linux/drivers/gpio/gpio-pcf857x.c
Biju Das db3b16dcc7 gpio: pcf857x: Extend match data support for OF tables
The driver has OF match table, but still it uses an ID lookup table for
retrieving match data. Currently, the driver is working on the
assumption that an I2C device registered via OF will always match a
legacy I2C device ID. Extend match data support for OF tables by using
i2c_get_match_data() instead of the ID lookup for both OF/ID matches by
making similar OF/ID tables.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
2023-08-22 11:41:17 +02:00

443 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Driver for pcf857x, pca857x, and pca967x I2C GPIO expanders
*
* Copyright (C) 2007 David Brownell
*/
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
static const struct i2c_device_id pcf857x_id[] = {
{ "pcf8574", 8 },
{ "pcf8574a", 8 },
{ "pca8574", 8 },
{ "pca9670", 8 },
{ "pca9672", 8 },
{ "pca9674", 8 },
{ "pcf8575", 16 },
{ "pca8575", 16 },
{ "pca9671", 16 },
{ "pca9673", 16 },
{ "pca9675", 16 },
{ "max7328", 8 },
{ "max7329", 8 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf857x_id);
static const struct of_device_id pcf857x_of_table[] = {
{ .compatible = "nxp,pcf8574", (void *)8 },
{ .compatible = "nxp,pcf8574a", (void *)8 },
{ .compatible = "nxp,pca8574", (void *)8 },
{ .compatible = "nxp,pca9670", (void *)8 },
{ .compatible = "nxp,pca9672", (void *)8 },
{ .compatible = "nxp,pca9674", (void *)8 },
{ .compatible = "nxp,pcf8575", (void *)16 },
{ .compatible = "nxp,pca8575", (void *)16 },
{ .compatible = "nxp,pca9671", (void *)16 },
{ .compatible = "nxp,pca9673", (void *)16 },
{ .compatible = "nxp,pca9675", (void *)16 },
{ .compatible = "maxim,max7328", (void *)8 },
{ .compatible = "maxim,max7329", (void *)8 },
{ }
};
MODULE_DEVICE_TABLE(of, pcf857x_of_table);
/*
* The pcf857x, pca857x, and pca967x chips only expose one read and one
* write register. Writing a "one" bit (to match the reset state) lets
* that pin be used as an input; it's not an open-drain model, but acts
* a bit like one. This is described as "quasi-bidirectional"; read the
* chip documentation for details.
*
* Many other I2C GPIO expander chips (like the pca953x models) have
* more complex register models and more conventional circuitry using
* push/pull drivers. They often use the same 0x20..0x27 addresses as
* pcf857x parts, making the "legacy" I2C driver model problematic.
*/
struct pcf857x {
struct gpio_chip chip;
struct i2c_client *client;
struct mutex lock; /* protect 'out' */
unsigned int out; /* software latch */
unsigned int status; /* current status */
unsigned int irq_enabled; /* enabled irqs */
int (*write)(struct i2c_client *client, unsigned int data);
int (*read)(struct i2c_client *client);
};
/*-------------------------------------------------------------------------*/
/* Talk to 8-bit I/O expander */
static int i2c_write_le8(struct i2c_client *client, unsigned int data)
{
return i2c_smbus_write_byte(client, data);
}
static int i2c_read_le8(struct i2c_client *client)
{
return i2c_smbus_read_byte(client);
}
/* Talk to 16-bit I/O expander */
static int i2c_write_le16(struct i2c_client *client, unsigned int word)
{
u8 buf[2] = { word & 0xff, word >> 8, };
int status;
status = i2c_master_send(client, buf, 2);
return (status < 0) ? status : 0;
}
static int i2c_read_le16(struct i2c_client *client)
{
u8 buf[2];
int status;
status = i2c_master_recv(client, buf, 2);
if (status < 0)
return status;
return (buf[1] << 8) | buf[0];
}
/*-------------------------------------------------------------------------*/
static int pcf857x_input(struct gpio_chip *chip, unsigned int offset)
{
struct pcf857x *gpio = gpiochip_get_data(chip);
int status;
mutex_lock(&gpio->lock);
gpio->out |= (1 << offset);
status = gpio->write(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static int pcf857x_get(struct gpio_chip *chip, unsigned int offset)
{
struct pcf857x *gpio = gpiochip_get_data(chip);
int value;
value = gpio->read(gpio->client);
return (value < 0) ? value : !!(value & (1 << offset));
}
static int pcf857x_get_multiple(struct gpio_chip *chip, unsigned long *mask,
unsigned long *bits)
{
struct pcf857x *gpio = gpiochip_get_data(chip);
int value = gpio->read(gpio->client);
if (value < 0)
return value;
*bits &= ~*mask;
*bits |= value & *mask;
return 0;
}
static int pcf857x_output(struct gpio_chip *chip, unsigned int offset, int value)
{
struct pcf857x *gpio = gpiochip_get_data(chip);
unsigned int bit = 1 << offset;
int status;
mutex_lock(&gpio->lock);
if (value)
gpio->out |= bit;
else
gpio->out &= ~bit;
status = gpio->write(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
return status;
}
static void pcf857x_set(struct gpio_chip *chip, unsigned int offset, int value)
{
pcf857x_output(chip, offset, value);
}
static void pcf857x_set_multiple(struct gpio_chip *chip, unsigned long *mask,
unsigned long *bits)
{
struct pcf857x *gpio = gpiochip_get_data(chip);
mutex_lock(&gpio->lock);
gpio->out &= ~*mask;
gpio->out |= *bits & *mask;
gpio->write(gpio->client, gpio->out);
mutex_unlock(&gpio->lock);
}
/*-------------------------------------------------------------------------*/
static irqreturn_t pcf857x_irq(int irq, void *data)
{
struct pcf857x *gpio = data;
unsigned long change, i, status;
status = gpio->read(gpio->client);
/*
* call the interrupt handler iff gpio is used as
* interrupt source, just to avoid bad irqs
*/
mutex_lock(&gpio->lock);
change = (gpio->status ^ status) & gpio->irq_enabled;
gpio->status = status;
mutex_unlock(&gpio->lock);
for_each_set_bit(i, &change, gpio->chip.ngpio)
handle_nested_irq(irq_find_mapping(gpio->chip.irq.domain, i));
return IRQ_HANDLED;
}
/*
* NOP functions
*/
static void noop(struct irq_data *data) { }
static int pcf857x_irq_set_wake(struct irq_data *data, unsigned int on)
{
struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
return irq_set_irq_wake(gpio->client->irq, on);
}
static void pcf857x_irq_enable(struct irq_data *data)
{
struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
irq_hw_number_t hwirq = irqd_to_hwirq(data);
gpiochip_enable_irq(&gpio->chip, hwirq);
gpio->irq_enabled |= (1 << hwirq);
}
static void pcf857x_irq_disable(struct irq_data *data)
{
struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
irq_hw_number_t hwirq = irqd_to_hwirq(data);
gpio->irq_enabled &= ~(1 << hwirq);
gpiochip_disable_irq(&gpio->chip, hwirq);
}
static void pcf857x_irq_bus_lock(struct irq_data *data)
{
struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
mutex_lock(&gpio->lock);
}
static void pcf857x_irq_bus_sync_unlock(struct irq_data *data)
{
struct pcf857x *gpio = irq_data_get_irq_chip_data(data);
mutex_unlock(&gpio->lock);
}
static const struct irq_chip pcf857x_irq_chip = {
.name = "pcf857x",
.irq_enable = pcf857x_irq_enable,
.irq_disable = pcf857x_irq_disable,
.irq_ack = noop,
.irq_mask = noop,
.irq_unmask = noop,
.irq_set_wake = pcf857x_irq_set_wake,
.irq_bus_lock = pcf857x_irq_bus_lock,
.irq_bus_sync_unlock = pcf857x_irq_bus_sync_unlock,
.flags = IRQCHIP_IMMUTABLE,
GPIOCHIP_IRQ_RESOURCE_HELPERS,
};
/*-------------------------------------------------------------------------*/
static int pcf857x_probe(struct i2c_client *client)
{
struct pcf857x *gpio;
unsigned int n_latch = 0;
int status;
device_property_read_u32(&client->dev, "lines-initial-states", &n_latch);
/* Allocate, initialize, and register this gpio_chip. */
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
mutex_init(&gpio->lock);
gpio->chip.base = -1;
gpio->chip.can_sleep = true;
gpio->chip.parent = &client->dev;
gpio->chip.owner = THIS_MODULE;
gpio->chip.get = pcf857x_get;
gpio->chip.get_multiple = pcf857x_get_multiple;
gpio->chip.set = pcf857x_set;
gpio->chip.set_multiple = pcf857x_set_multiple;
gpio->chip.direction_input = pcf857x_input;
gpio->chip.direction_output = pcf857x_output;
gpio->chip.ngpio = (uintptr_t)i2c_get_match_data(client);
/* NOTE: the OnSemi jlc1562b is also largely compatible with
* these parts, notably for output. It has a low-resolution
* DAC instead of pin change IRQs; and its inputs can be the
* result of comparators.
*/
/* 8574 addresses are 0x20..0x27; 8574a uses 0x38..0x3f;
* 9670, 9672, 9764, and 9764a use quite a variety.
*
* NOTE: we don't distinguish here between *4 and *4a parts.
*/
if (gpio->chip.ngpio == 8) {
gpio->write = i2c_write_le8;
gpio->read = i2c_read_le8;
if (!i2c_check_functionality(client->adapter,
I2C_FUNC_SMBUS_BYTE))
status = -EIO;
/* fail if there's no chip present */
else
status = i2c_smbus_read_byte(client);
/* '75/'75c addresses are 0x20..0x27, just like the '74;
* the '75c doesn't have a current source pulling high.
* 9671, 9673, and 9765 use quite a variety of addresses.
*
* NOTE: we don't distinguish here between '75 and '75c parts.
*/
} else if (gpio->chip.ngpio == 16) {
gpio->write = i2c_write_le16;
gpio->read = i2c_read_le16;
if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
status = -EIO;
/* fail if there's no chip present */
else
status = i2c_read_le16(client);
} else {
dev_dbg(&client->dev, "unsupported number of gpios\n");
status = -EINVAL;
}
if (status < 0)
goto fail;
gpio->chip.label = client->name;
gpio->client = client;
i2c_set_clientdata(client, gpio);
/* NOTE: these chips have strange "quasi-bidirectional" I/O pins.
* We can't actually know whether a pin is configured (a) as output
* and driving the signal low, or (b) as input and reporting a low
* value ... without knowing the last value written since the chip
* came out of reset (if any). We can't read the latched output.
*
* In short, the only reliable solution for setting up pin direction
* is to do it explicitly. The setup() method can do that, but it
* may cause transient glitching since it can't know the last value
* written (some pins may need to be driven low).
*
* Using n_latch avoids that trouble. When left initialized to zero,
* our software copy of the "latch" then matches the chip's all-ones
* reset state. Otherwise it flags pins to be driven low.
*/
gpio->out = ~n_latch;
gpio->status = gpio->read(gpio->client);
/* Enable irqchip if we have an interrupt */
if (client->irq) {
struct gpio_irq_chip *girq;
status = devm_request_threaded_irq(&client->dev, client->irq,
NULL, pcf857x_irq, IRQF_ONESHOT |
IRQF_TRIGGER_FALLING | IRQF_SHARED,
dev_name(&client->dev), gpio);
if (status)
goto fail;
girq = &gpio->chip.irq;
gpio_irq_chip_set_chip(girq, &pcf857x_irq_chip);
/* 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_level_irq;
girq->threaded = true;
}
status = devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
if (status < 0)
goto fail;
dev_info(&client->dev, "probed\n");
return 0;
fail:
dev_dbg(&client->dev, "probe error %d for '%s'\n", status,
client->name);
return status;
}
static void pcf857x_shutdown(struct i2c_client *client)
{
struct pcf857x *gpio = i2c_get_clientdata(client);
/* Drive all the I/O lines high */
gpio->write(gpio->client, BIT(gpio->chip.ngpio) - 1);
}
static struct i2c_driver pcf857x_driver = {
.driver = {
.name = "pcf857x",
.of_match_table = pcf857x_of_table,
},
.probe = pcf857x_probe,
.shutdown = pcf857x_shutdown,
.id_table = pcf857x_id,
};
static int __init pcf857x_init(void)
{
return i2c_add_driver(&pcf857x_driver);
}
/* register after i2c postcore initcall and before
* subsys initcalls that may rely on these GPIOs
*/
subsys_initcall(pcf857x_init);
static void __exit pcf857x_exit(void)
{
i2c_del_driver(&pcf857x_driver);
}
module_exit(pcf857x_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("David Brownell");