gpio-pca9570.c

  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#define SLG7XL45106_GPO_REG	0xDB
 19
 20/**
 21 * struct pca9570_chip_data - GPIO platformdata
 22 * @ngpio: no of gpios
 23 * @command: Command to be sent
 24 */
 25struct pca9570_chip_data {
 26	u16 ngpio;
 27	u32 command;
 28};
 29
 30/**
 31 * struct pca9570 - GPIO driver data
 32 * @chip: GPIO controller chip
 33 * @chip_data: GPIO controller platform data
 34 * @lock: Protects write sequences
 35 * @out: Buffer for device register
 36 */
 37struct pca9570 {
 38	struct gpio_chip chip;
 39	const struct pca9570_chip_data *chip_data;
 40	struct mutex lock;
 41	u8 out;
 42};
 43
 44static int pca9570_read(struct pca9570 *gpio, u8 *value)
 45{
 46	struct i2c_client *client = to_i2c_client(gpio->chip.parent);
 47	int ret;
 48
 49	if (gpio->chip_data->command != 0)
 50		ret = i2c_smbus_read_byte_data(client, gpio->chip_data->command);
 51	else
 52		ret = i2c_smbus_read_byte(client);
 53
 54	if (ret < 0)
 55		return ret;
 56
 57	*value = ret;
 58	return 0;
 59}
 60
 61static int pca9570_write(struct pca9570 *gpio, u8 value)
 62{
 63	struct i2c_client *client = to_i2c_client(gpio->chip.parent);
 64
 65	if (gpio->chip_data->command != 0)
 66		return i2c_smbus_write_byte_data(client, gpio->chip_data->command, value);
 67
 68	return i2c_smbus_write_byte(client, value);
 69}
 70
 71static int pca9570_get_direction(struct gpio_chip *chip,
 72				 unsigned offset)
 73{
 74	/* This device always output */
 75	return GPIO_LINE_DIRECTION_OUT;
 76}
 77
 78static int pca9570_get(struct gpio_chip *chip, unsigned offset)
 79{
 80	struct pca9570 *gpio = gpiochip_get_data(chip);
 81	u8 buffer;
 82	int ret;
 83
 84	ret = pca9570_read(gpio, &buffer);
 85	if (ret)
 86		return ret;
 87
 88	return !!(buffer & BIT(offset));
 89}
 90
 91static int pca9570_set(struct gpio_chip *chip, unsigned int offset, int value)
 92{
 93	struct pca9570 *gpio = gpiochip_get_data(chip);
 94	u8 buffer;
 95	int ret;
 96
 97	mutex_lock(&gpio->lock);
 98
 99	buffer = gpio->out;
100	if (value)
101		buffer |= BIT(offset);
102	else
103		buffer &= ~BIT(offset);
104
105	ret = pca9570_write(gpio, buffer);
106	if (ret)
107		goto out;
108
109	gpio->out = buffer;
110
111out:
112	mutex_unlock(&gpio->lock);
113	return ret;
114}
115
116static int pca9570_probe(struct i2c_client *client)
117{
118	struct pca9570 *gpio;
119
120	gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
121	if (!gpio)
122		return -ENOMEM;
123
124	gpio->chip.label = client->name;
125	gpio->chip.parent = &client->dev;
126	gpio->chip.owner = THIS_MODULE;
127	gpio->chip.get_direction = pca9570_get_direction;
128	gpio->chip.get = pca9570_get;
129	gpio->chip.set = pca9570_set;
130	gpio->chip.base = -1;
131	gpio->chip_data = device_get_match_data(&client->dev);
132	gpio->chip.ngpio = gpio->chip_data->ngpio;
133	gpio->chip.can_sleep = true;
134
135	mutex_init(&gpio->lock);
136
137	/* Read the current output level */
138	pca9570_read(gpio, &gpio->out);
139
140	i2c_set_clientdata(client, gpio);
141
142	return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
143}
144
145static const struct pca9570_chip_data pca9570_gpio = {
146	.ngpio = 4,
147};
148
149static const struct pca9570_chip_data pca9571_gpio = {
150	.ngpio = 8,
151};
152
153static const struct pca9570_chip_data slg7xl45106_gpio = {
154	.ngpio = 8,
155	.command = SLG7XL45106_GPO_REG,
156};
157
158static const struct i2c_device_id pca9570_id_table[] = {
159	{ "pca9570", (kernel_ulong_t)&pca9570_gpio},
160	{ "pca9571", (kernel_ulong_t)&pca9571_gpio },
161	{ "slg7xl45106", (kernel_ulong_t)&slg7xl45106_gpio },
162	{ /* sentinel */ }
163};
164MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
165
166static const struct of_device_id pca9570_of_match_table[] = {
167	{ .compatible = "dlg,slg7xl45106", .data = &slg7xl45106_gpio},
168	{ .compatible = "nxp,pca9570", .data = &pca9570_gpio },
169	{ .compatible = "nxp,pca9571", .data = &pca9571_gpio },
170	{ /* sentinel */ }
171};
172MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
173
174static struct i2c_driver pca9570_driver = {
175	.driver = {
176		.name = "pca9570",
177		.of_match_table = pca9570_of_match_table,
178	},
179	.probe = pca9570_probe,
180	.id_table = pca9570_id_table,
181};
182module_i2c_driver(pca9570_driver);
183
184MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
185MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
186MODULE_LICENSE("GPL v2");