gpio-pca9570.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for PCA9570 I2C GPO expander
*
* Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
*
* Based on gpio-tpic2810.c
* Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
* Andrew F. Davis <afd@ti.com>
*/
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
/**
* struct pca9570 - GPIO driver data
* @chip: GPIO controller chip
* @lock: Protects write sequences
* @out: Buffer for device register
*/
struct pca9570 {
struct gpio_chip chip;
struct mutex lock;
u8 out;
};
static int pca9570_read(struct pca9570 *gpio, u8 *value)
{
struct i2c_client *client = to_i2c_client(gpio->chip.parent);
int ret;
ret = i2c_smbus_read_byte(client);
if (ret < 0)
return ret;
*value = ret;
return 0;
}
static int pca9570_write(struct pca9570 *gpio, u8 value)
{
struct i2c_client *client = to_i2c_client(gpio->chip.parent);
return i2c_smbus_write_byte(client, value);
}
static int pca9570_get_direction(struct gpio_chip *chip,
unsigned offset)
{
/* This device always output */
return GPIO_LINE_DIRECTION_OUT;
}
static int pca9570_get(struct gpio_chip *chip, unsigned offset)
{
struct pca9570 *gpio = gpiochip_get_data(chip);
u8 buffer;
int ret;
ret = pca9570_read(gpio, &buffer);
if (ret)
return ret;
return !!(buffer & BIT(offset));
}
static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct pca9570 *gpio = gpiochip_get_data(chip);
u8 buffer;
int ret;
mutex_lock(&gpio->lock);
buffer = gpio->out;
if (value)
buffer |= BIT(offset);
else
buffer &= ~BIT(offset);
ret = pca9570_write(gpio, buffer);
if (ret)
goto out;
gpio->out = buffer;
out:
mutex_unlock(&gpio->lock);
}
static int pca9570_probe(struct i2c_client *client)
{
struct pca9570 *gpio;
gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
if (!gpio)
return -ENOMEM;
gpio->chip.label = client->name;
gpio->chip.parent = &client->dev;
gpio->chip.owner = THIS_MODULE;
gpio->chip.get_direction = pca9570_get_direction;
gpio->chip.get = pca9570_get;
gpio->chip.set = pca9570_set;
gpio->chip.base = -1;
gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev);
gpio->chip.can_sleep = true;
mutex_init(&gpio->lock);
/* Read the current output level */
pca9570_read(gpio, &gpio->out);
i2c_set_clientdata(client, gpio);
return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
}
static const struct i2c_device_id pca9570_id_table[] = {
{ "pca9570", 4 },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
static const struct of_device_id pca9570_of_match_table[] = {
{ .compatible = "nxp,pca9570", .data = (void *)4 },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
static struct i2c_driver pca9570_driver = {
.driver = {
.name = "pca9570",
.of_match_table = pca9570_of_match_table,
},
.probe_new = pca9570_probe,
.id_table = pca9570_id_table,
};
module_i2c_driver(pca9570_driver);
MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
MODULE_LICENSE("GPL v2");