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