static unsigned int base[MAX_NUM_WS16C48];
static unsigned int num_ws16c48;
module_param_array(base, uint, &num_ws16c48, 0);
MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");
static unsigned int irq[MAX_NUM_WS16C48];
module_param_array(irq, uint, NULL, 0);
MODULE_PARM_DESC(irq, "WinSystems WS16C48 interrupt line numbers");
/**
* struct ws16c48_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
* @lock: synchronization lock to prevent I/O race conditions
* @irq_mask: I/O bits affected by interrupts
* @flow_mask: IRQ flow type mask for the respective I/O bits
* @base: base port address of the GPIO device
* @irq: Interrupt line number
*/
struct ws16c48_gpio {
struct gpio_chip chip;
unsigned char io_state[6];
unsigned char out_state[6];
spinlock_t lock;
unsigned long irq_mask;
unsigned long flow_mask;
unsigned base;
unsigned irq;
};
static int ws16c48_gpio_get_direction(struct gpio_chip *chip, unsigned offset)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
return !!(ws16c48gpio->io_state[port] & mask);
}
static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
unsigned long flags;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->io_state[port] |= mask;
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
unsigned long flags;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->io_state[port] &= ~mask;
if (value)
ws16c48gpio->out_state[port] |= mask;
else
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
unsigned long flags;
unsigned port_state;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for input */
if (!(ws16c48gpio->io_state[port] & mask)) {
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return -EINVAL;
}
port_state = inb(ws16c48gpio->base + port);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return !!(port_state & mask);
}
static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
unsigned long flags;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for output */
if (ws16c48gpio->io_state[port] & mask) {
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return;
}
if (value)
ws16c48gpio->out_state[port] |= mask;
else
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_irq_ack(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
const unsigned port = offset / 8;
const unsigned mask = BIT(offset % 8);
unsigned long flags;
unsigned port_state;
/* only the first 3 ports support interrupts */
if (port > 2)
return;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
port_state = ws16c48gpio->irq_mask >> (8*port);
outb(0x80, ws16c48gpio->base + 7);
outb(port_state & ~mask, ws16c48gpio->base + 8 + port);
outb(port_state | mask, ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_irq_mask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
const unsigned long mask = BIT(offset);
const unsigned port = offset / 8;
unsigned long flags;
/* only the first 3 ports support interrupts */
if (port > 2)
return;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->irq_mask &= ~mask;
outb(0x80, ws16c48gpio->base + 7);
outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_irq_unmask(struct irq_data *data)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
const unsigned long mask = BIT(offset);
const unsigned port = offset / 8;
unsigned long flags;
/* only the first 3 ports support interrupts */
if (port > 2)
return;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->irq_mask |= mask;
outb(0x80, ws16c48gpio->base + 7);
outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
{
struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned long offset = irqd_to_hwirq(data);
const unsigned long mask = BIT(offset);
const unsigned port = offset / 8;
unsigned long flags;
/* only the first 3 ports support interrupts */
if (port > 2)
return -EINVAL;
spin_lock_irqsave(&ws16c48gpio->lock, flags);
switch (flow_type) {
case IRQ_TYPE_NONE:
break;
case IRQ_TYPE_EDGE_RISING:
ws16c48gpio->flow_mask |= mask;
break;
case IRQ_TYPE_EDGE_FALLING:
ws16c48gpio->flow_mask &= ~mask;
break;
default:
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return -EINVAL;
}
outb(0x40, ws16c48gpio->base + 7);
outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
static struct irq_chip ws16c48_irqchip = {
.name = "ws16c48",
.irq_ack = ws16c48_irq_ack,
.irq_mask = ws16c48_irq_mask,
.irq_unmask = ws16c48_irq_unmask,
.irq_set_type = ws16c48_irq_set_type
};
static irqreturn_t ws16c48_irq_handler(int irq, void *dev_id)
{
struct ws16c48_gpio *const ws16c48gpio = dev_id;
struct gpio_chip *const chip = &ws16c48gpio->chip;
unsigned long int_pending;
unsigned long port;
unsigned long int_id;
unsigned long gpio;
int_pending = inb(ws16c48gpio->base + 6) & 0x7;
if (!int_pending)
return IRQ_NONE;
/* loop until all pending interrupts are handled */
do {
for_each_set_bit(port, &int_pending, 3) {
int_id = inb(ws16c48gpio->base + 8 + port);
for_each_set_bit(gpio, &int_id, 8)
generic_handle_irq(irq_find_mapping(
chip->irqdomain, gpio + 8*port));
}
int_pending = inb(ws16c48gpio->base + 6) & 0x7;
} while (int_pending);
return IRQ_HANDLED;
}
static int ws16c48_probe(struct device *dev, unsigned int id)
{
struct ws16c48_gpio *ws16c48gpio;
const char *const name = dev_name(dev);
int err;
ws16c48gpio = devm_kzalloc(dev, sizeof(*ws16c48gpio), GFP_KERNEL);
if (!ws16c48gpio)
return -ENOMEM;
if (!devm_request_region(dev, base[id], WS16C48_EXTENT, name)) {
dev_err(dev, "Unable to lock port addresses (0x%X-0x%X)\n",
base[id], base[id] + WS16C48_EXTENT);
return -EBUSY;
}
ws16c48gpio->chip.label = name;
ws16c48gpio->chip.parent = dev;
ws16c48gpio->chip.owner = THIS_MODULE;
ws16c48gpio->chip.base = -1;
ws16c48gpio->chip.ngpio = 48;
ws16c48gpio->chip.get_direction = ws16c48_gpio_get_direction;
ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
ws16c48gpio->chip.get = ws16c48_gpio_get;
ws16c48gpio->chip.set = ws16c48_gpio_set;
ws16c48gpio->base = base[id];
ws16c48gpio->irq = irq[id];
spin_lock_init(&ws16c48gpio->lock);
dev_set_drvdata(dev, ws16c48gpio);
err = gpiochip_add_data(&ws16c48gpio->chip, ws16c48gpio);
if (err) {
dev_err(dev, "GPIO registering failed (%d)\n", err);
return err;
}
/* Disable IRQ by default */
outb(0x80, base[id] + 7);
outb(0, base[id] + 8);
outb(0, base[id] + 9);
outb(0, base[id] + 10);
outb(0xC0, base[id] + 7);
err = gpiochip_irqchip_add(&ws16c48gpio->chip, &ws16c48_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[id], ws16c48_irq_handler, IRQF_SHARED, name,
ws16c48gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
goto err_gpiochip_remove;
}
return 0;
err_gpiochip_remove:
gpiochip_remove(&ws16c48gpio->chip);
return err;
}
static int ws16c48_remove(struct device *dev, unsigned int id)
{
struct ws16c48_gpio *const ws16c48gpio = dev_get_drvdata(dev);
free_irq(ws16c48gpio->irq, ws16c48gpio);
gpiochip_remove(&ws16c48gpio->chip);
return 0;
}
static struct isa_driver ws16c48_driver = {
.probe = ws16c48_probe,
.driver = {
.name = "ws16c48"
},
.remove = ws16c48_remove
};
module_isa_driver(ws16c48_driver, num_ws16c48);
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
MODULE_DESCRIPTION("WinSystems WS16C48 GPIO driver");
MODULE_LICENSE("GPL v2");
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