tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 { "pca9571", 8 },
125 { /* sentinel */ }
126};
127MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
128
129static const struct of_device_id pca9570_of_match_table[] = {
130 { .compatible = "nxp,pca9570", .data = (void *)4 },
131 { .compatible = "nxp,pca9571", .data = (void *)8 },
132 { /* sentinel */ }
133};
134MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
135
136static struct i2c_driver pca9570_driver = {
137 .driver = {
138 .name = "pca9570",
139 .of_match_table = pca9570_of_match_table,
140 },
141 .probe_new = pca9570_probe,
142 .id_table = pca9570_id_table,
143};
144module_i2c_driver(pca9570_driver);
145
146MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
147MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
148MODULE_LICENSE("GPL v2");