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linux/drivers/gpio/gpio-ws16c48.c
William Breathitt Gray 7a702691d0 gpio: ws16c48: Mask read inputs for get_multiple 
This patch masks the read inputs with the word mask in order to ensure
only requested input states are returned in the bits array.

Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-11-05 08:54:42 +01:00

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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/bitmap.h>
#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_hw_array(base, uint, ioport, &num_ws16c48, 0);
MODULE_PARM_DESC(base, "WinSystems WS16C48 base addresses");
static unsigned int irq[MAX_NUM_WS16C48];
module_param_hw_array(irq, uint, irq, 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
*/
struct ws16c48_gpio {
struct gpio_chip chip;
unsigned char io_state[6];
unsigned char out_state[6];
raw_spinlock_t lock;
unsigned long irq_mask;
unsigned long flow_mask;
unsigned base;
};
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;
raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->io_state[port] |= mask;
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
raw_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;
raw_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);
raw_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;
raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for input */
if (!(ws16c48gpio->io_state[port] & mask)) {
raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return -EINVAL;
}
port_state = inb(ws16c48gpio->base + port);
raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return !!(port_state & mask);
}
static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
const unsigned int gpio_reg_size = 8;
size_t i;
const size_t num_ports = chip->ngpio / gpio_reg_size;
unsigned int bits_offset;
size_t word_index;
unsigned int word_offset;
unsigned long word_mask;
const unsigned long port_mask = GENMASK(gpio_reg_size - 1, 0);
unsigned long port_state;
/* clear bits array to a clean slate */
bitmap_zero(bits, chip->ngpio);
/* get bits are evaluated a gpio port register at a time */
for (i = 0; i < num_ports; i++) {
/* gpio offset in bits array */
bits_offset = i * gpio_reg_size;
/* word index for bits array */
word_index = BIT_WORD(bits_offset);
/* gpio offset within current word of bits array */
word_offset = bits_offset % BITS_PER_LONG;
/* mask of get bits for current gpio within current word */
word_mask = mask[word_index] & (port_mask << word_offset);
if (!word_mask) {
/* no get bits in this port so skip to next one */
continue;
}
/* read bits from current gpio port */
port_state = inb(ws16c48gpio->base + i);
/* store acquired bits at respective bits array offset */
bits[word_index] |= (port_state << word_offset) & word_mask;
}
return 0;
}
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;
raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for output */
if (ws16c48gpio->io_state[port] & mask) {
raw_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);
raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
unsigned int i;
const unsigned int gpio_reg_size = 8;
unsigned int port;
unsigned int iomask;
unsigned int bitmask;
unsigned long flags;
/* set bits are evaluated a gpio register size at a time */
for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
/* no more set bits in this mask word; skip to the next word */
if (!mask[BIT_WORD(i)]) {
i = (BIT_WORD(i) + 1) * BITS_PER_LONG - gpio_reg_size;
continue;
}
port = i / gpio_reg_size;
/* mask out GPIO configured for input */
iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
bitmask = iomask & bits[BIT_WORD(i)];
raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* update output state data and set device gpio register */
ws16c48gpio->out_state[port] &= ~iomask;
ws16c48gpio->out_state[port] |= bitmask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
/* prepare for next gpio register set */
mask[BIT_WORD(i)] >>= gpio_reg_size;
bits[BIT_WORD(i)] >>= gpio_reg_size;
}
}
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;
raw_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);
raw_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;
raw_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);
raw_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;
raw_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);
raw_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;
raw_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:
raw_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);
raw_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->irq.domain, gpio + 8*port));
}
int_pending = inb(ws16c48gpio->base + 6) & 0x7;
} while (int_pending);
return IRQ_HANDLED;
}
#define WS16C48_NGPIO 48
static const char *ws16c48_names[WS16C48_NGPIO] = {
"Port 0 Bit 0", "Port 0 Bit 1", "Port 0 Bit 2", "Port 0 Bit 3",
"Port 0 Bit 4", "Port 0 Bit 5", "Port 0 Bit 6", "Port 0 Bit 7",
"Port 1 Bit 0", "Port 1 Bit 1", "Port 1 Bit 2", "Port 1 Bit 3",
"Port 1 Bit 4", "Port 1 Bit 5", "Port 1 Bit 6", "Port 1 Bit 7",
"Port 2 Bit 0", "Port 2 Bit 1", "Port 2 Bit 2", "Port 2 Bit 3",
"Port 2 Bit 4", "Port 2 Bit 5", "Port 2 Bit 6", "Port 2 Bit 7",
"Port 3 Bit 0", "Port 3 Bit 1", "Port 3 Bit 2", "Port 3 Bit 3",
"Port 3 Bit 4", "Port 3 Bit 5", "Port 3 Bit 6", "Port 3 Bit 7",
"Port 4 Bit 0", "Port 4 Bit 1", "Port 4 Bit 2", "Port 4 Bit 3",
"Port 4 Bit 4", "Port 4 Bit 5", "Port 4 Bit 6", "Port 4 Bit 7",
"Port 5 Bit 0", "Port 5 Bit 1", "Port 5 Bit 2", "Port 5 Bit 3",
"Port 5 Bit 4", "Port 5 Bit 5", "Port 5 Bit 6", "Port 5 Bit 7"
};
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 = WS16C48_NGPIO;
ws16c48gpio->chip.names = ws16c48_names;
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.get_multiple = ws16c48_gpio_get_multiple;
ws16c48gpio->chip.set = ws16c48_gpio_set;
ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
ws16c48gpio->base = base[id];
raw_spin_lock_init(&ws16c48gpio->lock);
err = devm_gpiochip_add_data(dev, &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);
return err;
}
err = devm_request_irq(dev, irq[id], ws16c48_irq_handler, IRQF_SHARED,
name, ws16c48gpio);
if (err) {
dev_err(dev, "IRQ handler registering failed (%d)\n", err);
return err;
}
return 0;
}
static struct isa_driver ws16c48_driver = {
.probe = ws16c48_probe,
.driver = {
.name = "ws16c48"
},
};
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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