1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Driver for PCA9570 I2C GPO expander
  4 *
  5 * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
  6 *
  7 * Based on gpio-tpic2810.c
  8 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
  9 *	Andrew F. Davis <afd@ti.com>
 10 */
 11
 12#include <linux/gpio/driver.h>
 13#include <linux/i2c.h>
 14#include <linux/module.h>
 15#include <linux/mutex.h>
 16#include <linux/property.h>
 17
 18/**
 19 * struct pca9570 - GPIO driver data
 20 * @chip: GPIO controller chip
 21 * @lock: Protects write sequences
 22 * @out: Buffer for device register
 23 */
 24struct pca9570 {
 25	struct gpio_chip chip;
 26	struct mutex lock;
 27	u8 out;
 28};
 29
 30static int pca9570_read(struct pca9570 *gpio, u8 *value)
 31{
 32	struct i2c_client *client = to_i2c_client(gpio->chip.parent);
 33	int ret;
 34
 35	ret = i2c_smbus_read_byte(client);
 36	if (ret < 0)
 37		return ret;
 38
 39	*value = ret;
 40	return 0;
 41}
 42
 43static int pca9570_write(struct pca9570 *gpio, u8 value)
 44{
 45	struct i2c_client *client = to_i2c_client(gpio->chip.parent);
 46
 47	return i2c_smbus_write_byte(client, value);
 48}
 49
 50static int pca9570_get_direction(struct gpio_chip *chip,
 51				 unsigned offset)
 52{
 53	/* This device always output */
 54	return GPIO_LINE_DIRECTION_OUT;
 55}
 56
 57static int pca9570_get(struct gpio_chip *chip, unsigned offset)
 58{
 59	struct pca9570 *gpio = gpiochip_get_data(chip);
 60	u8 buffer;
 61	int ret;
 62
 63	ret = pca9570_read(gpio, &buffer);
 64	if (ret)
 65		return ret;
 66
 67	return !!(buffer & BIT(offset));
 68}
 69
 70static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value)
 71{
 72	struct pca9570 *gpio = gpiochip_get_data(chip);
 73	u8 buffer;
 74	int ret;
 75
 76	mutex_lock(&gpio->lock);
 77
 78	buffer = gpio->out;
 79	if (value)
 80		buffer |= BIT(offset);
 81	else
 82		buffer &= ~BIT(offset);
 83
 84	ret = pca9570_write(gpio, buffer);
 85	if (ret)
 86		goto out;
 87
 88	gpio->out = buffer;
 89
 90out:
 91	mutex_unlock(&gpio->lock);
 92}
 93
 94static int pca9570_probe(struct i2c_client *client)
 95{
 96	struct pca9570 *gpio;
 97
 98	gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
 99	if (!gpio)
100		return -ENOMEM;
101
102	gpio->chip.label = client->name;
103	gpio->chip.parent = &client->dev;
104	gpio->chip.owner = THIS_MODULE;
105	gpio->chip.get_direction = pca9570_get_direction;
106	gpio->chip.get = pca9570_get;
107	gpio->chip.set = pca9570_set;
108	gpio->chip.base = -1;
109	gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev);
110	gpio->chip.can_sleep = true;
111
112	mutex_init(&gpio->lock);
113
114	/* Read the current output level */
115	pca9570_read(gpio, &gpio->out);
116
117	i2c_set_clientdata(client, gpio);
118
119	return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
120}
121
122static const struct i2c_device_id pca9570_id_table[] = {
123	{ "pca9570", 4 },
124	{ /* sentinel */ }
125};
126MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
127
128static const struct of_device_id pca9570_of_match_table[] = {
129	{ .compatible = "nxp,pca9570", .data = (void *)4 },
130	{ /* sentinel */ }
131};
132MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
133
134static struct i2c_driver pca9570_driver = {
135	.driver = {
136		.name = "pca9570",
137		.of_match_table = pca9570_of_match_table,
138	},
139	.probe_new = pca9570_probe,
140	.id_table = pca9570_id_table,
141};
142module_i2c_driver(pca9570_driver);
143
144MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
145MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
146MODULE_LICENSE("GPL v2");